摘要:
该文根据通量观测塔上2003年12个月连续的通量观测资料,应用Schmid (1994)的FSAM (The Flux-Source Area Model)模型,分析不同大气条件下源区分布.结果表明:①源(汇)区分布的基本特点是:不稳定条件下,传感器测得的通量信息源区比稳定条件时近,源区面积相对小;相同水平下非生长季的信息源区比生长季的信息源区大.②在主风方向200°~290°,生长季不稳定条件下,通量测量的信息源区(P=0.8)迎风方向范围在0~600m之间,垂直于迎风方向范围在-300~300m之间;稳定条件下,分别为0~1500m,-1000~1000m;在非生长季相同大气条件下,迎风方向和垂直迎风方向的范围较均值略大些,而风向在0°~90°、90°~200°、290°~360°时,相同大气条件下,其范围与主风向生长季的范围近似.③ 12个月统计结果表明,76%的信息来自于西南至西北方相对均质的阔叶红松原始林,其中footprint取得最大值的源区在塔西南方100~400m范围内,几乎没有来自北偏东方向的城镇下垫面的信息,而在塔东南方0.5km以外的其他类型下垫面对通量测量的影响约3%左右.
Abstract:
Based on the FSAM model(Schmid,1994), footprint and source area functions were calculated according to the continuous flux measurement with the open path eddy covariance system from Jan 1,2003 to Dec 31,2003. The spatial representative of flux measurement of the mixed forest of Broad-leaved and Korean pine in Changbai Mountain was explained. The results showed that:① under unstable stratification, source areas were smaller than those under stable conditions, and source areas in the dormant season are larger than those in the growing season at the same level;② in the prevailing wind direction 200°-290°, the upwind range of source areas was in the magnitude of 0 600 m and vertical upwind range was -300-300 m at a 0.8 level under unstable stratification in the growing season. Under the stable stratification, they were 0-1500 m and -1 000-1 000 m. In the dormant season, the range was larger. In the other wind directions, the ranges were similar than those of the growing season in the prevailing wind direction under the same atmospheric conditions; ③ in 2003, 76% of the flux information came from the relatively homogenous mixed Broad-leaved and Korean pine forests from northwest to southwest, and the source areas of the maximum footprint were located in the range of 100-400 m southwest. There was little information from the town northeast. Only about 3% information came from other surfaces apart from 0.5 km east.
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