Spatiotemporal trends of extreme weather events in the West Antarctic Peninsula and their impact on penguin foraging behavior
Date
2023
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Publisher
University of Delaware
Abstract
The West Antarctic Peninsula (WAP), a region known for its rugged, ice-strewn environment, has undergone rapid warming and sea ice melt in recent decades. While prior studies have demonstrated changes in local atmospheric and oceanic conditions, the multi-decadal trends in extreme weather events (i.e., storms) remain unclear along the WAP. Storms are key contributors to climate variability because they can significantly alter local winds, precipitation rates, and temperatures. To investigate the spatiotemporal shifts of storms along the WAP, we performed wavelet analysis on local wind speed magnitudes measuring variations in signals within the 2-7 day period range as a proxy for storm activity. We also studied the influence of wind stress on penguin foraging behavior as a case study of the impacts of extreme weather on the WAP ecosystem. From 1978 to 2021, we found significant increases in mean wavelet power in the north and south WAP and a decrease in the central WAP. Storminess is changing during the summer, spring, and fall, with no significant trends in the winter. While area-averaged analysis of the north, central, and south WAP regions do not show significant long-term trends in seasonally-averaged storminess, detailed maps of this variable do show significant trends in smaller regions during every season except winter. Climate modes, particularly the Southern Annular Mode (SAM) and the Amundsen Sea Low (ASL), are positively and negatively correlated with storms in the south WAP. Regarding penguin foraging behavior, we found that both Adélie and gentoo penguins dove, on average, 2.68 and 6.31 m deeper during periods of high wind stress, respectively. The generalized mixed-effects models explained more variance (higher R2 value) for gentoos than Adélie penguins, which may indicate storms and surface wind-driven mixing have a greater impact on deeper-diving penguins. Our research highlights the critical role storms play in the WAP climate and provides insight into how the local ecosystem will respond to future changes along the WAP.
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Keywords
Penguins, Storms, Wavelet analysis, West Antarctic Peninsula