Influence of baroclinicity in the atmospheric boundary layer and Ekman friction on the surface wind speed during cold-air outbreaks in the Arctic

• Published in: Izvestiya, Atmospheric and Oceanic Physics
• Main Authors: Chechin, D. G., Zabolotskikh, Elizaveta, Repina, I. A., Chapron, Bertrand
• Other Authors: Laboratoire d'Océanographie Spatiale (LOS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDU]Sciences of the Universe [physics]; Arctic
• Online Access: https://hal.science/hal-04200597; https://doi.org/10.1134/S0001433815020048

Extreme cases of cold-air outbreaks in the Arctic during spring 2013 are identified using MODIS images from Terra and Aqua satellites. Spatial variability of the surface wind speed during considered cases of cold-air outbreaks is quantified using the ERA Interim reanalysis and data retrieved from the satellite microwave radiometer AMSR2. To explain the observed variability of wind speed in the atmospheric boundary layer (ABL) the contributions of baroclinicity in the ABL and Ekman friction are quantified. For this purpose diagnostic relationships based on the concept of a mixed-layer model are used. It is demonstrated that baroclinic component of the geostrophic wind caused by the horizontal temperature gradients in the ABL over the open water has a strong effect on the spatial variability of wind speed during considered cases of cold-air outbreaks.