Moisture flux changes and trends for the entire Arctic in 2003-2011 derived from EOS Aqua data

The Arctic sea ice acts as a barrier between the ocean and lower atmosphere, reducing the exchange of heat and moisture. In recent years the ice pack has undergone many changes, in particular a rapid reduction in sea ice extent and compactness in summer and autumn. This, along with modeling studies, would cause one to believe that the moisture flux would be increasing. We estimate the daily moisture flux from 2003 to 2011 using geophysical data from multiple sensors onboard NASA's Aqua satellite, taking advantage of observations being collected at the same time and along the same track. Our findings show the moisture flux, averaged over the entire Arctic, has had large interannual variations, with smallest fluxes in 2010, 2003, and 2004, and largest ones in 2007, 2008, and 2005. Increases in air specific humidity tend to reduce the moisture flux, whereas the decrease in sea ice cover tends to increase the flux. Statistically significant seasonal decreasing trends are seen in December, January, and February because of the dominating effect of increase in 2 m air specific humidity increasing, reducing the surface-air specific humidity difference by -0.0547 kg/kg in the Kara/Barents Seas, E. Greenland Sea, and Baffin Bay regions where there is some open water year round. Our results also show that the contribution of the sea ice zone to the total moisture flux (from the open ocean and sea ice zone) has increased by 3.6% because the amount of open water within the sea ice zone has increased by 4.3%.