大尺度降雨异常对地面过程的影响——一类气候反馈机制的初步研究

STUDY ON THE INFLUENCES OF LARGE SCALE PERSISTENT RAINFALL ANOMALIES ON THE LAND SURFACE PROCESSES- ONE KIND OF CLIMATIC FEEDBACK PROCESSES

本文以华北地区春季两个多雨年和两个少雨年为例,研究半干旱地区大范围持续性降雨对地面物理过程的影响。 根据地面边界层热通量和辐射通量的参数化公式以及地面水份倾向方程,计算分析了春季降雨异常增多后地面热状况、热量平衡各分量和水文状况的变化,发现降雨异常增多后,地面土壤温度和地面气温明显降低,土壤湿度和地面蒸发潜热明显增大,地面反照率也有所降低。值得指出的是,地面物理状况的变化相对于降雨异常过程有明显的时间上的后延现象,在空间场上有较好的配合关系。

In this paper, two wet springs and two dry springs of North China have been chosen to study the effect of large-scale persistent rainfall anomalies on the land surface processes in semi-arid regions. The results show that the soil moisture and the land surface evaporation increase significantly after the development of anomalous rainfall, which reduces the soil temperature and the surface air temperature. It should be emphasized that there is a significant time-lag effect of anomalous rainfall on the land surface processes.