Climate change impacts on groundwater and stream discharge in Denmark

Transcription

1 Climate change impacts on groundwater and stream discharge in Denmark Lieke van Roosmalen Dept. of Geography and Geology University of Copenhagen Contributions by: M.B. Butts, B.S.B. Christensen, J.H. Christensen, K.H. Jensen, J.C. Refsgaard, T.O. Sonnenborg. Identifying water and climate related topics for research DWF/VIVA meeting 13 March 2009

2 Sensitivity to climate change Objective:To get a better understanding of how future climate change can affect hydrological systems in Denmark. Main focus: groundwater Common assumption: other system characteristics remain the same Requires a thorough understanding of the system and a robust representation of the most significant processes? INPUT OUTPUT

3 Study area Zealand Jutland 5459 km km 2

4 Observed climate ( ) in Denmark Jutland: P ann = 1073 mm, PET ann = 570 mm Zealand: P ann = 762 mm, PET ann = 611 mm

5 Geology study areas Altitude (m) Jutland -100 Sea Quaternary clay Quaternary sand Miocene quartz sand Miocene mica sand Pre-Quaternary clay and silt Altitude (m) 50 0 Zealand Sea Fractured clayey till Quaternary clay Quaternary sandy clay Quaternary sand Limestone and chalk

6 National Water Resource Model MIKE-SHE model code Physically-based, deterministic model Integrated groundwater/ surface water model Grid resolution 500 m Comprehensive 3D groundwater component Distributed recharge

7 Downscaling and bias correction of GCM data Statistical downscaling regression statistical relations between air pressure, circulation, T from GCM and precipitation (weather typing) weather generators delta change method using GCM data Dynamical downscaling Regional Climate Models (RCMs) delta change method using RCM data

8 Regional climate model HadAM3H HIRHAM4 Δx = 12 km

9 Emissions scenario

10 Pyramid of uncertainties Change in mean groundwater head Hydrological model structure and parameterization Downscaling and bias correction method Regional climate model Emissions scenario GCM Uncertainty range

11 Observed and RCM precipitation Observed Precipitation Simulated

12 Biases in annual HIRHAM output Temperature bias Precipitation bias (mm) Ref. evapotranspiration bias (mm) 0.7 C -87 mm (11%) 9 mm (2%)

13 Biases in monthly RCM precipitation

14 Delta change method Climate model output Current Climate Monthly Output delta factor Future P,T,ET Climate Output Hydrological model input Monthly delta factor Observed Future Database Database P,T,ET P,T,ET P ( i, j) ( j)* P ( i, j) P obs where P ( j) P P scen cont ( ( j) j) T ( i, j) T ( i, j) ( j) obs T where ( j) T scen( j) T cont( j) T

15 ETref (mm) Precipitation (mm) Temperature ( C) Meteorological input to hydrological model current J F M A M J J A S O N D Month current J F M A M J J A S O N D Month current J F M A M J J A S O N D Month

16 Delta change value Delta change value Comparison with other RCMs 1.6 Precipitation Precipitation 4.8 Temperature Temperature J F M A M J J A S O N D Month 2.0 J F M A M J J A S O N D Month

17 Annual climate input Jutland Zealand Present Present climate climate P (mm) (12%) (16%) (9%) (14%) T ( C) (3.2) (2.3) (3.1) (2.2) ET ref (mm) (19%) 649 (14%) (19%) 695 (14%)

18 Recharge (mm/day) Recharge Mean annual recharge (mm) Present Jutland (13%) 708 (22%) Zealand (14%) 366 (27%) 6,0 5,0 Jylland 4,0 3,0 2,0 1,0 0,0-1,0 Present J F M A M J J A S O N D Month

19 Groundwater head - Jutland Change in mean annual groundwater head in primary aquifer (m) Change in head (m)

20 Groundwater head - Zealand Change in mean annual groundwater head in primary aquifer (m) Change in head (m)

21 discharge (m3/s) relative change (%) Stream discharge - Zealand Sjaelland station current Sjaelland station J F M A M J J A S O N D 0 J F M A M J J A S O N D month month

22 Irrigation (Mm 3 ) Effects on irrigation in Jutland Current Irrigation (10 6 m 3 ) (89%) 148 (50%) Mean annual irrigation Mean monthly irrigation Year

23 Thanks for your attention! Contact information: Lieke van Roosmalen Department for Geography and Geology, University of Copenhagen Øster Voldgade Copenhagen K Denmark tel. nr: lvr@geo.ku.dk References: van Roosmalen, L., Christensen, B.S.B., Sonnenborg, T.O., Regional differences in climate change impacts on groundwater and stream discharge in Denmark. Vadose Zone J. 6, , doi: /vzj van Roosmalen, L., Sonnenborg, T.O., Jensen, K.H., The impact of climate and land use change on the hydrology of a large-scale agricultural catchment. Water Resources Research (in press)