Lower-Tropospheric Warming and Drying in Tropical Mesoscale Convective Systems: Implications for the Problem of Cumulus Parameterization

Observations from the International Winter Monsoon Experiment (Winter MONEX) have been used to determine temperature changes in the lower troposphere beneath the stratiform components of tropical mesoscale convective systems. It is found that while the apparent heat source Q1 in the lower troposphere beneath the stratiform cloud systems is negative (due to hydrometeor melting and evaporation), the time tendency of dry static energy (*s/*t) is positive. This low-level warming is a result of mesoscale downdrafts within the mesoscale convective systems. The warming and drying at low levels in such systems may contribute importantly to temperature and moisture changes in large-scale tropical disturbances. The effects, if important, will need to be considered in the development of schemes for the parameterization of cumulus convection.