Trends and oscillations in arctic mediterranean atmospheric static stability during recent arctic warming

Abstract

The long-term variation in the static stability of lower atmosphere (SSLA) in the Arctic Mediterranean is investigated using reanalysis data. Climatological SSLA is categorized into a high-value region (Polar Region) and two low-value regions in the Norwegian Sea (Region-A) and southern part of Iceland (Region-B). The variations of SSLA are divided into trends and oscillations. In the Polar Region, SSLA exhibited a decreasing trend due to Arctic warming and sea ice decline, with negligible oscillatory variations. In Region-A and Region-B, the trends of SSLA are insignificant, while the oscillatory variation becomes obvious. SSLA there are highly correlated to Arctic Oscillation (AO) Index and vertical velocity. The driving factors in weakening SSLA are vertical velocity and surface heating, related to enhanced warm water advection dominated by AO. The variation of SSLA in turn feeds back the vertical velocity and AO.