绿洲荒漠过渡带涡动相关仪和大孔径闪烁仪的通量源区特征  

Characteristic Analysis of Source Area Distribution of Eddy Covariance and Large Aperture Scintillometer in an Oasis-Desert Ecotone

作　　者：荣星星 王鹤松 褚建民[2] 艾金龙 RONG Xing-xing;WANG He-song;CHU Jian-min;AI Jin-long(School of Ecology and Nature Conservation,Beijing Forestry University,Beijing 100083,China;Research Institute of Forestry,Chinese Academy of Forestry/Key Laboratory of Tree Breeding and Cultivation,National Forestry and Grassland Administration,Beijing 100091;Department of Biology and Information Engineering,Yiyang Vocational&Technical College,Yiyang 413049)

机构地区：[1]北京林业大学生态与自然保护学院,北京100083 [2]中国林业科学研究院林业研究所/国家林业和草原局林木培育实验室,北京100091 [3]益阳职业技术学院生物与信息工程系,益阳413049

出　　处：《中国农业气象》2021年第10期823-835,共13页Chinese Journal of Agrometeorology

基　　金：国家自然科学基金项目(31770765;31370707);湖南省自然科学基金青年基金项目(2020JJ5557)。

摘　　要：以甘肃民勤绿洲荒漠过渡带涡动相关仪(EC)和大孔径闪烁仪(LAS)的同步观测数据为基础,借助通量足迹模型,分析生长季和非生长季通量源区的分布与变化特征,比较了源区在不同风向下,足迹权重比的变化对二者观测值之间差异的影响。结果表明:(1)研究区在非生长季盛行西北风,在生长季则盛行东风,EC和LAS源区的空间分布与盛行风向一致,二者在非生长季源区的面积均大于生长季。(2)大气稳定条件下EC和LAS的源区面积普遍大于不稳定条件下。随着源区贡献率的增加(由50%增至90%),EC和LAS源区的重叠面积和足迹权重比也增加,并且非生长季的源区重叠程度优于生长季。在生长季和非生长季,EC和LAS源区都呈现不规则分布的特点。(3)相比于东西风向,生长季南北风向下的足迹权重比更高,二者所观测显热通量值更为接近,决定系数(R^(2))也更高。说明源区的足迹权重比在一定程度上可以解释EC和LAS在观测结果上的差异,这为地表通量的尺度扩展提供了方法学上的参考。Eddy covariance(EC)and large aperture scintillometer(LAS)are two commonly used methods for surface flux observation.Investigating the distribution of source area is helpful to improve the spatial representativeness and enhance the understanding of scaling issues such as up-scaling of surface flux data.Based on the observation data from EC and LAS in Minqin,an oasis-desert ecotone,the distribution and variation of source areas were analyzed.In different directions of the source area,the influence of the ratio of weighted-footprint area between EC and LAS(CEC&LAS)on the difference of observed values was compared.The results indicate that:(1)the northwest wind prevails in the non-growing season,while the east wind prevails in the growing season.The spatial distribution of source areas consistent with the prevailing wind direction,and the source areas in the non-growing season are larger than those in the growing season.(2)Source areas of EC and LAS in stable atmospheric conditions are generally larger than those in unstable conditions.With the increase of source contribution(from 50%to 90%),the overlapping area and CEC&LAS also increase.In growing and non-growing season,source areas of EC and LAS distributed in an irregular shape.(3)Compared with the value in east and west,the CEC&LAS in north and south of growing season is higher.Meanwhile,the determination index(R2)in north and south is also greater than it is in east and west.It reveals that in some degree,CEC&LAS can explain the difference of the observation results between these two methods.This study has contributed to the improvement of the spatial representativeness of surface flux and provide a reference of methodology for the up-scaling of surface flux.

关 键 词：涡动相关 大孔径闪烁仪 通量源区 大气稳定度 足迹权重比 

分 类 号：P414[天文地球—大气科学及气象学]