Application of spatial weather generator for the assessment of climate change impacts on a river runoff

Abstract

In this study, the impacts of climate change on streamflow are investigated. The ensemble of outputs from three different Global Circulation Models models: GISS, CCCM, GFDL developed for the emission scenario A1B were analyzed to infer projected changes in climatological conditions for the region of the Upper and Middle Odra basin. Obtaining hydrological scenarios of future changes for the scale of subcatchment required simulating short-term and fine scaled weather patterns for this area. SWGEN model (Spatial Weather GENerator) was applied to downscale projected changes of climatological conditions to the ones required by hydrological model temporal and spatial resolution. Daily time series of solar radiation, temperature and precipitation were generated for the reference period 1981–2000 and for the time horizon 2030 and 2050. The generated data from SWGEN model were integrated in the hydrological model NAM to simulate streamflow under changed conditions with daily time step. The results show considerable changes in annual and seasonal runoff daily distributions for selected study catchment in the future time horizons of 2030 and 2050.

Simulation of the minimum annual river flows based on the RCP climatic scenario, time horizon up to 2060-2080 and the Kaczawa River

“…These data are used to simulate river flows using the hydrological rainfallrunoff model (step 3). The described procedure is presented in Figure 1 and has been used many times to simulate the maximum flows [1,2,3,4]. Finally, the probability distributions of the minimum flows were adjusted and analyzed based on literature analysis [1][2][19][20][21][22][23][24][25].…”

“…Our research has been conducted for many years in the Kaczawa river basin in south-western Poland (Fig.2) [1][2][3]5]. This choice is related to the Institute of Meteorology and Water Management National Research Institute (IMGW) recommendation and very good meteorological and hydrological data of high quality.…”

“…In earlier works [1 -3] simulations for maximum flows and runoff were presented while now the minimum flows were focused on. In the present study, a spatial generator was used as before, but verified on new extended meteorological data [1,4,5].…”

“…In addition, potential climate changes will have a significant impact on the entire hydrology of river flows and outflows in river basins [3,[6][7][8][9][10][11][12][13][14]. In the sense that there will be seasonal changes and redistribution of basic components such as rainfall, temperature, evaporation deciding on the water balance [1,9,12]. For this reason, actions should be taken today to limit the negative effects of climate change, preceded by comprehensive simulation studies.…”

“…The present study uses the procedure used in previous simulations for maximum flows and uses three elements: climate change scenarios, weather generator and hydrological model [1-3, 9, 15-18]. Seasonal flow simulations were performed for a small catchment of the Kaczawa river, the left tributary of the Odra (south-west region of Poland) and selected scenarios of climate change in RCP [1][2][3]9].…”