资源环境科技发展态势分析平台

Numerous observational and modeling studies have addressed the impact of soil moisture on subsequent precipitation (primarily its initiation), yet consensus remains elusive. Here we quantify the relationship between soil moisture and precipitation amplification over the U.S. Southern Great Plains. Warm season (June-September) days for the 2002-2011 period (with similar to 1220 total days) are partitioned into three dynamic regimes based on daily water vapor convergence, among which afternoon precipitation event days are identified based on simple criteria. We find that antecedent soil moisture conditions are negatively correlated with subsequent afternoon precipitation magnitude for low dynamic regimes, but this correlation becomes positive for high dynamic regimes. In contrast, this correlation is markedly reduced in magnitude and becomes insignificant when all regime days are considered. These results are also confirmed by analyzing the precipitation histogram and diurnal cycle. Furthermore, different pathways are provided for precipitation amplification for low and high dynamic regimes.

Plain Language Summary Numerous studies have addressed the effect of soil moisture on subsequent rainfall, yet consensus remains elusive. While the impact of precipitation on soil moisture is intuitive, the effect of antecedent soil moisture on precipitation is not fully understood. Here we address the relationship between morning soil moisture and afternoon rainfall accumulations over the Southern Great Plains during warm season (June-September) days for the 2002-2011 period. Days are partitioned into different dynamic regimes based on daily water vapor convergence, among which afternoon rainfall event days are identified based on simple criteria. We find that antecedent soil moisture is negatively correlated with afternoon rainfall accumulation for low dynamic regimes (with low water vapor convergence), but this correlation becomes positive for high dynamic regimes. However, this correlation is much smaller and insignificant when all regime days are considered. Different pathways are provided for precipitation amplification for low and high dynamic regimes.