鄱阳湖地区湖-陆-气相互作用的观测分析

OBSERVATION ANALYSES OF THE LAKE-LAND-ATMOSPHERE INTERACTION IN POYANG LAKE REGION

利用2013年6月1日—2014年5月31日鄱阳湖东岸70m铁塔的涡动相关观测资料、鄱阳湖水文观测资料、鄱阳气象站常规气象观测资料等,对鄱阳湖地区湖-陆-气相互作用过程进行了分析。结果表明：鄱阳湖地区潜热通量明显较感热通量大,感热通量最大值出现时间较潜热通量早约10h。摩擦速度则是白天比夜间大,且下半夜大于上半夜,正午最强,日落日出时段最小。湖-陆-气相互作用同样具有显著的季节变化特征,潜热通量最大出现在夏季,最小出现在冬季;而感热通量最大出现在秋季,最小出现在夏季。摩擦速度则是下半年大于上半年。该地区Bowen比全年小于10,夏季7月最小,冬季2月最大,大部分维持在014-061。分析湖体区的感热通量和潜热通量得到,来自湖体区的感热通量中午前后较明显,但夜间表现出季节差异,春季下半夜湖体区感热通量明显加大,夏季则整个夜间湖体区感热通量均较大,秋季相差不大,而冬季下半夜湖体区感热通量最小。潜热通量方面,来自湖体区的潜热通量总体较大,但同样存在季节差异。春季湖体区潜热通量均较大,而夏季除中午前后较小外,其余时段都明显大,秋季夜间湖体区潜热通量明显偏小,冬季午后湖体区潜热通量增大。同时,秋冬季节湖体区常会出现逆温现象。分析还得到,水面蒸发量、鄱阳湖水域面积和最高气温与潜热通量关系较大。

By using the eddy-covariance data from a 70-m tower on the east bank of Poyang Lake, the hydrolog- ical observation data of Poyang Lake, and the conventional meteorology observational data from Poyang station during the period of June 1 2013-May 31 2014, we analyzed lake-land-atmosphere interaction processes. The results show that latent heat flux （LHF） is significantly larger than the sensible heat flux （SHF）. The largest SHF occurs near midday, which is about 1.0 h earlier than the LHF. The friction velocity is larger during day- time and increases with time during night time, and the minimum friction velocity occurs during sunrise or sunset. The lake-land-atmosphere interaction process also presents a seasonal feature. The maximum LHF occurs in summer and the minimum in winter, while the maximum SHF occurs in autumn and the minimum in summer. The friction velocities in the first half year are smaller than those in the second half year. Most of the Bowen ra- tios are 0. 14 -0. 61, with the largest in July and the smallest in February. The SHF from the Lake （Hsr） is larger than that from other regions （nse） around midday, however, it presents seasonal difference in the evening. The Hsr obviously increases after midnight in spring. In the whole summer evening, it is larger than Hse. In au- tumn it is almost the same as Hse, while in winter, it is smaller than Hse. The LHF from the Lake （LEr） is gen- erally larger than that from other regions （LEe） except for the periods of late noon in summer and evening in au- tumn, which also presents seasonal difference. Meanwhile, temperature inversion always occurs in the autumn and winter evenings. The results also show that the LHF is related to evaporation over the Lake, the water area of the Lake and the highest air temperature.