[Eoas-seminar] MET Seminar - Thursday September 28 - Dr. Arianna Varuolo-Clarke (CU Boulder)

[eoas-seminar at lists.fsu.edu]

Dear all,

Please join us next Thursday September 28 for a Meteorology seminar, given by Dr. Arianna Varuolo-Clarke<https://amvaruolo-clarke.github.io>. Dr. Varuolo-Clarke is a NOAA Climate & Global Change Postdoctoral fellow at the University of Colorado Boulder. She will speak about "The mystery of observed and simulated precipitation trends in Southeastern South America since the early 20th century” (abstract below).

Dr. Varuolo-Clarke will be joining us virtually but we will gather in EOA 1044 to participate in the seminar. If you cannot attend in person due to a medical reason or approved work out of town, please contact Allison Wing (awing at fsu.edu<mailto:awing at fsu.edu>) for remote access. Otherwise, we look forward to seeing everyone in 1044! Please join us for refreshments prior to the beginning of the talk at 3:15 PM.

If you would like to meet with the speaker over Zoom, please contact Allison Wing.

DATE: Thursday September 28
SEMINAR TIME: Refreshments at 3 PM, Talk 3:15 PM - 4:15 PM.
SEMINAR LOCATION: EOA 1044 (Speaker remote)
SPEAKER: Dr. Arianna Varuolo-Clarke

TITLE: The mystery of observed and simulated precipitation trends in Southeastern South America since the early 20th century

ABSTRACT: Southeastern South America (SESA), a region encompassing Paraguay, Southern Brazil, Uruguay, and northern Argentina, experienced a 23% increase in austral summer precipitation from 1902-2022, one of the largest observed precipitation trends globally. There is little consensus on the drivers of the precipitation trend, but Atlantic multidecadal variability, stratospheric ozone depletion, and greenhouse gas emissions stand out as key contributing factors. In this presentation, I will walk through my process of trying to understand first, what are the historical drivers of the SESA precipitation increase. And second, why do climate models struggle to simulate the observed SESA precipitation trend? To address the first question, I explore simulations from the Coupled Model Intercomparison Project (CMIP) Phases 3, 5, and 6 and find that not only do fully-coupled climate models simulate positive SESA precipitation trends that are much weaker over the historical interval, but some models persistently simulate negative precipitation trends. In an attempt to understand this apparent model bias, and why climate models seem to miss the trend, I investigate one driver of SESA precipitation variability: the South American low-level jet. I find that the SESA precipitation trend from 1951-2020 is partly attributable to jet intensification arising from both natural variability and anthropogenic forcing.


--------------------------------------------
Allison A. Wing, Ph.D.
Werner A. and Shirley B. Baum Professor
Associate Professor, Department of Earth, Ocean, and Atmospheric Science
Florida State University
awing at fsu.edu

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