GCIP/EOP GEM Model Location Time Series (MOLTS) 1.0 General Description The GEM Model Location Time Series is one of the model output data sets provided in the GEWEX Continental-scale International Project (GCIP) for the Enhanced Observation Period (EOP). The full GEM MOLTS data set covers most of North America (up to 252 locations). MOLTS are hourly time series output at selected locations that contain values for various surface parameters and `sounding' profiles at GEM model levels and are derived from the GEM model output. The MOLTS output files were converted into JOSS Quality Control Format (QCF) the same format used for atmospheric rawinsonde soundings processed by JOSS. The MOLTS output provided by JOSS on-line includes only the initial analysis output (i.e. no forecast MOLTS) and only state parameters (pressure, altitude, temperature, humidity, and wind). The full output, including the forecast MOLTS and all output parameters, in its orignal format (BUFR) is available from the NCAR/Scientific Computing Division. This data set will eventually cover the entire GCIP/EOP and presently (06 June 2001) includes April 1997 through December 2000. 2.0 Detailed Data Description The Atmospheric Environment Service/Canadian Meteoroligical Centre (AES/CMC) operates the GEM model with a resolution of 35 km and 28 vertical levels. The GEM analysis and forecast fields are generated every 12 hours at 0000 and 1200 UTC daily. MOLTS are hourly vertical profile and surface time series derived from the GEM model output. The complete MOLTS output includes 13 informational items, 27 parameters for each level and 28 parameters at the surface (a full listing is provided in section 2.2). Output are available each hour beginning at the initial analysis (the only output available from JOSS) and ending at the 36 hour forecast. JOSS converts the raw format (BUFR) files into JOSS QCF format which is the same format used for atmospheric sounding data such as NWS soundings. A description of JOSS QCF format is included within section 2.1. JOSS calculated the total wind speed and direction from the u and v wind components. JOSS calculated the mixing ratio from the specific humidity (Pruppacher and Klett 1980) and the dew point from the mixing ratio (Wallace and Hobbs 1977). Then the relative humidity was calculated from the dew point (Bolton 1980). JOSS did not conduct any quality control on this output. 2.1 Detailed Format Description 2.1.1 Header records The header records (15 total records) contain output type, project ID, the location of the nearest station to the MOLTS location (this can be a rawinsonde station, an ARM/CART station, a wind profiler station, a surface station, or just the nearest town), the location of the MOLTS output, and the valid time for the MOLTS output. The five header lines contain information identifying the sounding, and have a rigidly defined form. The following 6 header lines are used for auxiliary information and comments about the sounding, and they vary significantly from dataset to dataset. The last 3 header records contain header information for the data columns. Line 13 holds the field names, line 14 the field units, and line 15 contains dashes ('-' characters) delineating the extent of the field. The six standard header lines are as follows: Line Label (fixed to 35 char in length) Contents Data Type: GEM MOLTS Project ID: GCIP class format derived sounding Launch Site Type/Site ID: CLN COLLINS, MS Launch Location (lon,lat,alt): 089 32.40'W, 31 37.80'N, -89.54, 31.63, 75.0 GMT Launch Time (y,m,d,h,m,s): 1997, 08, 08, 12:24:00 Nearest Location (lon,lat): 89 24.60'W, 31 42.60'N, -89.41, 31.71 Grid Point Location (lon,lat,alt): 1 Data Type: Description of type of data. 2 Project ID: ID of weather project. 3 Launch Site Type/Site ID: Description of the nearest location. 4 Launch Location (lon,lat,alt): Position of MOLTS output in format described below. 5 GMT Launch Time (y,m,d,h,m,s): Time of release in UTC, in format: yyyy, mm, dd, hh:mm:ss 6 Nearest Location (lon,lat): Description of the nearest location. 7 Grid Point Location (lon,lat,alt): Position of MOLTS output in format described below. 8 CAUTION: A warning that this is not actual rawinsonde data, but rather model output. The release location is given as: lon (deg min), lat (deg min), lon (dec. deg), lat (dec. deg), alt (m) Longitude in deg min is in the format: ddd mm.mm'W where ddd is the number of degrees from True North (with leading zeros if necessary), mm.mm is the decimal number of minutes, and W represents W or E for west or east longitude, respectively. Latitude has the same format as longitude, except there are only two digits for degrees and N or S for north/south latitude. The decimal equivalent of longitude and latitude and station elevation follow. The seven non-standard header lines may contain any label and contents. The label is fixed to 35 characters to match the standard header lines. Sample header records are provided in the sample data file in section 2.1.3. 2.1.2 Data records The data records each contain time from release, pressure, temperature, dew point, relative humidity, U and V wind components, wind speed and direction, ascent rate, balloon position data, altitude, and quality control flags (see QC code description). Each data line contains 21 fields, separated by spaces, with a total width of 130 characters. The data are right-justified within the fields. All fields have one decimal place of precision, with the exception of latitude and longitude, which have three decimal places of precision. The contents and sizes of the 21 fields that appear in each data record are as follows: Field Format Missing No. Width Parameter Units Value ---------------------------------------------------------------------- 1 6 F6.1 Time Seconds 9999.0 2 6 F6.1 Pressure Millibars 9999.0 3 5 F5.1 Dry-bulb Temperature Degrees C 999.0 4 5 F5.1 Dew Point Temperature Degrees C 999.0 5 5 F5.1 Relative Humidity Percent 999.0 6 6 F6.1 U Wind Component Meters/Second 9999.0 7 6 F6.1 V Wind Component Meters/Second 9999.0 8 5 F5.1 Wind Speed Meters/Second 999.0 9 5 F5.1 Wind Direction Degrees 999.0 10 5 F5.1 Ascension Rate Meters/Second 999.0 11 8 F8.3 Longitude Degrees 9999.0 12 7 F7.3 Latitude Degrees 999.0 13 5 F5.1 Variable (see below) 999.0 14 5 F5.1 Variable (see below) 999.0 15 7 F7.1 Altitude Meters 99999.0 16 4 F4.1 QC flag for Pressure Code (see below) 99.0 17 4 F4.1 QC flag for Temperature Code (see below) 99.0 18 4 F4.1 QC flag for Humidity Code (see below) 99.0 19 4 F4.1 QC flag for U Component Code (see below) 99.0 20 4 F4.1 QC flag for V Component Code (see below) 99.0 21 4 F4.1 QC flag for Ascension Rate Code (see below) 99.0 ---------------------------------------------------------------------- Fields 13 and 14 are `variable' because depending on the sounding system the variables used in these positions can vary. For the MOLTS output, these columns have been set to missing. Fields 16 through 21 contain the Quality Control information (flags) generated locally at JOSS. These flags are based on the automatic or visual checks made. No quality control was performed on this data set. The JOSS QC flags are as follows: Code Description 99.0 Unchecked (QC information is `missing.') (`UNCHECKED') 1.0 Checked, datum seems physically reasonable. (`GOOD') 2.0 Checked, datum seems questionable on physical basis. (`MAYBE') 3.0 Checked, datum seems to be in error. (`BAD') 4.0 Checked, datum is interpolated. (`ESTIMATED') 9.0 Checked, datum was missing in original file. (`MISSING') 2.1.3 Sample data The following is a sample portion of an JOSS QCF file including header records. The data portion is much longer than 80 characters and, therefore, wraps around to a second line. Data Type: GEM MOLTS Project ID: GCIP class format derived sounding Launch Site Type/Site ID: CLN COLLINS, MS Launch Location (lon,lat,alt): 089 32.40'W, 31 37.80'N, -89.54, 31.63, 75.0 GMT Launch Time (y,m,d,h,m,s): 1997, 08, 08, 12:24:00 Nearest Location (lon,lat): 89 24.60'W, 31 42.60'N, -89.41, 31.71 Grid Point Location (lon,lat,alt): 89 32.40'W, 31 37.80'N, -89.54, 31.63, 75.0 Caution: This is not actual rawinsonde data,it is output from the CMC GEM model Caution: lon/lat for Launch Site Type/Site ID in Nearest Location (lon,lat) / / Nominal Launch Time (y,m,d,h,m,s): 1997, 08, 08, 12:24:00 Time Press Temp Dewpt RH Uwind Vwind Wspd Dir dZ Lon Lat Rng Ang Alt Qp Qt Qh Qu Qv Qdz sec mb C C % m/s m/s m/s deg m/s deg deg km deg m code code code code code code ------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- ------- ----- ----- ------- ---- ---- ---- ---- ---- ---- 9999.0 1008.7 22.5 22.6 100.7 -3.0 1.1 3.2 110.0 999.0 -89.540 31.630 999.0 999.0 99999.0 99.0 99.0 99.0 99.0 99.0 9.0 9999.0 1003.6 23.1 23.3 101.7 -3.1 2.0 3.7 123.0 999.0 -89.540 31.630 999.0 999.0 99999.0 99.0 99.0 99.0 99.0 99.0 9.0 9999.0 993.5 24.3 23.5 95.9 -3.3 3.5 4.8 137.0 999.0 -89.540 31.630 999.0 999.0 99999.0 99.0 99.0 99.0 99.0 99.0 9.0 . . . etc. 2.2 Full AES/CMC GEM MOLTS parameter listing for GCIP As previously mentioned, the full MOLTS output is not avaialbe from JOSS. It is, however, available from NCAR/SCD. A listing of the parameters available follows. WMO BLOCK NUMBER Numeric WMO STATION NUMBER Numeric YEAR Year MONTH Month DAY Day HOUR Hour TIME INCREMENT Hour LATITUDE OF STATION (COARSE) Degrees LATITUDE OF GRID POINT MODEL (COARSE) Degrees LONGITUDE OF STATION (COARSE; West < 0.0) Degrees LONGITUDE OF GRID POINT MODEL (COARSE; West < 0.0) Degrees LAND/SEA QUALIFIER Code Table TIME SIGNIFICANCE Code Table ZONAL WIND m/s MERIDIONAL WIND m/s VERTICAL MOTION Pa/s SURFACE WIND SPEED (10 M) m/s AIR TEMPERATURE K WET BULB POTENTIAL TEMPERATURE K SURFACE (SKIN) TEMPERATURE K SPECIFIC HUMIDITY kg/kg SURFACE ALBEDO Numeric PLANETARY ALBEDO Numeric OUTGOING IR FLUX AT THE TOP OF ATMOSPHERE (INSTANTANEOUS) W/m**2 OUTGOING VIS FLUX AT THE TOP OF ATMOSPHERE (INSTANTANEOUS) W/m**2 BOUNDARY LAYER THICKNESS m SENSIBLE HEAT FLUX (INSTANTANEOUS) W/m**2 DOWNWARD IR RADIATION AT SFC (INSTANTANEOUS) W/m**2 UPWARD IR RADIATION AT SFC (INSTANTANEOUS) W/m**2 HEAT FLUX IN THE GROUND (INSTANTANEOUS) W/m**2 MOMENTUM FLUX AT SFC (INSTANTANEOUS) Pa VIS RADIATION FLUX ABSORBED BY GROUND (INSTANTANEOUS) W/m**2 DOWNWARD VIS RADIATION FLUX AT SFC (INSTANTANEOUS) W/m**2 UPWARD VIS RADIATION FLUX AT SFC (INSTANTANEOUS) W/m**2 LATENT HEAT FLUX (INSTANTANEOUS) W/m**2 SFC MASK (0:WATER; 1:LAND/SNOW; 2:ICE; 3:LAND) Table GROUND MOISTURE (FRACTION 0 to 1) Numeric INCOMING VIS RADIATION AT THE TOP OF ATMOSPHERE W/m**2 NET RADIATION BUDGET OF THE ATMOSPHERE (INSTANTANEOUS) W/m**2 2-D TOTAL CLOUD COVER FRACTION Numeric SURFACE PRESSURE Pa CONVECTIVE PRECIPITATION ACCUMULATION BETWEEN 2 OUTPUT TIMES kg/m**2 CONVECTIVE PRECIPITATION RATE kg/m**2/s STRATIFORM PRECIPITATION ACCUMULATION BETWEEN 2 OUTPUT TIMES kg/m**2 STRATIFORM PRECIPITATION RATE kg/m**2/s TOP OF BOUNDARY LAYER sigma level NET BALANCE OF IR RADIATION AT SFC W/m**2 DEEP GROUND TEMPERATURE K SURFACE SOIL MOISTURE (0.3:SATUR.; 1:WATER) Numeric ROUGHNESS LENGTH meter TURBULENT KYNETIC ENERGY m**2/s**2 GRAVITY WAVE DRAG TENDENCY OF THE ZONAL WIND m/s**2 GRAVITY WAVE DRAG TENDENCY OF THE MERIDIONAL WIND m/s**2 VERTICAL DIFFUSION COEFFICIENT FOR MOMENTUM m**2/s VERTICAL DIFFUSION COEFFICIENT FOR HEAT m**2/s CONVECTIVE CLOUD FRACTION Numeric STRATIFORM CLOUD FRACTION Numeric 3-D CLOUD FRACTION Numeric MOISTENING DUE TO CONVECTION & GRID SCALE CONDENSATION kg/kg/s CLOUD WATER/ICE CONTENT kg/kg MOISTENING DUE TO VERTICAL DIFFUSION kg/kg/s MOISTENING DUE TO CONVECTION kg/kg/s HEATING RATE DUE TO SOLAR RADIATION K/s TOTAL PRECIPITATION LATENT HEATING RATE K/s HEATING RATE DUE TO VERTICAL DIFFUSION K/s POTENTIAL TEMPERATURE K HEATING RATE DUE TO IR RADIATION K/s CONVECTIVE PRECIPITATION LATENT HEATING RATE K/s STABLE PRECIPITATION LATENT HEATING RATE K/s VERTICAL DIFFUSION TENDENCY OF THE ZONAL WIND M/s**2 VERTICAL DIFFUSION TENDENCY OF THE MERIDIONAL WIND M/s**2 SIGMA LEVEL OF THE MODEL Numeric PRESSURE CORRESPONDING TO THE MODEL LEVEL Pa ETA LEVEL OF THE MODEL Numeric 2.3 Data Remarks No remarks. 3.0 Quality Control Processing No quality control was performed by JOSS. 4.0 References Bolton, D., 1980: The Computation of Equivalent Potential Temperature. Mon. Wea. Rev., 108, 171-180. Pruppacher, H. R., and J. D. Klett, 1980: Microphysics of Clouds and Precipitation. D. Reidel Publishing Company. 714 pp. Wallace, J. M., and P. V. Hobbs, 1977: Atmospheric Science: An Introductory Survey. Academic Press. 467 pp.