淮河流域农田生态系统能量变化特征及闭合率分析
Analysis of Energy Change Characteristics and Closure Rate of Cropland Ecosystem in Huaihe River Basin
中文摘要：
农田生态系统能量变化特征及闭合率对农田下垫面区域上大气边界层的动力、热力结构研究以及区域数值模式陆气交换参数化的改进等具有重要意义。基于寿县国家气候观象台2007年7月—2013年4月通量观测系统中的显热、潜热、土壤热通量以及辐射通量等观测资料，分析淮河流域农田生态系统能量变化特征及闭合率。结果表明：显热、潜热通量、波恩比以及土壤热通量日变化均呈单峰型分布，年平均波恩比为0.43，表明下垫面潜热通量占主导地位。各辐射分量和净辐射日变化幅度差异较大，其中向下短波辐射变化幅度最大，而向下长波辐射变化幅度最小；从月变化来看， 均呈现单峰型分布，地面向上长波辐射总平均值最大，而向上短波辐射最小。有效能量和湍流通量线性回归线基本在1:1线以下，表明能量存在不闭合，且湍流通量小于有效能量。能量平衡比平均为94%，5月最大，12月最小；春季的能量闭合率最大，其次是夏季，冬季最小。总体来看，淮河流域农田生态系统能量闭合率相对较高，通量观测系统资料质量是可靠的。
中文关键词：
热通量，辐射通量，闭合率，农田生态系统，淮河流域
KeyWords：
heat flux, radiation flux, closure rate, cropland ecosystem, Huaihe River Basin
Abstract：
The energy change characteristics and closure rate of cropland ecosystem are of great significance to the study of the dynamic and thermal structure of the atmospheric boundary layer over the cropland underlying surface and the improvement of the parameterization of land-atmosphere interaction of the regional numerical model. Based on the observation data of sensible heat flux, latent heat flux, soil heat flux and radiation flux in flux observation system in Shouxian National Climatological Observatory from July 2007 to April 2013, this paper studies the energy change characteristics and closure rate of cropland ecosystem in Huaihe River Basin. Results show that the daily variation characteristics of sensible heat flux, latent heat flux, Bowen ratio and soil heat flux are all of unimodal distributions, and the annual average Bowen ratio is 0.43, which shows that latent heat flux of underlying surface is dominant. The daily variation amplitude of each radiation component and net radiation are quite different, among which the variation amplitude of downward shortwave radiation is the largest, while that of downward longwave radiation is the smallest. From the perspective of monthly variation, they all present the single peak distributions. The total average of the surface upward longwave radiation is the largest, while the upward shortwave radiation is the smallest. The linear regression line of effective energy and turbulent flux is basically below 1:1, which indicates that there is no closure of energy and the turbulent flux is less than the effective energy. The average energy balance ratio is 94%, which is the largest in May and the smallest in December. The energy closure rate in spring is the largest, followed by that in summer, and it is the smallest in winter. In general, the energy closure rate of cropland ecosystem in Huaihe River Basin is relatively high, and the data in flux observation system is reliable.