Climate change projections and hydrological impacts
Climate change projections and hydrological impacts assessment in Central Asia Case study on three pilot areas in Central Asia PIK and CAREC Cooperation. Iulii Didovets, Anastasia Lobanova, Christoph Menz, Valentina Krysanova, Fred Hattermann
Aim of the project
temperature and precipitation trends in three pilot areas
To estimate
To evaluate
in qualitative terms risks to irrigated agriculture, pastures and disaster management in the districts
To assess
hydrological impacts of projected climate change in two river basins, the Aspara and Isfara;
To analyze
CLIMATE ADAPTATION AND MITIGATION PROGRAM FOR THE ARAL SEA BASIN (CAMP4ASB) Project AIMS:
the existing framework for climate impact assessment and perform knowledge gap analysis
Pilot areas
Methodology
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Input data for hydrological modeling Land Use GlobeLand30 DEM SRTM 90m resolution
Soil Map HWSD, 1 km resolution
Climate data WATCH Era40 Product
Discharge GRDC Database, only for Isfara
Climate change projections CORDEX Database CORDEX is a scientific community based initiative to provide dynamically downscaled CMIP5 simulations. Freely available on the Internet. 16 different domains, including Central Asia, number of simulations depends on the domain considered
ISI-MIP Database ISI-MIP database contains simulations of selected CMIP5 GCMs which were later interpolated to a 0.5 deg grid and biascorrected to the WATCH Era40 re-analysis product
Model Calibration for Isfara River • •
Very sensitive to snowmelt parameters The WATCH Era40 has to be checked
Period
NSE
RVE
Full (1963‐1991)
0.66
2.4
Nash–Sutcliffe (NSE) efficiency can range from −∞ to 1. An efficiency of 1 (E = 1) corresponds to a perfect match
Calibration (1965‐1980)
0.66
‐4.9
RVE can range from −∞ to +∞, 0 is a
Validation (1981‐1991)
0.63
14.1
perfect fit
Climate projections fitting of WATCH Era40 • •
ISI‐MIP ‐ perfect fitting, as bias‐corrected to this dataset CORDEX comparison shows significant biases in the Isfara and Aspara Regions, especially in the mountainous regions Precipitation
Temperature
Climate projections for the pilot areas. Aspara RCP 2.6 Precipitation CORDEX
Precipitation ISI-MIP
RCP 8.5
Climate projections for the pilot areas. Aspara RCP 2.6 Temperature CORDEX
Temperature ISI-MIP
RCP 8.5
Climate projections for the pilot areas. Priaralye RCP 2.6 Precipitation CORDEX
Precipitation ISI-MIP
RCP 8.5
Climate projections for the pilot areas. Priaralye RCP 2.6 Temperature CORDEX
Temprature ISI-MIP
RCP 8.5
Hydrological impacts of projected climate change Aspara River, CORDEX •
Discharge deviations, expressed in % with respect to the reference period
RCP 2.6
RCP 8.5
Hydrological impacts of projected climate change Aspara River, ISI-MIP •
Discharge deviations, expressed in % with respect to the reference period RCP 2.6
RCP 8.5
Selected indicators for quantification of the risks associated with the impacts of projected climate change •
Aim: to quantify risks, associated with the projected climate change to agriculture, disaster management and pastures
•
Due to constraint ‐> decided to concentrate on Temperature related indicators 9HJHWDWLRQ SHULRG IRU & DQG & SODQWV 7 H[FHHGLQJ DQG GHJUHHV H[WUHPH KHDW HYHQWVHJGD\V ZLWK GDLO\ 7 ! GHJUHHV
Qualitative analysis RISURMHFWHGFKDQJHVLQULYHU GLVFKDUJHYVH[LVWLQJFURSSLQJ LUULJDWLRQSDWWHUQVLQWKHSLORWDUHDV
Duration of vegetation period •
The C3 and C4 vegetation periods are expected to extend in all pilot areas , as a direct consequence of the increase in temperatures
•
The prolongation depends strongly on the climate change scenario. At the end of the century under RCP8.5 the starting date will be shifted up to one month earlier and the ending date up to one month later Aspara, C3 CORDEX
ISI-MIP
Priaralye, C3
Conclusions for the pilot areas
No or minor (or uncertain) trends in the precipitation for all pilot areas
Strong increase in the temperature for the areas, reaching up to plus 6 ‐ 7 degrees under RCP8.5
Large multi‐model spreads in the precipitation simulations indicate model disagreement
Poor quality of the CORDEX Projections
The snowmelt processes are very important ‐> the temperature increase has a big influence
Increase in temperature may lead to increased evapotranspiration rates but at the same time may also lead to higher sums of effective temperatures of crops for the same period of time, and could shorten the ripening periods of crops
The prolongation of the vegetation period and shift of high flows to an earlier period may offer some room for adaptation, potentially also more time for cattle grazing, but depends on the condition of the pastures
Conclusions for the pilot areas Aspara:
•
• • •
•
Isfara:
•
• • •
Priaralye:
•
• •
Increase of water flow in April‐March, decrease in Jul‐September ‐> during the vegetation period possibly the existing cropping patterns have to be revised and altered, as the water resources will decrease during the vegetation period Extreme heat events only slight change in the future Moderate decrease of the low flows may signal for increased frequency of droughts Slight increase in the high flow segment ‐> the amount of water for irrigation but also can signal about the possible increase in the high flow events Contradicting projections from CORDEX and ISI‐MIP: but both indicate increase in the discharge in March‐April The winter cereals are better off in the case of discharge increase in the spring period Rise in extreme heat events may negatively impact the crop yields Likely a strong decrease in the low flow quantiles ‐> less water for irrigation, possibly droughts, the DRR strategy has to be re‐considered Reduction of high flows would lead also to problems with reservoir fillings No modelling was done, but the revision of the recent studies revealed similar trends as in the Isfara and Aspara River, shifts of the high flow period to an earlier date and overall reduction in the discharge Strong rise in extreme heat events may negatively impact the crop yields Rice and cotton may suffer more often from water stress in the future, as discharge of the Amu Darya would very likely decrease.
Thank you for your attention!
Informational and technological gaps for improving the climate change impact assessment frameworks at the regional scale •
Better climate projections and better model calibration, especially for an improved understanding of hydrological extremes
•
Observed climate data is needed to verify the synthetically generated observational datasets, like WATCH Era40
•
Hydrological data is needed for better model calibration and verification Soil data: finer resolution data is needed, with information on the soil depth
•
Data on cropping patterns is needed
•
Water management data: it is possible to include them in the SWIM Model, which could then become a DSS tool for river basin managers
Aim of the project
temperature and precipitation trends in three pilot areas
To estimate
To evaluate
in qualitative terms risks to irrigated agriculture, pastures and disaster management in the districts
To assess
hydrological impacts of projected climate change in two river basins, the Aspara and Isfara;
To analyze
CLIMATE ADAPTATION AND MITIGATION PROGRAM FOR THE ARAL SEA BASIN (CAMP4ASB) Project AIMS:
the existing framework for climate impact assessment and perform knowledge gap analysis
Pilot areas
Methodology
6HOHFWHG 5&3V
,QSXW'DWD )RU6HWXS
,6,0 ,33URMHFWLRQV &2 5'(;3URMHFWLRQV
$QDO\VLVRI +\GURORJLFDO ,P SDFWVRI&OLP DWH FKDQJHDQG DVVRFLDWHGULVNV
5HVXOWV
6: ,0
Input data for hydrological modeling Land Use GlobeLand30 DEM SRTM 90m resolution
Soil Map HWSD, 1 km resolution
Climate data WATCH Era40 Product
Discharge GRDC Database, only for Isfara
Climate change projections CORDEX Database CORDEX is a scientific community based initiative to provide dynamically downscaled CMIP5 simulations. Freely available on the Internet. 16 different domains, including Central Asia, number of simulations depends on the domain considered
ISI-MIP Database ISI-MIP database contains simulations of selected CMIP5 GCMs which were later interpolated to a 0.5 deg grid and biascorrected to the WATCH Era40 re-analysis product
Model Calibration for Isfara River • •
Very sensitive to snowmelt parameters The WATCH Era40 has to be checked
Period
NSE
RVE
Full (1963‐1991)
0.66
2.4
Nash–Sutcliffe (NSE) efficiency can range from −∞ to 1. An efficiency of 1 (E = 1) corresponds to a perfect match
Calibration (1965‐1980)
0.66
‐4.9
RVE can range from −∞ to +∞, 0 is a
Validation (1981‐1991)
0.63
14.1
perfect fit
Climate projections fitting of WATCH Era40 • •
ISI‐MIP ‐ perfect fitting, as bias‐corrected to this dataset CORDEX comparison shows significant biases in the Isfara and Aspara Regions, especially in the mountainous regions Precipitation
Temperature
Climate projections for the pilot areas. Aspara RCP 2.6 Precipitation CORDEX
Precipitation ISI-MIP
RCP 8.5
Climate projections for the pilot areas. Aspara RCP 2.6 Temperature CORDEX
Temperature ISI-MIP
RCP 8.5
Climate projections for the pilot areas. Priaralye RCP 2.6 Precipitation CORDEX
Precipitation ISI-MIP
RCP 8.5
Climate projections for the pilot areas. Priaralye RCP 2.6 Temperature CORDEX
Temprature ISI-MIP
RCP 8.5
Hydrological impacts of projected climate change Aspara River, CORDEX •
Discharge deviations, expressed in % with respect to the reference period
RCP 2.6
RCP 8.5
Hydrological impacts of projected climate change Aspara River, ISI-MIP •
Discharge deviations, expressed in % with respect to the reference period RCP 2.6
RCP 8.5
Selected indicators for quantification of the risks associated with the impacts of projected climate change •
Aim: to quantify risks, associated with the projected climate change to agriculture, disaster management and pastures
•
Due to constraint ‐> decided to concentrate on Temperature related indicators 9HJHWDWLRQ SHULRG IRU & DQG & SODQWV 7 H[FHHGLQJ DQG GHJUHHV H[WUHPH KHDW HYHQWVHJGD\V ZLWK GDLO\ 7 ! GHJUHHV
Qualitative analysis RISURMHFWHGFKDQJHVLQULYHU GLVFKDUJHYVH[LVWLQJFURSSLQJ LUULJDWLRQSDWWHUQVLQWKHSLORWDUHDV
Duration of vegetation period •
The C3 and C4 vegetation periods are expected to extend in all pilot areas , as a direct consequence of the increase in temperatures
•
The prolongation depends strongly on the climate change scenario. At the end of the century under RCP8.5 the starting date will be shifted up to one month earlier and the ending date up to one month later Aspara, C3 CORDEX
ISI-MIP
Priaralye, C3
Conclusions for the pilot areas
No or minor (or uncertain) trends in the precipitation for all pilot areas
Strong increase in the temperature for the areas, reaching up to plus 6 ‐ 7 degrees under RCP8.5
Large multi‐model spreads in the precipitation simulations indicate model disagreement
Poor quality of the CORDEX Projections
The snowmelt processes are very important ‐> the temperature increase has a big influence
Increase in temperature may lead to increased evapotranspiration rates but at the same time may also lead to higher sums of effective temperatures of crops for the same period of time, and could shorten the ripening periods of crops
The prolongation of the vegetation period and shift of high flows to an earlier period may offer some room for adaptation, potentially also more time for cattle grazing, but depends on the condition of the pastures
Conclusions for the pilot areas Aspara:
•
• • •
•
Isfara:
•
• • •
Priaralye:
•
• •
Increase of water flow in April‐March, decrease in Jul‐September ‐> during the vegetation period possibly the existing cropping patterns have to be revised and altered, as the water resources will decrease during the vegetation period Extreme heat events only slight change in the future Moderate decrease of the low flows may signal for increased frequency of droughts Slight increase in the high flow segment ‐> the amount of water for irrigation but also can signal about the possible increase in the high flow events Contradicting projections from CORDEX and ISI‐MIP: but both indicate increase in the discharge in March‐April The winter cereals are better off in the case of discharge increase in the spring period Rise in extreme heat events may negatively impact the crop yields Likely a strong decrease in the low flow quantiles ‐> less water for irrigation, possibly droughts, the DRR strategy has to be re‐considered Reduction of high flows would lead also to problems with reservoir fillings No modelling was done, but the revision of the recent studies revealed similar trends as in the Isfara and Aspara River, shifts of the high flow period to an earlier date and overall reduction in the discharge Strong rise in extreme heat events may negatively impact the crop yields Rice and cotton may suffer more often from water stress in the future, as discharge of the Amu Darya would very likely decrease.
Thank you for your attention!
Informational and technological gaps for improving the climate change impact assessment frameworks at the regional scale •
Better climate projections and better model calibration, especially for an improved understanding of hydrological extremes
•
Observed climate data is needed to verify the synthetically generated observational datasets, like WATCH Era40
•
Hydrological data is needed for better model calibration and verification Soil data: finer resolution data is needed, with information on the soil depth
•
Data on cropping patterns is needed
•
Water management data: it is possible to include them in the SWIM Model, which could then become a DSS tool for river basin managers
