The Diabatic Heating Structure Of Tropical Cloud Systems

Cloud,precipitation and radiation data based on observations of MODIS,AMSR-E,TRMM PR,CloudSat and CALIPSO are synergized to evaluate latent heat and radiative heating structures of tropical deep convective systems and contributions of tropical diabatic heating structure from different cloud systems are constructed.Cross-Orbital dataset are constructed by collocating TRMM and Aqua orbits and synergizing corresponding TRMM PR and Aqua-MODIS datasets and latent heat characteristics of tropical deep convective systems according to Yuan and Houze(2010)are investigate.We found that in the mesoscale convective systems(MCSs),the latent heat heating profile resulted from convective precipitation is almost entirely orthogonal to that of stratiform precipitation.Thus,we define a stratiform index to quantitatively represent the relative contribution of the stratiform heating structure to the whole latent heat structure.It is found that the level of maximum heating of the MCSs system varies with scale in each convective region.The small MCSs have the strongest heating effect in the 5-6km layer,while larger MCSs usually have their heating maximum at 6-7km(land)and 7-8km(ocean).Such differences are largely resulted from the change of relative weighting of stratiform heating.Lower stratiform indices of MCSs are found in continental convective regions than that in oceanic convective areas.Among oceanic regions,MCSs in the east Pacific inter tropical convergence zone show higher stratiform index compared to other regions.This is also consistent with the domain mean properties based on TRMM PR(Schumacher and Houze 2003)showing that the stratiform rain fraction is higher than other tropical regions.Based on the properties of the latent heat structure derived from the cross-orbital data,tropical latent heat structures resulted from different cloud systems including organized deep convective systems and other precipitating clouds are estimated based on the MODIS cloud properties and precipitation from the AMSR-E.Tropical radiative heating structures resulted from different cloud systems are derived from the observations of MODIS,CloudSat and CALIPSO.The annual average radiative forcing of the MCSs system in the tropical region is evaluated,and the three-dimensional structure of the radiative heating distribution in the tropical region is obtained.By comparing with the latent heat structure,it is found that the distribution of radiative forcing mainly concentrates above 9 km,and the corresponding latent heat is mainly below 9 km.In MCSs,their latent heating is larger in magnitude compared to their radiative forcing.However,they heat the atmosphere at different heights,which certainly result in totally different dynamic responses.By combining the three-dimensional structures of latent heat in the tropical region and radiative heating,the vertical velocity of the tropical region was calculated simply by the heat flow equation and compared with the reanalysis data.The diabatic heating is a crucial factor determining the tropical circulation structure.Thus the diabatic heating structures derived based on current-date observations will benefit future studies about the dynamic responses to diabatic heating from different cloud systems.