洋面动量、感热和潜热通量计算的研究

COMPUTATIONS OF MOMENTUM, SENSIBLE HEAT AND LATENT HEAT FLUXES ON PACIFIC OCEAN

整体传输公式是一种常用的计算洋面海气通量的方法。在作气候平均计算时,存在两种平均方法:方法一F_1=AB及方法二F_2=AB。显然,方法一是合理的,而方法二是对方法一的近似。本文利用COADS资料针对不同的平均时间计算分析了方法二对方法一的近似程度,结果表明:利用方法二计算长期气候平均,平滑时间超过5天则对计算结果必须进行订正;对感热和潜热通量,月平均方法二在20％的精度内可代替方法一,而旬平均方法二则可在10％的精度内代替方法一;动量通量月平均和旬平均精度分别为40％和20％。因此方法二在计算月平均动量通量时必须作订正,或直接用方法一进行计算,本文同时计算比较了1972年(E1 Nino年)和1975年(非E1 Nino年)太平洋洋面的各项能量及总能量收支,发现1972年洋面能量收支年变化幅度比1975年小得多,其差别主要决定于感热和潜热的变化。

The bulk transfer formula is often used to calculate the air-sea exchanges. There are two average methods to compute mean fluxes: (1) F1=ABand, (2 )F2 = AB, Obviously method (1) (M1) is reasonable, while method (2) (M2) is an approximate form in which the turbulent correlation term is omitted. In this paper the mean fluxes are calculated by using CO ADS date with M 1 and M2, respectively, under different average time to answer in what extent M2 approximates to M 1 . The results show that when M 2 is used to calculate longterm average, the calculating results should be corrected if the average time is longer than 5 days. For using M2. the monthly and ten-day mean errors in sensible and latent heat fluxes are less than 20% and 10% respectively, which is accurate enough to calculate the average fluxes. For the momentum flux, the monthly and the momentum flux can only be calculated with Ml, or by using M2 with correction. The energy budgets on Pacific Ocean in 1972 and 1975 are also calculated. It is found that the yearly variations of energy budget in 1972 is much less than that in 1975, which is mainly caused by the changes of sensible and latent heat fluxes.