Laboratory for Mathematical Modelling of Environmental and...
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0 200 400 600 800 1000 1200 1400 1600 0 2 4 6 8 10 12 14 Daugava CTL A2 RCM based hydrological forecast for Eastern Baltic region P. Bethers, J. Sennikovs Laboratory for Mathematical Modelling of Environmental and Tehnological Processes, University of Latvia 0 50 100 150 200 250 0 2 4 6 8 10 12 14 Lielupe CTL A2 0 50 100 150 200 250 0 2 4 6 8 10 12 14 Gauja CTL A2 0 50 100 150 200 250 300 350 400 0 2 4 6 8 10 12 14 Venta CTL A2 River Area R2 Abava 1830 0.804 Aiviekste 7200 0.794 Bārta 1700 0.756 Bērze 904 0.775 Dubna 2060 0.819 Gauja 2230 0.800 Irbe 1920 0.794 Ogre 1660 0.835 Pededze 1670 0.754 Salaca 3220 0.798 1. Introduction The main goal of our study is to forecast possible changes in the discharge patterns in Latvian river drainage basin. In our study we used a modified Regional climate model (RCM) data based on SMHI RCAO forced by HadAM3H (which where modified comparing RCMs data with the observations in the reference period) and Mike Basin with a conceptual hydrological model NAM by DHI Denmark. Using these we simulated the runoff for the climate reference period (1961-1990) and for the future scenarios A2 and B2 (2071-2100). 3. Calibration Calibration was done using Mike 11 NAM conceptual model in 10 river basins with area aggregating to 24000 sq km. The calibration was made for the reference period (1961- 1990), using observation data from meteorological stations in the region. The R2, water balance and seasonal analysis was used to determine the best parameter set, and R2 values from 0.75 to 0.84 were obtained. 2. Area of study The whole area consists of four river basins (Daugava, Gauja, Lielupe, Venta), which covers 130 thousand sq km, in the territory of Latvia and parts of Lithuania, Estonia, Belarus and Russia. 4. Results Using the modified RCM data for the reference period (1961-1990; CTL) and for the future scenarios A2 and B2 (2071-2100) we simulated the runoff for each period. Comparison of the acquired time series shows the possible changes in discharge patterns in the future. River Change Venta -8% Lielupe -21% Daugava -18% Gauja -24% Simulated and observed discharge in Ogre for the reference period (1961-1990) 5. Analysis We also created a map which represents, the amplitude of changes in each sub basin, to understand the geographic distribution of future alterations. 6. Conclusions 1. The spring floods will be decreased and shifted to an earlier period. 2. There will be a decrease of runoff in the whole Latvian river drainage basin. 3. The winter runoff will become a more significant part of the annual runoff. 4. The summer dry periods will prolong in to the first autumn months. The qualitative changes can already be noticed in the observations after the reference period (1991-2009), but the quantitative changes, are unnoticeable, which could be explained bythe rise of precipitation exceeding expectations. 0 0.5 1 1.5 2 2.5 3 0 2 4 6 8 10 12 14 P, mm/day Q, m^3/s CTL A2 Annual cycle of precipitation and runoff in the reference period and scenario A2 Decrease of runoff in the subbasins comparing reference period (CTL) and scenario A2. Annual discharge (m^3/s) patterns in the main river basins in the ref period (CTL) and scenario A2
Transcript of Laboratory for Mathematical Modelling of Environmental and...
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Daugava
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RCM based hydrological forecast for Eastern Baltic regionP. Bethers, J. Sennikovs
Laboratory for Mathematical Modelling of Environmental and Tehnological Processes,University of Latvia
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Lielupe
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Gauja
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Venta
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River Area R2
Abava 1830 0.804
Aiviekste 7200 0.794
Bārta 1700 0.756
Bērze 904 0.775
Dubna 2060 0.819
Gauja 2230 0.800
Irbe 1920 0.794
Ogre 1660 0.835
Pededze 1670 0.754
Salaca 3220 0.798
1. IntroductionThe main goal of our study is to forecast possible changes in the discharge patterns in Latvian river drainage basin.In our study we used a modified Regional climate model (RCM) data based on SMHI RCAO forced by HadAM3H(which where modified comparing RCMs data with the observations in the reference period) and Mike Basin witha conceptual hydrological model NAM by DHI Denmark. Using these we simulated the runoff for the climatereference period (1961-1990) and for the future scenarios A2 and B2 (2071-2100).
3. CalibrationCalibration was done using Mike 11 NAM conceptual model in 10 river basins with areaaggregating to 24000 sq km. The calibration was made for the reference period (1961-1990), using observation data from meteorological stations in the region. The R2, water balance and seasonal analysis was used to determine the best parameter set, and R2 values from 0.75 to 0.84 were obtained.
2. Area of studyThe whole area consists of four river basins (Daugava, Gauja, Lielupe, Venta), which covers 130 thousand sq km, in the territory of Latvia and parts of Lithuania, Estonia, Belarus and Russia.
4. ResultsUsing the modified RCM data for the reference period (1961-1990; CTL) and for the future scenarios A2 and B2 (2071-2100) we simulated the runoff for each period. Comparison of the acquired time series shows the possible changes in discharge patterns in the future.
River Change
Venta -8%
Lielupe -21%
Daugava -18%
Gauja -24%
Simulated and observed discharge in Ogre for the reference period (1961-1990)
5. Analysis
We also created a map which represents, the amplitude of changes in each sub basin, to understand the geographic distribution of future alterations.
6. Conclusions1. The spring floods will be decreased and shifted to an earlier period.2. There will be a decrease of runoff in the whole Latvian river drainage basin.3. The winter runoff will become a more significant part of the annual runoff. 4. The summer dry periods will prolong in to the first autumn months.
The qualitative changes can already be noticed in the observations after the reference period (1991-2009), but the quantitative changes, are unnoticeable, which could be explained bythe rise of precipitation exceeding expectations.
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Annual cycle of precipitation and runoff in the reference period and scenario A2
Decrease of runoff in the subbasins comparing reference period (CTL) and scenario A2.
Annual discharge (m^3/s) patterns in the main river basins in the ref period (CTL) and scenario A2
