The physical processes inside clouds are one of the most unknown components of weather and climate systems. A description of cloud processes through the use of standard meteorological parameters in numerical models has to be strongly improved to accurately describe the characteristics of hydrometeors, latent heating profiles, radiative balance, air entrainment and 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 it is necessary to perform simulations taking into account all of these cloud processes described above. Another important application which requires this knowledge is satellite precipitation estimation.

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 focusing on the microphysical evolution and cloud life cycle, different precipitation estimation algorithms, the development of thunderstorms and lightning formation, processes in the boundary layer and cloud microphysical modeling. This project intends to extend the knowledge of these cloud processes to reduce the uncertainties in precipitation estimation, mainly from warm clouds and, consequently, improving the knowledge of the water and energy budget and cloud microphysics. This research project will carry out studies on climate and physical processes by way 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 at the development of a database that can be carried out to improve remote sensed precipitation estimation, thus validating and improving cloud microphysical parameterization in cloud models. This project will especially focus on the warm cloud precipitation produced by different types of convection.

THE PRE - CHUVA - GPM 2010 CAMPAING - MARCH, 1^st TO 25^th, 2010

Pre-Chuva GPM 2010 is a preliminary field campaign to prepare the series of campaign that will start at the end of 2010. The Campaign is supoorted by AEB, INCT-Mudanças Climáticas (CNPq/MCT-FAPESP), INPE and NASA.

The scientific campaign GPM-CHUVA 2010, began on Monday (2010-03-01), the Alcântara Launch Center (CLA) in Maranhão, in order to study the formation of raindrops from warm clouds, trying to improve models for weather forecasting and the estimation of precipitation from meteorological satellite data. The trial, expected to close March 20^th, is part of the international Global Precipitation Measurement (GPM) - Medidas Globais de Precipitação in Portuguese - led by the space agencies of the United States (NASA) and Japan (JAXA).

Alcântara (MA) was chosen for ease of logistics (CLA), but also because much of the precipitation in the region is related to the formation of warm clouds; i.e., without ice formation. It is expected that better understanding of rainfall will result in the improvement of model precipitation data from satellites, operationally and also for those who will be part of GPM.

Among the foreign institutions, to the campaign to NASA, Colorado State University, the United States and University of Bonn, Germany. On the Brazilian side, in addition to the DCTA, the following institutions will also participate: The Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG) of USP, Institute of Energy and Nuclear Research (IPEN), National Institute for Amazonian Research (INPA), Instituto Tecnológico SIMEPAR , State University of Ceará (UECE) and Ceará Foundation for Meteorology and Water Management (FUNCEME).

Preliminary results from the campaign will be presented in June this year (2010) in Helsinki, Finland, the Workshop on Global Precipitation Measurement (GPM) Ground Validation. The data collected will be discussed in order to validate the instrument that measures will be taken on board the satellite program GPM. This project includes seven satellites. The possibility of Brazil participating in the program with the development of a satellite using the Multimission Platform (MMP) is being reviewed by the AEB.

During the campaign, the following instruments are being employed: a polarimetric radar, the CLA for measures of precipitation and cloud structure, a Bandeirante aircraft, UECE for data on cloud droplet, a micro-radar and an advanced radiometer microwave ADMIRARI, University of Bonn, passive microwave radiometer, lidar LIDAR, GPS, INPE, and the NASA disdrometer (for size distribution of raindrops) to understand microphysics of clouds.