EOL Seminar – Andrew Dzambo: Is the Arctic boundary layer de-stabilizing? скачать в хорошем качестве

EOL Seminar – Andrew Dzambo: Is the Arctic boundary layer de-stabilizing?

#eolseminarseries Seminar Series Webpage: https://www.eol.ucar.edu/news-events/... Title: Is the Arctic boundary layer de-stabilizing? Trends from atmospheric reanalysis and field campaign datasets Abstract: Over the last several decades, the region of the globe inside the Arctic Circle has warmed faster than any other region of the globe. Sea ice extent and concentration have decreased because of this temperature change, and by extension, has resulted in changes to the Arctic environment that haven’t been fully captured by present-day climate models. In this study, we hypothesize that the increase in surface temperature, sensible and latent heat fluxes from decreasing sea ice extent/concentration and increase in latent energy transported by baroclinic eddies into the Arctic have caused the Arctic boundary layer (ABL) to destabilize over the last 80 years. In the first study, Latent Energy (LE) and Kinetic Energy (KE) from the European Center for Medium Range Weather Forecasting (ECMWF) ERA-5 reanalysis data are used to investigate trends in moisture and energy related to baroclinic eddies transiting the high latitudes. A 2–8- day Lanzcos bandpass filter is applied to ECMWF LE and KE data to assess how ETCs have changed from 1940 to 2020 relative to full-scale changes in LE and KE. Full-scale KE trends are more positive at high latitudes relative to mid-latitudes, confirming several previous studies that ETCs have shifted poleward. LE increases have occurred globally, and trends in both full-scale LE and KE are statistically significant in the southern high latitudes. The high relative fractional contribution of 2–8-day LE wave power and trend clearly suggest that ETCs have an increasingly important role in poleward moisture transport but are not solely responsible for the observed statistically significant increases.