半干旱区农田生态系统通量贡献区分析  

Analysis of agro-ecosystem footprint of flux in semi-arid areas

作　　者：董军[1] 党慧慧[1] 孔凡亮[2] 岳宁[1] 王刚[3] 郭映[1] 魏国孝[1] 

机构地区：[1]兰州大学资源环境学院/西部环境教育部重点实验室,兰州730000 [2]山东水利职业学院,日照276826 [3]山东农业大学水利土木工程学院,泰安271000

出　　处：《中国生态农业学报》2015年第12期1571-1579,共9页Chinese Journal of Eco-Agriculture

基　　金：国家自然科学基金项目(41471023;41202174)资助~~

摘　　要：通量贡献区是指对湍流交换过程有贡献的有效源（汇）区域,它与生态系统和大气间的通量交换密切相关。在实际观测中复杂的下垫面增加了通量观测的难度和不确定性,对通量贡献区评价能有效解决通量空间代表性的问题。为了研究半干旱区农田生态系统在完整的作物生育期通量贡献区的变化特点,该文根据位于黄土高原丘陵沟壑区的兰州大学半干旱区农业生态系统试验站的通量观测塔2014年12个月连续的玉米农田通量观测资料,应用Schmid的FSAM模型对半干旱区玉米农田的通量贡献区进行了分析。结果表明：本研究区的主风向是90°-180°（东南方向）,次主风方向是270°-360°（西北方向）;在主风向上,迎风方向非生长季的通量信息最远点大于生长季,而在垂直于迎风方向上则相反;生长季内迎风向通量信息最远距离呈现出先减小后变大的趋势,其中在抽雄期最小,垂直于迎风方向最大宽度变化无明显规律。大气稳定条件下通量贡献区面积比不稳定条件下大,且大气稳定条件下90%的通量信息来源于迎风向8-92 m,垂直于迎风向？35-35 m;不稳定条件下则分别为7-83 m和-25-25 m。白天90%的通量源区分布在离观测塔9-86 m,夜晚源区分布在离观测塔10-100 m,垂直于迎风向由白天的-21-21 m增加到夜晚的？35-35 m。由FSAM模型测得的通量贡献区可以较准确地反映农田生态系统的通量信息。The footprint of flux is effective for observation of the contribution of turbulent exchange to the atmosphere. It is closely related to the exchange of flux between the atmosphere and ecosystem. However, in practice, the complexity of the underlying surface increases the difficulty and uncertainty in calculating flux. Evaluation of flux footprint can solve the problem of spatial representativeness of flux, which makes it easy to calculate flux exchange. In order to study the variation in flux footprint for complete growth seasons of maize in semiarid area, flux footprint and source area functions were calculated from continuous flux measurements for the period from 1st January 2014 to 31 st December 2014 using the eddy covariance system driven by FSAM model. The eddy covariance system was in the maize field in the Experiment Station of Agro-ecosystem in Semiarid Area（ESASA） of Lanzhou University, which is in a hilly area of the Loess Plateau. The flux measurement in the agro-ecosystem in semiarid area was spatially representative. The results showed that the prevailing wind direction in the research area was 90°-180°. Wind frequencies in that direction during active growth and non-growing seasonsof maize were respectively 59.11% and 55.28% of the total wind frequency. The second main wing direction was 270°-360°.In the prevailing wind direction, the upwind footprint tail of the growing season was longer than that of non-growing season.However, the reverse was the case for the vertical upwind direction. The comparison between non-growing season 1（January 1to March 31） and non-growing season 2（November 1 to December 31） showed a stable area of flux footprint for the non-growing season. In the prevailing wind direction, flux footprint decreased from seedling stage to tasseling stage while it increased from tasseling stage to maturity stage of maize. The farthest point of flux source area was significantly affected by aerodynamic roughness. Under stable stratification, source areas were larger than t

关 键 词：FSAM模型 农田生态系统 通量贡献区 半干旱区 玉米农田 

分 类 号：P404[天文地球—大气科学及气象学]