Cloud Radiative Heating Profiles in the Indo-Pacific Warm Pool Region Affected by the MJO and Kelvin Wave

Abstract:

Cloud radiative heating is an important component of diabatic heating, hence it is also an fundamental factor modulating the large-scale atmospheric circulation. It is crucial to accurately estimate cloud radiative heating profiles associated with the Madden－Julian Oscillation (MJO) and Kelvin Waves (KW) to better understand these large-scale convective phenomena.

A new method based on ARM surface long term remote sensing data was developed to account deviations of radiative heating derived from the 1:30 and 13:30 A-Train sampling from the dirunally averaged heating. The new method was applied to CloudSat and CALIPSO 1:30 and 13:30 radiative heating structures associated with MJO and KW were investigated. It is found that under the “large-scale active convection” scenario the net heating was consistently over estimated if only using the two-time sampling. The adjusted net radiative heating associated with active phases of both MJO and long-wave KW (wave numer <=4) were more “bottom heavy”. The radiative heating associated with MJO is more “bottom heavy” than that associated with KW whose feature is dominated by waves with wave number>4. However, when the wave numer is less than 4 (ie. the spatial scale of its convection is comparable to that of MJO), the KW radiative heating structure is similar to that of MJO.