What have I learnt about tropospheric composition using space-based
observations?
Paul Palmer, University of Leedswww.env.leeds.ac.uk/~pip
Correlation of high ozone with temperature is driven by:1) Stagnation, 2) Biogenic hydrocarbon emissions, 3) Chemistry
Ozone exceedances of 90 ppbv,summer 2003 (#days)
Model values forpreindustrial ozone
}European mountain-top observations[Marenco et al., 1994]
Observed rise in ozone background at northern
midlatitudes
0-1; 1-5; 5-10; >10
60
50
40
30
20
10
01870 1890 1910 1930 1950 1970 1990
NO
HO2OH
NO2
O3hv
HC+OH HCHO + productsNOx, HC,
CO
Tropospheric O3 is an important climate forcing agent
IPCC, 2001
Level of Scientific Understanding
Natural VOC emissions (50% isoprene) ~ CH4 emissions.
Bottom-up Isoprene
emissions, July 1996
MEGAN
3.6 Tg C
GEIA
7.1 Tg C
[1012 atom C cm-2 s-
1]
Guenther et al, JGR, 1995
EPA BEIS2
2.6 Tg C
Pierce et al, JGR, 1998
Guenther et al, ACP, 2006
E = A ∏iγi
Emissions (x,y,t); fixed base emissions(x,y); sensitivity parameters(t)
Global Ozone Monitoring Experiment (GOME) &the Ozone Monitoring Instrument (OMI)
• GOME (European), OMI (Finnish/USA) are nadir SBUV instruments• Ground pixel (nadir): 320 x 40 km2 (GOME), 13 x 24 km2 (OMI)• 10.30 desc (GOME), 13.45 asc (OMI) cross-equator time • GOME: 3 viewing angles global coverage within 3 days• OMI: 60 across-track pixels daily global coverage• O3, NO2, BrO, OClO, SO2, HCHO, H2O, cloud properties
Launched in 2004
GOME HCHO columns
July 2001
[1016 molec cm-
2]
0 1 20.5
1.5
2.5
Biogenic emissions
Biomass burning
* Columns fitted: 337-356nm * Fitting uncertainty < continental signals
Data: c/o Chance et al
May
Jun Jul Aug
Sep
1996
1997
1998
1999
2000
2001
GOME HCHO column [1016 molec cm-2]
0 1 20.5
1.5
2.5
Palm
er
et
al, JG
R,
2006.
Relating HCHO Columns to VOC Emissions
VOC HCHOhours
OH
hours
h, OH
Local linear relationship between HCHO and E
kHCHO
EVOC = (kVOCYVOCHCHO)HCHO
___________
VOC source
Distance downwind
HCHO Isoprene
-pinenepropane
100 km
EVOC: HCHO from GEOS-CHEM and MCM models
Palmer et al, JGR, 2003.
Net
MCM HCHO yield calculationsC
um
ula
tive H
CH
O y
ield
[p
er
C]
0 2 4 6 8 10 12 14 16 18 20 220.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
HC
HO
YIE
LD
PE
R C
RE
AC
TE
D
DAYS
NOX= 1 PPB NOX= 100 PPT
pinene
( pinene similar)DAYS
0.4
0 20 40 60 80 100 120 1400.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55C
umm
ula
tive
HC
HO
Yie
ld fr
om
iso
pren
e o
xid
atio
n (p
er C
)
TIME (HOURS)
NOX = 0.1 PPB
NOX =1 PPB
Figure 18. Formation of HCHO from isoprene. Vertical lines denote midnight of each day
Isoprene
HOURS
0.5NOx = 1 ppb
NOx = 0.1 ppb
Parameterization (1ST-order decay) of HCHO production from monoterpenes in global 3-D CTM
Higher CH3COCH3 yield from monoterpene oxidation delayed (and smeared) HCHO production
Palmer et al, JGR, 2006.
C5H8+OH(i) RO2+NOHCHO, MVK, MACR
(ii) RO2+HO2ROOH
ROOH recycle RO and RO2
Monthly mean AVHRR LAI
MEGAN (isoprene)Canopy model
Leaf ageLAI
TemperatureFixed Base factors
MODEL BIOSPHERE
GEIAMonoterpenes
MBOAcetoneMethanol
Modeling Overview
GEOS-CHEMGlobal 3D CTM
PAR, T
Emissions
MCM: parameterized HCHO source from monoterpenes and MBO
Seasonal Variation of Y2001 Isoprene Emissions
•Good accord for seasonal variation, regional distribution of emissions (differences in hot spot locations – implications for O3 prod/loss).
•Other biogenic VOCs play a small role in GOME interpretation
May
Jun
Aug
Sep
Jul
0 3.5
7
1012 atom C cm-2s-
1
GOME MEGAN MEGAN GOME
Palmer et al, JGR, 2006.
GOME Isoprene Emissions: 1996-2001May Jun Jul Aug Sep
1996
1997
1998
1999
2000
2001
[1012 molecules cm-2s-1]0 5 10
Relatively inactive
Palm
er
et
al, JG
R,
2006.
Isop
ren
e fl
ux [
10
12 C
cm
-2 s
-1]
Julian Day, 2001
MEGANObsGOME
Sparse ground-truthing of GOME HCHO columns and derived isoprene flux estimates
Seasonal Variation: Comparison with eddy correlation isoprene flux measurements (B. Lamb) is encouraging
Atlanta, GA
May Jun July Aug Sep
PAMS Isoprene, 10-12LT [ppbC]
GO
ME H
CH
O [
10
16 m
ole
c c
m-2]
1996 1997 1998 1999 2000 2001Interannual Variation:
Correlate with EPA isoprene surface concentration data. Outliers due to local emissions.
Atlanta, GA
PROPHET Forest Site, MI
Surface temperature explains 80% of GOME-observed variation in HCHO
NCEP Surface Temperature [K]
GO
ME H
CH
O S
lant
Colu
mn
[10
16 m
ole
c cm
-2]
G98 fitted to GOME data
G98 Modeled curves
Time to revise model parameterizations of isoprene emissions?
Palm
er
et
al, JG
R,
2006.
Tropical ecosystems represent 75% of biogenic NMVOC emissions
1996
1997
1998
1999
2000
2001
What controls the variability of NMVOC emissions in tropical ecosystems?
Importance of VOC emissions in C budget?
Kesselmeier, et al, 2002
GOME HCHO column, July
Challenges: Cloud cover, biomass burning, and lack of fundamental understanding of NMVOC emissions…
em
issio
n r
ate
(C
)(µ
g g
-1 h
-1)
PA
R(µ
mol m
-2 s
-1)
assim
ilati
on
(C
)(m
g g
-1 h
-1) 0
123456
limonene myrcene b-pinene a-pinene sabinene
500
1000
1500
00:0006:0012:00
18:0000:00
06:0012:00
18:0000:00
0
2
4
local time [hh:mm]
10
20
30
40
tem
pera
ture
[°C
]
0
2
4
G93
for
isop
.[s
um
of
mon
ote
rpen
es]
tran
sp
irati
on
(mm
ol m
-2 s
-1)
monoterpene emission of Apeiba tibourbou
OMI, 24/9-19/10, 2004
13x24 km2
TES data @ 6km, 11/04
O3
CO
MODIS Firecount
O3-CO-NO2-HCHO-firecount correlations import to utilize when looking at the tropics
Improved cloud-clearing algorithms and better spatial resolution data help.
TES data c/o Bowman, JPL
A more integrated approach to understanding controls of NMVOCs, e.g., surface data, lab data,
40
45
50
55
60
65
70
- 60 - 50 - 40 - 30 - 20 - 10 0 10
“Normal” airmass flow
44
46
48
50
52
54
56
- 20 - 15 - 10 - 5 0 5 10
Stagnant airmass flow
0
200
400
600
800
1000
1200
1400
27-Jul
29-Jul
31-Jul
2-Aug
4-Aug
6-Aug
8-Aug
10-Aug
12-Aug
14-Aug
16-Aug
18-Aug
20-Aug
22-Aug
24-Aug
26-Aug
28-Aug
30-Aug
0
5
10
15
20
25
30
35
40
Tem
pera
ture
(C
)
Isop
ren
e (
pp
t)
Estimated up to 700 extra deaths attributable to air pollution (O3 and PM10) in UK during this period
O3 > 100 ppb on 6 consecutive days
2pm, 6th Aug, 2003
Compiled from UK ozone network data
Isoprene c/o Ally Lewis
“Expect harmful levels of ozone and PM2.5 over the next couple of days; please keep small children and animals inside. Transatlantic pollution represents 20% of today’s UK surface ozone.”
2010
Resolution of new satellite data allows study UK AQ from space
SCIA NO2 @ 0.4x0.4o, Aug 2004
GOME NO2 @ 1x1o
Aug 1997
NAEI NOX emissions as NO2, 2002
GOME and SCIA NO2 c/o R. Martin; OMI (unofficial) NO2 c/o
T. Kurosu
Length
of
day
[hours
]
Day of Year
Edinburgh, 56N
Denver, 40N Cloud cover [%], ISCCP August 83-04
30 10070
OMI NO2 @ 0.1ox0.1o, Jul 2004
The increasing role of BVOCs: constraints from OMI HCHO?
Stewart et al, 2003Isoprene
MonoterpenesBVOC fluxes for a “hot, sunny” day
BOE:
0.5-1 ppb isoprene = 1-5x1012 molec cm-
2 s-1 (cf. SE USA 5-7x1012 molec cm-2 s-1)10
16 [m
ole
c cm-
2]
OMI HCHO2
<0.3
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
218.
00
218.
17
218.
33
218.
50
218.
67
218.
83
219.
04
219.
21
219.
38
219.
54
219.
75
219.
92
220.
08
220.
25
220.
42
220.
58
220.
75
220.
92
221.
08
221.
25
221.
42
221.
58
221.
75
221.
92
222.
13
222.
29
222.
46
222.
63
222.
79
222.
96
JDay
Rat
e N
O2
pro
du
ctio
n p
pb
h-1
NO
2 p
rod
ucti
on
pp
b h
-1
Isoprene HCHO
c/o Jenny Stanton
NO + RO2 NO2 + RO, Aug 2003
• Unclear what PM characteristics affect health
• Secondary PM is formed from:– Oxidation of organic
compounds
– Oxidation of SO2
– Difficult to estimate offline – need models and data
MISRSurface PM2.5 =
ModelSurface [PM2.5] x MISR AOT
Model AOT2003
roadside (primary)
PM10
MISR AOT can help estimate total PM2.5:
Space-based aerosol optical properties can help map emissions of particulate matter
Liu
et
al,
2004