A Study on the Influence of Soil Moisture on Deep Convection around Ulaanbaatar, Mongolia, as an Arid Environment Using AMSR-E Soil Moisture

摘要

This study aims to describe the influence of soil moisture on deep convection around Ulaanbaatar, Mongolia, as an arid environment based on observation data. Variation in the volumetric soil moisture was evaluated using the AMSR-E microwave data, and the convective activity was estimated using C-band airport radar. The following results were obtained for the influence of soil moisture on deep convection.1. Soil moisture averaged over the analysis region was strongly influenced by the variations in the precipitation amount. 2. Onset of deep convection and the peak of convective activity were delayed for 1-2 h on moist soil days as compared to those on dry soil days. 3. Deep convection tended to develop over an area with positive anomalies of soil moisture under dry soil moisture conditions. 4. Deep convection could occur even for relatively high stability of the SSI (Showalter’s stability index) values ranging from 1 to 5°C on dry soil days, whereas the SSI values of less than 1°C were necessary for the occurrence of deep convection on the moist soil days. 5. Deep convection during the early afternoon over the mountains tended to be weak when the soil moisture content over the mountains was higher than 11%.