Progress and overview of the Arctic System Reanalysis

An overview of the Arctic System Reanalysis (ASR) is presented. The ASR is a multi-institutional, interdisciplinary collaboration to provide a description of the Arctic's atmosphere/sea-ice/land system at high spatial (10 km) and temporal (3 h) resolution by assimilating a diverse suite of observations into a regional model. The project is designated as an International Polar Year (IPY) full project and the domain includes all of the river basins that drain into the Arctic Ocean. The full ASR will span the years 2000-2010. A 30-km horizontal resolution prototype for 2007-2008 was initially produced, and a 10-year representation "ASR-Interim" at 30-km resolution is being finalized. Realistic testing of the modeling and data assimilation components have been performed with version 3.2.1 of the polar-optimized Weather Research and Forecasting (WRF) model. The data assimilation uses WRF-Var's 3D-Var system developed at the National Center for Atmospheric Research (NCAR) and optimized for the Arctic with the help of NCAR's Mesoscale and Microscale Meteorology division. Land surface observations are ingested with High-Resolution Land Data Assimilation (HRLDAS). Plans include an ingestion of broad-based historical data streams from the surface and space, along with measurements of the physical components. Gridded output fields from the ASR will serve a variety of uses such drivers for coupled ice-ocean, land surface and other models, and will offer a focal point for coordinated model inter-comparison efforts. The ASR will permit detailed reconstructions of the Arctic system's variability and is contributing to improved atmospheric and land-surface modeling for the Arctic.