毛乌素沙地降水和气温变化特征及其与植被因子的关系

为了研究毛乌素沙地土地利用/覆被变化(LUCC)对气候变化的影响,采用观测资料减去再分析法(OMR)和土地利用转移矩阵等方法,分析毛乌素沙地沙漠化逆转期前后(1980—1999年和2000—2016年)两个时期LUCC对气候变化的影响,讨论该时期LUCC引起区域气候效应的驱动机制。结果表明:(1)沙漠化逆转后期与前期相比,气温和降水变化特征存在差异。沙地和非沙地气候变化无明显差异,下垫面物质组成对气候变化影响不显著;(2)降水量变化主要受到地面蒸散发的影响。气温变化是LUCC引起蒸散发、反射率、净辐射量等变化的综合效应,LUCC对气温的影响更明显;(3)相比平均气温,最高气温和最低气温对于LUCC的响应更敏感。因此,植被恢复显著改变了毛乌素沙地降水和温度的变化特征,而且这种变化与下垫面物质组成无关。

Changes of Precipitation and Temperature and Their Relationships to Vegetation in the Mu Us Desert

In order to study the effect of land use/vegetation cover change(LUCC)on climate change in the Mu Us Desert,we used observation minus reanalysis(OMR)and matrix of dynamic change of land use to analyze the impact of LUCC on climate change before and after desertification reversal in Mu Us Desert and assessed how LUCC drove regional climate change in the study region.The results showed significant differences in precipitation and temperature changes before and after desertification reversal.However,the changes in precipitation and temperature were similar between sandy and loess sites,indicating that the underlying surface situation had not significantly influenced the response of precipitation and temperature.Change in precipitation was mainly regulated by evapotranspiration.The LUCC resulted in the changes in evapotranspiration,reflectivity,net radiation,etc.,ultimately led to change in temperature.The result showed that effect of LUCC on temperature was greater than the effect on precipitation.Compared with the average temperature,the maximum and minimum temperature were more sensitive in responding to LUCC.These results suggested that the changes of precipitation and temperature were mainly caused by vegetation restoration regardless of substance composition of underlying surface.