Atmospheric teleconnections between the Arctic and the Baltic Sea region as simulated by CESM1-LE

• Published in: Earth System Dynamics
• Main Authors: E. Jakobson, L. Jakobson
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2024
• Subjects: Science; Q; Geology; QE1-996.5; Dynamic and structural geology; QE500-639.5; Climate change; Greenland; North Atlantic; North Atlantic oscillation; Sea ice; Svalbard
• Online Access: https://doi.org/10.5194/esd-15-155-2024; https://doaj.org/article/163b4676cb8a46f69eda4827c93e1030

This paper examines teleconnections between the Arctic and the Baltic Sea region and is based on two cases of Community Earth System Model version 1 large ensemble (CESM-LE) climate model simulations: the stationary case with pre-industrial radiative forcing and the climate change case with RCP8.5 radiative forcing. The stationary control simulation's 1800-year long time series were used for stationary teleconnection and a 40-member ensemble from the period 1920–2100 is used for teleconnections during ongoing climate change. We analyzed seasonal temperature at a 2 m level, sea-level pressure, sea ice concentration, precipitation, geopotential height, and 10 m level wind speed. The Arctic was divided into seven areas. The Baltic Sea region climate has strong teleconnections with the Arctic climate; the strongest connections are with Svalbard and Greenland region. There is high seasonality in the teleconnections, with the strongest correlations in winter and the lowest correlations in summer, when the local meteorological factors are stronger. North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) climate indices can explain most teleconnections in winter and spring. During ongoing climate change, the teleconnection patterns did not show remarkable changes by the end of the 21st century. Minor pattern changes are between the Baltic Sea region temperature and the sea ice concentration. We calculated the correlation between the parameter and its ridge regression estimation to estimate different Arctic regions' collective statistical connections with the Baltic Sea region. The seasonal coefficient of determination, R 2 , was highest for winter: for T 2 m , R 2 =0.64 for sea level pressure (SLP), R 2 =0.44 and for precipitation (PREC), R 2 =0.35 . When doing the same for the seasons' previous month values in the Arctic, the relations are considerably weaker, with the highest R 2 =0.09 being for temperature in the spring. Hence, Arctic climate data forecasting capacity for the Baltic Sea region is weak. ...