EGU24-13775, updated on 09 Mar 2024
https://doi.org/10.5194/egusphere-egu24-13775
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Impacts of projected Arctic sea ice loss on daily weather patterns over North America

Melissa Gervais1, Lantao Sun2, and Clara Deser3
Melissa Gervais et al.
  • 1Penn State, Meteorology and Atmospheric Sciences, University Park PA, United States of America (mmg62@psu.edu)
  • 2Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado
  • 3National Science Foundation National Center for Atmospheric Research, Boulder, Colorado

Future Arctic sea ice loss has a known impact on Arctic Amplification (AA) and mean atmospheric circulation. Furthermore, several studies have shown it leads to a decreased variance in temperature over North America. In this study, we analyze results from two fully-coupled Community Earth System Model (CESM) Whole Atmosphere Community Climate Model (WACCM4) simulations with sea ice nudged to either the ensemble mean of WACCM historical runs averaged over the 1980-1999 period for the control (CTL) or projected RCP8.5 values over the 2080-2099 period for the experiment (EXP). Dominant large-scale meteorological patterns (LSMPs) are then identified using self-organizing maps applied to winter daily 500 hPa geopotential height anomalies (𝑍′500) over North America. We investigate how sea ice loss (EXP-CTL) impacts the frequency of these LSMPs and, through composite analysis, the sensible weather associated with them. We find differences in LSMP frequency but no change in residency time indicating there is no stagnation of the flow with sea ice loss. Sea ice loss also acts to de-amplify and/or shift the 𝑍′500 that characterize these LSMPs and their associated anomalies in potential temperature  at 850hPa. Impacts on precipitation anomalies are more localized and consistent with changes in anomalous sea level pressure. With this LSMP framework we provide new mechanistic insights,  demonstrating a role for thermodynamic, dynamic and diabatic processes in sea ice impacts on atmospheric variability. Understanding these processes from a synoptic perspective is critical as some LSMPs play an outsized role in producing the mean response to Arctic sea ice loss.

How to cite: Gervais, M., Sun, L., and Deser, C.: Impacts of projected Arctic sea ice loss on daily weather patterns over North America, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13775, https://doi.org/10.5194/egusphere-egu24-13775, 2024.

Supplementary materials

Supplementary material file

Comments on the supplementary material

AC: Author Comment | CC: Community Comment | Report abuse

supplementary materials version 1 – uploaded on 17 Apr 2024, no comments