Impact Of Climate Change On Runoff In Liaohe River Basin

Global climate change has a serious impact on the sustainable development of Liaoheriver basin which suffers from water resources shortage. By analyzing precipitation anddischarge data in this area for over the past50years and the coming40years, the purpose ofthis paper is to provide data support to better address the climate change, and at the same timeto offer scientific basis for the local water resources management strategies and actions.The major conclusions are summarized as follows:(1) Data of25meteorological observation stations were analyzed and indicate thatannual temperature had a significant upward trend for0.31℃/10a during1961to2010; Thewarming trend became more significant since1980s, and the temperature rose0.5℃during1990s and2000s; The climate tendency rate in winter reached0.45℃/10a, while it wasbetween0.2~0.3℃/10a in the other seasons.Precipitation in the Liaohe river basin decreased slightly with average annualprecipitation of540mm；The interannual precipitation had an8-10years change cycle; Thedecadal variability remained minimal during1961to2000with an exception in2000s whichhad a decrease for6%.Analysis of runoff data from the Liaozhong hydrological station showed that annualrunoff was on a slightly downward trend during1961to2000; The runoff affected by bothclimate change and human activities.(2) In this paper, a high-resolution regional climate model CCLM was selected toinvestigate the climate change in the Liaohe Basin. By comparative analysis of analog datafrom CCLM and meteorological observation data during1961to2000, CCLM model isverified to be capable of simulating spatial and temporal distribution of annual temperatureand precipitation in Liaohe river basin.Projected data shows that the annual temperature would have an upward trend for0.61℃/10a before2050. Annual precipitation would have a weak downward trend. By2030,precipitation would in a fluctuating wave and there would be three peak years around the yearof2014,2020and2024. In2030s there would be a significant increase until2040s when it would turn to decline rapidly.Inter-annual precipitation would vary from-60%to60%and would possibly cause moreextreme events and also more droughts and floods. In the spatial distribution, variability ofannual precipitation would increase with a weak increasing trend in eastern and decreasingtrend in other regions. As a result, water supply conditions of Liaohe River would still bepoor.(3) Projected precipitation and temperature data from CCLM supported artificial neuralnetworks (ANNs). Simulation results showed that runoff would decline in the next40years,and decadal rate of inter-annual change would have a significant change while hydrologicaldroughts and floods would increase substantially.Standardized Discharge index (SDI) showed wet and dry period would change. Duringthe periods of2015to2016,2035to2040,2047to2048, the basin would suffer increasedlikelihood of floods; while during the periods of2017to2025,2030to2035，there would bemore droughts. Continuous droughts and floods and quick change between them would bemuch more frequent in the future40years.Therefore, it becomes urgent to strengthen our capability of adaptation to climate changeand water resources management.