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Title: Improved NLDAS-2 Noah-simulated Hydrometeorological Products with an Interim Run

In NLDAS-2 Noah simulation, the NLDAS team introduced an intermediate fix suggested by Slater et al. (2007) and Livneh et al. (2010) to reduce large sublimation. The fix is used to constraint surface exchange coefficient (CH) using CH =CHoriginal x max (1.0-RiB/0.5, 0.05) when atmospheric boundary layer is stable. RiB is Richardson number. In NLDAS-2 Noah version, this fix was used for all stable cases including snow-free grid cells. In this study, we simply applied this fix to the grid cells in which both stable atmospheric boundary layer and snow exist simultaneously excluding the snow-free grid cells as we recognize that the fix constraint in NLDAS-2 is too strong. We make a 31-year (1979-2009) Noah NLDAS-2 interim (NoahI) run. We use observed streamflow, evapotranspiration, land surface temperature, soil temperature, and ground heat flux to evaluate the results simulated from NoahI and make the reasonable comparison with those simulated from NLDAS-2 Noah (Xia et al., 2012). The results show that NoahI has the same performance as Noah does for snow water equivalent simulation. However, NoahI significantly improved the other hydrometeorological products’ simulation as described above when compared to Noah and the observations. This simple modification is being installed to the nextmore » Noah version. The hydrometeorological products simulated from NoahI will be staged on NCEP public server for the public in future.« less
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Resource Type:
Journal Article
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Journal Name: Hydrological Processes, 29(5):641-816
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
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Country of Publication:
United States
NLDAS-2; Noah; simulated; hydrometeorological; products; interim