SRES A2和B2情景下宁夏可利用降水资源的变化

Variation of Available Precipitation in Ningxia under SRES A2 and B2 Scenarios

利用1961─2008年宁夏气温、降水资料,计算水资源各分量,并结合PRECIS模式模拟结果,对气候基准时段（1961─1990年）和1991─2008年各量的模拟值和观测值进行对比检验,并着重分析了SRES A2和B2情景下21世纪各量的变化。对比检验结果表明,虽然量值上有一定的模拟偏差,但模式对各量的基本气候态和局地特征模拟的较为准确。各量的变化表明,21世纪宁夏区域年平均蒸发增加趋势较降水更明显,可利用降水的减少主要来自于夏季南部山区;与气候基准时段相比,夏季可利用降水的增加主要在21世纪前半叶,引黄灌区增幅最大达120%左右,21世纪后半叶南部山区减少最明显为20%-60%;相较2011—2040年,2070—2100年夏季可利用降水呈全域性减少;温室气体含量的变化没有改变各量的分布型,但对量级的影响较大,且可利用降水的变化远大于降水的变化;A2情景下各量的变化较B2情景更明显。随着温室气体排放量的持续增加宁夏水资源短缺的状况将进一步加剧,尤其是南部山区。

Based on a data set of precipitation and temperature in Ningxia during 1961-2008,the available precipitation is calculated;a comparison between observed values and simulated values by the PRECIS model is made;and variation of available precipitation in future decades is simulated and analyzed under SRES A2 and B2 scenarios.The comparison results show that although there is a certain deviation in simulation,PRECIS model can well simulate the basic and local climate characteristics of available precipitation.Simulation of available precipitation in the 21st century under SRES A2 and B2 scenarios shows that the increasing amplitude of the annual evaporation in Ningxia is greater than that of precipitation,and the decrease of the available precipitation is mainly caused by the decrease of precipitation in summer in the south mountainous area;available precipitation in summer increases in the first half of the 21st century with the maximum amplitude of about 120% in the Yellow River irrigated region,and it decreases in the second half of the 21st century with the maximum amplitude of 20%-60% in the south mountainous area;there will be an overall decreasing trend of available precipitation in Ningxia in 2071—2100 in comparison with that in 2011—2040;variation of greenhouse gas stock will exert more impact on available precipitation than on precipitation;the variation of available precipitation is more obvious under A2 scenario than under B2 scenario.Water shortage in Ningxia（especially in the south mountainous area） will aggravate further if greenhouse gas emission increase continuously.