Natural Hazards: State-of-the-Art at the End of the Second Millennium

NATURAL HAZARDS State-of-the-Art at the End of the Second Millennium
Edited by
T.MURTY W. F. Baird & Associates Coastal Engineers Ltd., Ottawa, Canada
S. VENKATESH Meteorological Service of Canada, Downsview, Canada
and
Reprinted from Natural Hazards, Volume 21, Nos. 2 & 3, 2000
.. SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.
A C.I.P. Catalogue record for this book is available from the Library of Congress.
ISBN 978-90-481-5571-2 ISBN 978-94-017-2386-2 (eBook) DOI 10.1007/978-94-017-2386-2
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All Rights Reserved © 2000 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 2000 Softcover reprint of the hardcover 1st edition 2000 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner
Table of Contents
Editorial vii s. VENKATESH, W. GONG, A. KALLAUR, P. A. MAKAR, M. D.
MORAN, B. PABLA, C. RO, R. VET, W. R. BURROWS and R. MONTPETIT / Regional Air Quality Modelling in Canada - Applications for Policy and Real-Time Prediction 101-129
M. L. KHANDEKAR, T. S. MURTY, D. SCOTT and W. BAIRD / The 1997 El Nino, Indonesian Forest Fires and the Malaysian Smoke Problem: A Deadly Combination of Natural and Man- Made Hazard 131-144
NINING SARI NINGSIH, TAKAO YAMASHITA and LOTFI AOUF I Three-Dimensional Simulation of Water Circulation in the Java Sea: Influence of Wind Waves on Surface and Bottom Stresses 145-171
A. C. HINTON I Tidal Changes and Coastal Hazards: Past, Present and Future 173-184
Y. ALTINOK and ~. ERSOY / Tsunamis Observed on and Near the Turkish Coast 185-205
SALVADOR F. FARRERAS I Post-Tsunami Field Survey Procedures: An Outline 207-214
LE KENTANG / An Analysis of the Recent Severe Storm Surge Dis- aster Events in China 215-223
C. EMDAD HAQUE / Risk Assessment, Emergency Preparedness and Response to Hazards: The Case of the 1997 Red River Valley Flood, Canada 225-245
V. CUOMO, G. DI BELLO, V. LAPENNA, S. PISCITELLI, L. TELESCA, M. MACCHIA TO and C. SERIO / Robust Statist ical Methods to Discriminate Extreme Events in Geoelectrical Precursory Signals: Implications with Earthquake Prediction 247-261
P. F. BIAGI, A. ERMINI, E. COZZI, Y. M. KHATKEVICH and E. I. GORDEEV / Hydrogeochemical Precursors in Kamchatka (Russia) Related to the Strongest Earthquakes in 1988-1997 263-276
P. P. DIMITRIU, E. M. SCORDILIS and V. G. KARACOSTAS / Multi- fractal Analysis of the Arnea, Greece Seismicity with Potential Implications for Earthquake Prediction 277-295
D. I. MAKARIS, N. P. THEODULIDIS and G. N. STAVRAKAKIS / Estimation of Strong Ground Motion Due to Hypothetical Fault Ruptures and Comparison with Recorded Values: The Zakyn- thos, Western Greece Earthquake of 18 November 1997 297-315
TABLE OF CONTENTS
G. NOVER, S. HEIKAMP and D. FREUND I Electrical Impedance Spectroscopy Used as a Tool for the Detection of Fractures in Rock Samples Exposed to either Hydrostatic or Triaxial Pres- sure Conditions 317-330
V. SCHENK, Z. SCHENKOvA, P. KOTTNAUER, B. GUTERCH and P. LABAK I Earthquake Hazard for the Czech Republic, Poland and Slovakia - Contribution to the ILCIIASPEI Global Seismic Hazard Assessment Program 331-345
FRANCISCA G6MEZ-FERNANDEZ I Contribution of Geographical Information Systems to the Management of Volcanic Crises 347-360
M. T. PARESCHI, L. CAVARRA, M. FAVALLI, F. GIANNINI and A. MERIGGI/GIS and Volcanic Risk Management 361-379
A. AMENDOLA, Y. ERMOLIEV, T. Y. ERMOLIEVA, V. GITIS, G. KOFF and J. LINNEROOTH-BAYER I A Systems Approach to Modeling Catastrophic Risk and Insurability 381-393
M. L. KHANDEKAR I Hazards-98: Summary of Papers 395-398
v
This issue is dedicated to the memory of Mohammed Ibrahim EI-Sabh, 1939-1999, founding President of the Natural Hazards Society and founding editor of Natural Hazards.
vii
Editorial
This issue of Natural Hazards contains a selection of articles that were present ed at the Seventh International Symposium on Natural and Man-Made hazards (Hazards-98) held in Chania, Greece, 17-20 May 1998. The symposium was organized by the International Society for the Prevention and Mitigation of Nat ural Hazards (NHS), the lAPSO commission on natural marine hazards and the Tsunami Society. The theme of the symposium was "Natural Disasters - How Do We Mitigate Them?".
Hazards-98 was very timely, given the large number of natural disasters that occurred in various parts of the world during the 1990's, which was also the United Nations' International Decade for Natural Disasters Reduction. Along with the traditional hazards such as earthquakes, volcanic eruptions, cyclones, storm surges and river floods that caused great devastation and significant loss of life during this decade, the issue of climate change and the anticipated hazards associated with it have attracted great attention, particularly in this decade.
The climate change problem is much broader than the Greenhouse warming issue and possible sea level rise. Climate change has occurred throughout Earth's history and will continue to occur due to natural processes, whether there is human interference or not. One of the most important aspects of climate change is the geographical shift in cyclone tracks leading to large scale changes in the patterns of floods and droughts. The extremely serious large scale smoke problem in South East Asia during the second half of the year 1997 and the early part of 1998 was directly attributed to the major El-Nifio event of that time and reminded everybody of our susceptibility to large scale atmospheric pollution hazards.
The symposium included sessions on the following topics: "Earthquakes", "Vol canic Hazards", "Tsunamis", "Meteorological Hazards", "Geological Hazards", "Socioeconomic Aspects' and "Miscellaneous". Participants from 20 countries around the world presented over 120 papers during 13 sessions of the symposium. The abstracts of all of the papers presented can be found in the symposium abstracts volume. Sixteen papers were accepted to be included in this post-symposium pub lication after rigorous scientific peer review. This special issue of Natural Hazards summarizes the state of the art in natural hazards research at the end of the second millennium. A summary report of the Hazards-98 symposium is also included in this special issue.
We wish to thank all the authors that submitted their papers in this special issue as well as more than 20 reviewers for spending time in order to review and increase with their recommendations the scientific quality of the articles.
G. A. PAPADOPOULOS, T. MURTY, S. VENKATESH and R. BLONG Editors
Natural Hazards 21: 101-129,2000. © 2000 Kluwer Academic Publishers.
Regional Air Quality Modelling in Canada - Applications for Policy and Real-Time Prediction
101
S. VENKATESH, W. GONG, A. KALLAUR, P. A. MAKAR, M. D. MORAN, B. PABLA, C. RO, R. VET, W. R. BURROWS and R. MONTPETIT Atmospheric Environment Service, 4905 Dufferin Street, Downsview, Ontario M3H 5T4, Canada
(Received: 2 October 1998; in final form: 14 June 1999)
Abstract. Acid rain and photochemical smog are two regional air-quality issues that have re ceived considerable attention in the last two decades due to their harmful effects. Health impacts of particulate matter (PM) in the atmosphere is another issue of concern.
Sulphur dioxide emission controls were introduced in both Canada and the U.S.A. to reduce acid-deposition-related damage. While these emission reductions have already resulted in reduced sulphate deposition, based on results from modelling studies much of southeastern Canada is still expected to experience damaging levels of acid deposition even after all currently legislated emission controls are fully implemented. Moreover, there has not been a corresponding reduction in the acidity of precipitation. This may be attributable to a concurrent reduction in base-cation concentration in precipitation.
Models were also developed to understand the formation, transport and diffusion of tropospheric ozone. The models have been used to provide policy guidance for emission control options to reduce ground-level ozone to acceptable limits. In the summer of 1997 a Canadian pilot project was initiated to provide real-time forecasts of ground-level ozone in the southeastern part of the province of New Brunswick in eastern Canada.
With the emergence of fine Particulate Matter (PM2.S) as a health concern, efforts are underway in Canada to develop a "unified" regional air-qUality model that will address the combined impacts of various pollutants in the atmosphere. In this effort the atmosphere is viewed as a single entity where the impacts of multiple pollutants are considered at the same time.
Key words: acid rain, photochemical smog, ground-level ozone, particulate matter, modelling, monitoring, real-time prediction, policy application.
1. Introduction
Air pollution is known to have a significant impact on the health of the human population and also on vegetation and materials. For example, acid rain, which causes damage to vegetation and materials, and photochemical smog, which can result in respiratory problems in humans, are two regional air-quality issues that have received considerable attention in the last two decades due to their harmful effects. There is now also heightened concern about the health impacts of fine particulate matter (PM2.5) in the atmosphere. Regional air-quality modelling has played a key role in understanding these issues and their impacts.
102 s. VENKATESH ET AL.
In the last two years Canada has completed assessments of the state of science for dealing with the problems associated with acid deposition and photochemical smog. A series of reports have been published describing the results of the as sessments. (For acid deposition see EC (1998), and for photochemical smog see Canadian 1996 NOxIVOC Science Assessment (1997a).) The regional air-quality models that were part of the assessments were used to study the impact of various emissions reductions options to assist in the development of policies to reduce acid deposition and photochemical smog. In this paper some modelling results from the two assessments are briefly described. Also discussed are pilot studies that are underway in Canada for the real-time prediction of ground-level ozone, an important component of smog.
2. Acid Deposition
Acid deposition, sometimes called "acid rain" or "acid precipitation", is the re moval of acidic compounds from the atmosphere to the earth's surface by both wet deposition and dry deposition. Concerns raised in North America in the 1970s over the effects of acid deposition on the environment led first to extensive national acid-deposition research programs and then to legislation controlling and reducing acidifying emissions in both Canada and the U.S. The 1985 Eastern Canada Acid Rain Control Program required the seven easternmost Canadian provinces to re duce their total annual S02 emissions to the atmosphere by roughly 40% from 1980 levels by 1994 (BC, 1994). The 1990 U.S.A. Clean Air Act Amendments (CAAA90) similarly require U.S. national annual S02 emissions to be reduced by roughly 40% from 1980 levels by 2010 (BC, 1994). Once implemented, such large S02 emission reductions should have a correspondingly large and measur able impact on the levels of acid deposition experienced in eastern North America (ENA).
The Canadian federal acid deposition research program's recent 1997 Acid Deposition Science Assessment (EC, 1998) has evaluated the effectiveness of the control actions taken in Canada and now being implemented in the U.S.A. The effectiveness to date can be evaluated through an analysis of acid deposition mon itoring data. Note, though, that since the first year for implementation of U.S. S02 emission controls under the CAAA90 was 1995, the analysis of the impacts of CAAA90 controls on deposition are beyond the scope of this paper, which only considers monitoring data up until 1994.
3. Acid Deposition Monitoring
Emissions estimates show that sulphur emissions (S02 as S), integrated over east ern North America [the integration region being Canada and the U.S. east from the OntariolManitoba border and the Mississippi River and north from Florida up to 55°N], decreased markedly during the first half of the 1980s, declining from
REGIONAL AIR QUALITY MODELLING IN CANADA
12~~==~"~------------------~ I I I I I
,a) S-sa! EMSSIONS ,
- - - - -, , ,
O~~~~-r .. -. .. -.-.-.~~~r-t 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94
103
Figure 1. Integrated (a) sulphur (S) and (b) nitrogen (N) emissions in eastern North America from all anthropogenic sources.
about 10.6 MT y-l (megatonnes per year) in 1980 to about 8.6 MT y-l in 1986 (Figure 1). After 1986, the emissions remained roughly constant until 1993, then decreased by 0.54 MT in 1994. Over the 15-year period (1980--1994), most of the sulphur emissions in ENA (87%) originated in the eastern United States. Integrated nitrogen emissions (NOx as N) showed a slight decrease in the early 1980s (from about 3.7 MT y-l to 3.5 MT y-l, but rapidly increased from 1985 to 1988 to 4.0 MT y-l, thereafter varying between 3.8 and 4.0 MT y-l (Figure 1). Eastern United States emissions constituted 91 % of the total ENA nitrogen emissions over the 15-year period.
The Atmospheric Environment Service of Environment Canada operates the National Atmospheric Chemistry (NAtChem) Database and Analysis Facility, a federal-provincial facility for the archival and analysis of North American atmo spheric chemistry data (Ro et al., 1997). Acid deposition data from all of the monitoring networks in Canada and the United States are combined in the NAt Chern Database to produce gridded (approx. 45 km x 45 km) fields using the universal Kriging method. The fields obtained by interpolation are then contoured to produce maps of acid deposition for Eastern North America.
Figure 2 shows the mean non-sea-salt sulfate (nssS04') and nitrate (NO;-) wet deposition patterns for the periods 1980--1984 and 1990--1994. The multi-year av eraging reduces the effects of year-to-year variations in meteorology, which can
104 S. VENKATESH ET AL.
a) \980-84 XS04 (kg/ha/yr)
Figure 2(a). 5-year mean nonsea-salt sulphate and nitrate wet deposition patterns for 1980-1984 and 1990-1994.
be extreme. The changes in the overall deposition patterns are consistent with the reductions in emissions shown in Figure 1. For example, the 1980-1984 area with nssS04 deposition over 30 kg ha- I y-I had almost disappeared by the beginning of the 1990s and the area encompassed by the 20 kg ha- I y-I contour line had decreased by 35% (see Figures 2(a) and 2(b)). The total sulphur (S from nssS04) wet deposition integrated over ENA decreased about 20% between the periods of 1980-1984 and 1990-1994. This compares to a decrease of about 15% in the mean sulphur emissions in the region between the two periods. The changes between the 1980-1984 and 1990-1994 spatial patterns of N03" wet deposition (see Figures 2(c) and 2(d)) reflect an 8% increase in the mean NOx emissions between the two periods.
The time series of annual nssS04= wet deposition integrated over ENA (Fig ure 3(a)) follows a pattern similar to that of the integrated sulphur emissions shown
REGIONAL AIR QUALITY MODELLING IN CANADA 105
b) 1990-94 XS04 = (kg/ha/yr)
Figure 2(b).
in Figure 1, with a statistically-significant linear correlation coefficient of 0.92 between the two. No systematic long-term trend was found in the time series of yearly nitrogen wet deposition values integrated over ENA (Figure 3( c». The correlation coefficient (r = 0.41) between the nitrogen wet deposition and nitrogen emissions was not statistically significant at a 90% confidence level.
One would expect that the 20% reduction in nssS04' wet deposition between the early 1980s and the early 1990s would result in a similar level of change in the pH (on an equivalence basis, assuming that all other ions contributing to the pH had not changed markedly) of precipitation between the two periods (i.e., a decrease in H+ wet deposition). Although there was a slight decrease of about 9% in H+ deposition (Figures 4(a) and (b», it was much less pronounced than expected from the change in the sulphate deposition.
c) 1980-84 N03- (kg/ha/yr)
Figure 2( c).
The fact that the large decrease in nssS04' wet deposition was not associated with a similar decrease in H+ wet deposition indicates that there must have been roughly equivalent changes in the deposition of some other ion or ions in ENA precipitation. As we have seen, N03 wet deposition did not show a long-term in crease sufficient to offset the decline in nssS04' deposition, and ammonium (NHt) wet deposition (not shown) did not decrease as would be necessary. This leaves the major cations (i.e., Ca++, Mg++ and K+) as the most likely cause of the small decline in H+ deposition.
As Figures 4( c) and (d) show, there was a large decrease in the integrated wet deposition of Cations (defined as Ca++ + Mg++ + K+). The decrease was signific ant over all of ENA but predominant over the Appalachian Mountains, west of the Mississippi River, and in Canada except near the Atlantic coast and in the Great Lakes area. Integrated over ENA, the Cations wet deposition decreased by about
d) \990-94 NO,, - (kg/ha/yr)
Figure 2(d).
80 81 12 83 84 86 " 87 ... 00 ~t tI2 ga at
(N.N03) 1.5 lonnesIYear 0.3
0.2
as 0 .• 80 81 82 83 84 85 86 87 88 89 90 91 92 93 ~
Figure 3. Integrated wet deposition in eastern North America: (a) (S-XS04'). (b) (Ca++ + Me++ + K+). (c) (N-NO;-) and (d) H+.
a) \980-84 H (kg/ha/yr)
Figure 4(a). 5-year mean H+ and cations (Ca++ + Mg++ + K+) wet deposition patterns for 1980-1984 and 1990-1994.
41 % between 1980-1984 and 1990-1994. The same marked decrease is noticeable if one considers the changes in the annual integrated wet deposition values shown in Figure 3(b). The decrease seems to have occurred predominantly in the first half of the 1980s, about the same period as the main decrease in nssS04' wet deposition. It is interesting to note that the decrease in Cations loadings from 1980-1984 to 1990-1994 was about 3.15 x 1010 eq y-l, about 75% of the change of 4.17 x 1010 eq y-l of nssS04' deposition. Hence, the decline in base-cation deposition appears to be a major factor in explaining why H+ deposition changed so little between the two periods.
From these analyses, the most important point is that the general decrease in nssS04' concentrations in precipitation and wet deposition observed over ENA from 1980 to 1994 was not accompanied by a similar order decrease in H+ wet
". :'"
" -""
b) 1990-94 II (kg/ha/yr)
deposition. The main cause of this appears to be the concurrent decrease in major cations. It can be concluded that declining S02 emissions in ENA were successful at reducing sulphur wet deposition up to and including 1994, but generally were unsuccessful at reducing the acidity of precipitation to a similar degree.
4. Acid Deposition Modelling
In addition to evaluating the effectiveness of emission control actions to date, an other important question addressed in the 1997 Canadian Acid Rain Assessment was whether the Canadian and U.S. emission control programs together will be sufficient to protect the Canadian environment from acid deposition once they are fully implemented (not until 2010 for CAAA90). The only practical way to address a question about the future is to use a numerical model.
c) 1980-84 ation (kg/hn/yr)
Figure 4(c).
A comprehensive, three-dimensional , episodic Eulerian acid deposition model, the Acid Deposition and Oxidant Model (ADOM) (e.g., Venkatram et al. (1988); Macdonald et al. (1993); Moran (1998», was used to estimate the levels of annual S04 wet deposition to be expected in ENA at four stages in the implementation of currently legislated S02 emission control programs and for three additional future-year S02 emission scenarios corresponding to possible further S02 emission reductions (see Table 1). The model-predicted future-year SO; wet deposition fields were then compared against two environmental objectives for annual SO; wet deposition in order to assess whether current S02 emission controls are adequate or whether additional S02 emission reductions will be needed.
The first four emission scenarios correspond to the following implementation stages: (i) no national control programs (BASE case); (ii) Canadian emission controls only (CCONLY); (iii) Canadian controls and u.S. CAAA90 Phase 1 con-
d) \990-94 Cations (kg/ha/yr)
Figure 4(d).
Table I. Total S02 emissions within ADOM domain for ENA base case and six future-year emissions scenarios
Scenario Nominal S02 emissions (KTonnes/y) Fraction
name year U.S . Canada Total of BASE
BASE 1989 17,511 2,688 20,199 1.00
CCONLY 1994 17,862 1,939 19,801 0.98
CCUSAI 1997 14,865 1,939 16,804 0.83
CCUSA2 20lO 12,446 1,939 14,385 0.71
25FCAP 2030 9,335 1,738 11,072 0.55
5CCUS2 2030 6,223 969 7,192 0.36
75FCAP 2030 3,1l2 579 3,691 0.18
troIs (CCUSA1); and (iv) Canadian controls and U.S. CAAA90 Phase 2 controls (CCUSA2). Both country's S02 control programs target selected large stationary sources: coal-fired power stations in Canada and in the U.S. and base-metal smelt ers in Canada. Since ADOM treats emIssions from major point sources separately from grid-based area sources, it was possible to model these targeted, facility specific emission reductions individually. The three post-201O scenarios, on the other hand, were simple uniform-rollback control scenarios starting from the 2010 (CCUSA2)-scenario emission fields for increasing percentage reductions.
As a comprehensive episodic model, the nominal time step for ADOM is one hour. One consequence of this is that ADOM reads from its emissions and met eorological input data files once per simulation hour. During model integration the one-hour time step is further subdivided into substeps as small as a few seconds by the gas-phase and aqueous-phase chemistry solvers. For such fine time resolution, long-term simulations on the order of one year are very expensive computationally. Moreover, as noted in the discussion of acid-deposition monitoring, there is con siderable interannual variability in deposition patterns due to interannual variations in meteorology. If ADOM is run to simulate a full one-year period in order to be able to predict annual concentration and deposition fields, the question then arises as to whether the particular year simulated is climatologically representative.
The approach chosen to address concerns over both computational cost and cli matological representativeness was to use the semi-empirical episode-aggregation technique to estimate annual concentration and deposition fields as the weighted average of a set of short-term model simulations (e.g., Dennis et al., 1990; Brook et al., 1995a,b). As implemented for ADOM, 33 three-day episodes were first se lected from a two-year period on the basis of their ability to represent as closely as possible (i) the climatological range of synoptic weather patterns experienced in ENA for all four seasons, (ii) the chemical climatology of ENA as defined by 1985-1990 mean wet deposition of S04', NO;, NHt. and H+ at 19 precipitation chemistry stations and ambient S04' air concentrations at eight air-chemistry stations, and (iii) regional source-receptor relationships as represented by multi year 850-hPa trajectory roses at four sites in eastern Canada. In order to estimate an annual field, ADOM was then run for each of these 33 episodes (starting two days before each episode as a "spin-up" period) and then the 33 episode fields were com bined or aggregated as a weighted average. The pre-determined, episode-specific weighting functions used in the aggregation step were based on observations of the frequency of occurrence of these episodes and the mean precipitation amount (if any) and pollutant concentrations associated with them (EC, 1998).
Figure 5 shows the predicted annual wet S04' deposition fields for two of the S02 emission scenarios, the BASE scenario, which corresponds to 1989, and the CCUSA2 or 2010 scenario (see Moran (1997) and EC (1998) for details). ADOM predicts that by 2010 nearly all of eastern Canada will be in compliance with one of the environmental objectives - the 20 kg S04' ha -I y-1 target load for S04' wet deposition proposed in the early 1980s - once current S02 control programs have
ADOM Predicted Base-case Annual Wet 504 Deposition
30
25
20
15
10
5
o
a Figure 5(a). Predicted annual wet sulphate deposition fields (kg S04' ha-1 y-I) for (a) 1989 BASE S02 emisssion scenario and (b) 2010 CCUSA2 S02 emission scenario.
been fully implemented in both Canada and the U.S. (see Figure 5b). However, this target load was only intended to be an interim objective and does not account for geographic variations in ecosystem sensitivity to acid deposition.
Figure 6 shows the spatial variation in a second Canadian environmental ob jective, the aquatic-effects-based critical load, also expressed in terms of annual wet S04 deposition. This field, which corresponds to the amount of annual S04' wet deposition for which 95% of the lakes in each of 22 subregions of eastern Canada can maintain a pH level of 6.0 or greater, varies from over 20 to as little as 8 kg S04' ha- I y-l (EC, 1990; Jeffries et al. , 1999). Figure 7 shows the positive residual wet S04 deposition fields predicted by ADOM for 1989 and 2010, i.e., the amount by which the predicted annual wet S04 deposition (Figure 5) exceeds the annual critical load (Figure 6). For 1989, the positive-residual or critical-load "gap" region covers most of southeastern Canada. By 2010, both the magnitude of this gap and the area that it covers have decreased, but much of southeastern
ADOM Predicted 2010 Annual Wet 504 Deposit ion
30
25
20
15
10
5
o
Canada is still predicted by the model to have wet SO; deposition above critical load. That is, acid deposition in this region will remain above aquatic-ecosystem "carrying capacity" even after full implementation of current S02 emission control programs in both Canada and the U.S.
5. Photochemical Smog
Ground-level ozone, an important component of smog, is a secondary pollutant formed by photochemical reactions in the atmosphere involving nitrogen oxide (NOx) species and hydrocarbons (Volatile Organic Compounds - VOC). The Canadian NOxNOC Management Plan requires the use of photochemical oxid ant models to examine the effects of NOxNOC precursor emission controls on maximum ozone concentrations in regions of concern where hourly ozone concen trations exceed the Canadian objective of 82 ppb. In eastern Canada, these areas are the Windsor-Quebec City Corridor (WQC) and the Southern Atlantic Region
W et
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D ep
os it
io n
C ri
ti ca
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ad s
fo r
Ea st
er n
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ad a
ADOH Predicted Base-~$e Cl Residual S04 n.position
15
10
5
o
a
15
10
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b
Figure 7. Predicted positive annual wet sulphate residual deposition fields (kg SO; ha- i y- i) for (a) 1989 BASE S02 emission scenario and (b) 2010 CCUSA2 S02 emission scenario.
(SAR), while in western Canada it is the Lower Fraser Valley (LFV) area, including the city of Vancouver. Photochemical oxidant models help us in understanding the interaction between meteorological and chemical processes in a polluted at mosphere and ultimately improve our ability to forecast ozone episodes. In this paper the discussion is limited to modelling for the WQC and SAR. Details of the modelling for the LFV can be found in the Canadian 1996 NOxNOC Science Assessment (1997c).
6. NOxIVOC Modelling in the WQC and SAR
The model simulations for both the WQC and SAR use the comprehensive oxidants chemistry mechanism from ADOM. For the SAR version of the model the advec tion algorithm is the one that is part of ADOM. For the WQC the numerical method applied for solving the reactive transport problem is based on nonoscillatory semi Lagrangian approximations for fluids. The meteorological information for both models is obtained from a mesoscale dynamical model, MC2 (Benoit et al., 1997). The complete details of the models, including comparison with observations from the period August 1--6, 1988, are given in Pudykiewicz et al. (1997) for the WQC (henceforth referred to as the Chemical Transport Model CTMlMC2) and in Gong et al. (1999) (henceforth referred to as ADOMlMC2) for the SAR. In general, while high levels of ground-level ozone in the WQC, with its many anthropogenic emis sions sources, result from both local production and transport into the region from u.s. mid-western regions, those in the SAR are mainly influenced by transport from the u.s. eastern seaboard.
The CTM/MC2 and ADOMlMC2 models were used to study the impact of various emission reduction scenarios on ground-level ozone levels in the WQC and SAR, respectively. This study considered a series of simple emission reduction scenarios applied on a province-wide (in Canada) and state-wide (in the U.S.) basis (see Table 2). The examination was limited to the one meteorological episode from August 1 to 6, 1988. The period is characterized by a fairly stagnant and light wind situation during the first half, followed by a more transient and strong wind situation during the latter half of the period. Complete details of the scenario studies are given in the Canadian 1996 NOxIVOC Science Assessment (1997b).
There are a number of ways to quantify the effectiveness of a particular emission control. In the WQC modelling study we define the following parameter, a time integral:
(1)
where T is the time of simulation, <P is the concentration of ozone [ppb] for a given scenario run, <Pt is the threshold ozone concentration, e is the step function (=1, <P > <Pt; =0, <P < <Pt), and Xs is the position vector of the site for which the function Es is calculated. Es represents, for the given site, a combined measure of both strength and duration of the ozone exceedances (with respect to the threshold value <Pt) over the entire simulation period T.
The effectiveness of an emission-control scenario can then be evaluated by com paring the above parameter calculated for the emission-control scenario simulation with that from the base-case simulation. In order to examine the impact of the
~ 1 ~ ~
0 = 1 4 6 Se 10b 11
Scenario Number Figure 8. The set of values of Ew with I/>t = 60 ppb (this threshold, which is lower than the Canadian objective of 82 ppb, is chosen to obtain a reasonable number of values to evaluate Equation (2» for the selected emission control scenarios according to the list specified in Table 2. This figure shows the impact of various emission-control scenarios in the Canadian part of the CfMlMC2 model domain.
emission-control scenarios on Canadian locations only, we consider the following ratio:
1n W(X, y) J: (¢ - ¢t)8(¢ - ¢t) dr dx dy Ew = T ' 1n w(x, y) Jo ('P - ¢t)8('P - ¢t) dr dx dy
(2)
where: 'P is the concentration of ozone for the base run, and other parameters are as defined in Equation (1). Equation (2) signifies the ratio of time-integrated ozone values above a threshold ¢t over the domain Q to similar values for the base case. The coefficient w has the value of lover the territory of Canada and zero over the remaining part of the model domain.
The set of values of the ratio defined above calculated for different emission control scenarios from the CTMlMC2 simulations is presented in Figure 8.
It is clear that the most evident effect of emission control is observed for scen arios 8(c) and 11 (see Table 2). In the case of scenario 11 the good overall reduction of ozone is achieved by a moderate reduction of both NOx and VOc. In the case of the scenario 8(c) the ozone reduction is achieved by a massive 75% reduction of stationary and mobile source emissions of NOx in Canada and the u.s. The most general conclusion from the presented emission control runs is that, short of massive reductions in NOx emissions, one of the better ways of controlling the tropospheric ozone problem is through moderate reductions of both NOx and VOC.
For the separate study on the SAR oxidants, three scenarios considered were (a) Canadian NOx/VOC Management Plan's Phase I control (scenario 4 in Table 2), (b) Ozone Transport Region (OTR) emission control (scenario 7) and (c) both the CAAA90 and the OTR emission control (scenario 11). In this case, a slightly different parameter (index) is used to examine the overall impact of these emission control scenarios: total number of grid-hours with 0 3 levels exceeding a set
Table II. Proposed NOxIVOC control strategies
Strategy focus Area of Reductions from 1990 emission
impact inventories
Canada U.S.
LFV
stationary sources: NOx LFV
sources: NOx LFV
on NOx and VOC LFV
emissions
management plan LFV
5(c) 100% 100%
commission mobile and
8(b) (stationary and mobile) 50% 50%
8(c) 75% 75%
9(b) 50%
9(c) 75%
lO(b) 75%
Scenario 7
* Emission reductions for Greater TorontolHamilton areas only. ** The reductions vary from state to state. - No change from 1990 emission.
120 S. VENKATESHET AL.
Figure 9. The ADOMlMC2 model domain for SAR simulations with region A defined for the discussion on emission control scenarios. Halifax is marked for geographical reference.
threshold for a given region of interest and time period. This index gives a com bined measure of the spatial extent and the duration of an ozone event. We will focus our discussion on a region A defined as in Figure 9, which includes the Canadian southern Atlantic region and north-eastern Maine. This region is mostly rural and well away from major urban centres. Index values were calculated daily (August 1-6, 1988) for each of the scenario runs as well as the base case and are presented in Figure 10. The threshold levels were set at 60 ppb (see caption of Figure 8).
Synthesis of the information leads to the following observations:
• The evolution of the index over the 6-day period for the base case shown is consistent with the meteorological conditions for the region. The index level is higher in the latter part of the period under study with the New York - Boston ozone plume being advected into the SAR.
• The Canadian Phase 1 controls by themselves have a minimal effect on ozone index levels in this region, with a reduction of only about 1.5%.
• The index levels are sensitive to the emissions in the Ozone Transport Region states with significant reductions resulting from the OTR scenario reductions. The average reduction over the 6-day period is 75.4% for region A.
• Furthermore, by comparing the index levels between the OTR and the CAA scenarios, it is shown that the ozone exceedance in the SAR and north-eastern Maine is predominantly controlled by the emissions in the upstream OTR states for this particular time period.
REGIONAL AIR QUALITY MODELLING IN CANADA
o
base case
Phase 1
3I-Jul I-Aug 2-Aug 3-Aug 4-Aug 5-Aug 6-Aug 7-Aug
Figure 10. A comparison of the region A grid-hour indices calculated from the simulations for base case, emission control scenario # 4,7 and II (see Table 2 for details on scenarios).
7. Real-Time Prediction
7.1. SITE-SPECIFIC FORECASTS OF GROUND-LEVEL OZONE USING CANFIS
A pilot program to provide statistically-based forecasts of ground-level ozone began in July, 1997 for seven sites in southeastern New Brunswick. The program was part of Environment Canada's Clean Air Strategy and was carried out in co operation with a number of other regional health and environmental organizations (see Cote et al., 1998). The objective was to provide advance warning of high ozone days so that the susceptible population can take appropriate precautionary meas ures to minimize health impacts, which are predominantly respiratory in nature. Forecasts are issued twice a day out to 60 hours. There are three predictions for each 6-hour interval: (1) maximum hourly ozone; (2) maximum 3-hour running average ozone; and (3) average ozone.
From a learning data base consisting of hourly observations of the predictand matched with predictors, nonlinear statistical models of each predictand were built for each site using CANFlS, a recent data-mining methodology (Burrows et al., 1997; Burrows et ai., 1998). The CANFIS procedure combines the strengths of two modem data-mining methods, Classification and Regression Trees (CART) (Brieman et al., 1984) and the Neuro-Fuzzy Inference System (NFIS) (Chiu, 1994). CART is used to select a few relevant predictors from a much larger pool of potential predictors. Using these predictions, NFIS creates a model to output a predictand value. Forecasts are produced by running the CANFIS models when the same predictors are calculated from forecasts of meteorological fields by the Canadian Meteorological Center (CMC).
CART is a decision-tree algorithm that minimizes the variance of the fitted predictand data by splitting the predictand data by a tree structure into a set of separate "terminal nodes", each with a distinct value. Predictors that appear in internal node-splitting decisions are ranked in "importance" on a scale from 0- 100. In CANFIS those predictors that are assigned a nonzero rank are retained; the rest are dropped. The total number of selected predictors is limited to 20. The NFIS algorithm generates a final data model with the selected predictors. NFIS is a fast algorithm that produces a highly-optimized model in one pass. Data dimen sionality is first reduced by calculating a "potential" for each data point based on its Euclidean distance from other data points, then finding clusters by "subtractive clustering". The clusters form the basis for a fuzzy rule-based system that outputs a predictand value.
Ozone observations were available for at least 5-10 years or more at most sites. There are 643 potential predictors at each of four times daily (0000 UTC, 0600 UTC, 1200 UTC, 1800 UTC). Five types of potential predictors were used: (1) persistence; (2) biogenic emissions; (3) sea-breeze potential; (4) local met eorology; and (5) long-range transport of pollutants. There are several hundred meteorology and emissions potential predictors at 6-h intervals from O-h to 72-h along back-trajectories at 925 hPa from each site. Upper-air analyses needed for back-trajectory predictors were taken from data generated by Kalnay et ai. (1996). Separate models were built with persistence included and not included since real-time ozone data transmission can be interrupted.
For operational forecast runs at CMC, combinations of analysis data and pro gnosis data are assembled so that 72-h trajectories run backwards at six-hour intervals from future times at each site. For example, a 48-h forecast is obtained by putting 48 hours of prognosis data in front of 24 hours of analysis data to make 72 hours of sequential data. Trajectories run from each site at t + 48 h back to t - 24 h, thus the CANFlS model output is a 48-h forecast. Forecasts are produced every six hours at CMC from 6 to 60 hours twice daily at 0000 UTC and 1200 UTC. The CMC forecasts and predictor data are transferred to the New Brunswick Weather Office, where they can be updated in real time by a meteorologist. This is facilitated through a Graphical User Interface (see Figure 11).
Figure 11. Graphical user interface used to update ground level ozone forecasts for New Brunswick using the Statistical Air Quality Package. The top panel shows meteorological parameters that can be modified; the bottom panel shows the operations that can be performed (load, run, save, etc.) and the middle panel displays the results.
An evaluation of the pilot program, including a comparison of model forecasts with observations, can be found in Cote et al. (1998). The verification results show that while there is skill in forecasting low to medium ozone levels, the accuracy goes down for extreme values. Work is underway to extend predictions to all of southern Canada in 1999.
7.2. REGIONAL FORECASTS OF GROUND-LEVEL OZONE USING CHRONOS
During the summer of 1998 the CTM (now referred to as the Canadian Hemi spheric and Regional Ozone and NOx System - CHRONOS) was implemented in a development mode to produce daily forecasts of ground-level ozone over eastern North America. In the development mode the forecasts were available for internal use but were not used to produce public forecasts. The model was linked to the output from the Global Environmental Model (GEM) run operationally at the CMC to produce meteorological forecasts. Figure 12 shows an example of an output product from CHRONOS.
An important consideration for the real-time operation of CHRONOS was that the model should run within certain time constraints. This meant that the model execution time had to be reduced by a factor of at least 8 to 10. It was already known that a major part of the computational time was spent in the gas-phase chemistry part of the model. Given that the model was to be run on a supercomputer, vector izing the computer code to take advantage of the supercomputer architecture was seen as a necessary step.
O.on~
159
130
110
100
90
90
70
60
50
40
30
20
10
21 houde.t valid 21:002 July 161999
Figure 12. Regional ground level ozone forecast obtained from the CHRONOS model for July 16,1998. Figure shows high ozone levels around New York, DetroitlWindsor. Ozone levels of 70--80 ppb are evident around the Kejimkujik area of Nova Scotia (see Figure 9).
7.3. VECTORIZED ADOM CHEMISTRY SOLVER
Recently, it has been shown that the computational time required to simulate gas phase chemistry can be greatly reduced for the case of a highly accurate predictor corrector method (Jacobson and Turco, 1994; Gear, 1971). The key concept employed was that of "vectorization over gridpoints", in which mathematical operations are carried out on large numbers of model gridpoints simultaneously.
The concept of vectorization by gridpoint was applied to the chemical solver of ADOM and also used in CHRONOS (Pudykiewicz et al., 1997). The results for four gas-phase solvers were compared: the original ADOM solver; the vectorized
ADOM solver (Makar, 1995); a conventional Gear solver (Gear, 1971); and the vectorized Gear solver (Jacobson and Turco, 1994). The details of the solvers are discussed elsewhere (Makar, 1995). However, two main concepts of the vectorized ADOM solver are worth mention.
First, the conventional ADOM solver had two different forms of both the predictor equation and the corrector equation; one for variables with very short chemical lifetimes ("stiff"), and one for the longer lifetime variables ("nonstiff"). At every stage in the integration, a logical "IF' statement was required, using the variable's current chemical lifetime to determine which solution equation should be used. To avoid the halt to vectorization which would result from this decision point, a logical flag was used to determine the nature of the variable:
Sj,i = (sign(1.0, Lj,i - 0.9/8tj ) + 1.0)/2, (3)
where L j,i is the loss rate at the jth gridpoint of the ith chemical species, and 8tj is the time substep at the given gridpoint. Sj,i will be 1.0 if the species is "stiff" and 0.0 if the species is "nonstiff". In subsequent calculations, both stiff and nonstiff solutions were calculated for all species, with the results combined using Sj,i:
Final solutionj,i = Sj,i(stiff solution) + (1- Sj,i) (nonstiff solution), (4)
Although the amount of work has doubled (two solutions are being calculated for each variable instead of just one), the elimination of the decision point allows the code to vectorize, with a substantial decrease in processing time.
The other important concept used in vectorizing the ADOM solver was the use of a fixed (and maximum) number of corrector iterations in the corrector equation. The original code allowed for up to three iterations, with error checking after each iteration to determine whether convergence had occurred. In the vectorized version, three iterations were always taken. However, the iteration at which convergence first took place was retained for each grid point, as it was used for subsequent calculations which determined the size of the next integration time step for that grid point.
Initial tests of the vectorized code were carried out on the Atmospheric En vironment Service's NEC SX-3 supercomputer, with later implementation of the vectorized code on a newer SX-4 supercomputer. A selection of 1195 test cases was used to represent a large number of regional model gridpoints. The average CPU-time per gridpoint is given below.
Method Processing time/gridpoint (ms)
126 S. VENKATESHET AL.
The solution results were compared to the standard Gear solver results for ac curacy. The vectorized ADOM solver errors were essentially identical to those for the original ADOM solver. However, both ADOM solvers tended to have lower accuracy than SMVGEAR. The ADOM solvers' errors were less than the itera tion convergence criterion for 0 3, S02, SO;, H20 2, HN03, C3Hs, C2R., toluene, formaldehyde, methyl-ethyl-ketone, organic nitrates, lumped higher alkanes, and lumped higher aromatics (i.e., as accurate as possible within the round-off error of the iteration). However, for some species at low concentrations (e.g., night time NO), the errors could be as high as 100%. These errors only occurred for cases in which the species concentration had no significant impact on the rest of the gas-phase system. For example, in a particular test, the standard Gear solver NO value was 3.7E-I0 ppmv, while the vectorized ADOM solver NO result was 6.6E-I0 ppmv. Both of these values are indistinguishable from zero with currently available measurement technology. Ozone values for this test were identical to four figures, and most species had less than one percent error. The R02 error was 17% for this test. The other high error cases were similar; errors occurring as the integ ration methods approached very low values for NO or other species. The overall error was not seriously impacted by these cases; the concentrations of the species in question were sufficiently low that their effect on the rest of the system was minimal.
The vectorized ADOM solver was then incorporated into the regional ozone forecast model in the place of the original solver. The processing time of the entire model was reduced from almost four hours to approximately 18 minutes, allowing the use of the regional model in forecast mode.
8. Summary and Concluding Remarks
In this paper the results from the recent Canadian Acid Deposition and NOx/VOC science assessments have been discussed. For acid deposition the expected res ults from the control programs carried out to date to reduce acid deposition have been evaluated with observed effects. While there has been a reduction in sulphate deposition, there has not been a corresponding reduction in the acidity of precipita tion. Based on results from modelling studies, much of southeastern Canada is still expected to experience damaging levels of acid deposition even after all currently legislated emission controls are fully implemented.
In NOx/VOC modelling, models have been developed incorporating recent in novations in numerical techniques. As an example of modelling as a tool, scenario runs show that to achieve reasonable reductions in ground-level ozone levels, emis sions reductions will be required in both Canada and the United States. Operational real-time predictions of ground-level ozone have been made possible through vec torization of computer code on a supercomputer and also using statistical prediction models.
Building on the knowledge gained from the acid deposition and ground-level ozone programs, efforts are underway to model the effects of particulate matter. This requires consideration of more chemical, physical, and dynamical processes than in modelling acid deposition or photochemical smog (e.g., aerosol nucleation, condensation, coagulation, and sedimentation; emissions of both primary PM and gaseous precursors). The development of a PM air quality model is effectively equivalent to the development of a multi-pollutant, multi-issue air quality model. We are currently in the process of building a speciated, size-distributed PM air quality model (Moran et aI., 1998). This model will ultimately be capable of as sessing the impact of emission reduction scenarios separately or simultaneously for PM, ground-level ozone, acidic deposition, and air toxics.
Acknowledgements
The authors would like to express special thanks to the Canadian provincial and federal governments, which contributed their precipitation chemistry data. B. Beat tie and K. Keddy of Environment Canada Atlantic Region created the gridded critical-load field for eastern Canada. The authors also gratefully acknowledge the contribution of data from agencies and organizations in the United States of America, specifically the Environmental Protection Agency and the National At mospheric Deposition Program. The authors would like to thank Dr. J. Pudykiewicz of AES for many helpful discussions on the CTMlMC2 model and its applications. Finally, the authors would like to thank the anonymous referees whose many useful comments and suggestions helped to improve the quality of the paper.
References
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Burrows, W. R., Walmsley, J. L., Faucher, M., and Montpetit, J.: 1998, Combining classification and regression trees and the neuro-fuzzy inference system for improved data modeling when large numbers of predictors are involved, J. Appl. Meteor. (submitted).
Burrows, W. R., Montpetit, J., and Pudykiewicz, J.: 1997, CANFIS: A non-linear regression procedure to produce statistical air-quality forecast models, Proc. Air & Waste Management Association's 90th Annual Meeting & Exhibition, June 8-13, 1997, Toronto, Ontario, Canada, Paper TP2B.04.
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Chiu, S.: 1994, Fuzzy model identification based on cluster estimation, J. Intelligent & Fuzzy Systems 2,269-278.
Cote, c., Howe, M. C., and Waugh, D.: 1998, Southern New Brunswick smog prediction pilot project, 1997 evaluation report. Environment Canada, 77 Westmorland St., Fredericton, NB, E3B 6Z3, Canada.
Dennis, R. L., Barchet, W. R., Clark, T. L., Seilkop, S. K., and Roth, P. M.: 1990, Evaluation of regional acidic deposition models (Part I), sosrr Report 5, National Acid Precipitation Assess ment Program, Washington, D.C., September. [Available from NAPAP, Office of the Director, 722 Jackson Place NW, Washington, D.C. 20503, U.S.A.].
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Natural Hazards 21: 131-144,2000. © 2000 Kluwer Academic Publishers.
131
The 1997 EI Nino, Indonesian Forest Fires and the Malaysian Smoke Problem: A Deadly Combination of Natural and Man-Made Hazard *
M. L. KHANDEKAR**, T. S. MURTY, D. SCOTT and W. BAIRD Baird & Associates, Ottawa, Ontario, Canada
(Received: 6 October 1998; in final form: 26 March 1999
Abstract. The EI Nino of 1997-1998 produced the most intense impact on the conterminous U.S.A., generating a series of powerful rain and wind storms off the coast of California in early February 1998. The 1997-1998 EI Nino also produced severe flooding and extensive mud slides along the west coast of South America and prolonged drought conditions in northeast Brazil. On the other (west) side of the equatorial Pacific, the EI Nino produced the worst drought in 50 years over Indonesia and helped spread the ongoing forest fires on the island of Borneo to well over one million acres. In this paper, the smoke and pollution problem over Malaysia will be analyzed in the context of ongoing Indonesian forest fires and the severity of the 1997 EI Nino - a deadly combination which led to the most hazardous smoke problem over Malaysia during August-September 1997. The severity of the smoke pollution is documented using media reports and available API (air pollution index) values over selected cities in Malaysia. The role of the EI Nino and its evolution in enhancing the smoke pollution over Malaysia is further discussed and suitably documented. Some of the mitigation measures presently being adopted in Malaysia to combat the smoke pollution are briefly discussed.
Key words: EI Nino, Indonesian forest fires, South Asian drought, extreme smoke pollution, health hazards.
1. Introduction
The oncoming of the 1997-1998 EI Nino was recognized as early as March 1997 with the appearance of a positive sea-surface temperature (SST) anomaly off the coast of equatorial South America, a sure sign of an EI Nino arrival (Rasmusson and Carpenter, 1982). By the end of May 1997, the SST anomaly off the equatorial South America had reached a value of +2.9 °C - highest since August 1983. This prompted meteorologists and oceanographers to speculate that the approaching EI Nino would be at least as strong as the 1982-1983 EI Nino which had caused worldwide havoc in terms of torrential rains on the west coast of South America, severe drought in Indian and south Asian monsoon rainfall, and major swings in
* Paper presented at the Seventh International Symposium on Natural and Man-Made Hazards, Chania, Greece, 17-22 May 1998.
** Address for correspondence: 52 Montrose Crescent, Unionville, Ontario, L3R 7Z5, Canada, e-mail: [email protected]
132 M. L. KHANDEKAR ET AL.
world grain yields (Garnett and Khandekar, 1992). By August/September 1997, the warm water of the equatorial eastern Pacific had spread along the west coasts of the Americas stretching from the Vancouver Island (off the west coast of Canada) to the northern shores of Chile (South America). The warm waters were already generat ing heavy rains and mud slides in coastal regions of Peru and Chile, while residents in coastal California and Mexico were bracing themselves for the onslaught of El Nino.
The early winter (first week of December 1997) storm which brought snow in many parts of Mexico was triggered by the southward extension of the mid-latitude jet stream which pulled in colder air over Mexico. The fury of El Nino began in early February 1998 with a series of storms developing over the warm waters of the central equatorial Pacific and being steered towards the California coast by the anomalous westerlies at the 850 mb level (see Climate Diagnostics Bulletin, 1997). These storms, which were accompanied by high winds and heavy rains, caused extensive damage to properties and claimed several lives in the coastal communities in California (Time Magazine, 1998). As these storms moved east ward, some of them redeveloped over the Gulf of Mexico producing heavy rain and violent weather (i.e., high winds, tornadoes) along the coastal states from Louisiana to Florida. A few of these El Nino-driven storms that struck California moved along a northeasterly track producing heavy snowfall and blizzard-like conditions in the adjoining mountainous states of Arizona and Utah. The Canadian-American prairie region of the mid-west North America experienced a much milder and a drier (1997-1998) winter as suggested in a couple of recent studies (Bunkers et al. 1996; Shabbar and Khandekar, 1996).
The 1997 El Nino produced an equally intense impact on the other (western) side of the equatorial Pacific, in particular over Malaysia and the Kalimantan province of Indonesia (see Figure I), which experienced the worst drought in 50 years. With the onset of the E1 Nino around April 1997 , the positive SST anomalies in the central and eastern equatorial Pacific started to grow and this helped relocate the convective activity off the South American coast as shown in Figure 2( a, b) which illustrates the mean and anomalous values of the outgoing longwave radi ation (OLR) for February and September 1997. The mean OLR value (in W/m2)
for a month is calculated from the daily reflected radiance as measured by the polar orbiting weather satellites, while the anomalous values are departures from the 1979-1995 base-period monthly means. The anomalous values of the OLR for February 1997 show a large area of negative value over the Indonesian/Malaysian region indicating increased convective activity (lower mean value and below nor mal or negative departures from mean) in the western equatorial Pacific, while for September 1997 the Indonesian/Malaysian region has a positive anomaly indicat ing decreased convection while the eastern equatorial Pacific region has a negative anomaly indicating increased convective activity off the South American coast. Figure 3 shows the areal distribution of rainfall as estimated by the special sensor microwave/imager (SSM/I) aboard the polar orbiting satellite. The rainfall anomaly
THE 1997 EL NINO, INDONESIAN FOREST FIRES 133
LocationM:ap for S·arawak
c· ~o:. .. Q ..
Figure 1. Map of Malaysia and the neighbouring countries of southeast Asia. Note the four major cities of the province of Sarawak (island of Borneo), namely, Kuching, Sibu, Bintulu andMiri.
of Figure 3 (bottom) shows an increased rainfall activity in the central and eastern equatorial Pacific while showing a drastic reduction in the rainfall activity over the Indonesian region. The decreased rainfall activity over Indonesia-Malaysia was primarily due to the large-scale subsidence associated with the onset of the 1997 El Nino and this helped produce one of the worst instances of smoke pollution over the island of Borneo and particularly over the Sarawak province of Malaysia.
In the following section, a brief account of the ongoing forest fires in Indonesia and over the island of Borneo is presented. This is followed by selected examples of extreme pollution instances over Malaysia during August-September 1997. An analysis of the episodic pollution instances is made using the large-scale flow pat terns (in particular the large-scale subsidence) associated with the evolution of the 1997 El Nino. Finally, some mitigation measures presently adopted in Malaysia to combat the smoke pollution are briefly discussed.
Figure 2(a). Mean (top) and anomalous (bottom) OLR for February 1997. The OLR is meas ured by the polar orbiting satellite NOAA 12 of the U.S. Weather Bureau. OLR contour interval is 20 W/m2 with values greater than 280 W/m2 indicated by dashed contours. Anom aly contour interval is 15 W/m2 with positive values indicated by dashed contours and light shading. Anomalies are departures from the 1979-1995 base-period monthly means (from Climate Diagnostics Bulletin, 1997).
Figure 2(b). Same as Figure 2(a), but for September 1997.
100 WHr-~~r--------'------__ -7<r-.-~r-~---.~~-r------~ 50H
~OH
.!ON
20N
l(»j
Figure 3. Areal distribution of rainfall in mm (Top) and rainfall anomaly in mm (Bottom) estimated using the Special Sensor MicrowavelImager (SSMII) precipitation index. Con tour interval for mean (anomalies) is 100(50) mm. Anomalies are computed from the July 1987-June 1996 base period mean. (From Climate Diagnostics Bulletin, \997.)
2. Indonesian Forest Fires: An Ongoing Problem
The ongoing forest fires in Indonesia in general and in the province of Kalimantan in particular is a man-made problem created primarily by socio-economic condi tions. Farmers and landowners in Kalimantan and elsewhere have been burning trees of the southeast Asian rainforest for the last 20 years or so as an inexpensive technique of clearing land areas for industrial and commercial development (see Malingreau et al., 1985). Most of these man-made forest fires are at their low point during the rainy season from about October through March. During the relative dry season from about April through September, the forest fires appear to strengthen and reach their peak activity by September which may be looked upon as the transition month from the relatively dry season to the beginning of the wet season.
The EI Nino/Southern Oscillation (ENSO) phenomena has a significant im pact on the rainfall and convective activity over southeast Asia in general and over Indonesia-Malaysia in particular. Some of the classical studies conducted by Dutch meteorologists more than 70 years ago (Braak, 1919; Burlarge, 1927) have investigated the relationship between the rainfall of Java and the surface pressure variation over the Indonesian region. Many recent studies (Quinn et al. 1978; Hastenrath,1987; Ropelewski and Halpert,1987) have analyzed the impact
Table l. EI Nino events (since 1976) and haze problems in Malaysia
Year Haze problem EI Nino
1976 Moderate Moderate strength
1982-1983 Very severe Strongest EI Nino of the 20th century until that time
1986-1987 Small to moderate Weak to moderate strength
1090-1991 Moderate Moderate strength
1997 Very severe Strongest EI Nino of the 20th century
of ENSO on the Indonesian rainfall and it is now generally recognized that the warm phase of ENSO (warmer waters off the coast of equatorial South America and a negative value for the southern oscillation index, which is measured as the sea-level pressure difference between Tahiti and Darwin), is associated with re duced rainfall and convective activity over the Indonesian archipelago. According to McBride et al. (1998), the Southern Oscillation influences the rainfall of the dry season more than that of the rainy season. Table I provides a list of years (beginning with 1976) which were associated with moderate to strong EI Nino conditions and which were also associated with moderate to severe haze problem over Malaysia and parts of Indonesia. The EI Nino years are easily identified using historical records of SST values over the equatorial central and eastern Pacific while the extent and severity of haze problem were determined using media reports and the Malaysian government archives. During the strong EI Nino of 1982-1983, the most extensive forest fires in Kalimantan took place from August to October 1982, and from March to May 1983 (Malingreau et al., 1985), and this led to a serious haze and smoke problem in the Sarawak province.
The government of Indonesia has outlawed the burning of rainforests in Ka limantan and elsewhere since 1994. Despite the government's efforts, the forest fires have continued unabated in recent years, primarily due to illegal operations. The EI Nino of 1997 produced its dramatic impact during July through September 1997 when the rainfall and associated convective activity were suppressed over most of southeast Asia in general, and over Indonesia and the island of Borneo in particular. A lack of convective activity significantly reduced vertical mixing of surface-level smoke and particulate matter leading to unusually high values of air pollution index (API) on certain days in August-September at selected cities in Malaysia. The rainy season from about mid-October 1997 through mid-March 1998 provided some relief from the hazardous smoke pollution. However, the forest fires continued to smoulder through the rainy season and helped ignite the coal and peat deposits in some locations. As the rainy season came to an end in March 1998, the smouldering fires were rekindled in early April leading to hazardous smoke pollution incidences once again in mid-April 1998. This time the pollution
incidences occurred in the northern part of Sarawak and in and around Miri (see Figure 1) where several localized fires were reported.
3. Incidences of Extreme Smoke Pollution: Analysis and Discussion
The Sarawak provincial government has been monitoring the forest fire situation in the Indonesian province of Kalimantan and its impact on the air quality in selected cities such as Kuching and Miri (in Sarawak) for the last two years or so. The air quality at selected locations in Malaysia is monitored using daily (and in some cases, hourly) values of the API. The API is typically determined as a weighted measure of six pollutants, namely, carbon monoxide (CO), lead (Pb), nitrogen dioxide (N02), sulphur dioxide (S02) and particulate matter (PM-lO), whose aero dynamic size is ~10 microns (see for example, EPA,1993, the U.S. Environmental Protection Agency Report). The government of Malaysia has been using the same definition of the API as in the U.S.A. However, in practice the API values at many locations in Malaysia are often based on the PM-lO measurements only. Since the onset of the EI Nifio by March/April 1997, the API values in Kuching have been slowly but surely increasing indicating a slow deterioration of the air quality in and around Kuching. By mid-August 1997, the SST anomalies off the equatorial South American coast had reached a value of +4.0 °C and higher, leading to increased convective activity and rainfall along the South American coast while inhibiting the same in the western equatorial Pacific (see Figure 2 (a, b)). The decreased rainfall activity over Borneo during August and September 1997 helped strengthen the forest fires and, in the absence of large-scale atmospheric convective activity (as revealed by Figure 2(b)), the smoke concentration in the atmospheric boundary layer over Kuching and vicinity increased dramatically leading to extremely high API values (800 or more) as shown in Figure 4. (It should be noted here that an API value of 100 or more is considered dangerous to human health according to the EPA standard.) Figure 4 shows high API values at Kuching from about the 20-25 September 1997 during which time the wind speed values at Kuching were rather low and its direction was predominantly southeasterly which allowed the smoke to be transported from the forests of Kalimantan to the population centres of Kuching.
Figure 5 shows a pressure-longitude section (lOa °E to 80 OW) of the mean and anomalous relative humidity and divergent circulation over the equatorial belt from 5 ON to 5 aS for August 1997. The divergent circulation is calculated in the vertical equatorial plane and is represented by vectors of combined pressure vertical velo city and divergent zonal wind. The divergent circulation depicts areas of rising and sinking motion at different pressure levels in the atmosphere. Of interest here is the anomalous circulation relative to climatology, which shows strong sinking motion over the western equatorial Pacific from 100 °E to the International Dateline in the central equatorial Pacific. This large area of sinking motion in conjunction with very little rainfall and moderate wind flow in the boundary layer (wind speed about 5-7 mls) blowing predominantly from the forest fire region towards the Sarawak
Daily Maximum Air Pollution Index
;: 1000 _r_-------------------, ~ 800 . . .. . . .. . . . .. . ...... -. - . - - - -' - . ~/\ .§ 600 -.......... '" ....... -. - - - ./-, j'\ ----- )-( . \. . ~ 400 -.... . .. ... -.' ./ .. - - . - \
... 200 ... - . -1\ .. -.. . ...... "-', - -,,~ .. ---- '. ----". :; ......... • ...... _ •• _.1 ••• -. 't_. Q O~~-~~~----~-------------~
30·Aug 4-Sep 9-Sep 14-Sep 19-5ep 24·Sep 19-5ep 4·0c!
September 1997
Wind Speed
30-Aug 4-Scp 9-Sep 14-Sep 19·5ep 24-Sep 29·Sep 4-0ct
September 1997
Wind Direction
~ t~g : _~~~~~~,~:~:::::.: ~:~~':~:: :::::: ~'~::::: ~: ~ :'::::: :;:: :':::::::: ~ 0
September 1997
24-Sep 29-Scp 4-0ct
Figure 4. Values of daily maximum API (Air Pollution Index), wind speed (km/hr) and wind direction (deg.) at Kuching airport, Sarawak during September 1997.
province led to unusually high API values for several days during September 1997. The peak value of API (over 800) on 23 September 1997 was associated with a light southeasterly wind blowing from the forest fire regions in Kalimantan and a continued dry spell at Kuching during the first three weeks of September (see Fig ure 6 which shows the observed daily rainfall and accumulated rainfall at Kuching since April 1997). The continued dry spell together with very little vertical mixing due to large-scale subsidence (Figure 5), led to a very high value of API at Kuching on 23 September 1997.
With the onset of the wet season by mid-November 1997, the API values started to decline rapidly as the bulk of the smoke was being washed away by daily rain fall amounts of about 1-2 cm as reported at Kuching (Figure 6). The wet season brought fair to moderate amount of rainfall over the island of Borneo as shown in Figure 7 which illustrates the daily and accumulated precipitation at a representat ive location in Borneo. The wet season also helped curb the forest fire situation over Kalimantan, although fire continued to smoulder over some regions where coal and peat deposits are known to exist. The API values during the wet season were about 200 or less at Kuching and Miri - the regular air pollution monitoring sites in Sarawak. In early April 1998, there was a dry spell of several days over Borneo and the adjoining region which helped rekindle the smouldering fire and with a steady easterly to southeasterly wind, the API values showed a dramatic increase to over 500 at Miri during the second week of April 1998. With the onset of rainfall activity during the latter part of April, which was partly due to seasonal change and partly due to a dramatic increase in the SO index (between March and April 1998), the API values started to drop rapidly indicating a substantial improvement in the air quality over Sarawak. An increase in the SO index is generally associated with lower sea-level pressure over the Indonesian region and this usually leads to increased rainfall activity.
The severity of the smoke pollution over Malaysia and the associated health haz ards were reported in many national and international newspapers and magazines. The leading newspaper in Canada (The Toronto Star, dated 25 September 1997) carried a picture of Malaysian firefighters leaving for Sumatra to battle forest fires; the picture was accompanied by the headlines: SMOG FROM BUSH FIRES CHOKING SOUTH ASIA. A leading newspaper in the U.S.A. (USA Today,dated 29 September 1997) reported on the Malaysian smoke pollution with a picture of a young girl wearing a face mask and accompanied by headlines: MALAYSIA SMOG EASES, BUT STILL COATS REGION.
The health and environmental hazards of the forest fires and the smoke pollu tion were also highlighted in several newspaper and media reports. The Canadian newspaper (The Toronto Star, dated 24 and 28 March 1998) provided the following reports: ''Thousands of residents (in Indonesia) have developed respiratory prob lems due to a thick haze created by the fires on the island of Borneo. The massive cloud of smoke caused almost 300 cases of pneumonia with at least two deaths reported. Wildlife on the island of Borneo, especially orangutans and elephants,
100.-----------------------------------------------, , I~ ('--... __ ---, ... ~ •• ,,-----... ~ ••• \ ••• ..... ~\ . . ... _ ..... .... .- ~ .. " .. ;,,,,,
100 ~----------~-------------------------------------~
200
300
~oo
500
60
40
5
-E
Figure 5. Pressure-longitude section (lOOoE-800W) of the mean (Top) and anomalous (Bottom) relative humidity and divergent circulation (SON-50 S) for September 1997. The divergent circulation is represented by vectors of combined pressure vertical velocity and divergent zonal wind. Shading and contours denote relative humidity (%). Anomalies are de partures from the 1979-1995 base period monthly means. (From Climate Diagnostics Bulletin, 1997.)
has been hard hit by smoke and loss of habitat". The health hazards of the forest fires and smoke pollution have also been reported in many government documents prepared by the province of Sarawak. A brief report in the International Time magazine, dated 4 May 1998 (see Figure 8) expressed concern about the impact of the release of large amount of carbon dioxide into the atmosphere on global warming. Although the global warming impact of the forest fires may be hard to assess accurately, the health hazards of the forest fires and smoke pollution have
Precip itotion Inches Kuehi Sorowok mm 200~--------------------~~--~~~~~~--------------------~~
1110 Accumulated Observed: thick line . 500
Accumulated Normal: thin line
e 150 , tlb
• 100 3 7~
0
Figure 6. Observed daily rainfall and accumulated rainfall (inches and mm) at Kuching, April 1997 through April 1998. (Courtesy by the Climate Prediction Center, Washington, U.S.A.)
Precipitotion Inches Bond ormosin Ulin. Borneo mm ISO,---------------~~~~--~~--~~~~~~~--------------~
13' 120 lOS eo ,~
SO ~
~~~~~~~~~~~~=_~~~~~~~~~~~~U-llo
Figure 7. Observed and accumulated rainfall (inches and mm) at a representative location on the island of Borneo, April 1997 through April 1998. (Courtesy by the Climate Prediction Center, Washington, U.S.A.)
142
14
Asia's Burning, and the Whole World Suffers THE rOlu :sr flUS 1U4;ING 0"" 'nn:
island of Hornco h.l\(, been glv1nl£ Soothea~l A~l31\S Ji;lnnlOg H3.)hb .. 1Ck. ..
10 the .real 11 <11" ~J( 1997 In . me wa"s Um ve.lr·:, bI.lu· ... , Iok,'(t by the drou~h t
c-.iU,..(,.'d by 1-:1 :":100. hd.\(' bet-n ('ven worse. ~p,c:.aLll11l( into IClllote .... I1.:!It::)o(thc Y'ligin r.lln (orot. Sin ' Ian,,:at) . tires ha\'c dillmed 28Q.OOO IUo"C't.lrcs o( ",'ood.l:tnd, c: ..... h nS .. ,>all o( ~lnoke 0\'("1 th(' Inoonesi.1n prrwint.."C'"o( Ea~ Kaliman tan and the \l ala)'!'iIM staIb- o( ... bah and 5.arnw;l lc Wlule recent rams ha\'c quencht..-'d many o( the fires. the SltWtiOtl rem:uO$ \"'OI.!lhlc.
\1otl.«t\t·r thl' ~ hQll' ,,-. .. Id m.I\' t '1 Ih. ~
h\-'.It rhe hurnmg fun ..... h .lf~ .Iddm:.' ton .. ClI.',lI 1Mln d"l~lde te, tht· II ' Il()\J')ht°r.
wo~nllut thl' I' ,reOl t ,,( I!IOllal" 'Oll'Ollnt: \ IJrrn .. '<i by th~ m.)~nlll.cJI· ,)llh,.
pmbl 'm. thl' L mh.'fi '\dIIUfl~ ('tJn\cnt:d In t.'lIlt,;rt(enc\ Ilwchnt; 11\ I .I.°nc\. .. J.1\1 wt-1.,k
1(, dra\\ up p ..III ' lor inh"rn 11 100.11
IOh:r\'en lh)n '\\ (' mil»t io I~,\(,I"\ nmJ.!, In Ollr po,"\!r 10 J'W\o'Cnl.1 r"p'~t ·1 LI'j.! \ I-ar\
dl~~h!1 "...a.td Kl.a1J: Tupici. ,:\l-(: t h l'
d m .'t'tor 01 the t..~ f.n\1 nllh:"1
Program. "\."1";0111 pr.\CIIC'~l at-tlOu 1\
nf'f'dt'CI ~ nfl\\ T"llfn hUI'If"<o th4" I 111.1 other n,mnn .. can won ht: r<:':Iat1cd tn .tnte up J tot.11 or It) million. t:nou~h 10 PiI) tor CqUl ppll lf and fratnllle: 1,()f)() fm.: fighters - By I . M~ Huh
M. L. KHANDEKAR ET AL.
It Hasn't Been This Sizzling in Centuries TlfltEt 0 '" TIlt; WA~ \l fST \"E.\K~ (H' n il
20th (.."Cntun "'-t'n- bUfl(.'ht:d In the 1990s ~ thl~ reH\..'Ct a hlns·lenn
\\.'Unmng Of the ~k>be by carbon dioxide and oth~r gret:nhoU$f! g:.1.\CS, ~ "'JOY ..ttrn~phc~nc Wlt.'fltl .. t~ tu\ol.' cunlt;!nded~
Or \'\'~.a.1 the hoi ~lX'lI JU!'It .. random. une'l'cept lonru AlIltUlIlll.)Il In th~ we .. lhcr ~
-\ study pubbd.cd L'L .. t !'l'lc: In Xatunt mag.u.int' byt'llm;tMI • .g1 .. 1 \I it·h:tpl \ 1.lnn .and t'OlIe.agut·o, (1 0m the UO\\ cNh 01 \t~s.1c:huse1b Amh~rsC mOl) help mdt .!wav Uft) Imgt'rlllg douhl ahout J!lubaJ "annln\( Tht.· ~"lcnlJ,b dc\'clopcd what ... mounts to Of tlme~tr:;tvelln)( thermometel \ ppl> 1IlJ( m nm';lt1"\'C" ~ tdtJ tlc:tilool, Itl r{'aln~ of e\!den(:e !!,3thcrcd from ~ncu:nt ItC )..I.mplh. h~ nn.l'S .ind coldl
!mgmcnt .. , th('v t'lft.,,(otl\'c1\ 1)IJ .. ht.."\f Ih~ ll'm~'I";lturt!" ro'<. ... ,nl t .. K·l.. mQr,>lh ,ul ~,oc.,
p·ar ... Cnnf'lu .. u')tl rhl"hT4"(' w;urn(>'o.1
W 3t'i o( the 199(h \\t!n.' h!nt("t Ih .. m .any nl hl r Ill'nod \IIHI' the \l lddlc> -\"l"
Figure 8. A picture of forest fires in Borneo from Time magazine dated 4 May 1998.
been well recognized and some measures are already underway as discussed in the following section.
4. Mitigation Measures
As mentioned earlier, the government of Sarawak has been closely monitoring the forest fire situation in Indonesia, and assessing its smoke pollution potential over various population centres in the province of Sarawak. At present, there are four city centres where the API values are monitored regularly for about a year or so. These API values (hourly as well as daily) are being analyzed in conjunction with a variety of weather parameters (such as surface temperature, wind speed and direction, daily as well as accumulated rainfall values, suitable measures of vertical atmospheric stability, etc.) to develop an operational procedure for short-term (24- 72 hr) prediction of API values at these locations, namely, Kuching, Sibu, Bintulu and Miri. A recently developed statistical technique called CART (classification
and regression trees) - a powerful nonparametric technique developed by Brieman et al. (1984) - is being used to identify important weather parameters that influence the pollution levels in and around the cities of Kuching, Sibu, etc. The CART tech nique has been used in a wide variety of applications in recent years and a couple of studies (Burrows et al. 1995; Tag and Peak, 1996) suggest its utility for predicting ground-level ozone and fog, among other weather parameters. Preliminary results suggest that the CART technique can be useful for predicting high pollution levels at Kuching with a lead time of 24 hr or so. Further work on the CART technique is in progress. At present, a simple trajectory model is being used to monitor the transport of haze from the forest fire region to the population centres of Sarawak. Also, the forest fires are being monitored and smoke pollution warnings based on variation of API values are issued by the Sarawak Government on a daily to weekly basis.
Besides the API monitoring and prediction measures, other mitigation measures are also being implemented. Adequate information on the health hazards of smoke and atmospheric particulate matter is being disseminated by the Sarawak Govern ment, and suitable face-masks are being made available to those more frequently exposed to higher pollution levels. According to recent media reports, the govern ment of Indonesia, in co-operation with Malaysia and Singapore, is looking into various ways to control the ongoing forest fires in Kalimantan and elsewhere.
5. Summary and Conclusions
The dramatic impact of the 1997 EI Nino on the large-scale atmospheric flow pat terns over southeast Asia, together with the ongoing forest fires in Kalimantan and Borneo, led to the hazardous smoke pollution problem over Malaysia in general, and over the province of Sarawak in particular, during the summer of 1997. The extremely high values of API over several cities in Malaysia were caused by the severity of the EI Nino which produced large-scale sinking motion and drastic reduction in rainfall activity over the entire Indonesian archipelago.
A simple operational technique to monitor haze transport from the forest fire region is capable of providing suitable guidance for regulatory measures and allows the issuance of warnings about increasing levels of smoke pollution. Appropriate monitoring of EI Nifio (or its inverse, called 'La Nina') situations in the equatorial eastern Pacific, and their possible impact on the large-scale atmospheric flow pat terns over southeast Asia, will be important for suitable monitoring and predicting of future incidences of high pollution. Suitable measures to bring the ongoing forest fires under control are being considered by the various governments of that region.
Acknowledgements
We would like to express our sincere thanks to Ms Che Gayah Ismail and her coworkers at the Malaysian Meteorological Service Department in Kuching,
Sarawak for their assistance in providing a large amount of weather data from the province of Sarawak and the island of Borneo.
References
Berlage, H. P.: 1927, East-Monsoon Forecasting in Java, Verhandelinger, No. 20, Koninklijk Mag netisch en Meteorologisch Observatorium te Batavia, Indo

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