Analysis of the Temperature Structures Associated with Tropical Precipitation

Atmospheric deep convection is known to depend on the amount of low-to-midtropospheric moisture. Here, the vertical temperature structures associated with precipitation over tropical oceans are studied in order to understand more about the relationship between deep convection and low-to-midtropospheric humidity. The Integrated Radiosonde Archive soundings and Tropical Rainfall Measuring Mission precipitation data from eight stations located over the Eastern Indian Ocean and Western Pacific are used. The soundings are divided into groups based on the amount of previous precipitation. The soundings made after precipitation surprisingly reveal lower tropospheric warm anomalies between roughly 800-950 hPa, which are strong enough to hinder subsequent convection. The warm anomalies are observed over stations with low climatological humidity in the 500-700 hPa layer, whereas over moister stations the warm anomalies are not observed. Other characteristics of the soundings made after precipitation are upper tropospheric warm anomalies above the 500 hPa pressure level, low-to-midtropospheric cold anomalies between 500-700 hPa and cold anomalies near the surface. The 800-950 hPa warm anomaly and its formation mechanism are studied with idealized simulations using the Weather Research and Forecasting Model (WRF). Results from both the observational analysis and WRF simulations will be discussed.