四川盆地丘陵区地表显热通量分析

Analysis of Sensible Heat Flux over Hilly Land in Sichuan Basin

利用2000～2007年四川省乐至县大口径闪烁仪（Large Aperture Scintillometer,LAS）观测资料,对比分析了降水日与非降水日、干旱日与非干旱日地表热量通量的时间变化特征。分析结果表明：非降水日显热通量具有明显的日变化特征,最大值出现在13：00左右,降水日显热通量的日变化受降水影响,降水使显热通量减小;非降水日的月平均显热通量有2个峰值,分别出现在5月和8月,最小值在1月;降水日也有2个明显的月平均显热通量峰值,它们是4月和7月,12月最小;夏秋交替的9月非降水日与降水日的显热通量差异最大;干旱日和非干旱日的显热通量都是1月最小,干旱日8月显热通量最大,非干旱日是4月最大;6～10月干旱与非干旱日的显热通量具有明显差异;干旱越严重的月份,月平均显热通量越偏大;相同时次的显热通量平均值,干旱日较非干旱日的明显偏大。

The sensible heat fluxes are analyzed by using LAS（Large Aperture Scintillometer） over hilly land in Sichuan Basin and meteorological observations from 2000 to 2007.The results show that the average sensible heat fluxes change regularly in daytime,increasing gradually after sunrise and reaching the maximums around 13：00,then decreasing gradually.The fluxes for the rainy days are influenced greatly by precipitation.The fluxes are smaller for the rainy days than the days with no precipitation.For the days without rain the highest peak value of the monthly average sensible heat fluxes occurs in August,the lower peak value occurs in May and the lowest value occurs in January.For the rainy days the highest value occurs in April,the lower occurs in July and the lowest occurs in December.The maximal difference between the rainy days and the days without rain occurs in September.Both the minimum for the drought days and normal days occur in January.The peak value is in August for the drought days or in April for the normal days.The obvious difference between drought days and normal days occurs in Jun to October.The more serious the drought is,the more the difference between drought and normal is.The average sensible heat for the drought days is bigger than the normal days at the same time.