Trends and variability of cloud fraction cover in the Arctic, 1982–2009
Climatology, trends and variability of cloud fraction cover (CFC) data over the Arctic (north of 70°N), were analysed over the 1982–2009 period. Data, available from the Climate Monitoring Satellite Application Facility (CM SAF), are derived from satellite measurements by AVHRR. Climatological means confirm permanent high CFC values over the Atlantic sector during all the year and during summer over the eastern Arctic Ocean. Lower values are found in the rest of the analysed area especially over Greenland and the Canadian Archipelago, nearly continuously during all the months. These results are confirmed by CFC trends and variability. Statistically significant trends were found during all the months over the Greenland Sea, particularly during the winter season (negative, less than −5 % dec −1) and over the Beaufort Sea in spring (positive, more than +5 % dec −1). CFC variability, investigated by the Empirical Orthogonal Functions, shows a substantial “non-variability” in the Northern Atlantic Ocean. Statistically significant correlations between CFC principal components elements and both the Pacific Decadal Oscillation index and Pacific North America patterns are found.
This study was carried out using data from EUMETSAT’s Satellite Application Facility on Climate Monitoring (CM SAF) (DOI: 10.5676/EUM_SAF_CM/CLARA_A/V001). The authors are also grateful to: The Climate Prediction Center of the National Weather Service (USA) for providing monthly NAO, PNA and PDO indices. NOAA National Centers for Environmental Information (USA) for providing the monthly AO index. The National Snow and Ice Data Center (USA) for the land-sea mask.
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