Life Cycle Effects of Cloud Clusters on the Moisture Distribution over the Eastern Atlantic

[摘要] Life cycle effects of cloud clusters on the moisture distribution are studied using GATE data. As clusters develop, moisture supply exceeds precipitation, the excess being transported upward by convective clouds and stored in the midlevel outflow divergence region. The fraction of moisture supply going into storage decreases during growth. Total moisture content and moisture supply attain their maxima when the radar echo intensity is strongest.When the upper level is cloudiest, both the moisture supply and the radar echo intensity weaken. The middle level divergence is replaced by convergence that maintains the upper level stratiform clouds. Precipitation exceeds moisture supply and the moisture content is depleted. Depletion of moisture below 600mb is caused primarily by the drying effect of mesoscale sinking beneath the upper level cloud decks. However, moisture continues to increase in the upper troposphere. As clusters dissipate moisture is depleted throughout the entire troposphere.

[学科分类] 大气科学