2003-2018年青藏高原草地的地表层土壤热通量时空变化  

Temporal and spatial variation in grassland ground surface soil heat flux on the Qinghai-Tibetan Plateau from 2003 to 2018

作　　者：李颖 吴静[1] 李纯斌[1] 秦格霞 LI Ying;WU Jing;LI Chun-bin;QIN Ge-xia(College of Resources and Environment Science,Gansu Agricultural University,Lanzhou 730070,China)

机构地区：[1]甘肃农业大学资源与环境学院,甘肃兰州730070

出　　处：《草业学报》2022年第11期1-14,共14页Acta Prataculturae Sinica

基　　金：国家自然科学基金(31760693)资助。

摘　　要：根据青藏高原7个站点实测数据,计算站点地表层土壤热通量(G_(0))并分析站点的日、季变化特征;结合MODIS数据、中国西部1 km全天候地表温度数据集和中国区域地面气象要素驱动数据集,用Ma模型反演2003-2018年青藏高原地表土壤热通量,并且分析不同草地类型的G_(0)变化。结果表明:1)站点地表层土壤热通量G_(0)比不同深度的土壤热通量值大。G_(0)的日变化曲线呈倒“U”形状,在夜晚相较于白天变化较为平缓。2)站点地表层土壤热通量G_(0)的季节振幅变化呈现夏>春>秋>冬,春夏季G_(0)均值整体为正值,秋冬季G_(0)均值基本为负值。夏季高原西北地区的地表层土壤热通量相对于东南地区的较高,而冬季则相反。3)高原草地的土壤热通量值为40~80 W·m^(-2),16年各类草地G_(0)平均值最高的是温性草原化荒漠类(76.557 W·m^(-2)),最低的是高寒草甸类(46.118 W·m^(-2))。4)高原草地的G_(0)一年内呈现出先增后降的变化趋势。高原各类草地G_(0)的季节变化呈现夏>春>秋>冬,夏春季G_(0)最低的均为高寒草甸类,较高的分别是温性草原化荒漠类和温性草原类;秋冬季G_(0)最高的均为暖性灌草丛类,最低的均为高寒荒漠类。以上结果可为高原草地地表能量平衡研究提供一定参考依据。Based on measured data from 7 stations on the Qinghai-Tibetan Plateau,the ground surface soil heat flux(G_(0))was calculated,and the diurnal and seasonal variations were analyzed.Combining this data with a MODIS,1 km resolution all-weather surface temperature data set for Western China and a China regional surface meteorological element driven data set,the Ma model was used to retrieve the ground surface soil heat flux of Qinghai-Tibetan Plateau from 2003 to 2018,and the differences in surface soil heat fluxes of different grassland types were analyzed.It was found that:1)The soil heat flux G_(0) in the surface layer was greater than that in the subsurface layers.The diurnal curve of G_(0) showed an inverted“U”shape,and the flux was relatively gentle at night compared with that during the day.2)The seasonal amplitude of soil heat flux,G_(0) in the surface layer ranked summer>spring>autumn>winter.The average value of G_(0) in spring and summer was typically positive,while the average value of G_(0) in autumn and winter was basically negative.The ground surface soil heat flux in the northwest of the plateau in summer is higher than that in the southeast,while the opposite occurs in winter.3)The soil heat flux of plateau grassland ranged between 40 and 80 W·m^(-2).The highest average value of G_(0) among all categories of grassland in the 16 years surveyed was 76.557 W·m^(-2) for the‘desertification’category of temperate grassland,and the lowest was 46.118 W·m^(-2) for the alpine meadow category.4)The G_(0) of plateau grassland increased and then decreased through any one calendar year and seasonally was ranked summer>spring>autumn>winter.The lowest G_(0) in spring and summer occurred in alpine meadow,while the highest in spring was in‘desertification’temperate grassland and the highest in summer was in the temperate grassland category;The highest G_(0) in autumn and winter was in the warm shrub grassland,while the lowest was in the alpine deserts steppe.The above results can provide reference data fo

关 键 词：青藏高原 地表层土壤热通量G_(0) Ma模型 时空变化 草地类型 

分 类 号：S812[农业科学—草业科学]