Comparative satellite study of mesoscale disturbances in polar regions.

Claud C., Katsaros K.B., Mognard N.M., Scott N.A.

The Global Atmosphere-Ocean System 4, 233-273.

Mesoscale disturbances in cold air outbreaks (polar lows) occur quite often in high latitude areas of both hemispheres. The lack of conventional meteorological observations over these areas implies heavy reliance on satellite remotely-sensed information. Several lows which formed at different places around the world have been examined in order to derive their dominant features and environments. For this purpose, the combination of a vertical atmospheric sounder (TOVS), a microwave imager (SSM/I) and an altimeter (Geosat) has been used. While most retrieved atmospheric parameters are quite variable from case to case, a number of general statements about polar lows can be made: they all occur in areas of cold and dry air outbreaks; in agreement with the low integrated water vapor content values, the amount of liquid precipitation is very light, and the cloud liquid water content moderate; both SSM/I and Geosat indicate that surface wind speeds in the cloud bands forming the systems are of strong to gale force, while the cloud-free center is characterized by low values. Strongest winds and largest wave heights occur on the southwestern flank of the lows in the northern hemisphere and on the northeastern flank in the southern hemisphere.

Last update : 2011/01/25

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