资源环境科技发展态势分析平台

This study examines the representation of the multi-scale temporospatial variability of the East Asian summer monsoon stationary front (MSF) in the High-Resolution Atmospheric Model (HiRAM) of the National Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory. Compared with the observed variability of the MSF in the European Center for Medium-Range Weather Forecasts Reanalysis Interim (ERA-Interim), HiRAM reproduces reasonably well the seasonal mean precipitation pattern and the seasonal migration of MSF. However, wet biases are found over the northern and eastern China and northern Japan, and dry biases extend from the southern China to the western North Pacific. These rainfall biases are directly tied to a northwestward bias in the model simulated seasonal mean location of MSF and this location bias is most pronounced in the month of May. In general, the MSF in HiRAM is more intense, located more northwestward, and more stationary with weaker interannual variations compared to the observed. A pronounced positive bias in the ocean-land sea level pressure contrast over East Asia, largely manifested as the westward expansion of the western North Pacific subtropical high, is hypothesized to be the main cause of the northwestward location bias of MSF in HiRAM. This bias in sea level pressure contrast likely results from the missing of realistic air-sea interactions in the HiRAM simulations.