Från nederbörd till flöden: Vad är avgörande i processen?

Transcription

1 Från nederbörd till flöden: Vad är avgörande i processen? Georgia Destouni Fernando Jaramillo, Carmen Prieto, Ype van der Velde, Steve Lyon

2 Variabilitet och förändringar i hydroklimat - vattenfödens långtidsstatistik Problem och frågeställning Specifik studie och resultat Rum-tid-, dåtid-framtid-, modell-observationsanalys & jämförelser Implikationer

3 Hydroklimat & vattenmiljöer ändras

4 Fundamental needs to understand change drivers-impacts for variety of reasons Climate: Temperature Precipitation P Evapotranspiration ET Land-Water Use Changes to statistics of water flow partitioning and variability (extreme event likelihood)?? Runoff R distributed across different pathways Groundwater flow & pollutants Surface water flow & pollutants Interacting fresh-sea water flows & pollutants

5 Freshwater flows and their partitioning Relatively readily observable T P Calculated in different ways physically constrained by water balance in basins / catchments ET wb =P-R- S R S

6 Changes to the flows and their partitioning different change drivers Climate change Natural Anthropogenic T P ET wb =P-R- S Distinguishable?? Other anthropogenic change R in the landscape S

7 Change drivers - distinguished from -long-term observation data - basin-scale water balance constraints Different land-water uses Comparative irrigated regional basins T Start 20 th century P End 20 th century Destouni et al. (2012, Nature Climate Change)

8 Water flow (R) changes not uniquely given from climate (P) changes R change Destouni et al. (2012, Nature Climate Change) P change Distinct shifts in temporal R variability for catchments with different land-water uses 1:1 Agriculture, Hydropower Decreased / Unchanged R under P Increase R change regulated by ET shifts - driven by land-water use changes

9 Change drivers - distinguished from -long-term observation data - basin-scale water balance constraints Different land-water uses Comparative irrigated regional basins T Start 20 th century Basin example P End 20 th century Destouni et al. (2012, Nature Climate Change)

10 Example: Climate development in Norrström catchment T at different times, observed and modeled: Expected future change magnitude already occurred in 20th century basin-scale analysis shows what it meant for water flow changes Observed Observed Modelled Modelled Van der Velde et al. (2012, in preparation) 24 regional climate models (RCMs; ENSEMBLES archive (

11 P Increased precipitation R Decreased runoff Example: Climate and water flow development in Norrström basin T Increased temperature Shifted evapotranspiration ET wb =P-R(- S) Destouni et al. (2012, Nature Climate Change)

12 Relative insensitivity of shift in long-term Et wb to different S assumptions

13 Solid lines: ET wb =P-R Dashed lines: Calculations of ET based only on T and P Agricultural basins Hydropower basins Control unregulated - basins

14 ET wb shifts coincide with distinct shifts in temporal R variability for different land-water uses Unregulated catchments fluctuations but no shifts in CV(R) unchanged likelihood of extreme R Hydropower catchments shifteddecreased CV(R) contributing to decreased likelihood of extreme R Agricultural catchments shiftedincreased CV(R) contributing to increased likelihood of extreme R Destouni et al. (2012, Nature Climate Change)

15 Typical co-developments in unregulated basins ET wb and CV(R) Typical codevelopments in hydropower basins ET wb, CV(R) and hydropower Typical codevelopments in agricultural basins ET wb, CV(R) and agriculture Destouni et al. (2012, Nature Climate Change)

16 Land cover data for Sweden Data-given ET indicators for different land cover types across Sweden ET / P Land cover development pathways drive water flow changes Energy use efficiency AET/PET ET / PET van der Velde et al. (2012, in review)

17 Changes to inland water flow partitioning Climate change Natural Anthropogenic T P ET wb =P-R- S Other anthropogenic change Distinguishable - and should be distinguished R in the landscape S

18 Models need further development for improved account of different types of anthropogenic change drivers across different scales and regions

19 Modelled vs Observed Change Trends in Sweden Blue: observation data T P ET R Green: model average Gray: model spreading model results from 24 regional models (RCMs; ENSEMBLES archive ( van der Velde et al. (2012, in review)

20 Vattnet i landskapet: 1.Interagerar med alla andra geosystem, samhället och ekosystem som koherent egen sfär Weather and climate Land and ice Coast and sea Pollution and health Inland water Ecosystems Management Food Water utilities Energy G. Destouni

21 Förändringar i landskapets vatten: 2. Flödesprocesserna och partitioneringen genom den koherenta sfären + interaktionerna med andra sfärer och samhället Coast and sea Weather and climate Land and ice Pollution and health Inland water Ecosystems Management Flow and transport Food Water utilities Energy G. Destouni