CASES-97 PRELIMINARY 10 Second Vertical Resolution Sounding Data Set -------------------------------------------------------------------- 1.0 Site Information Sites: Beaumont, Kansas 096 32.31'W, 37 37.63'N, 478 m Oxford, Kansas 097 05.75'W, 37 16.41'N, 360 m Whitewater, Kansas 097 11.25'W, 37 51.01'N, 420 m Typical Release Times: variable Dates Available: Beaumont - 19 April to 21 May 1997 Oxford - 20 April to 21 May 1997 Whitewater - 19 April to 22 May 1997 (occasional days without soundings) Source Agency: National Center for Atmospheric Research/ Atmospheric Technology Division (NCAR/ATD) `Native Vertical Resolution': 10 seconds Total Releases Available in `Native Resolution': Beaumont - 89 Oxford - 98 Whitewater - 96 2.0 Radiosonde Information Radiosonde Type: VAISALA RS80-15LH Windfinding System: LORAN-C 3.0 NCAR/ATD CLASS Format (ASCII text) Description and Quality Control 3.1 Header records The header records (15 total records) contain data type, project ID, site ID, site location, actual release time, sonde type, meteorological processor and smoothing, wind type and smoothing, surface data source, and system operator comments. The first five header lines contain information identifying the sounding, and have a rigidly defined form. The following seven header lines are used for auxiliary information and comments about the sounding. 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 standard header lines are as follows: Line Label (fixed to 35 char in length) Contents 1 Data Type: Description of type and resolution of data. 2 Project ID: ID of weather project. 3 Launch Site Type/Site ID: Description of launch site. 4 Launch Location (lon,lat,alt): Position of launch site, in format described below. 5 GMT Launch Time (y,m,d,h,m,s): Time of release, in format: yyyy, mm, dd, hh:mm:ss 6 Sonde Type/ID/Sensor ID/Tx Freq: Description of sonde type used. 7 Met Processor/Met Smoothing: The meteorological data processor and smoothing interval used. 8 Winds Type/Processor/Smoothing: The wind type, processor, and smoothing interval used. 9 Pre-launch Met Obs Source: Source of surface data point. 10 System Operator/Comments: Comments by the operator. The release location is given as: lon (deg min), lat (deg min), lon (decimal deg), lat (decimal 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. Sample header records are provided in the sample data file in section 3.3. 3.2 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 Range Kilometers 999.0 14 5 F5.1 Azimuth Angle Degrees 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 Wind Speed Code (see below) 99.0 ---------------------------------------------------------------------- Fields 16 through 21 contain the Quality Control information (flags) generated by NCAR/ATD. The NCAR/ATD QC flags are as follows (Miller 1993): Code Description ---------------------------------------------------------------------- 77.0 Good data with no error estimate 88.0 Questionable data due to interpolation (if interpolation interval was not too large) 99.0 Missing data (or Bad data if a large interpolation interval was used) ---------------------------------------------------------------------- All remaining QC flags (so called "std. error) are the square roots of the variances of the parameter estimates generated from the smoothing intervals used for their calculation. The units of the quality parameters are the same as those for the parameters measured. The interpolation constraints are as follows: parameter Interp Interval (sec) QC flag value ------------------------------------------------------ pressure <= 100 std. error 100 < interval <= 200 88.0 > 200 99.0 temperature <= 50 std. error 50 < interval <= 100 88.0 > 100 99.0 relative hum <= 50 std. error 50 < interval <= 100 88.0 > 100 99.0 wind <= 50 std. error 50 < interval <= 100 88.0 > 100 99.0 3.3 Sample data The following is a sample portion of a NCAR/ATD CLASS format file including header records. The data portion is much longer than 80 characters and, therefore, wraps around to a second line. Data Type: CLASS 10 SECOND DATA Project ID: CASES 97, WHITEWATER-KANSAS Launch Site Type/Site ID: FIXED, WHI Launch Location (lon,lat,alt): 097 11.25'W, 37 51.01'N, -97.1875, 37.85017, 420 GMT Launch Time (y,m,d,h,m,s): 1997, 04, 26, 12:01:13 Sonde Type/ID/Sensor ID/Tx Freq: VAISALA RS80-15LH 0, 0, 404.475 Met Processor/Met Smoothing: NCAR RS80 PROCESSOR, 10 SECONDS Winds Type/Processor/Smoothing: LORAN-C, ANI-7000, 60 SECONDS Pre-launch Met Obs Source: CAMPBELL SCIENTIFIC CR10 System Operator/Comments: OZ, (REPROCESSED),GREAT FLIGHT. 3 METERS NE. / / Time Press Temp Dewpt RH Uwind Vwind Wspd Dir dZ Lon Lat Rng Az Alt Qp Qt Qh Qu Qv Quv sec mb C C % m/s m/s m/s deg m/s deg deg km deg m mb C % m/s m/s m/s ------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- ------- ----- ----- ------- ---- ---- ---- ---- ---- ---- -102.0 970.9 15.6 4.2 46.6 -4.3 1.1 4.4 104.9 0.0 -97.188 37.850 0.0 0.0 420.0 77.0 77.0 77.0 77.0 77.0 77.0 10.0 9999.0 999.0 999.0 999.0 999.0 999.0 999.0 999.0 99.0 -97.188 37.850 0.0 284.9 99999.0 99.0 99.0 99.0 99.0 99.0 99.0 20.0 960.1 13.0 .9 43.6 999.0 999.0 999.0 999.0 9.4 -97.188 37.850 0.0 284.9 514.1 .2 0.0 .1 99.0 99.0 99.0 4.0 JOSS Quality Control Procedures This data set has undergone no quality control by UCAR/JOSS and UCAR/JOSS has not made any changes to these soundings. 5.0 Data Set Remarks AN IMPORTANT NOTE REGARDING THE NCAR CLASS SOUNDINGS CURRENTLY (June 1998) AVAILABLE FROM CASES: These soundings have undergone the standard SSSF sounding processing which for the most part has yielded a reasonable product. Extreme care was taken at launch to reduce humidity biases as much as possible - reduce any bias introduced at launch due to the sensor not being in equilibrium with the environment (e.g. sensor arm heating). The sondes were ventilated by swinging prior to launch in an attempt to bring the RH sensor into equilibrium with its environment. Please BE AWARE that this careful handling would NOT necessarily eliminate any inherent bias in the sensor due to other causes. Recent investigations have shown the POSSIBILITY (not certainty) of a dry bias in RH due to sensor contamination (that dry bias being a function of sonde age). Raw 1.5 second resolution PTH data (available off-line from UCAR/JOSS via CODIAC) have been made available with the standard sounding files to help the investigator with accessment of the sonde data quality (and perhaps help in a correction of any bias apparent). The extent of a dry bias in these soundings has not yet been determined. Such a bias may exist. SSSF will be evaluating this in the future and if needed make the appropriate corrections. 6.0 References Miller, E., 1993: TOGA COARE integrated sounding system data report - Volume 1 surface and sounding data. Surface and Sounding Systems Facility, National Center for Atmospheric Research, 41 pp.