The Development of a Dynamic Snow Load for Cryosat-2 Sea Ice Thickness Retrievals
CryoSat-2 data are now being used internationally to produce estimates of Arctic-wide sea ice thickness and volume [1-5]. However, current estimates rely (to varying degrees) on the use of a snow climatology in the conversion of ice freeboard to thickness, and this is currently the largest source of error in sea ice thickness and volume estimates[6, 7]. To reduce this uncertainty we have developed a dynamic snow load for application with our sea ice processor. The snow load is initialised using precipitation and evaporation data from the ERA-Interim reanalysis , and developed with a dependence on sea ice concentration, drift, and atmospheric temperature. This enables us to apply a snow load that varies in space and time, rather than relying on a constant monthly snow climatology. To perform an initial evaluation of our dynamic snow load, we compared estimates of sea ice thickness that we obtained using the climatological and dynamic snow loads, to ice thickness measurements from NASA’s Operation IceBridge (OIB) campaign. Although both of our sea ice thickness datasets agree well with OIB in the region north of Greenland, there is some spatial variation in the thickness differences at lower latitudes. This presentation will summarise the development, application, and evaluation of the new snow load in relation to our sea ice thickness estimates and comment on future considerations.
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