冬小麦蒸散源区代表性分析  

Analyzing the Areas Contributing to Evapotranspiration Measured from the Eddy Covariance System in a Winter Wheat Field

作　　者：谢静 宋妮[1] 陈智芳[1] 王景雷[1] XIE Jing;SONG Ni;CHEN Zhifang;WANG Jinglei(Institute of Farmland Irrigation,Chinese Academy of Agricultural Sciences/Key Open Laboratory of Crop Water Demand and Regulation,Xinxiang 453002,China;Graduate School of Chinese Academy of Agricultural Sciences,Beijing 100081,China)

机构地区：[1]中国农业科学院农田灌溉研究所/农业部作物需水与调控重点开放实验室,河南新乡453002 [2]中国农业科学院研究生院,北京100081

出　　处：《灌溉排水学报》2021年第8期57-65,72,共10页Journal of Irrigation and Drainage

基　　金：国家自然科学基金项目(51709262)。

摘　　要：【目的】利用涡度相关技术观测冬小麦生育期内湍流通量,结合通量模型分析试验区农田生态系统通量贡献区的时空分布。【方法】使用闭路涡度系统对2019年10月—2020年6月新乡综合试验基地冬小麦进行通量观测,采用足迹解析模型中的FFP模型和基于土地利用信息的KM模型对通量源区分布和规律进行了分析。【结果】①整个生育期主风向为西南风,次风向为东北风,白天(大气非稳定状态)的主风向为西南风,夜间(大气稳定状态)的主风向为西南风。②不同生育期、不同大气状态下的源区面积存在一定的差异,大气稳定状态下源区面积均大于非稳定状态,源区方向与长度受风向风速的影响。③FFP模型和KM模型计算的源区面积间存在线性关系(S_(KM)=0.93S_(FFP)-1962.5,R^(2)=0.96),其中KM模型计算通量足迹值整体大于FFP模型。【结论】不同模型得到的源区不同,风向和风速是源区分布的主要影响因素,田块是试验区内湍流通量重要贡献的主要来源。【Background and objective】Evapotranspiration from managed and natural ecosystems is an important process in hydrological cycle but not trivial to measure at large scales.The eddy covariance developed over the past decade is a technique to measure atmospheric turbulent fluxes which can be used to estimate evapotranspiration and fluxes of other gases.Calculating evapotranspiration from the measurements of eddy covariance is complicated,and the aim of this paper is to experimentally investigate the areas in a farmland system that contribute to the fluxes measured from an eddy covariance.【Method】Atmospheric fluxes were measured from October 2019 to June 2020 using the closed-path eddy covariance system installed in a winter wheat field at Xinxiang comprehensive experimental station in Henan province.Distribution and variation of the measured flux sources were analyzed using the footprint models and FFP and KM methods.【Result】(1)Southwest-northeast wind was the dominant wind during the experimental period,following by northeast-southwest wind.(2)The results calculated under different growth stages and atmospheric conditions revealed that the areas that contributed to the fluxes measured from the device were larger under stable atmospheric conditions than under less stable atmospheric conditions.The direction and length of the areas were affected by wind direction and speed.(3)The results calculated by the FFP and KM models showed a linear relationship between the source areas with S_(KM)=0.93 S_(FFP)-1962.5 and R^(2)=0.96,and that,in the general,the areas calculated by the KM method were greater than that calculated by the FFP model.【Conclusion】The flux source areas calculated by the FFP and KM methods differed,and the wind direction and speed were the main factors affecting the flux source distribution.For our experiment,the winter wheat was the main contributor to the fluxes measured from the eddy covariance system.

关 键 词：涡度相关技术 通量源区 FFP模型 KM模型 

分 类 号：S274[农业科学—农业水土工程]