NESOB 1996 ARM-CART CLASS Format Upper Air Sounding Datasets 1.0 General Description This is one of the upper air sounding datasets developed for the GEWEX Continental-scale International Project (GCIP) 1996 Near Surface Observation Data Set (NESOB-96) conducted from 01 April to 30 September 1996. Included in this dataset are five Department of Energy (DOE) Atmospheric Radiation Measurement - Clouds And Radiation Testbed (ARM-CART) sounding stations; Lamont (Central Facility), Morris (B5), Purcell (B6), and Vici (B4), OK and Hillsboro (B1), KS. The area covered by the NESOB 1996 experiment extends from approximately 94.5W to 100.5W longitude and 34N to 39N latitude. The soundings are terminated at the point nearest to, but not over, 3000 m above the surface. 2.0 Detailed Data Description All upper air soundings were converted to University Corporation for Atmospheric Science/Joint Office for Science Support (UCAR/JOSS) Cross Chain LORAN Atmospheric Sounding System (CLASS) Format (JCF). JCF is a version of the National Center for Atmospheric Research (NCAR) CLASS format and is an ASCII format consisting of 15 header records for each sounding followed by the data records with associated Quality Control (QC) information. At each of the boundary facilities (B1, B4, B5, and B6) soundings were typically released once per weekday at 1800 UTC and at the central facility five times per weekday at 06, 12, 15, 18, and 21 UTC. However, during Intensive Observing Periods (IOPs) the sounding frequency increased to up to 8 per day (3-hourly; including weekends) at each of the sites. 2.1 Detailed Format Description All upper air soundings were converted to University Corporation for Atmospheric Science/Joint Office for Science Support (UCAR/JOSS) Cross Chain LORAN Atmospheric Sounding System (CLASS) Format (JCF). JCF is a version of the National Center for Atmospheric Research (NCAR) CLASS format and is an ASCII format consisting of 15 header records for each sounding followed by the data records with associated Quality Control (QC) information. Header Records The header records (15 total records) contain data type, project ID, site ID, site location, release time, sonde type, meteorological and wind data processors, and the operator's name and comments. The first five header lines contain information identifying the sounding, and have a rigidly defined form. The following 7 header lines are used for auxiliary information and comments about the sounding, and may vary 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 five standard header lines are as follows: Line Label (padded to 35 char) 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 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 padded to 35 characters to match the standard header lines. Data Records The data records each contain time from release, pressure, temperature, dewpoint, relative humidity, U and V wind components, wind speed and direction, ascent rate, balloon position data, altitude, and quality control flags (see the 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 No. Width Parameter Units Missing 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 Degrees 999.0 15 7 F7.1 Altitude Meters 99999.0 16 4 F4.1 QC for Pressure Code (see below) 99.0 17 4 F4.1 QC for Temperature Code (see below) 99.0 18 4 F4.1 QC for Humidity Code (see below) 99.0 19 4 F4.1 QC for U Component Code (see below) 99.0 20 4 F4.1 QC for V Component Code (see below) 99.0 21 4 F4.1 QC for Ascension Rate Code (see below) 99.0 Fields 16 through 21 contain the Quality Control information derived at the UCAR Joint Office for Science Support (UCAR/JOSS). Any QC information from the original sounding is replaced by the following JOSS codes: 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") Sample Data The following is a sample record of NESOB 1996 ARM-CART High-Resolution Upper-Air data in JOSS CLASS format. The data portion is much longer than 80 characters and, therefore, wraps around to a second line. See section 2.1 for an exact format specification Data Type: Sounding Project ID: NESOB ARM-CART 2 sec class format sounding Launch Site Type/Site ID: C1 : Central_Facility Launch Location (lon,lat,alt): 097 30.00'W, 36 36.00'N, -97.50, 36.60, 315.0 GMT Launch Time (y,m,d,h,m,s): 1996, 04, 15, 05:30:00 / / / / / / Nominal Launch Time (y,m,d,h,m,s): 1996, 04, 15, 06:00:00 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 ------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- ------- ----- ----- ------- ---- ---- ---- ---- ---- ---- 0.0 979.7 5.2 -1.5 62.0 3.2 -5.4 6.3 329.0 999.0 -97.490 36.610 999.0 999.0 315.0 2.0 2.0 2.0 99.0 99.0 99.0 2.0 977.0 4.7 -2.0 62.0 9999.0 9999.0 999.0 999.0 11.0 -97.490 36.610 999.0 999.0 337.0 2.0 2.0 2.0 9.0 9.0 99.0 4.0 976.3 4.7 -2.0 62.0 9999.0 9999.0 999.0 999.0 3.0 -97.490 36.610 999.0 999.0 343.0 2.0 2.0 2.0 9.0 9.0 99.0 2.2 Data Remarks ARM-CART files from 1 April through 30 September were delivered as netcdf files which JOSS converted to JCF. These files have two-second vertical resolution thermodynamic data and 10-sec vertical resolution wind data. At each of the boundary facilities (B1, B4, B5, and B6) soundings were typically released once per weekday at 1800 UTC and at the central facility five times per weekday at 06, 12, 15, 18, and 21 UTC. However, during Intensive Observing Periods (IOPs) the sounding frequency increased to up to 8 per day (3-hourly; including weekends) at each of the sites. 3.0 Quality Control Processing ARM-CART soundings were Quality Controlled (Lesht 1995) and provided to UCAR/JOSS by the ARM-CART Project. This dataset underwent a JOSS QC process which consisted of internal consistency checks. This included gross limit checks on all parameters and rate-of-change checks on temperature, pressure and ascension rate. JOSS did not perform visual quality control procedures on this data. Some further information on the QC processing conducted by JOSS can be found in Loehrer et al. (1996) and Loehrer et al. (1998). 3.1 Gross Limit Checks These checks were conducted on each sounding and data were automatically flagged as appropriate. Only the data point under examination was flagged. JOSS conducted the following gross limit checks on the ARM/CART 1996 sounding dataset. In the table P = pressure, T = temperature, RH = relative humidity, U = U wind component, V = V wind component, B = bad, and Q = questionable. ________________________________________________________________ Parameter(s) Flag Parameter Gross Limit Check Flagged Applied ________________________________________________________________ Pressure < 0 mb or > 1030 mb P B Altitude < 0 m or > 35000 m P, T, RH Q Temperature < -80C or > 45C T Q Dew Point < -99.9C or > 30C RH Q > Temperature T, RH Q Relative Humidity < 0% or > 100% RH B Wind Speed < 0 m/s or > 100 m/s U, V Q > 150 m/s U, V B U Wind Component < 0 m/s or > 100 m/s U Q > 150 m/s U B V Wind Component < 0 m/s or > 100 m/s V Q > 150 m/s V B Wind Direction < 0 deg or > 360 deg U, V B Ascent Rate < -10 m/s or > 10 m/s P, T, RH Q ________________________________________________________________ 3.2 Vertical Consistency Checks These checks were conducted on each sounding and data were automatically flagged as appropriate. These checks were started at the lowest level of the sounding and compared to neighboring 6-sec averaged values to reduce the flagging frequency of the checks. In the case of checks ensuring that the values increased/decreased as expected, only the data point under examination was flagged. However, for the other checks, all of the data points used in the examination were flagged. All items within the table are as previously defined. _________________________________________________________________ Vertical Consistency Parameter(s) Flag Parameter Check Flagged Applied _________________________________________________________________ Time decreasing/equal None None Altitude decreasing/equal P, T, RH Q Pressure increasing/equal P, T, RH Q > 1 mb/s or < -1 mb/s P, T, RH Q > 2 mb/s or < -2 mb/s P, T, RH B Temperature < -15 C/km P, T, RH Q < -30 C/km P, T, RH B > 5 C/km (not applied at p , 150mb) P, T, RH Q < 30 C/km (not applied at p , 150mb) P, T, RH B Ascent Rate change of > 3 m/s or < -3 m/s P Q change of > 5 m/s or < -5 m/s P B _________________________________________________________________ 3.3 Data Quality Issues In terms of items checked by the automated quality control processing, the ARM CART soundings performed well, with about average numbers of data points flagged. However, since these data have not undergone visual quality control processing, there are many problems that have not been flagged. This is especially true for the wind and relative humidity values. So these values should be used with some caution. As in past years, the B4 (Vici, OK) soundings had much higher occurrence rates of superadiabatic layers than the other sites. This year, however, the problem has been significantly reduced. The other sites had 0.5 - 0.7% of all data points registering as superadiabatic (< -15 C/km). These values were typical of soundings from other projects. B4, however, had 1.3% of all data points registering as superadiabatic. 4.0 References Lesht, B. M., 1995: An evaluation of ARM radiosonde operational performance. Preprints, Ninth Symposium on Meteorological Observations and Instrumentation, Charlotte, NC, Amer. Meteor. Soc., 6-10. Loehrer, S. M., T. A. Edmands, and J. A. Moore, 1996: TOGA COARE upper-air sounding data archive: development and quality control procedures. Bull. Amer. Meteor. Soc., 77, 2651-2671. Loehrer, S. M., S. F. Williams, and J. A. Moore, 1998: Results from UCAR/JOSS quality control of atmospheric soundings from field projects. Preprints, Tenth Symposium on Meteorological Observations and Instrumentation, Phoenix, AZ, Amer. Meteor. Soc., 1-6.