Examining the influence of spring soil moisture anomalies on summer precipitation in the U.S. Great Plains using the Community Atmosphere Model version 3

摘要

The influence of spring soil moisture anomalies on summer precipitation variations in the U.S. Great Plains was investigated using the coupled version of the Community Atmosphere Model version 3-Community Land Model version 3. A series of experiments were conducted to examine how spring soil moisture anomalies influence summer precipitation. Results demonstrate that there are significant differences in precipitation response depending on the timing, sign, and magnitude of the spring soil moisture anomalies. Timing is the most important factor that controls the soil moisture-precipitation interaction. Soil moisture anomalies imposed on 1 May and 1 June tend to have significant influences on summer precipitation, depending on the sign of the soil moisture anomalies. Dry soil moisture anomalies tend to affect subsequent precipitation for longer than wet soil moisture anomalies when initialized on 1 May. Wet soil moisture anomalies can have more immediate and larger impacts on summer precipitation when they are imposed on 1 June. April soil moisture anomalies do not have a statistically significant impact on summer precipitation. The precipitation response is stronger as the magnitude of the soil moisture anomalies increases. Significant differences in the temporal variations of soil moisture exist not only between dry and wet experiments but also among the 10 soil layers. Generally the near-surface layers respond much more rapidly than the deep soil layers. Further study is needed to determine whether these findings are model specific.