Observational Analysis of the Vertical Temperature Structures Associated with Deep Convection over Tropical Oceans

Deep convection is known to be sensitive to the amount of moisture in the lower free-troposphere. In order to understand more about the reasons for this sensitivity, temperature structures associated with precipitation over the tropical oceans are studied. Soundings from the Integrated Global Radiosonde Archive (IGRA) and precipitation data from the Tropical Rainfall Measuring Mission (TRMM) are analyzed over eight stations located over the Western Pacific Ocean and the Eastern Indian Ocean. The soundings from each station are divided into groups based on the amount of previous precipitation and compared to a piecewise average profile of temperature. The results strikingly reveal that, in addition to the well known upper tropospheric warm anomalies and low-to-midtropospheric cold anomalies, shallow but strong warm anomalies between 800 and 950 hPa are observed after precipitation. The magnitudes of these lower tropospheric warm anomalies, as well as the low-to-midtropospheric cold anomalies and the upper tropospheric warm anomalies, increase with larger amounts of previous precipitation. It is shown that the warm anomaly is larger over stations with smaller low-to-midtropospheric relative humidity and is absent over the moistest stations even after intense precipitation. The formation mechanisms of these temperature structures and their potential effects on subsequent convection are discussed.