CPP-12. New regional masks for Arctic and Antarctic sea ice trends and climatologies

Abstract
Overall, Arctic sea ice is declining and Antarctic sea ice has a near-zero trend over the past 40+ years. However, there are distinct regional variations in these trends. Regional masks were developed to investigate these trends, but the masks were created in a non-rigorous fashion for defined grids at low spatial resolution; and there are inconsistencies in masks, even within products at NSIDC. Here we derive a new Arctic regional mask based on International Hydrographic Organization (IHO) definitions, with adaptations to better suit sea ice applications. A new Antarctic regional mask is derived based on previous studies of coherent variability of ice features rather than arbitrary longitudinal boundaries. The masks are created in vector shapefile format and high spatial resolution EASE2 polar grids, which provides flexibility and adaptability for different grid resolutions and projections. We demonstrate the grids via statistics on regional trends and variability in the passive microwave sea ice climate record.