To understand the causes of the past water cycle variations and the influence of climate variability on the streamflow, lake storage, and flood potential, we analyze the changes in streamflow and the underlying drivers in four typical watersheds (Gaosha, Meigang, Saitang, and Xiashan) within the Poyang Lake Basin, based on the meteorological observations at 79 weather stations, and datasets of streamflow and river level at four hydrological stations for the period of 1961-2000. The contribution of different climate factors to the change in streamflow in each watershed is estimated quantitatively using the water balance equations. Results show that in each watershed, the annual streamflow exhibits an increasing trend from 1961-2000. The increases in streamflow by 4.80 m3 s??'1 yr??'1 and 1.29 m3 s??'1 yr??'1 at Meigang and Gaosha, respectively, are statistically significant at the 5% level. The increase in precipitation is the biggest contributor to the streamflow increment in Meigang (3.79 m3 s??'1 yr??'1), Gaosha (1.12 m3 s??'1 yr??'1), and Xiashan (1.34 m3 s??'1 yr??'1), while the decrease in evapotranspiration is the major factor controlling the streamflow increment in Saitang (0.19 m3 s??'1 yr??'1). In addition, radiation and wind contribute more than actual vapor pressure and mean temperature to the changes in evapotranspiration and streamflow for the four watersheds. For revealing the possible change of streamflow due to the future climate change, we also investigate the projected precipitation and evapotranspiration from of the Coupled Model Intercomparison Project phase 3 (CMIP3) under three greenhouse gases emission scenarios (SRESA1B, SRESA2 and SRESB1) for the period of 2061-2100. When the future changes in the soil water storage changes are assumed ignorable, the streamflow shows an uptrend with the projected increases in both precipitation and evapotranspiration (except for the SRESB1 scenario in Xiashan watershed) relative to the observed mean during 1961-2000. Furthermore, the largest increase in the streamflow is found at Meigang (+4.31%) and Xiashan (+3.84%) under the SRESA1B scenario, while the increases will occur at Saitang (+6.87%) and Gaosha (+5.15%) under the SRESB1 scenario.
展开▼
机译：为了了解过去水循环变化的原因以及气候变化对水流，湖泊蓄水和洪水潜力的影响，我们分析了四个典型流域（高沙，梅岗，赛塘和下山）的水流变化及其潜在驱动因素。 ）在on阳湖流域内，基于对79个气象站的气象观测，以及1961-2000年期间四个水文站的流量和水位数据集。使用水平衡方程，可以定量估算出不同气候因素对每个流域内径流变化的贡献。结果表明，从1961-2000年开始，每个流域的年流量都呈增加趋势。在梅岗和高沙，流量分别增加了4.80 m3 s ?? 1'1yr ?? 1和1.29 m3 s ?? 1'1yr ?? 1，在5％的水平上具有统计学意义。降水增加是梅岗（3.79 m3 s ?? 1年?? 1），高沙（1.12 m3 s ?? 1年?? 1）和下山（1.34 m3）的流量增加的最大贡献。 s ??'1 yr ??'1），而蒸散量的减少是控制塞唐河流量增加的主要因素（0.19 m3 s ??'1 yr ??'1）。此外，辐射和风对四个流域的蒸散量和水流变化的贡献超过实际的蒸气压和平均温度。 为了揭示未来气候变化可能引起的径流变化，我们还研究了三种温室气体排放情景（SRESA1B，SRESA2）下的耦合模型比较项目第3阶段（CMIP3）的预计降水量和蒸散量。和SRESB1）的时间段为2061-2100。如果假定未来土壤蓄水量的变化是可忽略的，则相对于1961-2000年期间的观测平均值，水流量显示出上升的趋势，降水量和蒸散量预计都将增加（下山流域的SRESB1情景除外）。此外，在SRESA1B情景下，梅岗（+ 4.31％）和下山（+ 3.84％）的流量增加最大，而在SRESA1B情景下，塞塘（+ 6.87％）和高沙（+ 5.15％）的流量增加最大。 SRESB1方案。
展开▼
