A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

SOME CHARACTERISTICS OF THE TEMPORAL EVOLUTION OF THEATMOSPHERIC BOUNDARY LAYER ABOVE PANTANAL WETLANDEliana Soares de Andrade 1 , Leonardo D. A. Sá 1 , Maria Paulete P.M. Jorge 1 , Amaury deSouza 2(1) Laboratório Associado de Meteorologia e Oceanografia, Centro de Previsão de Tempo eEstudos Climáticos, Instituto Nacional de Pesquisas Espaciais, Avenida dos Astronautas1758, 12227-010, São José dos Campos, Brazil; (2) Departamento de Física, UniversidadeFederal do Mato Grosso do Sul, Campo Grande, MS, Brazileliana@cptec.inpe.brAbstract: Pantanal is one of the biggest wetland regions of the world, with an area ofapproximately 150,000 km 2 . It is located in central part of the South America (19 o S, 57 oW) and presents a climatology which is characterized by a very dry season and a wet periodin which strong floods are often observed. The Interdisciplinary Pantanal Experiment (IPE)aims to investigate the micrometeorological aspects and the differences between these twoseasons. An important goal of IPE researches is to characterize the atmospheric boundarylayer (ABL) structure above Pantanal wetland, particularly the nocturnal boundary layer(NBL). For this purpose, it is important to take into account the meteorological processeswhich drive the early evening transition (EET) and define classes of the NBL. In Pantanalsome cases studies have shown two distinct classes of EET: a) one with the generation of astrong low level jet (LLJ), below 600 m height; b) one without a well defined LLJ. LLJ ismore frequent during the dry season and seems to be generated as a response to the strongstability created by next surface intense radiative cooling process after the sunset. Besidesthe LLJ, other aspects of the dry and wet CLA structure are presented and some possiblephysical explanations of the results are discussed.