Comparing Arctic Cloud Amounts MODIS and APP-x MOD35 and AVHRR Polar Pathfinder – Extended Data Sets Richard Frey Cloud Climatology Workshop Madison, WI July 7, 2006

Not a climatology comparison: Preliminary investigation Waiting on fully reprocessed Terra and Aqua Compared monthly means of Collection 5 Terra MODIS “Provisional C5” data from August 2001 – July 2002 Brief comparison with GLAS and surface observations As MODIS cloud detection algorithms mature: How do MODIS polar cloud amounts compare with long-term records like APP-x? Gain experience when inter-comparing polar data from different instruments of same type, differing types

Large + diff’s: N. Canada, N. Russia, Siberia

Large diff’s: Bering Strait, Norwegian Sea, Central Arctic Ocean

Arctic has low sun but still very cold.

Large + diff’s: N. Canada, N. Russia, Central Arctic Ocean Large – diff’s: Beaufort Sea, Hudson Bay, Foxe Basin, Davis Strait, SE Greenland

Greater uncertainty during transition seasons and terminator regions.

Large + diff’s: N. Canada, N. Russia, Greenland coast

Large + diff’s: East Siberian Sea

Large + diff’s: N. Russia, E. Siberia, Yukon, Hudson Bay, Baffin Bay Large – diff’s: W Arctic Ocn, E Greenland

Little information for clear vs. cloudy sky discrimination during polar winter leads to greater uncertainties.