Justin Sheffield's Web Pages: Current Research: NLDAS
From the LDAS web page http://ldas.gsfc.nasa.gov/: The North American LDAS system is being developed to improve reanalysis and forecast simulations by numerical weather prediction (NWP) models. Specifically, this system will reduce the errors in the stores of soil moisture and energy which are often present in NWP models and which degrade the accuracy of forecasts. NLDAS is currently running retrospectively and in near real-time on a 1/8th-degree grid. The system is currently forced by terrestrial precipitation data, space-based radiation data and numerical model output. In order to create an optimal scheme, the project involves several LSMs, many sources of data, and several institutions.
The VIC model requires spatially distributed soil, vegetation and elevation parameters.
Sheffield, J., M. Pan, E. F. Wood, K. E. Mitchell, P. R. Houser, J. C. Schaake, A. Robock, D. Lohmann, B. A. Cosgrove, Q. Duan, L. Luo, R. W. Higgins, R. T. Pinker, J. D. Tarpley, B. H. Ramsay, Snow Process Modeling in the North American Land Data Assimilation System (NLDAS). Part I: Evaluation of Model Simulated Snow Cover Extent, 2003.
Pan, M., J. Sheffield, E. F. Wood, K. E. Mitchell, P. R. Houser, J. C. Schaake, A. Robock, D. Lohmann, B. A. Cosgrove, Q. Duan, L. Luo, R. W. Higgins, R. T. Pinker, J. D. Tarpley, Snow Process Modeling in the North American Land Data Assimilation System (NLDAS). Part II: Evaluation of Model Simulated Snow Water Equivalent, 2003.
All variables are instantaneous except for precipitation which is an accumulation From EDAS: 1 2 Meter Temperature [k] 11 2 2 Meter Specific Humidity [kg/kg] 51 3 Surface Pressure [Pa] 1 4 U wind component 10m [m/s] 33 5 V wind component 10m [m/s] 34 6 Downward Short Wave Radiation [W/m2] 204 7 Downward Long Wave Radiation [W/m2] 205 8 Total Precipitation [kg/m2] 61 9 Convective Precipitation [kg/m2] 63 10 Convective Avail Pot Energy (CAPE) [J/kg] 157 From GOES (Pinker) 11 Downward Short Wave Radiation [W/m2] 204 12 Skin Temperature [K] 118 13 PAR [W/m2] 101 From EDAS/StageIV/Gage Combo 14 Total Precipitation [kg/m2] 61 From StageIV 15 Total Precipitation [kg/m2] 61
PU versus UW
Comparison between Princeton near-term retrospective (1996-1999) and UW long-term retrospective (1950-1999)