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Title:Isolating the observed influence of vegetation variability of La Plata River basin on the climate of South America
Author(s):Chug, Divyansh
Advisor(s):Dominguez, Francina
Department / Program:Atmospheric Sciences
Discipline:Atmospheric Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Land-atmosphere interactions
La Plata River Basin
Abstract:Land surface variability and change can affect the overlying atmosphere through biogeophysical and biogeochemical feedbacks. The goal of our work is to isolate and quantify the local and remote influences of vegetation on the climate of South America using observational records. We find that the dominant mode of vegetation variability over the La Plata River basin in austral Spring is linked with warmer temperature and enhanced precipitation over central and south La Plata basin. A key aspect of this study is the use of remotely sensed land-surface characteristics alongside reanalysis data, and the use of the generalized equilibrium feedback assessment (GEFA) to isolate the effects of each forcing. The analysis uses a 34-year (1981-2014) record of the modified enhanced vegetation index (EVI2) from the NASA MEaSUREs Vegetation Index and Phenology dataset and the third generation normalized difference vegetation index (NDVI3g) from the Global Inventory Modeling and Mapping Studies. The dominant patterns of variability in space and time are analyzed using empirical orthogonal function/principal component (EOF/PC) analysis on a basin-wide scale. The dominant mode looks like a vegetation dipole, and can be explained using observed records of precipitation provided by the University of Delaware and the University of East Anglia Climate Research Unit. The second part of the study analyzes how these dominant modes of variability affect the overlying atmosphere at the continental scale. We use GEFA and its refinement, the stepwise GEFA, to statistically quantify the observed seasonal impacts of dominant terrestrial and oceanic forcings on the South American climate. This observed impact of vegetation on the seasonal accumulation of precipitation in the agricultural growing season holds crucial importance for the most heavily populated and economically active region of South America.
Issue Date:2018-07-13
Rights Information:Copyright 2018 Divyansh Chug
Date Available in IDEALS:2018-09-27
Date Deposited:2018-08

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