结合遥感数据对云贵地区蒸散发量及干湿变化特征的研究

利用卫星遥感观测MOD16和全球陆面数据同化系统(GLDAS)的逐月实际蒸散量(MOD16_ETa及GLDAS_ETa)与潜在蒸散发(MOD16_ETp及PM_ETp),探讨了2000-2014年云贵地区蒸散发时空变化规律,并综合利用蒸散发数据与降水数据计算多种干湿指数,分析了云贵地区近15年的干湿变化状况以及蒸散发、降水与地区干湿演变的关系。结果表明:①云贵高原的年均ETa在空间分布上表现为在云南南部最高,贵州东部次之,在云南北部最低的特点;变化趋势上,ETa在云南西南部显著增加,而在云南北部显著减小;②基于不同数据集计算的年均ETp在云贵高原空间分布上差异均较小,但变化趋势均反映出云南中部及北部区域ETp有显著上升趋势;③干湿指数的变化趋势反映贵州地区干湿情况较稳定,云南的中部地区具有较显著的变干趋势,原因是该区域的ETa和降水量在显著下降,而ETp在显著增加。

Research on the Characteristics of Evapotranspiration and Climate Aridity Based on Remote Sensing Data in Yunnan-Guizhou Region

The monthly actual and potential evapotranspiration(ET)data products,including satellite-retrieved MODIS MOD16 data(actual ET MOD_ETa and potential ET MOD_ETp)and simulated by GLDAS(actual ET GLDAS_ETa and potential ET PM_ETp),are used to investigate the temporal and spatial variations of ET in the Yunnan and Guizhou(YG)region.Besides,multiple aridity indicator are computed based on observed precipitation(P)and ET data to investigate the climate aridity of YG,the relationship between evapotranspiration,precipitation and regional aridity evolution are also discussed.Results show that:①The highest annual average ETa occurs in southern Yunnan followed by eastern Guizhou,and northern Yunnan has the least ETa.As for the trend of ETa,it inclines significantly in southwestern Yunnan and it declines significantly in northern Yunnan.②The spatial distribution of annual average MOD_ETp and PM_ETp indicate that the spatial variation of ETp is not very much,while both data sets indicate that ETp has a remarkable rise in central and northern Yunnan.③The trend analysis of multiple aridity indicators shows that climate aridity in Guizhou province is stable,while there is a considerable drying trend in central Yunnan because of the joint effects of significant decline of precipitation and ETa and the remarkable increase in ETp.