基于陆面模式Noah-MP的不同参数化方案在半干旱区的适用性

The Applicability of Different Parameterization Schemes in Semi-Arid Region Based on Noah-MP Land Surface Model

针对陆面模式Noah-MP对兰州大学半干旱气候与环境观测站(SACOL)2009年8月地表热通量模拟值偏差大的问题,通过分析相关物理过程和模拟试验来探究偏差的来源,并确定合适的参数化方案:采用Chen97方案计算感热输送系数可以改善感热通量的模拟;采用Jarvis气孔阻抗方案能增大植被蒸腾,改进模式对潜热通量的模拟效果,同时也使热通量在感热和潜热间的分配比例合理;采用LP92方案可减小土壤蒸发阻抗并有利于土壤蒸发,使得模式对潜热通量的模拟效果变好。不同参数化方案的组合试验表明:同时采用2组或3组新的参数化方案组合可以进一步减小模拟的地表感热和潜热通量的均方根误差,但是土壤湿度和温度的模拟效果并没有同步改善。

Considering the large bias of the simulated surface heat fluxes with Noah-MP model at the Semi-Arid Climate and Environment Observatory of Lanzhou University（SACOL） in August 2009, an analysis of the physical processes and a series of sensitivity tests are carried out to investigate the main reasons for the large bias and select appropriate parameterization schemes. Results show that the Chen97 parameterization scheme for the surface sensible heat exchange coefficient can improve the sensible heat flux simulation. The Jarvis stomatal resistance parameterization scheme can increase the transpiration of plants and thereby improves the latent heat flux simulation and produces a more reasonable distribution ratio of sensible and latent heat fluxes. The LP92 evaporation parameterization scheme for bare soil can significantly increase the evaporation compared with the original scheme and gives a better simulation of the latent heatflux. Finally, according to the results with different combinations of the above three parameterization schemes, it is found that using two or three new parameterization schemes simultaneously can further reduce the RMSE（Root Mean Square Error） of the simulated surface sensible and latent heat fluxes, but the simulated soil moisture and soil temperature are not improved accordingly.