科尔沁沙地梯级生态带水热通量变化特征及气候学足迹

荒漠化地区水热通量变化特征和气候学足迹对理解干旱、半干旱区气候变化及水分循环具有重要意义。以科尔沁沙地一条梯级生态带为研究区，运用2017年3-12月大孔径闪烁仪和自动气象站数据对研究区不同时间尺度水热通量和通量源区的动态变化特征进行分析。结果表明：水热通量日变化特征明显，各分支能量占比不同。晴天近地表能量各项分支曲线均呈显著单峰状，多云天水热通量变化无显著规律；水热通量季节变化显著，夏季显热通量值小于春季、秋季和冬季，潜热通量夏季最大，其次为春季和秋季，冬季最小；小时尺度和日尺度上源区变化较大；季节尺度上，源区面积春季 > 秋季 > 夏季，季节尺度间源区差异较小时尺度和日尺度降低；结合梯级生态带内下垫面类型看，生长季源区以光径中段的玉米农田占比最大，沙丘和草甸下垫面次之，光径内小型湖泊所占源区比例较小。不同月份各下垫面类型占比略有不同。

Characteristics of Water and Heat Fluxes and Its Footprint Climatology in Horqin Cascade Ecological Zone

The analysis of the variation characteristics of water and heat fluxes and climatological footprints in desertification areas is of great significance for understanding climate changes and water cycle in arid and semi-arid regions. Taking the Horqin cascade ecological zone as the study area, this paper analyzed the dynamic changes of water and heat fluxes and flux footprint in different temporal scales of the cascade ecosystem by using the large aperture scintillometer and automatic meteorological station data from March to December 2017. The results showed that:The diurnal variation of water and heat fluxes is obvious, the energy proportions of each branch are different. The near-surface energy fluxes curves show a significant unimodal trend in sunny days and there was no significant regular changes in on cloudy days; The seasonal variation of water and heat fluxes is significant.The sensible heat flux in summer is smaller than that in spring, autumn and winter, and the latent heat flux is the largest in summer, followed by spring and autumn, and the smallest in winter. The source area varies greatly on the hourly scale and daily scale; On the seasonal scale, the source area is spring > autumn > summer, and the differences of flux footprint between seasonal scales is lower than that of the hourly scale and daily scale.According to the types of underlying surface, the maize land in the middle of the light path was the largest proportion of the source area, followed by sand dune and meadow underlying surface, the small lake accounted for a smallest proportion of the source area. The source area at different temporal scales had different contribution sources.