Detecção das interações do sistema brisa marinha/terrestre com sistemas sinóticos na costa leste de Alagoas utilizando Transformada Wavelet.

• Ano de defesa: 2009
• Autor(a) principal: Ferreira, André Deodato
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Alagoas; BR; Processos de superfície terrestre; Programa de Pós-Graduação em Meteorologia; UFAL
• Palavras-chave em Português: Wavelet transform; Precipitation; NEB; Breezes; Transformada em ondeletas; Precipitação; Brisas; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIA
• Link de acesso: http://repositorio.ufal.br/handle/riufal/874

The eastern coast of the Northeast Brazil (NEB) is a region where transient weather systems interact with local systems, modulating their frequency and intensity. Understanding the mechanisms of such interactions may be instrumental in explaining the observed precipitation patterns in this region. The objective of this work is quite within this scope and takes a new approach, namely the study of time series using spectral decomposition. The wavelet transform was adopted for it has proven to be a very powerful tool in dealing with local data in many areas. It furnishes a hierarchical frame that allows the double location in time and frequency domains. The hourly averaged series of wind speed and direction, air temperature, humidity and precipitation were taken at an observing tower at the 12.40 high during the October, 2004 October 2005 period in the Santa Rita island (mangrove area) at 9° 42 18 S e 35° 48 32 W. Relevant characteristics of the seasonality, transport and intensity of the breeze systems were noted, showing a clear distinction among the rainy, dry and transitional periods. Mesoscale systems are more active during the dry period because they are quite dependent of the daily cycle of heating and cooling. Large scale transient systems are more prominent during the rainy season, being responsible for the highest observed precipitation rates. The local wind system of sea land breezes shows a predominant southeast (SE) direction, thus evidencing the sea breeze. It was also noted that the highest amplitudes and wind persistency from SE were reinforced by the SE Trade Winds, creating a constructive interference in the signal. The prevailing winds from northwest (NW) were only observed during the dawn, thus characterizing the land breeze branch of the local circulation. The sea/land breeze variability affected the precipitation regime, by forming a surface convergence zone (rising motions) in accord with the time of the precipitations. These also showed a conic multifractal pattern in the periodgram, typical of high space-time variability.