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PC-30 Abstract

How Resilient is the Hydrometerology of the Amazon Basin to Human Pressure?

Roni Avissar — Rosenstiel School of Marine and Atmospheric Science - University of Miami (US-PI)
Pedro Leite Silva Dias — USP - Universidade de Sao Paulo (SA-PI)

Based on short-term, high-resolution simulations with a regional atmospheric model and climatological simulations with a GCM, which we have performed as part of our current NASA-LBA funded project, we find that deforestation increases thunderstorm activity and rainfall in the Amazon Basin, and that a massive deforestation of the Amazon, through teleconnections, has hydrometeorological impacts beyond the basin boundaries. But to evaluate the strength, magnitude and persistence of this precipitation enhancement and its teleconnections outside of the Amazon Basin (and in particular in North America), it is necessary to bridge the spatial and temporal scales gap between the above-mentioned studies that each provide a piece of evidence of the overall hydrometeorological mechanism. The purpose of the study proposed here, which is a continuation of our ending current investigation, is to evaluate the impact of various levels of partial deforestation on the regional and global hydrometeorological system in a realistic, transient climate environment. Our ultimate goal is to establish how resilient is the hydroclimatological system to human pressure (through deforestation) in the Amazon Basin.

The study proposed here consists of two major tasks, to be accomplished within three years. Each task will last about 1.5 year and will overlap mostly during the second year of the project. The first task will focus on long-term mesoscale simulations forced by reanalysis data and observed sea-surface temperatures (SSTs) that will explore the persistence, strength and magnitude of precipitation triggered by various levels of deforestation in the Amazon Basin. This research will be performed with the Regional Atmospheric Modeling System (RAMS), which will be evaluated as a regional climate model as part of this task. The simulations to be performed under the second task will be produced with the Goddard Institute for Space Studies GCM forced with observed SSTs or with an interacting ocean. They will be used to explore the strength and magnitude of teleconnections between the Amazon Basin and remote locations for various degrees of deforestation under various climatological regimes. The precipitation derived from the simulations and observations produced under the first task will be used to calibrate the precipitation simulated in the Amazon Basin with the GCM, which does not resolve convection triggered by subrid-scale deforestation, but needs an accurate account of their impact to improve the simulation of teleconnections. Satellite products will be used to initialize both models and to evaluate their results.

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