[Eoas-seminar] MET Seminar - Tuesday October 6 - 3 PM - Dr. Joonsuk Kang (Columbia University)

Tue Oct 6 12:19:10 EDT 2026

Hi everyone,

A friendly reminder for MET seminar this afternoon at 3 PM in RM1044.
Today's seminar will be given by Dr. Joonsuk Kang from Columbia University in person on the topic of "Midlatitude circulation response to anthropogenic forcings: the importance of experimental design and model biases".

Please find below email for the full abstract and more information about Dr. Kang.

Best,
Chelsea

---------------
Chaehyeon Chelsea Nam, Ph.D.
Assistant Professor
Department of Earth, Ocean, and Atmospheric Science (EOAS)
Florida State University
RM 5011, ccnam at fsu.edu
https://chelsea-nam.github.io/<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchelsea-nam.github.io%2F&data=05%7C02%7Ceoas-seminar%40lists.fsu.edu%7C0067798f03744840722d08df23c58da8%7Ca36450ebdb0642a78d1b026719f701e3%7C0%7C0%7C639269003519707828%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=PNZ1VR%2BgrvWxlQ%2Flc%2BAak6%2FAXhfRjXMIuYMwgLUvdKg%3D&reserved=0>

________________________________
From: Chelsea Nam <ccnam at fsu.edu>
Sent: Wednesday, September 30, 2026 11:21 AM
To: eoas-seminar--- via Eoas-seminar <eoas-seminar at lists.fsu.edu>; 'Allison Wing' via info at coaps <info at coaps.fsu.edu>
Subject: MET Seminar - Tuesday October 6 - 3 PM - Dr. Joonsuk Kang (Columbia University)

Dear all,

Our next MET Seminar will be given by Dr. Joonsuk Kang, a postdoctoral fellow at Columbia University. He will speak about "Midlatitude circulation response to anthropogenic forcings: the importance of experimental design and model biases" (see full abstract below).

Dr. Kang will be here in person to present the seminar in RM 1044. Zoom link is available for those with a medical excuse or approved work off-campus. Please contact Chlesea Nam (ccnam at fsu.edu) for the link.

Dr. Kang will be around and available for meetings on Monday and Tuesday, so if you're interested in meeting with him, let Chelsea know. I will also follow up with you on MET graduate student lunch with the speaker.

  *
DATE: Tuesday, October 6
  *
TIME: 3-4 PM, please join early for refreshments
  *
LOCATION: EOAS1044
  *
SPEAKER: Dr. Joonsuk Kang (Joonsuk's personal website: https://sites.google.com/view/joonsuk/home<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsites.google.com%2Fview%2Fjoonsuk%2Fhome&data=05%7C02%7Ceoas-seminar%40lists.fsu.edu%7C0067798f03744840722d08df23c58da8%7Ca36450ebdb0642a78d1b026719f701e3%7C0%7C0%7C639269003519834005%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=2s7r9DqtmrNJv1r20T7iVeFPKqdX6xccophetVeEGfY%3D&reserved=0>)

We look forward to seeing you there!

Best,
Chelsea on behalf of the MET seminar committee (Allison, Michael, and Chelsea)

=========
Title: Midlatitude circulation response to anthropogenic forcings: the importance of experimental design and model biases

Abstract
Climate model experiments are our main tool for understanding the physical processes underlying the atmospheric circulation changes under anthropogenic forcings. Their usefulness, however, depends on choosing experiments suited to the question and on understanding model biases.

First, I investigate how midlatitude zonal winds, or the jets, respond to CO2 forcing. Increasing CO2 is expected to shift the midlatitude jets poleward, but their relationship with global-mean surface warming remains unclear. Previous work focusing on abrupt CO2 quadrupling, or examining cross-model correlations, suggested that the poleward shift does not scale with warming. Here we revisit the question under more realistic transient 1%/yr CO2 forcing, and find that the jet shift scales linearly with warming as CO2 increases. The weak cross-model correlations reported previously can be explained by the jet shift's sensitivity to warming, which varies by a factor of three across models.

Second, I investigate how midlatitude meridional winds, or the stationary waves, are impacted by aerosol forcing. Reanalysis data reveal significant Eurasian summertime stationary wave trends, and aerosol-forcing simulations reproduce the reanalysis pattern. However, all-forcing simulations systematically underestimate the reanalysis trends, which limits attribution to aerosols. The source of this discrepancy is investigated by applying the thermal wind balance framework and using reanalysis-nudging simulations. It is found that the discrepancy is linked to the thermal structure trend discrepancy over the North Atlantic, which excessively offsets the zonal temperature gradient at the surface.

Together, these studies show how choosing the appropriate experiment and understanding model biases can improve physical insight into circulation responses to anthropogenic forcing.

---------------
Chaehyeon Chelsea Nam, Ph.D.
Assistant Professor
Department of Earth, Ocean, and Atmospheric Science (EOAS)
Florida State University
RM 5011, ccnam at fsu.edu
https://chelsea-nam.github.io/<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchelsea-nam.github.io%2F&data=05%7C02%7Ceoas-seminar%40lists.fsu.edu%7C0067798f03744840722d08df23c58da8%7Ca36450ebdb0642a78d1b026719f701e3%7C0%7C0%7C639269003519845266%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=STRIzcvOhfkbUCNbmVTzoWEMyR73aS4cmkyNb%2FyqCLM%3D&reserved=0>

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