大气光学湍流估算模式及其相似性函数

地表热通量和水汽通量对全球气候变化和大气环流有着重要而广泛的影响,而Monin-Obukhov(M-O)相似性函数在计算近地层热通量和水汽通量的过程中扮演着重要的角色；同时M-O相似性函数是大气光学湍流估算模式中不可或缺的因子。通过对合肥西郊35 m铁塔上气象数据的分析,利用非线性最小二乘法拟合得到了一套全新的M-O相似性函数。将之与前人提出的相似性函数作对比,展现出了较好的一致性。同时,该函数大气光学湍流的估算模式中,估算值与实测值具有较好的吻合度。分析结果表明:在稳定条件和非常不稳定条件下,可以认为温度相似性函数等于湿度相似性函数,在弱不稳定条件下两者不再满足这种相似性。

Estimation model of atmospheric optical turbulence and its similarity functions

Surface heat and water vapour fluxes have an important and extensive influence on global climate change and atmospheric circulation, while Monin-Obukhov(M-O) similarity function plays an important role in calculating surface layer heat and water vapour fluxes and it is an essential factor in estimation model of atmospheric optical turbulence. Therefore, it is necessary and urgent to propose a reasonable, scientific and effective similarity function. The meteorological datasets at the 35 m tower in the western suburbs of Hefei was analysed and a new set of M-O similarity functions are fitted by use of non-linear least squares method, which shows good consistency with the previous similarity functions. At the same time, the functions were applied to estimate atmospheric optical turbulence, the estimated values have a good agreement with the measured values. The analysis results show that under stable and very unstable conditions, the functions are similar, however, this similarity breaks down weakly unstable conditions.