Wednesday, 23 January 2008
Realtime GLDAS/LIS execution at NOAA/NCEP
Exhibit Hall B (Ernest N. Morial Convention Center)
Accurate assessment of land surface states, namely, soil moisture, soil temperature, vegetation, and snowpack, is critical in numerical weather and climate prediction systems because of their regulation of surface water and energy fluxes between the surface and atmosphere over a variety of spatial and temporal scales. To support the development of the NOAA/NCEP global weather and climate prediction systems, an uncoupled Land Information System (LIS) infrastructure has been launched on the NOAA/NCEP operational supercomputers. LIS, developed primarily at NASA Goddard Space Flight Center, Hydrological Sciences Branch, collaborating closely with NOAA/NCEP, aims to perform high-quality land surface simulation using state-of-art land surface models, observation-based precipitation, and satellite land data assimilation techniques. Currently, two jobs of LIS are executing on the NOAA/NCEP operational supercomputers in realtime on daily basis. The first is executing on T126 gaussian horizontal grid (~1 degree) to support the development of the NOAA Climate Forecast System (CFS), and Climate Data Assimilation System (CDAS). The second is executing on T382 gaussian horizontal grid (~1/3 degree) to support the development of the NOAA Global Forecast System (GFS), and Global Data Assimilation System (GDAS). The Noah land surface model is used which is the same land component of GFS and CFS. The LIS T126 performs a 27-year global land simulation from 1980 to present. Output from this simulation has been used to analyze global land climate variability and to generate alternative land initial conditions for CFS testing by the CFS developers of NCEP Environmental Modeling Center and Climate Prediction Center. The LIS T382 evaluates the sensitivity of various land surface physics and parameterization in modeling land-atmospheric interactions. Results have shown that this uncoupled execution of LIS can correctly identify the impact of alternatively tested options and additions of Noah in an efficient fashion, as opposed to a fully coupled execution of GFS. We have conducted CFS and GFS land initialization experiments and preliminary results are encouraging.
Supplementary URL: