Impacts of large-scale soil moisture anomalies on regional hydroclimate in southeastern South America

Advancing our understanding of the hydroclimate of southeastern South America (SESA) is imperative for a number of reasons. Within SESA is the La Plata River basin (LPRB), the second-largest river basin in South America. The LPRB includes a diverse array of ecosystems. The region is also significant for agricultural interests, and a majority of the economic output of five South American nations originates in the LPRB. Many studies of soil moisture-atmosphere coupling focus on local processes. This study adopts an emphasis on large-scale soil moisture anomalies within the LPRB and investigates the effects of these anomalies on regional-scale atmospheric conditions. Multivariate empirical orthogonal function (EOF) analysis is performed using two-meter temperature, root-zone soil moisture, and precipitation data sourced from atmospheric reanalysis products for multiple decades. EOF analysis allows us to jointly extract the dominant modes of variability for these three variables. We find that the dominant EOF pattern is consistent with a positive relation between soil moisture and precipitation, while the second EOF pattern is consistent with a negative relation between these two variables. The effects of amplified soil moisture anomalies are tested using CESM simulations in which soil moisture is decreased within a region in SESA. The CESM simulations suggest that dry soil moisture is initially co-located with decreased precipitation, then changes in atmospheric circulation associated with a thermal low draw moisture into the region and lead to increased precipitation. This study can add to current knowledge of land-atmosphere interactions in SESA. Additionally, its outcomes may be applied to advances in atmospheric prediction.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Atmospheric Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2020

Author dc:creator

• Bieri, Carolina A.

Contributors dc:contributor

• Dominguez, Francina

• Land-atmosphere interactions
• hydroclimatology
• climate variability
• climate modeling
• soil moisture
• EOF analysis

Statement dc:rights

• Copyright 2019 Carolina Bieri

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/106383

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/106383