关于用台站资料估算西北干旱区夏季感热通量的热力参数化比较

气象台站观测的气象要素可能受城市化等因子的影响而与野外试验站的观测存在一定的差异,这影响野外试验获取的热力参数直接应用于西北干旱区台站感热通量的估算。本文选取了一些常用的热力参数化方案(包括Z10、B82、Z98、Y08和Z12等方案),通过敦煌站夏季估算的感热通量与野外观测的比较以及对整个西北干旱区夏季感热通量的估算,评价了这些热力参数化对动量粗糙度的敏感性和在西北干旱区的适用性。结果显示,热力输送系数取定值的方案计算西北干旱区的感热通量可能存在较大不确定;台站的动量粗糙度可能受城市化等因子的影响,但在感热通量计算时建议取台站下垫面的动量粗糙度;Y08方案估算的感热通量相对比较合理,可以用来研究西北干旱区的夏季地表感热输送特征。

Testing of Surface Flux Parameterizations for Estimating Summer Sensible Heat Flux over the Arid Region of Northwest China from China Meteorological Administration Data

Meteorological variables observed at China Meteorological Administration(CMA) stations may differ from those in field stations due to the effects of urbanization and other factors related to CMA observations.This hampers the application of the determined thermodynamical parameters from field experiments in estimating the sensible heat flux over the arid region of Northwest China.This study chooses several broadly used surface flux parameterization schemes(including Z10, B82, Z98, Y08, Z12, etc.) and tests their sensitivities to momentum roughness length.It also tests their application in the arid region of Northwest China by comparing the sensible heat flux estimation at Dunhuang with observations and estimations of summer sensible heat flux over the whole arid region of Northwest China from CMA data. The results indicate that the scheme taking the bulk transfer coefficient for heat as a constant may bring much uncertainty to sensible heat flux estimation over the arid region.It is advised that the momentum roughness length at CMA stations should consider that of the natural underlying surface where the station is located when determining the sensible heat flux, although it may be disturbed by urbanization and other factors.The sensible heat flux estimated by the Y08 scheme seems relatively reasonable, and therefore the use of this scheme is advised when analyzing the characteristics of summer surface sensible heat flux over the arid region of Northwest China.