A genesis potential index for polar lows

Boyd, Kevin Patrick

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https://hdl.handle.net/2142/115479 Copy

Description

Title

A genesis potential index for polar lows

Author(s)

Boyd, Kevin Patrick

Issue Date

2022-04-26

Director of Research (if dissertation) or Advisor (if thesis)

Wang, Zhuo

Committee Member(s)

• Rauber, Robert
• Sriver, Ryan
• Walsh, John

Department of Study

Atmospheric Sciences

Discipline

Atmospheric Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Polar Lows
• Statistical Modelling
• Arctic
• Climate

Abstract

Polar lows (PL) are intense maritime mesocyclones that develop during marine cold-air outbreaks events over the high-latitudes. The impacts posed by these systems to humans and the broader environment demand a robust understanding of the environmental factors that promote PL formation, and in turn, skillful prediction of PL activity. We hypothesize that the variability of PL activity is associated with some key, large-scale climate variables skewed towards “extreme” values, which can provide predictable information on PL activity beyond the synoptic time scale. A PL genesis potential index (PGI) is developed that relates the climatological spatial distribution of PL genesis frequency and key climate variables in a Poisson regression framework. The optimal set of predictors consists of a static stability parameter and an environmental baroclinicity parameter. The optimal predictor categories are shown to be robust across different reanalyses and PL track datasets. The PGI well represents the observed spatial distribution and seasonal cycle of PL genesis frequency and also captures the interannual variability of PL activity skillfully. The effects of the Arctic Oscillation (AO), El Niño-Southern Oscillation (ENSO), and other climate modes on the interannual variability of PL activity are explored, and the application of the PGI to subseasonal to seasonal prediction of PL activity is briefly discussed.

Graduation Semester

2022-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Kevin Boyd

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