青藏高原土壤水分影响我国东部夏季降水的时空尺度

Soil moisture is a key factor in the land-atmosphere interaction, its memory modulates the land surface energy budget and atmospheric heat source persistently. The project aims to, based on regional numerical modeling (WRF-ARW) and the soil moisture product derived from assimilating microwave data into a land surface model, clarify the spatial-temporal impact of soil moisture over the TP on the summer rainfall in eastern China. The scientific issue is how the soil moisture over the TP affects the summer rainfall in eastern China via partitioning the surface energy fluxes. We are going to study on (1) the relationship between the variation of soil moisture over the TP and the surface thermal source and atmospheric heat source, based on observations and assimilation data; (2) incorporate the assimilated soil moisture product into WRF as a lower boundary condition over the TP, to analyze the intraseasonal change of the land surface heating and atmospheric heat source caused by the soil moisture, furthermore to reveal the spatial-temporal impact on the summer rainfall in eastern China. The implication of the project will contribute to understanding the relationship between land-atmosphere interaction over the TP and short-term climate in China.

青藏高原土壤水分是陆-气相互作用的关键因子，其记忆效应会持续影响地表能量分配和大气热源。本项目拟以微波卫星陆面同化系统产生的土壤水分数据和区域数值模式（WRF-ARW）为基础，揭示青藏高原土壤水分影响我国东部夏季降水的时空尺度。拟解决的关键问题是高原土壤水分如何通过影响高原热力作用而影响到我国东部夏季的降水。研究内容包括：（1）根据观测和同化资料分析青藏高原土壤水分变异对高原地表和大气热源的影响；（2）引入同化系统输出的土壤水分产品到WRF模式中，分析季节内青藏高原土壤水分对地表热源和大气热源的改变，进而研究这种改变影响我国东部夏季降水的时间尺度和空间范围。本项目的实施有助于认识青藏高原陆-气相互作用对我国短期气候的影响。