ALBERT

Description: The rapid warming in the Arctic and related sea ice decline, is making it more important than ever to better understand the tightly coupled interactions between Arctic sea ice and episodic weather events, such as cyclones; two of the main components of the Arctic climate system. This work uses a Lagrangian ice parcel database with coincident sea ice and atmospheric variables to study the impact extreme cyclones have on the Arctic Sea ice. The dataset includes daily 25km ice parcel tracks and associated atmospheric conditions including cyclone track data from 2002-2021. We examine multiple case studies of extreme cyclones, in all four seasons, with a focus on a diversity of cases with regard to location, sea ice concentration (SIC), and atmospheric conditions. Extreme cyclones are defined by their central pressure. The impacted ice parcels are then compared to those in identical situations (location, season, surrounding SIC) but without a cyclone present. The atmospheric conditions (precipitation, temperature, radiative balance) are contrasted between the extreme cyclone and non-cyclone conditions and the sea ice response to the passing cyclone is assessed by examining the change in albedo, SIC, sea ice thickness, snow depth over the ice parcel . This presentation will focus on the immediate response of the cyclone, lasting from a week before to two weeks after. Results will be presented for individual seasons, locations, and surrounding SIC to provide a better understanding of the different processes and elements that affect the cyclone impact on sea ice.

Description: Cyclones are synoptic weather events that transport heat and moisture into the Arctic, and have complex impacts on sea ice, marine ecosystems, and socio-economic activities. However, the effect of a changing climate on Arctic cyclone behavior remains poorly understood. This study uses a combination of reanalysis data, cyclone tracking techniques, and high-resolution numerical modeling to explore the effect of recent and future climate change on Arctic cyclone behavior across seasons.This work first examines the relative importance of changes in local surface conditions and turbulent fluxes and larger-scale baroclinicity and Eady growth rates with recent climate change in governing cyclone frequency, development, intensity, and trajectories. Then, Weather Research and Forecasting (WRF) model simulations are used to demonstrate the sensitivity of cyclone characteristics to recent and future climate change and explore thresholds of surface and large-scale atmospheric change. Simulations with downscaled CMIP6 global climate projections reveal that future sea ice loss and increasing surface temperatures by the year 2100 drive large increases in the near-surface temperature gradient, sensible and latent heat fluxes into the atmosphere, and deep convection during spring cyclone events. The future (warmer) climate further alters cyclone trajectories and increases and prolongs intensity, with significantly increased wind speeds, temperatures, and precipitation. Such changes in cyclone lifecycles and characteristics may exacerbate sea ice loss and Arctic warming through positive feedback mechanisms. The increasing extreme nature of weather events such as Arctic cyclones has important implications for atmosphere-ice-ocean interactions in the new Arctic.