Abstract
AbstractThe role of synoptic-scale cyclones in the trends and variability of Arctic sea ice conditions has remained uncertain. In recognition, we conduct a systematic investigation of how sea-ice concentration (SIC) changes with cyclone passage, including all individual storms that pass over any part of the region's ice pack. For all seasons, especially summer and autumn, we find a pattern of higher ice concentration after a region is influenced by a cyclone compared to when it is not, primarily due to thermodynamic effects. During warm months, cyclones appear to slow the general day-to-day decline in concentration; in cold months, cyclones augment the day-to-day increase. These relationships are changing over time, with cyclone-associated concentration changes becoming less distinct from overall changes. Cyclone effects on ice divergence are spatially variable; computed fields are noisy. In summer, these dynamic effects of cyclone passage generally decrease SIC, but are outweighed by the thermodynamic effects (e.g., reductions in air temperature, shortwave radiation). In autumn, cyclone-associated concentration changes are not as easily explained by observed cyclone conditions. Key questions remain regarding the extent to which our findings are influenced by artifacts of surface melt and weather effects on the passive microwave retrievals.
Highlights
Arctic sea-ice extent has declined in all months over the modern satellite record (1979– present), during late summer and early autumn (e.g., Nghiem and others, 2007; Serreze and others, 2007; Emery and others, 2011; Screen and others, 2011; Simmonds, 2015; Kapsch and others 2016; Parkinson and DiGirolamo, 2016; Kwok, 2018)
Our results argue that the overall influence of cyclones is to work against the climatological decrease in sea-ice concentration (SIC) during summer, and augment the climatological increase in SIC during autumn, with generally smaller influences in winter and spring
Separating the thermodynamic and dynamic drivers of the SIC change associated with cyclone passage is challenging; the divergence calculations are noisy, perhaps pushing past the accuracy limits of the ice velocity fields
Summary
Arctic sea-ice extent has declined in all months over the modern satellite record (1979– present), during late summer and early autumn (e.g., Nghiem and others, 2007; Serreze and others, 2007; Emery and others, 2011; Screen and others, 2011; Simmonds, 2015; Kapsch and others 2016; Parkinson and DiGirolamo, 2016; Kwok, 2018). Improved seasonal-scale forecasts of sea-ice conditions are increasingly needed to support such activities, but the 7–10 day limit of reasonably accurate weather prediction presents a formidable obstacle (Stroeve and others, 2014; Serreze and others, 2016). There appears to be an increasing trend in cyclone strength, which has been associated with the reductions in September ice extent (Simmonds and Keay, 2009), though generally seasons with fewer cyclones end with lower ice areas (Screen and others, 2011). Trends in frequency are unclear, and appear spatially variable (Zahn and others, 2018; Wickström and others, 2019)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
