NWS-CPC's New Systems for Monitoring & Prediction of Land Surface Variables

Land Data Assimilation Systems (LDAS):

The Noah Land Surface Model used here is one of the land surface models used in the North American Land Data Assinilation System (NLDAS) (Mitchell et al., 2000). The model takes observed precipitation, downward longwave radiation & shortwave radiation, surface wind speed, surface pressure, humidity, 2m temperature and calculates soil moisture & other land variables, such as soil temperature, snowpack etc.

Model parameters

Retrospective N -LDAS Run Project:

The 51-year (1948-1998) run of Noah Land Surface Model for the conterminous USA (Fan et al, JCL in press) has been completed under Office of Global Programs - GEWEX Continental-scale International Project (GCIP) sponsorship. The primary reason for this 51-year reanalysis is to define climate, including interannual variablity, placing extreme events in historical context, and to aid in forecast applications at the NCEP Climate Prediction Center (CPC), which currently runs a much simpler hydrological model (Huang et al., 1996; van den Dool et al, 2003).

The forcing input data consists of observed precipitation, derived from CPC new daily & hourly precip analysis (1948-1998), and downward solar and longwave radiation, surface pressure, humidity, 2m temperature and horizontal windspeed from NCEP/NCAR Global Reanalysis. All of these data are interpolated to the 1/8 by 1/8 degree grid and hourly resolution.

The output consists of soil temperature and soil moisture in four layers below the ground. At the surface itself we have all of the components of the energy and (water) mass balance, including snow cover, depth, and albedo. Runoff can be routed into streamflow. For more information see Fan et al. (2003). (2002).

Land Data Products:

Early Figs new analysis (1948-1998).