Wind Estimation – the Studies Made at Funceme

Atmospheric circulations in the tropics are not well known. Beyond of its complexity, the understanding of tropical meteorology has been prejudiced by the lack of observational data. Meteorological satellites appear as important source of information to complement in-situ observations. At FUNCEME, the Ceara State Foundation for Meteorology and Water Resources, the weather and climate monitoring and forecast are also based on satellite data, complementing meteorological radar, automatic data collection platforms (DCP), and conventional rain gages data. In this paper, we present the development of the high-level wind estimation from METEOSAT images made at FUNCEME and how this product can be helpful in monitoring weather and rainfall. These studies began in 1995, by the adaptation of the EUMETSAT ́s (European Organisation for the Exploitation of Meteorological Satellites) and LMD ́s (Laboratoire de Météorologie Dynamique) approaches. The present version of wind estimation uses water vapour instead of infrared channel, as well as a brightness temperature gradient procedure to define the centre of the target and search windows. An additional routine of spatial consistency improves the filtering of bad vectors. The high level divergence calculated from these wind fields provide very interesting information that can be associated to convective cloud systems. The use of such wind fields and related divergence are used at FUNCEME to monitor tropical convective cloud systems such as merged inside the Intertropical Convergence Zone (ITCZ), Upper Level Cyclonic Vortex (ULCV) and Mesoscale Convective System (MCS).