613 Seminar: Alek Petty

UMD-ESSIC/Cryospheric Sciences Laboratory

Precipitation is a significant contributor to the Arctic Ocean's freshwater budget, while the accumulation of solid precipitation (snowfall) over the floating sea ice cover controls the depth of its highly insulative snow layer. Precipitation over the Arctic Ocean is extremely variable across the different reanalyses currently available, however, while direct observations of precipitation/snow depth across the Arctic are limited. Here we examine the annual, seasonal, and regional differences across the reanalyses and compare the magnitude and frequency of precipitation events against snow depth data from Ice Mass Balance Buoys.
Poor knowledge of the snow depth over Arctic sea ice is also the primary source of uncertainty in our estimation of sea ice thickness from satellite altimetry. To produce new estimates of snow depth on sea ice, we have developed a new, open-source, two-layer Eulerian snow budget. The model includes several parameterizations to represent various sources and sinks of snow on sea ice through the accumulation season. The reanalysis synthesis and snow depth model results have been used to explore decadal changes in precipitation and snow depth across the Arctic. We also demonstrate the utility of the new snow depth product (available daily) to produce updated sea ice thickness estimates from ESA's CryoSat-2 mission (2008 onwards) and look ahead to the upcoming launch of ICESat-2 (summer 2018). We hope the open source framework will encourage community involvement in possible improvements and additions to the model physics (e.g. rain-on-snow, snow ice formation, snow melt processes).

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