LDAS Meeting Minutes
May 10th
2001
NWS/OHD
1. Ken Mitchell of NCEP/EMC reviewed the LDAS project Terms of Reference document for the realtime LDAS forcing and realtime LDAS LSMs runs (NOAH, MOSAIC, VIC, and SAC). This document is available from Ken Mitchell upon request. The group discussed and adopted a common file-naming convention of the realtime LDAS LSM hourly GRIB output files. This adopted convention will be added to the Terms of Reference document.
ACTION: Ken Mitchell will add a second section to the Terms of Reference document to provide guidelines and criteria for the retrospective LDAS forcing and LSM executions.
2. Brian Cosgrove of NASA/GSFC presented the forcing glitches he is finding in the NCAR GCIP archive of Eta/EDAS and Stage IV fields during the first months of this archive (Apr-Sep 96). He found very few such glitches after Sep 96. Thus it is likely that the retrospective forcing set that Brian is developing for LDAS use will begin in Oct 96.
3. Yun Duan of NWS/OHD presented the status of his work with John Schaake to identify a set of stream/river basins in the CONUS domain for use in validation of LDAS streamflow simulations, using retrospective and realtime USGS streamflow reporting stations.
ACTION: John Schaake will draft a letter to be sent to each RFC
requesting that each RFC recommend two basins that they would like added to the LDAS basin validation set.
4. Justin Sheffield of Princeton showed plots he had derived of May 99 (first full month of realtime LDAS hourly forcing) monthly mean diurnal cycle of GOES and EDAS solar insolation forcing extracted from the realtime LDAS hourly forcing files. These plots showed that the EDAS solar insolation had a distinct 1-3 hour phase lag error and a once-per-day non-physical jump or kink in the diurnal cycle trace, roughly during the mid-day portion of the solar day. NCEP will investigate this.
5. The group discussed a concern as to whether the output precision (packed bits) in the common LDAS GRIB PDS tables was sufficient to preserve water and energy balance.
ACTION: Justin Sheffield volunteered to compare the water balance precision between hourly output from full binary and packed GRIB forms of VIC LDAS output.