| 摘 要： |
The influence of soil moisture (SM) on atmospheric precipitation has been extensively studied, but few of these studies have considered the role of land-atmosphere (L-A) coupling in afternoon precipitation events (APEs) at a sub-daily timescale. Here, using in-situ observations and reanalysis data sets, we investigated the effect of the soil moisture anomaly (SMA) on warm seasons' afternoon precipitation in the North China Plain (NCP), identified as a strong L-A coupling region. APEs were separated from all precipitation events in the NCP during the warm seasons of 2010-2019. It follows from a comparative analysis that an APE is more likely to be initiated on drier soil, which has little dependence on the thresholds used for identifying an APE. However, no affirmative relationship is found between precipitation amount in the first hour of an APE (APE1hour) and the SMA. Further analyses indicate that larger amounts of APE1hour result from higher convective available potential energy (CAPE), higher moist static energy (MSE), or weaker vertical shear of horizontal wind. When considering the joint effects of SMA and atmospheric variables, APEs tend to occur on drier (wetter) soil with lower (higher) lower-tropospheric stability, CAPE, or MSE. This study highlights the significant roles of L-A interactions on local atmospheric precipitation, especially the joint roles of SM and atmospheric variables on precipitation. Atmospheric precipitation events (APEs) are mostly the consequence of atmospheric circulation anomalies and water vapor and energy transport supplies from the atmosphere and land surface. Previous studies have reported the important role of the soil moisture anomaly (SMA) on convective precipitation events, but how SMA influences the subsequent convective precipitation remains highly uncertain. In this work, we focus on the impact of morning SMA on subsequent local-scale afternoon precipitation during warm seasons. Using in-situ observations, we identified the North China Plain as a strong land-atmosphere (L-A) coupling area in China, further finding that warm seasons' APEs tend to occur on dry soil. However, the precipitation amount associated with an APE is almost independent of SMA. A joint analysis indicates that larger precipitation amounts result from higher moist static energy, convective available potential energy, or weaker vertical shear of horizontal wind. This study highlights the significant roles of L-A interactions on local atmospheric precipitation. The North China Plain is a strong land-atmosphere coupling area during warm seasons In general, afternoon precipitation events (APEs) are more likely to be initiated over dry soil However, for more stable and moister atmosphere, APEs are more likely to occur on wet soil |
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