The RUC40 forecast model is an updated version of the generalized vertical coordinate model described by Bleck and Benjamin (1993). Modifications to improve the RUC40 included use of the code structure of the NCAR/Penn State Mesoscale Model version 5 (MM5, Grell et al. 1994). This allowed relatively easy transfer of MM5 parameterizations (cloud microphysics, radiation) into the RUC40 model.
The RUC40 model contains 42 model fields produced by the Mesoscale Analysis and Prediction System (MAPS) coupled modeling system at the NOAA Forecast Systems Laboratory (FSL).
The MAPS MORDS data set used here was obtained from NCAR's GCIP Model Output Archive Summary (http://rda.ucar.edu/datasets/ds609.1/). The files were untarred and collected together into monthly directories, but there are known gaps in the times in the archive from NCAR. These gaps are documented more below in the File Naming Convention section.
The numerical characteristics of the RUC40 mode include:
- Arakawa-C staggered horizontal grid (Arakawa and Lamb, 1977); u and v horizontal wind points are offset from mass points to improve numerical accuracy.
- No vertical staggering.
- Time step is 60 seconds at 40-km resolution.
- Positive definite advection schemes are used for the continuity equation (advection of pressure thickness between levels) and for horizontal advection (Smolarkiewicz 1983) of virtual potential temperature, and all vapor and hydrometer moisture variables.
RUC40 data are stored in individual ASCII data files, with one file per hour. Within each hourly file, 42 data variables are stored in row-major order, starting at the lower-left coordinate. Because the analysis runs at a 00Z initial time do not contain the full set of the 42 fields (described in the table below), the 00Z forecast run at time of 01Z was selected as the nearest time value to the 00Z analysis output.
Record # |
Variable (:”level”) |
Name Description [Unit] |
---|---|---|
1 |
MSL |
1hr fcst:"Mean sea level pressure (MAPS) [Pa] |
2 |
PRES:sfc |
1hr fcst:"Pressure [Pa] |
3 |
HGT:sfc |
1hr fcst:"Geopotential height [gpm] |
4 |
TSOIL:sfc |
1hr fcst:"Soil temp. [K] |
5 |
SOILM:44-0 cm down |
1hr fcst:"Soil moisture content [kg/m^{2}] |
6 |
SOILM:0 cm down |
1hr fcst:"Soil moisture content [kg/m^{2}] |
7 |
WEASD:sfc |
1hr fcst:"Accum. snow [kg/m^{2}] |
8 |
TMP:2 m above gnd |
1hr fcst:"Temp. [K] |
9 |
SPFH:2 m above gnd |
1hr fcst:"Specific humidity [kg/kg] |
10 |
UGRD:10 m above gnd |
1hr fcst:"u wind [m/s] |
11 |
VGRD:10 m above gnd |
1hr fcst:"v wind [m/s] |
12 |
APCP |
0-1hr acc:"Total precipitation [kg/m^{2}] |
13 |
ACPCP:sfc |
0-1hr acc:"Convective precipitation [kg/m^{2}] |
14 |
WEASD:sfc |
0-1hr acc:"Accum. snow [kg/m^{2}] |
15 |
SNOM:sfc |
0-1hr acc:"Snow melt [kg/m^{2}] |
16 |
SSRUN:sfc |
0-1hr acc:"Storm surface runoff [kg/m^{2}] |
17 |
LHTFL:sfc |
0-1hr ave:"Latent heat flux [W/m^{2}] |
18 |
SHTFL:sfc |
0-1hr ave:"Sensible heat flux [W/m^{2}] |
19 |
SHTFL |
0 cm down 0-1hr ave:"Sensible heat flux [W/m^{2}] |
20 |
SNOHF:sfc |
0-1hr ave:"Snow phase-change heat flux [W/m^{2}] |
21 |
CD:sfc |
1hr fcst:"Drag coefficient [non-dim] |
22 |
SHTFL:sfc |
1hr fcst:"Sensible heat flux [W/m^{2}] |
23 |
LHTFL:sfc |
1hr fcst:"Latent heat flux [W/m^{2}] |
24 |
CAPE:sfc |
1hr fcst:"Convective Avail. Pot. Energy [J/kg] |
25 |
PWAT:atmos col |
1hr fcst:"Precipitable water [kg/m^{2}] |
26 |
LCDC |
1hr fcst:"Low level cloud cover [%] |
27 |
MCDC |
1hr fcst:"Mid level cloud cover [%] |
28 |
HCDC |
1hr fcst:"High level cloud cover [%] |
29 |
DSWRF:sfc |
0-1hr ave:"Downward short wave flux [W/m^{2}] |
30 |
DLWRF:sfc |
0-1hr ave:"Downward long wave flux [W/m^{2}] |
31 |
USWRF:sfc |
0-1hr ave:"Upward short wave flux [W/m^{2}] |
32 |
ULWRF:sfc |
0-1hr ave:"Upward long wave flux [W/m^{2}] |
33 |
ALBDO:sfc |
1hr fcst:"Albedo [%] |
34 |
TSOIL:5 cm down |
1hr fcst:"Soil temp. [K] |
35 |
TSOIL:20 cm down |
1hr fcst:"Soil temp. [K] |
36 |
TSOIL:40 cm down |
1hr fcst:"Soil temp. [K] |
37 |
TSOIL:160 cm down |
1hr fcst:"Soil temp. [K] |
38 |
SOILW:sfc |
1hr fcst:"Volumetric soil moisture [fraction] |
39 |
SOILW:5 cm down |
1hr fcst:"Volumetric soil moisture [fraction] |
40 |
SOILW:20 cm down |
1hr fcst:"Volumetric soil moisture [fraction] |
41 |
SOILW:40 cm down |
1hr fcst:"Volumetric soil moisture [fraction] |
42 |
SOILW:160 cm down |
1hr fcst:"Volumetric soil moisture [fraction] |
There are several places in the time span of the data in which gaps are found, and these gaps are documented in two files: (1) in an Excel spreadsheet file calledruc40-list.xls, and (2) a text file called RUC-all.out. These two files provide a list by month of all the files that are contained in the untarred/unzipped monthly directories.