Warm‐air advection, air mass transformation and fog causes rapid ice melt

• Published in: Geophysical Research Letters
• Main Authors: Tjernström, M, Shupe, MD, Brooks, IM, Persson, POG, Prytherch, J, Salisbury, DJ, Sedlar, J, Achtert, P, Brooks, BJ, Johnston, PE, Sotiropoulou, G, Wolfe, D
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2015
• Subjects: Bering Strait; East Siberian Sea; Sea ice
• Online Access: https://eprints.whiterose.ac.uk/87105/; https://eprints.whiterose.ac.uk/87105/7/Tjernstr-m_et_al-2015-Geophysical_Research_Letters.pdf; https://doi.org/10.1002/2015GL064373

Direct observations during intense warm-air advection over the East Siberian Sea reveal a period of rapid sea-ice melt. A semi-stationary, high-pressure system north of the Bering Strait forced northward advection of warm, moist air from the continent. Air-mass transfor-mation over melting sea ice formed a strong, surface-based temperature inversion in which dense fog formed. This induced a positive net longwave radiation at the surface, while reduc-ing net solar radiation only marginally; the inversion also resulted in downward turbulent heat flux. The sum of these processes enhanced the surface energy flux by an average of ~15 W m-2 for a week. Satellite images before and after the episode show sea-ice concentrations decreasing from > 90% to ~50% over a large area affected by the air-mass transformation. We argue that this rapid melt was triggered by the increased heat flux from the atmosphere due to the warm-air advection.