University of Illinois Urbana-Champaign

Analyzing the effects of unforced natural variability and anthropogenic forcing on ENSO variability using CESM

Vega-Westhoff, Benjamin Aaron

Content Files
VEGA-WESTHOFF-THESIS-2016.pdf

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https://hdl.handle.net/2142/95507

Description

Title
Analyzing the effects of unforced natural variability and anthropogenic forcing on ENSO variability using CESM
Author(s)
Vega-Westhoff, Benjamin Aaron
Issue Date
2016-12-05
Director of Research (if dissertation) or Advisor (if thesis)
Sriver, Ryan
Department of Study
Atmospheric Sciences
Discipline
Atmospheric Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2017-03-01T16:37:05Z
Keyword(s)
  • Climate
  • El niño-southern oscillation (ENSO)
  • Variability
  • Community earth system model (CESM)
  • El Niño
Abstract
The El Niño-Southern Oscillation (ENSO) is an important contributor to Earth’s inter-annual climate variability, with worldwide weather effects (Whetton and Rutherfurd, 1994; Hoerling and Zhong, 1997; Dai and Wigley, 2000). Understanding how ENSO may change with climate is a major challenge, given the internal variability of the system and relatively short observational record (Wittenberg, 2009). Much recent research has used multi-model ensembles to address the effects of climate change on ENSO (Stevenson, 2012; Cai et al., 2014; Kim et al., 2014). Here we analyze ENSO in a Community Earth System Model (CESM) ensemble that samples internal variability of the coupled Earth system. We present results from a 50-member climate change ensemble experiment, using historical climate forcings (1850-2005) and projections to 2100 following the representative concentration pathway 8.5 (RCP8.5). With this ensemble, and a ~5000 year control run with constant pre-industrial conditions, we examine ENSO variability under different forcing regimes. We compare the effects of anthropogenic climate change with the effects of natural modulations on ENSO sea surface temperature (SST). We find that any changes in ENSO SST due to climate change are secondary to natural modulations.
Graduation Semester
2016-12
Type of Resource
text
Permalink
http://hdl.handle.net/2142/95507
Copyright and License Information
Copyright 2016 Benjamin Vega-Westhoff

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