6. One paragraph description of your model (e.g. abstract from report or paper); The NCEP/OH/OSU CAPS model is a multi-layer soil model (2-4 soil layers typically) with an explicit seasonal cycle of vegetation, plus snowpack physics. The prognostic state variables are soil moisture and temperature in each soil layer, skin temperature, snowpack water, and canopy water. A single skin temperature is obtained from a single surface energy balance equation for the combined ground/vegetation/snowpack surface. The evaporation in the energy balance is a combination of three evaporation components: 1) direct from bare soil, 2) transpiration through plant canopy, and 3) canopy water evaporation. The weighting of these three evaporation components is controlled by a specified monthly annual cycle of NDVI-based green vegetation fraction, derived by NOAA/NESDIS from AVHRR satellite data. The vegetation resistance treatment is similar to that of Jarvis/Noilhan (e.g. in the French ISBA model). The soil hydraulics is governed by Darcy's Law, including both a hydraulic conductivity and diffusivity, which vary with soil moisture content. 50. Please provide references relevant to the model description and use. Without snow component (see snow component later at bottom): Chen, Fei, et al., 1996: Modeling of land surface evaporation by four schemes and comparison with FIFE observations. J. Geophysical Research, Vol 101, No D3, 7251-7268. Chen, Fei, Zavisa Janjic, Kenneth Mitchell, 1997: Impact of Atmospheric Surface-layer Parameterization in the new Land-surface Scheme of the NCEP Mesoscale Eta Model. Accepted in Boundary-Layer Meteorology. Betts, A., F. Chen, K. Mitchell, Z. Janjic, 1997: Assessment of the land-surface and boundary-layer models in two operational versions of the NCEP Eta model using FIFE data. Accepted in Monthly Weather Review. Ismail, Y., J. Shuttleworth, J. Washburne, 1997: Evaluating the Eta model derived data against observations. Submitted to Monthly Weather Review. With snow component: Ek, M., and L. Mahrt, 1991: OSU 1-D PBL Model User's Guide, A one-dimensional planetary boundary layer model with interactive soil layers and plant canopy. Version 1.0.4. March 1991. Available from Dept of Atmospheric Sciences, Oregon State University. Kenneth Mitchell (Kenneth.Mitchell@noaa.gov) (Ph: 301-763-8161, x7225) Environmental Modeling Center National Centers for Environmental Prediction W/NP2, Room 204 4700 Silver Hill Road Stop 9910 Washington DC 20233-9910 Co-developers (entire land-surface model): NCEP: Fei Chen (fchen@sun1.wwb.noaa.gov) NCEP: Hua-Lu Pan (wd23ph@sun1.wwb.noaa.gov) OSU: Michael Ek (ek@ats.orst.edu) OH: Victor Koren (Victor.Koren@noaa.gov) OH: Qingyun Duan (Qingyun.Duan@noaa.gov) OH: John Schaake (John.Schaake@noaa.gov)