ASR data assimilations with reduced resolution (30 km) have been performed and are known as ASR-Interim. The ASR-Interim version 1 (covering January 1, 2000 - December 31, 2010) is available from NCAR CISL RDA ds631.0. ASR-Interim version 2 (covering January 1, 2000 - December 31, 2011) with significant improvements has been completed.
The annual total accumulated precipitation from the ASR-Interim version 2 and from ERA-Interim are very similar. The added benefit of higher resolution with the ASR data assimilation (30 km for ASR versus ~80 km for ERA-Interim) can be seen along the mountainous west coast of North America, southeast Greenland, southeast Iceland, and western Scandinavia where more detailed and realistic features are evident in ASR. The results of the ASR-Interim version 2 are compared with 3-h surface observations from across the ASR domain. These comparisons are based on observations from more than 5,000 surface stations obtained from the National Climatic Data Center. Comparisons of results from ERA-Interim with the 3-h surface observations are also made. The much higher skill in resolving surface pressure, 2-m temperature, 2-m dew point temperature and 10-m wind speed are seen for both ASR analysis and forecast. ASR has much better performance than ERA-Interim.
Based upon the very encouraging ASR-Interim version 2 results, the ASR team is performing the final version with two nested domains at 15 km resolution for 2000-2012 (and at 10 km resolution for 2010-2012) and will be finished by May 2013.