Atmospheric Precursors of and Response to Anomalous Arctic Sea Ice in CMIP5 Models

• Published in: Advances in atmospheric sciences 2018, Vol.35 (1), p.27-37
• Main Authors: Kelleher, Michael, Screen, James
• Format: Article
• Language: English
• Subjects: Anomalies; Arctic sea ice; Atmospheric models; Atmospheric Sciences; Climate models; Computer simulation; Continents; Earth and Environmental Science; Earth Sciences; Eddy heat flux; Geophysics/Geodesy; Heat flux; Heat transfer; Height; Height anomalies; Ice; Ice environments; Induction heating; Latitude; Meteorology; Original Paper; Polar caps; Polar vortex; Sea ice; sea; ice-atmosphere; coupling,; stratosphere-troposphere; coupling,; atmospheric; circulation,; Eurasian; climate; Statistical analysis; Stratosphere; Stratospheric vortices; Surface temperature; Temperature; Towards Improving Understanding and Prediction of Arctic Change and its Linkage with Eurasian Mid-latitude Weather and Climate; Tropospheric circulation; Vortices; Winter temperatures
• ISSN: 0256-1530; 1861-9533
• DOI: 10.1007/s00376-017-7039-9

This study examines pre-industrial control simulations from CMIP5 climate models in an effort to better understand thecomplex relationships between Arctic sea ice and the stratosphere, and between Arctic sea ice and cold winter temperaturesover Eurasia. We present normalized regressions of Arctic sea-ice area against several atmospheric variables at extended leadand lag times. Statistically significant regressions are found at leads and lags, suggesting both atmospheric precursors of, andresponses to, low sea ice; but generally, the regressions are stronger when the atmosphere leads sea ice, including a weakerpolar stratospheric vortex indicated by positive polar cap height anomalies. Significant positive midlatitude eddy heat fluxanomalies are also found to precede low sea ice. We argue that low sea ice and raised polar cap height are both a response tothis enhanced midlatitude eddy heat flux. The so-called ＂warm Arctic, cold continents＂ anomaly pattern is present one to twomonths before low sea ice, but is absent in the months following low sea ice, suggesting that the Eurasian cooling and lowsea ice are driven by similar processes. Lastly, our results suggest a dependence on the geographic region of low sea ice, withlow Barents-Kara Sea ice correlated with a weakened polar stratospheric vortex, whilst low Sea of Okhotsk ice is correlatedwith a strengthened polar vortex. Overall, the results support a notion that the sea ice, polar stratospheric vortex and Eurasiansurface temperatures collectively respond to large-scale changes in tropospheric circulation.