Fontes de umidade continental e oceânica e impacto na disponibilidade de umidade para atmosfera na América do Sul

Abstract

This study aimed to evaluate the relative importance of sources of moisture continental and oceanic, moisture transportation and its impact on rainfall in South America, and how the disturbance in surface conditions affect moisture availability to the atmosphere. Reanalysis of data and simulations with the quasi-equilibrium tropical circulation model (QTCM) were used to explore the response of the atmosphere to the ocean and continental sources of moisture to South America, and their influence on atmospheric conditions. Con- ditions anomalous positive and negative SST were imposed in the northern and southern portions of the Atlantic Ocean Tropical, as well as idealized conditions of reduced trans- piration on the area of Amazon rainforest, and their results were compared. Overall the QTCM could represent the spatial distribution of precipitation maximum on the continent and their seasonal variations, among other features, in which make efficient QTCM in the evaluation of large-scale physical processes in the tropical region, associated with ocean patterns. On the ocean area ATN, besides being a source of moisture to the atmosphere, is an important and persistent regulator of the wind divergence patterns at low levels, so that disturbance or the development of hot anomalies or cold in its waters provides important impacts on the northern part of South America, and the Amazon sectors. The reduction in Amazon forest transpiration suggests a more direct impact on rainfall, but the effect tends to decrease with increased stress of vegetation. Compensation reducing transpiration by increasing the moisture convergence was simulated only in the austral winter season.