Land Data Assimilation in the Arctic System Reanalysis

The Arctic System Reanalysis (ASR), a blend of modeling and observations, will provide a high resolution description in space (10-20 km) and time (3 h) of the atmosphere-sea ice-land surface system of the Arctic. The ASR will provide a resource for the detection and diagnosis of change in the coupled Arctic climate system. The widespread applications of existing global reanalyses (e.g., ERA-40, NCEP/NCAR, JRA-25, NASA DAS) demonstrate the high impact that can be expected on Arctic research.

Land data assimilation is a vital component to ASR. The timing and amount of snow is a crucial component to both the energy and water cycles. The extent of the ASR domain also requires the accurate specification of vegetation condition. Observed albedo provides a constraint on the surface energy. The current ASR system incorporates NASA, NESDIS, and NOAA satellite observations for these vital surface properties.

An overview of the ASR system will be shown along with the land surface products used. Nine-year test results using the offline HRLDAS will be shown along with introductory results from one-month and one-year tests within the variational coupled atmosphere-ocean-land system.