IHOP 2002 Soundings Mobile MCLASS [NOAA/NSSL] 1.0 General Description This is one of the upper air data sets developed for the International H2O Project 2002 (IHOP 2002). This dataset contains high resolution sounding data from the Mobile Class System operated and deployed by the National Oceanic and Atmospheric Administration National Severe Storms Lab (NOAA/NSSL). The Mobile Class system was deployed at various locations within the IHOP 2002 domain. Rawinsondes were released from May 13th,2002 to June 25th, 2002. 2.0 Detailed Data Description 2.1 Detailed Format Description All upper air soundings were converted to University Corporation for Atmospheric Research/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 QC information. JOSS derived 10 second vertical resolution data from the RAW Mobile Class System souding files. These files consisted of 1.5 second vertical resolution profiles of thermodynamic parameters (temperature,dew point, humidity, etc) and seperate 10 second vertical resolution files containing just wind data. JOSS processing entailed creating data files merging the higher resolution thermodynamic data with the 10 second vertical resolution wind data. Ten second vertical resolution soundings were derived using linear interpolation of the nearest points contained in these data files. Ten second wind data points were used as is in the final soundings. The higher vertical resolution data files underwent "rate of change" vertical consistency checks (see Section 3.0) inorder to prevent the use of bad data values during the interpolation process. _________________________________________________________________ Vertical Consistency Parameter Check Action _________________________________________________________________ Time decreasing/equal data point removed Pressure increasing/equal > 3 mb/s or < -3 mb/s data point removed Temperature < -30 C/km (applied data point removed (Aloft) at p < 875 mb) < -100 C/km (applied data point removed (Near Surface) at p >= 875 mb) (Rapid Temperature Increase) > 200 C/km data point removed _________________________________________________________________ An important note to users: On May 19th, 2003, The IHOP 2002 Soundings Mobile MCLASS was reprocessed and the original dataset replaced. It was determined that the lapse (Temperature check), removed too many points in the near surface layers. To address this issue, JOSS applied a new lapse rate check employing different rates for data points whose pressures are below or above 875 mb. Plots of potential temperature versus altitude from the JOSS derived soundings (cleaned-NSSL2) and 10 second vertical resolution versions (uncleaned-NSSL1) of the soundings provided by (NOAA/NSSL) were overlaid and compared (http://www.joss.ucar.edu/data/ihop/docs/IHOP-NSSL-Class-plots). The results imply this problem has been corrected. 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 Release Site Type/Site ID: Description of launch site. 4 Release Location (lon,lat,alt): Position of launch site, in format described below. 5 UTC Release 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 labels are padded to 35 characters to match the standard header lines. Here is an example of the four non-standard header lines contained in this dataset. Line Label (padded to 35 char) Contents 6 Winds Type/Processor/Smoothing: LORAN-C, ANI-7000, 60 SECONDS 7 Met Processor/Met Smoothing: NCAR RS80 PROCESSOR, 10 SECONDS 8 System Operator/Comments: T. WAGNER, NONE 9 Input File: X6031715.NSL 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 records of the IHOP 2002 Mobile Class 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: IHOP_2002 NSSL Class Sndings Release Site Type/Site ID: NSSL Mobile Class Sounding Release Location (lon,lat,alt): 100 52.56'W, 36 58.62'N, -100.88, 36.98, 860.0 UTC Release Time (y,m,d,h,m,s): 2002, 06, 03, 17:15:00 Winds Type/Processor/Smoothing: LORAN-C, ANI-7000, 60 SECONDS Met Processor/Met Smoothing: NCAR RS80 PROCESSOR, 10 SECONDS System Operator/Comments: T. WAGNER, NONE Input File: X6031715.NSL / / Nominal Release Time (y,m,d,h,m,s):2002, 06, 03, 17:15:00 Time Press Temp Dewpt RH Uwind Vwind Wspd Dir dZ Lon Lat Elev Azim Alt Qp Qt Qh Qu Qv Qdz sec mb C C % m/s m/s m/s deg m/s deg deg deg deg m code code code code code code ------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- ------- ----- ----- ------- ---- ---- ---- ---- ---- ---- -341.0 908.5 33.6 12.9 28.6 2.4 -0.9 2.6 291.0 999.0 -100.876 36.977 999.0 999.0 859.8 3.0 3.0 3.0 99.0 99.0 9.0 10.0 908.0 32.8 12.3 28.6 0.9 0.3 0.9 252.0 0.0 -100.889 36.940 4.2 195.4 864.8 3.0 3.0 3.0 99.0 99.0 99.0 20.0 905.1 32.0 12.3 29.9 1.2 -1.2 1.7 315.0 2.9 -100.891 36.938 4.5 197.1 894.0 2.0 2.0 2.0 99.0 99.0 99.0 30.0 902.3 31.2 12.2 31.3 1.4 -2.0 2.4 325.0 2.8 -100.893 36.937 4.7 197.8 922.1 2.0 2.0 2.0 99.0 99.0 99.0 40.0 899.4 30.4 12.1 32.6 2.0 -2.9 3.5 325.0 2.9 -100.893 36.936 4.8 198.2 951.3 2.0 2.0 2.0 99.0 99.0 99.0 Data Type: Sounding Project ID: IHOP_2002 NSSL Class Sndings Release Site Type/Site ID: NSSL Mobile Class Sounding Release Location (lon,lat,alt): 100 53.16'W, 36 57.96'N, -100.89, 36.97, 860.0 UTC Release Time (y,m,d,h,m,s): 2002, 06, 03, 18:15:00 Winds Type/Processor/Smoothing: LORAN-C, ANI-7000, 60 SECONDS Met Processor/Met Smoothing: NCAR RS80 PROCESSOR, 10 SECONDS System Operator/Comments: T. WAGNER, NONE Input File: X6031815.NSL / / Nominal Release Time (y,m,d,h,m,s):2002, 06, 03, 18:15:00 Time Press Temp Dewpt RH Uwind Vwind Wspd Dir dZ Lon Lat Elev Azim Alt Qp Qt Qh Qu Qv Qdz sec mb C C % m/s m/s m/s deg m/s deg deg deg deg m code code code code code code ------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- ------- ----- ----- ------- ---- ---- ---- ---- ---- ---- -239.0 907.9 35.9 12.6 24.6 0.0 2.6 2.6 180.0 999.0 -100.886 36.966 999.0 999.0 859.8 99.0 99.0 99.0 99.0 99.0 9.0 10.0 908.0 35.0 13.2 26.9 0.4 -4.2 4.2 355.0 0.0 -100.871 37.047 9.1 8.6 858.8 3.0 3.0 3.0 99.0 99.0 99.0 20.0 907.7 35.4 13.5 26.8 1.2 -6.1 6.2 349.0 0.3 -100.871 37.046 9.1 8.6 861.8 3.0 3.0 3.0 99.0 99.0 99.0 30.0 907.4 35.8 13.8 26.9 2.0 -6.8 7.1 344.0 0.3 -100.871 37.046 9.0 8.7 864.9 3.0 3.0 3.0 99.0 99.0 99.0 40.0 902.4 34.3 13.7 28.9 9999.0 9999.0 999.0 999.0 5.1 -100.871 37.045 9.0 8.8 915.8 2.0 2.0 2.0 9.0 9.0 99.0 3.0 Quality Control 3.1 JOSS Quality Control Processing This dataset underwent am automated QC process. The dataset underwent internal consistency checks which included two types of checks,gross limit checks on all parameters and rate-of-change checks on temperature, pressure and ascension rate. Some further information on the QC processing conducted by JOSS can be found in Loehrer et al. (1996) and Loehrer et al. (1998). 3.1.1 Gross Limit Checks These checks were conducted on each sounding and data were automatically flagged as appropriate. Only the data point under When a 10 second data point was available in the high resoultion, this point was used in the examination was flagged. JOSS conducted the following gross limit checks on the IHOP Mobile Class 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 _________________________________________________________________ 3.1.2 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 neighboring 10-sec data points. 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 _____________________________________________________________________ 4.0 References 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.