Cloud processes of the main precipitation systems in Brazil: Overview and first results from the CHUVA project

In April 2011, the first field campaign of the CHUVA project took place in Fortaleza, on the norh-eastern coast of Brazil. The set-up of remote sensors consisted of a Gematronik X-band polarimetric weather radar, a Ka-band Micro Rain Radar, a Raman lidar, and an MP3000 passive microwave temperature and humidity profiler and was complemented by a wealth of ground-based (disdrometers, rain gauges, anemometric tower) and air-borne (triangle of radiosonde launches every six hours, research aircraft with particle detection) in-situ sensors. With this unprecedented sensor assembly deployed in the tropics, a detailed assessment of processes governing the formation of clouds and precipitation becomes feasible. The focus on the first campaign in Fortaleza is put on the detection of warm clouds, i.e., clouds that do not exceed the melting layer and therefore form precipitation without the influence of the ice phase. Rain events originating from warm clouds can be very hazardous, but detection with traditional satellite-based precipitation estimation schemes is difficult due to the lack of the ice phase of these clouds and therefore remains an unresolved problem. It is expected that the results from the Fortaleza campaign will improve the understanding of warm rain events and eventually lead to better rain estimates over land. Following the campaign in Fortaleza, the whole sensor assembly will be moved to Belem, a city in the north of Brazil, at the border of the Amazon and just slightly below the Equator. The focus of the Belem campaign, taking place in June and July 2011, is put on tropical squall-lines and their associated processes that form intense tropical precipitation. We will present an overview of the CHUVA project and first results obtained from the campaigns in Fortaleza and Belem. First data analysis includes the assessment of the performance of different radar attenuation correction schemes with respect to the variety of rain types as well as hydrometeor identification with different algorithms. In addition, the behavior of the vertical profiles of polarimetric observables during different meteorological situations is studied.