Regional-scale model intercomparison project & related pilot projects at PIK (SWIM group)

Transcription

1 Regional-scale model intercomparison project & related pilot projects at PIK (SWIM group) Valentina Krysanova & Fred Hattermann Potsdam Institute for Climate Impact Research

2 Model intercomparison SWIM modelling group at PIK is now involved in the intercomparison of impact models, which is ongoing for global and regional-scale models and for several sectors (following the intercomparison of climate models) project ISI-MIP*. Assessment of climate change impacts using globalscale models is necessary to provide information for the global policy makers. However, it is not sufficient for decision makers at the regional scale, where impacts occur and adaptation strategies are designed. Bridging the scales between global and regional impact research is needed. * Inter-Sectoral Impact Model Intercomparison Project

3 Regional-scale model intercomparison - how to do? It can be done as a top-down approach, if hot spots are identified at the global or continental level, and then investigated further by zooming in with the validated regional models. It can also follow a bottom-up approach, if the outputs of regional models are aggregated and compared with the global results either to increase the reliability of global analysis, or to identify problematic areas that need further research. Therefore, projections of climate impacts must be provided at the regional scale more systematically, and intercomparison of regional impact models is important to assure the robustness of simulated impacts.

4 Regional MIP, water sector: participants Modelling group leaders Institution Country 1 Valentina Krysanova, Fred Hattermann PIK Germany 2 Raghavan Srinivasan and Prasad Daggupati TAMU USA 3 Ann van Griensven VUB Belgium 4 Lutz Breuer and Jeff Exbrayat IFZ, UNSW Germany+Australia 5 Helge Bormann SU Germany 6 Alexander Gelfan, Motovilov, Krylenko WPI Russia 7 Chantal Donnelly, Berit Arheimer SMHI Sweden 8 Martin Volk UFZ Germany 9 Mikołaj Piniewski, Tomasz Okruszko WULS Poland 10 Ad De Roo, Luc Feyen JRC Italy 11 Antonio Lo Porto IRSA Italy 12 Tao Yang HU China 13 Martina Flörke, Stephanie Eisner CESR Germany 14 Su Buda, Jiang Tong NCC China 15 Luis Samaniego UFZ Germany 16 Ben Livneh CIRES USA

5 Models to be applied (11) Modelling group leader(s) Country Model(s) 1 Valentina Krysanova, Fred Hattermann Germany SWIM 2 Raghavan Srinivasan & Prasad Daggupati USA SWAT 3 Ann van Griensven Belgium SWAT 4 Lutz Breuer and Jeff Exbrayat Germany+Australia LASCAM, HBV 5 Helge Bormann Germany UHP 6 Alexander Gelfan, Motovilov, Krylenko Russia ECOMAG 7 Chantal Donnelly, Berit Arheimer Sweden HYPE 8 Martin Volk Germany SWAT 9 Mikołaj Piniewski, Tomasz Okruszko Poland SWAT 10 Ad De Roo, Luc Feyen Italy LISFLOOD 11 Antonio Lo Porto Italy SWAT 12 Tao Yang China VIC, HBV 13 Martina Flörke, Stephanie Eisner Germany WaterGAP 14 Su Buda, Jiang Tong China SWAT, SWIM, HBV, VIC 15 Luis Samaniego Germany mhm 16 Ben Livneh USA VIC

6 Choice of River Basins for modelling: all discussed

7 Six confirmed focus regions of ISI-MIP

8 11 River Basins for water sector intercomparison, regional scale

9 11 Basins and Gauges Gauge Drainage area Rhine Rees or Lobith km2 Tagus Almourol km2 Niger Dire or Lokoja km2 or km2 Ganges Farakka km2 Yellow (upper) Tangnaihai km2 Yangtze (upper) Pingshan km2 Mississippi (upper) Alton, Il km2 Murray-Darling Louth km2 Blue Nile Khartoum km2 Lena Stolb km2 Amazon (upper) Sao Paulo de Olivenca km2

10 Basins and Models SWIM WaterGAP mhm HBV LASCAM HYPE SWAT LISFLOOD UHP VIC ECOMAG No. of models Rhine X X X X X X X X X X 10 Tagus X X X 3 Niger X X X X X X X X X 9 Blue Nile X X X X X 5 Ganges X X X X X X X 7 Yellow (up) X X X X X X X 6 Yangtze (up) X X X X 4 Lena X X X X X 5 Mississippi (up) X X X X X X X X 8 Amazon X X X X 4 Murray D. X X X X 4 Total

11 Three pilot studies at PIK related to model intercomparison 1. Intercomparison of impact for four large basins in Africa: V. Aich, S. Liersch, Sh. Huang, T. Vetter, J. Tecklenburg et al. 2. The 3 x 3 x 3 study: intercomparison of impacts using 3 models in 3 basins on 3 continents T. Vetter, Sh. Huang, T. Yang et al. 3. Bridging the scales: intercomparison of global and regional impacts: F. Hattermann, V. Krysanova, Ch. Müller et al.

12 1. African intercomparison To be presented by Valentin Aich

13 3 x 3 x 3 study: river basins Rhine 170 Tkm m AvT=8.6 C AvP=987mm Upper Yellow 110 Tkm m AvT=-2 C AvP=520mm Niger 122 Tkm m AvT=26.5 C To prepare map: AvP=1495mm Lasse

14 3 x 3 x 3 study: Impact on seasonal dynamics: Rhine difference

15 3 x 3 x 3 study: Impact on seasonal dynamics: Niger difference

16 3. Bridging the scales: models SWIM: regional eco-hydrological model combining the relevant processes at the mesoscale such as runoff generation, nutrient and carbon cycling, river discharge, plant growth and crop yield, and erosion. LPJmL: global vegetation and water model simulating vegetation composition and distribution as well as stocks and land-atmosphere exchange flows of carbon and water, for both natural and agricultural ecosystems. Water-GAP global hydrological model is concerned with the various impacts of global change on water availability and water demand. ISI-MIP 12 global-scale hydrological models.

17 Bridging the scales two basins Rhine Upper Niger

18 Comparison of seasonal dynamics for the reference period Rhine LPJ slightly different dynamics, but it was not calibrated

19 Impact relative changes until 2099 Rhine Impacts produced by all 3 models are quite similar!

20 Comparison of seasonal dynamics for the reference period Niger SWIM output is close to observations WaterGAP and LPJ produce outputs quite different (!!!) from the observed Q, with peak coming too early (as no wetlands in models)

21 Impact relative changes until 2099 Niger SWIM results differ from the results by LPJ and WaterGAP (and probably are more reliable?) A possible reason: no wetlands in LPJ and WatrGAP.

22 Intercomparison of impacts Rhine HMs results differ very much from the observed Q SWIM, WaterGAP validated (and probably are more reliable), and produce similar sígnals LPJ not validated, signal differs Relative change as resulting from 12 HMs, SWIM and WaterGAP are similar

23 Intercomparison of impacts HMs results differ very much from the observed Q Niger SWIM, WaterGAP validated, and produce similar sígnals with high uncertainty due to CM LPJ not validated, signal very uncertain Relative change as resulting from 12 HMs, SWIM and WaterGAP are similar

24 Conclusions from the pilot studies WATCH data can be used for calibration, though they should be checked for bias (especially RAD); Uncertianty bands in impacts related to HM are lower compared to that related to CM (opposite to ISI-MIPglobal): to be investigated further; Comparison of impacts produced by global and regional models shows that: the absolute values can be critical if the model was not validated (often the case for global-scale models), hence, the use of absolute values for further studies (e.g. hotspots, irrigation) should be restricted; still, the results in terms of relative changes can be comparable (found for the studied basins), Zooming with the validated regional models can improve the quality of impact assessment.

25 Intercomparison for 11 river basins starts now

26 Welcome to the regional-scale model intercomparison project!