未来气候情景内蒙古蒸散和产水量的变化特征

评估预测区域蒸散变化趋势及其影响因素对干旱半干旱区的可持续发展至关重要。基于4种来自CMIP 5的全球气候模式数据和CLM 4.5模型,研究了在RCP 6.0和RCP 8.5情景下内蒙古地区2020—2099年的蒸散和产水量的时空变化特征及其影响因素。结果表明：在RCP 6.0和RCP 8.5情景下,未来内蒙古蒸散分别以0.37,0.69 mm/a速度增加（p<0.05）,呈西低东高分布。2种情景下产水量均无明显变化趋势（p>0.05）,但是存在明显显著的空间差异。空间上看,到21世纪末,在RCP 6.0情景下,全境产水量大部分地区呈增加趋势,在南部温带半干旱和半湿润区增加超过10 mm/a;但是在RCP 8.5情景下产水量减少区域占全境的46.32%,特别是干旱半干旱区和半湿润区产水量显著减少。蒸散影响因子存在较大区域差异,干旱半干旱区蒸散变化的主要影响因素是降水,半湿润区蒸散变化受降水和温度的共同影响,湿润区蒸散变化由温度主导;且在更高的升温情景下,增温影响进一步增加。同时,植被也是蒸散重要的影响因子,但其影响程度小于气候因子。

Characteristics of Evapotranspiration and Water Availability in Inner Mongolia Under Future Climate Scenarios

It is vital to evaluate and predict regional water resource variation and its influencing factors for sustainable development of arid and semi-arid areas. Based on four global climate models of CMIP5 and CLM 4.5, the temporal and spatial characteristics of evapotranspiration and water availability were studied in Inner Mongolia under two Representative Concentration Pathways (RCPs) from 2020 to 2099. The results showed that under RCP 6.0 and RCP 8.5 scenarios, the future evapotranspiration in Inner Mongolia would increase at a rate of 0.37 mm/a and 0.69 mm/a, respectively (p<0.05), decreasing form east to west. Water availability in Inner Mongolia did not show a significantly trend under the two scenarios (p>0.05), but there were significant spatial differences.From a spatial perspective, water availability in most areas showed an increasing trend and increased by more than 10 mm/a in the southern semi-arid and semi-humid regions of temperate zone by 2090s; however, the area with reduced water availability accounted for 46.32% of the entire territory under the RCP 8.5 scenario, especially in the arid, semi-arid and semi-humid areas. There were great regional differences influencing of driving factors in evapotranspiration. Precipitation was the main influencingfactor of evapotranspiration changes in arid and semi-arid area. The changes in semi humid area were jointly affected by precipitation and temperature. The changes in humid area were dominated by temperature and in the higher heating scenario, the effect further increased with temperature increased. At the same time, vegetation was also an important factor affecting evapotranspiration with less than climate factor.