Characteristics and Variability of the Melting Stable Layer during DYNAMO

High-vertical resolution upper-air sounding data from Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign are analyzed to study the characteristics and variability of stable layers over Indian Ocean during two MJO events in late 2011. Contoured Frequency by Altitude Diagrams (CFADs) of temperature lapse rate show three layers of enhanced stability: (1) near 800 hPa associated with the trade-wind stable layer, (2) near the 0°C level (~550-570 hPa) associated with the effects of melting below stratiform anvils and within other portions of precipitation systems, and (3) near the tropical tropopause (~100 hPa). At sites in the DYNAMO northern sounding array, the melting-level stability peak occurs slightly above the mean 0°C level in both moist (RH above 0°C level >75%) and drier (RH above 0°C level < 75%) conditions. Time series of lapse rate show that the melting-level stable layer is more prominent for sites in the northern sounding array (as opposed to the array centered south of the equator) where the MJO signal during DYNAMO was more pronounced. In addition to sounding data, cloud profiling radar and lidar data from Gan Island (0.69°S, 73.15°E) provided by the Pacific Northwest National Laboratory (PNNL) Combined Remote Sensor retrieval algorithm (CombRet) are analyzed to examine the relationship between melting-level stable layers and clouds based on their ice/liquid water content and radiative heating/cooling properties.