关于大气涡动热通量参数化问题研究

用NCEP/NCAR等再分析资料计算和分析表明,月平均瞬变涡动热通量和月平均温度梯度的局域相关性很低,甚至在一些纬度是负相关,更严重的是二者之间存在非线性的多值对应函数关系.如果用非局域参数化,参数化水平将有所提高,但改进并不明显.通过与分子运动论输运理论进行数学、特别是物理类比提出了考虑"风暴路径"效应的瞬变涡动热通量的参数化方案,经再分析资料的检验,结果表明它能大大提高参数化的水平.其次,还证实采用空间非局域参数化仍然是进一步提高瞬变涡动热通量参数化水平的方法之一.此外,资料分析显示中高纬度纬向平均温度梯度和纬偏涡动温度通量之间也存在负相关及多值函数关系,说明仅用温度梯度去参数化纬向平均涡动热通量难以得到好的结果,需要考虑多元参数化或非同步参数化等.

On the Parameterization of the Transient Eddy Heat Flux in Atmosphere

The parameterization of the transient eddy heat flux is made. NCEP/NCAR reanalysis data and ECMWF data shows that the heat flux is almost not correlated with monthly temperature gradient along a latitude circle, in which the positive and negative correlation coefficients exist over all latitude belts in the Northern Hemisphere. Moreover, there is no one-to-one corresponding functional relationship between them. In general, the cross-correlation between them is more significant than the local one, which implies the possibility of non-local parameterization for the heat flux. Owing to physical and mathematical comparisons between the transient eddy and the molecular heat transfer in statistic physics we translate the molecular heat transfer theory onto the transient eddy heat transfer, and then make a new parameterization scheme for the transient heat flux of atmosphere. An examination to the new scheme with the reanalysis data illustrates a great improvement for the parameterization of eddy heat flux, and the non-local parameterization is also necessary for the improving the parameterization, either. Besides, the correlation calculation shows that there are anti-correlation between the zonal mean temperature and zonal mean eddy heat flux in middle latitudes. A complex non-linear relationship also exists between them, which implies that it is difficult to parameterize the eddy heat flux with the zonal mean temperature gradient only.