An assessment of the land surface parameters on the simulated regional climate circulations: The 1997 and 1998 east Asian summer monsoon cases

摘要

In atmospheric modeling, the treatment of land surface processes is a critical component to the success of seasonal climate simulation. The purpose of this study is to assess the importance of the surface parameters of the land surface model in regional climate simulations for the 1997 and 1998 east Asian summer monsoon (EASM) cases. In order to reach this end, three ensemble experiments were conducted using the National Centers for Environmental Prediction Regional Spectral Model with different vegetation type data set, which leads to differences in surface albedo and roughness length. These two parameters which are mainly dependent on vegetation type are obtained from the corresponding climatological data sets externally during the model integration. As a result, it is found that the specification of surface albedo and roughness length for a given vegetation type is more crucial than either the number of classification types for vegetation and soil or the horizontal resolutions. It is concluded that the geographical uniqueness of the EASM region is also a major factor to be emphasized, as it causes dynamically driven impacts in association with the thermodynamical effects arising from the values in surface parameters.