Accuracy assessment of gridded precipitation Datasets in ... · University of Cambridge...

University of Cambridge

engrasif_civil@yahoo.com

Asif Khan

Post Doctorate (IIASA, Austria)

Ph.D (Cambridge, UK)

Accuracy assessment of gridded precipitation

Datasets in the HKH region

Academics:

Post Doctorate (Water-Energy-Food-Climate)

PGS in GIS and RS

EMBA Project Management

B.Sc Civil Engineering

PhD in Water and Climate

Current/Past Affiliations:

OutlineImportance of hydrological modelling in various regions of the

Why accurate hydrological modelling is vital in the Indus

Basin?

Gridded precipitation products, their variability and constraints

Accuracy assessment of various gridded precipitation

products

Conclusions and Recommendations

Questions and Answers Session

Global challengeso Population growth

o Global warming and climate change

Increased population will need more: i) water supply, ii) food production, iii) energy

production/supply, iv) flood and drought mitigation, v) urbanization, and

v) industrial development

Source: UN: facts and trends (2006)

Importance of Hydrological Modelling

Global challengeso Population growth

o Global warming and climate change

Global mean surface temperature increased by 0.74 +/- 0.18 °C during 1906-2005, while

projected expected increase is 1.4 to 5.8 °C during 1990 to 2100 (IPCC 2007, 2013)

Source: (Inman 2010)

Global warming is causing glacier retreat,

Severity in floods and droughts,

Increasing water scarcity,

Increasing slope instability and landslides,

Increasing Glacier Lake Outburst Floods (GLOFs)

Reservoir sedimentation,

Forest fires, and

Increasing water losses/evapotranspiration

1/5th of the global population lives in basins of the Himalayas (Asia)

engrasif_civil@yahoo.com1

Potential Adaptation/Mitigation measures

Decline in Green House Gas (GHG) emissions,

Construction of new irrigation, hydro-power groundwater recharge dams,

Renewable energy exploitation (hydropower, Bio fuel, solar and wind energy)

Adaptation of improved irrigation practices,

Adaptation of sustainable agricultural practices,

Precise and accurate policy making against floods and droughts,

Afforestation, and

Preparation of climate change adaptation strategies and policies

Hydrological Modelling Constraints

in the Upper Indus Basin

Constraints: variability in modelled flows

Constraints: potential causes

Use of different hydrological models

Use of different time period data

Use of different input datasets

Basin Boundaries

Precipitation Datasets

Snow-cover Datasets

Glacier-cover Datasets

Snow and ice-melt parameters

Calibration Parameters

Thus, improved hydro-climatic modelling is needed

Most important factor is accuracy of input precipitation datasets and glacier data

What is needed?

Potential Causes: use of different precipitation datasets

Data sets and Analysis:

Measured flow of six sub-basins

Average actual evapotranspiration based on 04 data sets

Average groundwater recharge based on 03 data sets

Average groundwater abstraction based on 02 data sets

Average glacier net-mass balance contributions to flows based on 05 datasets

Average potential evapotranspiration based on 05 data sets

𝑄 = 𝑃 − 𝐸𝑇𝑎𝑐𝑡 ± 𝐺𝑀 − 𝑛𝐺𝑊𝑅 ± ∆𝑆

Accuracy of 12 Gridded precipitation data sets (1999-2010) and 05

GCMs precipitation data (1986-1998) have been evaluated based on

mass balance relationship:

Results and Discussion: Precipitation Accuracy Assessment

Precipitation data sets

Precipitation datasets accuracy assessment

Results and Discussion: Precipitation Accuracy Assessment

Climatic stations density in

APHRODITE data based on

number of stations in 0.05o grid

Climatic stations density in

CRU TS 3.1 data based on

number of stations in 0.5o grid

Uncertainty in existing studies

Snowmelt runoff modelling

Uncertainty in existing studies

Constraints: variability in flow components

Hunza basin (Karakoram)

Astore basin (Himalayas)

ISI-MIP precipitation and modelled flow

Modelled monthly flows (ISI-MIP)

ISI-MIP water scarcity

FAO water scarcity

engrasif_civil@yahoo.comFig: variability in modelled flows

Climatic models precipitation (e.g., JRA 55) provide better precipitation in the

UIB compared to precipitation data based on climatic stations (e.g.,

APHRODITE)

Accuracy of available gridded precipitation datasets can be improved by using

additional available climatic stations data, together with installation of new

stations in the UIB (at least)

Modelled flows of ISI-MIP models are far less than measured flows in all sub-

basins of the UIB, except the Kharmong basin, and are mainly due to use of

underestimated precipitation

FAO water scarcity overestimation in the UIB is an artefact produced by CRU

underestimated precipitation, which lead to low modelled surface water

Extreme caution is deemed necessary to interpret global hydro-climatic

studies results without prior validation at regional scale, particularly in complex

mountain regions such as the HKH basins

In the HKH region hydro-climatic studies can be improved by using

appropriate hydrological models together with best available precipitation data

sets, JRA 55 and ERA interim for the UIB, although some precipitation bias

correction is inevitable at sub-basin level

Precipitation is one of the vital source of biased results, therefore other

sources of biases in the discussed and other hydro-climatic studies need to be

investigated

Model better today……Live better in future

Animation source: http://www.amazing-animations.com/animated-thanks6.php

Animation source: http://www.netanimations.net/Moving_Animated_Question_Marks_And_Exclamation_Point_Gif_Animations.htm

Accuracy assessment of gridded precipitation Datasets in ... · University of Cambridge...

Documents

GEOS-4 File Specification - GMAO - Global Modeling and … · 2012-06-12 · File Specification for GEOS-5 DAS Gridded Output Global Modeling and Assimilation Office ... • EFLUX

GRIDDED MOS TECHNIQUES, STATUS, AND PLANS

Global gridded precipitation over land: a description of ... · The Global Precipitation Climatology Centre (GPCC) was founded in 1989 and is operated by Deutscher Wetterdienst (DWD)

GRIDDED MOS - Weather

Global land-based gridded datasets of climate extremes indices …€¦ · Global land-based gridded datasets of climate extremes indices (ETCCDI) Markus Donat –and many others

A climatology of global aerosol mixtures to support ...seom.esa.int/atmos2015/files/presentation38.pdf · 4 Interpretation The gridded global multiyear mean and seasonal partitions

The Global Gridded Crop Model Intercomparison: data and … · 2020. 6. 23. · J. Elliott et al.: The Global Gridded Crop Model Intercomparison 263 Table 2. Priority 1 and 2 crops

Observations on WAFS Gridded Forecasts

A new global gridded data set of CO2 emissions from fossil

Global gridded crop model evaluation: …...1404 C. Müller et al.: Global gridded crop model evaluation Abstract. Crop models are increasingly used to simulate crop yields at the

National Aeronautics and Space Administration Soil …...Product Overview Product Attributes - Gridded version of time-ordered L1BTB - Gridded at 36 km on - Global Cylindrical EASE-Grid

Gridded Population of the World Version 4 (GPWv4) · 2016. 6. 3. · Gridded Population of the World • Gridded (raster) data product developed to provide a spatially-disaggregated

The Global Gridded Crop Model Intercomparison: data and ... · J. Elliott et al.: The Global Gridded Crop Model Intercomparison 263 Table 2. Priority 1 and 2 crops in Phase 1, along

Emulating maize yields from global gridded crop models ... · economic and social implications of policy alternatives. ... Emulating maize yields from global gridded crop models using

Gridded Population of the World

MESSIR-AERO & the Gridded Forecasts This presentation will show some MESSIR-AERO outputs for: Global Gridded Elements (wind direction, temperature...)

THE GRIDDED ELECTROMAGNET PROBE

OPEN Data Descriptor: High resolution global gridded data

The Global Gridded Crop Model Intercomparison...Ag-GRID • Organizing hub for gridded crop modeling and data within AgMIP. • Includes >18 modeling groups so far and >10 data partners

OPenpopgrid: An open gridded population dataset for ...openpopgrid.geodata.soton.ac.uk/OpenPopGrid_ProductDocumentatio… · Why do we need an Open Gridded Population dataset?