Cloud processes of the main precipitation systems in Brazil: a contribution to cloud resolving modeling and to the GPM (Global Precipitation Measurement)

Abstract

The physical process inside the clouds is one of the most unknown components of the weather and climate system. A description of the cloud processes through the use of standard meteorological parameters in numerical models has to be strongly improved to accurately describe the characteristics of hydrometeors, the latent heating profiles, the radiative balance, the air entrainment and the cloud updrafts and downdrafts. Numerical models have been improved to run at higher spatial resolutions where it is necessary to describe explicit these cloud processes. For instance, to analyze the effects of global warming in a given region is necessary to perform simulations considering all these cloud processes described above. Another important application that needs to have this knowledge is the precipitation estimation by satellite. The Brazilian space program is planning to launch, in 2014 a satellite to measure precipitation, which will be part of the GPM (Global Precipitation Measurement) constellation program. Warm clouds are responsible for a large amount of the precipitation in the tropics, especially in coastal regions. This cloud type is little studied and is not considered in satellite rainfall retrievals. This project will carry out field experiments at seven sites to investigate the different precipitation regimes in Brazil. To study these precipitation regimes, the field campaigns will make use of dual polarization radar, lidar, microwave radiometers, disdrometer, Radiosonde and various other instruments. The analysis will be performed considering the microphysical evolution and the cloud life cycle, the different precipitation estimation algorithms, the development of thunderstorms and lightning formation, the processes in the boundary layer and cloud microphysics modeling. This project intends to progress in the knowledge of the cloud processes to reduce the uncertainties in the precipitation estimation, mainly from warm clouds and consequently improving the knowledge of the water and energy budget and the cloud microphysics. This research project will carry studies on climate and physical processes by the means of conventional and special observations in order to create a database that can describe the cloud processes of the main precipitating system in Brazil. Accordingly, this proposal aims the development of a database that can be carried out to improve the remote sensing precipitation estimation thus validating and improving the cloud microphysical parameterization in the cloud models. This project will especially focus on the warm cloud precipitation produced by different types of convection. (AU)