Isolating the observed influence of vegetation variability of La Plata River basin on the climate of South America

Chug, Divyansh

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https://hdl.handle.net/2142/101699 Copy

Description

Title

Isolating the observed influence of vegetation variability of La Plata River basin on the climate of South America

Author(s)

Chug, Divyansh

Issue Date

2018-07-13

Director of Research (if dissertation) or Advisor (if thesis)

Dominguez, Francina

Department of Study

Atmospheric Sciences

Discipline

Atmospheric Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(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.

Graduation Semester

2018-08

Type of Resource

text

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http://hdl.handle.net/2142/101699

Copyright and License Information

Copyright 2018 Divyansh Chug

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