Student Seminar: Line Bourdages

Seasonality of projected Arctic temperature inversion changes in the CESM-LE

Abstract

The Arctic atmosphere is characterized by a pervasive low-level temperature inversion, resulting from the balance of surface heat fluxes, as well as upper-level atmospheric heat fluxes from the mid-latitudes. With a diminishing sea ice cover, surface heat fluxes are modified, with expected implications for the temperature inversion and related climatic features such as Arctic haze mixing in the boundary layer, cloud formation and the lapse-rate feedback, among others. In this study, we use the Community Earth System Model (CESM) Large Ensemble (Kay et al. 2014) to study projected changes in temperature inversion in response to changes in sea ice cover. We find a strong seasonal signal, with significant decreases and increases in temperature inversion strength during the winter and summertime, respectively. Wintertime decreases are shown to be linked to a decrease in sea ice thickness, whereas summertime increases are related to atmospheric warming in regions of ongoing sea-ice melt.