新疆气候的干湿变化及其趋势预估

Variation and Projection of Drought and Wet Conditions in Xinjiang

利用新疆气象局提供的90个气象台站的连续观测记录,计算了1961-2003年新疆地区年平均和季节平均自适应Palmer干旱指数的气候态及其变化趋势,表明新疆地区气候就平均态而言整体上属于正常的气候条件,研究时段内年平均和季节平均气候以湿润化趋势为主要变化特征,定性的分析显示地表气温的持续上升倾向于引起干旱化,而降水的增加则有利于气候的湿润化趋势。在SRES A2温室气体和气溶胶排放情景下,21世纪90年代新疆地区地表气温的升高会导致干旱化的发生,而降水的增加则有利于湿润化,在二者的联合作用下,新疆地区的干湿状况可能将发生一定程度的变化。

Based on the continuous observation data at the 90 meteorological sites in Xinjiang, a self-calibrating Palmer drought severity index （PDSI） is firstly used to investigate the annual and seasonal variation of drought and wet conditions in the region during 1961 - 2003. During the concerned period, Xinjiang is characterized by normal climate condition, and both annual and seasonal mean climates are prone to become wetter as a whole. Qualitative analysis reveals that the recorded surface warming tends to induce drought, whereas increased precipitation is favorable for wetness. Under the SRES A2 emission scenario for atmospheric greenhouse gasses and aerosols, projected surface warming tends to induce drought, whereas increased precipitation tends to induce wetness in the 2090s. Taking into account the above two factors together, the PDSI indicates that drought and wet conditions in Xinjiang alter to some extent in the 2090s.