UMRBPP Research Soundings High-Resolution Upper-Air Data Set 1.0 General Description This is one of the upper air sounding data sets developed for the Upper Missouri River Basin Pilot Project (UMRBPP) conducted from 05 April to 05 May 1999. The UMRBPP domain extends from 90W to 115W longitude and 36N to 51N latitude. This data set contains the two UMRBPP research sounding sites: the North Site Custer Crossing and the West Site Four Corners. The soundings were typically released at 00 and 12 UTC but there were occasional releases at 06 and 18 UTC. The final data set consists of 10-sec vertical resolution files. 2.0 Parameters in Raw Dataset Parameters Units -------------------------------------- Time Seconds Pressure Millibars Temperature Deg C Dew Point Deg C Relative Humidity % U wind component m/s V wind component m/s Wind Speed m/s Wind Direction Deg Ascension Rate m/s Longitude Deg Latitude Deg Altitude Geopotential Meters Pressure Quality Code mb Temp Quality Code Deg C Humidity Quality Code Deg C U comp Quality Code m/s V comp Quality Code m/s UV Quality Code m/s -------------------------------------- 3.0 Conversion to JOSS CLASS format (ASCII text) 3.1 The raw 10.0 sec vertical resolution time, temperature, relative humidity, altitude, pressure, dew point, wind direction, and wind speed were kept without change. 3.2 The ascension rate was calculated for each data point (excluding the launch point, where it was given a missing value) based on the altitude and time at two levels, the current 10.0 sec level and the previous 10.0 sec level. If the data point for which the ascension rate was being calculated had missing time or altitude, the ascension rate was not calculated at that level and was flagged as missing. If the data point prior to that for which the ascension rate was being calculated had a missing time or altitude, then the data point two data points prior to the present one was used, and so on until one with non-missing time and altitude was found. If there are no non-missing previous data points the ascension rate is set to missing. 3.3 Due to CLASS format constraints, Dew Points less than -99.9 Deg C were given a value of -99.9 Deg C and were flagged as being questionable. 4.0 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. 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 release site. 4 Release Location (lon,lat,alt): Position of release 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 label is padded to 35 characters to match the standard header lines. 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 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 Elevation Angle Degrees 999.0 14 5 F5.1 Azimuth Angle 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 are sample records of the UMRBPP Research Soundings 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 4.0 for an exact format specification Data Type: 10 Second Class Sounding Project ID: UMRBPP Release Site Type/Site ID: West Site Four Corners FCR Release Location (lon,lat,alt): 104 8.28'W, 44 4.62'N, -104.14, 44.08, 1768.0 UTC Release Time (y,m,d,h,m,s): 1999, 04, 10, 23:30:48 Radiosonde Manufacturer: VAISALA RS80-15L 0, 0, 405.05 Winds Type/Processor/Smoothing: LORAN-C, ANI-7000, 60 SECONDS Met Processor/Met Smoothing: NCAR RS80 PROCESSOR, 10 SECONDS System Operator/Comments: RON JOHNSON, type L Input File: x4102330.fcr.gz / UTC Release Time (y,m,d,h,m,s): 1999, 04, 10, 23:30:48 Time Press Temp Dewpt RH Ucmp Vcmp spd dir Wcmp Lon Lat Ele Azim Alt Qp Qt Qrh 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 ------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- ------- ----- ----- ------- ---- ---- ---- ---- ---- ---- -62.0 814.6 -3.3 -4.1 94.0 6.9 -6.4 9.4 313.0 999.0 -104.138 44.077 0.0 0.0 1768.0 2.0 2.0 2.0 99.0 99.0 9.0 120.0 813.9 -3.1 -3.8 94.8 3.2 -2.5 4.1 307.4 999.0 -104.142 44.068 1.1 193.6 1774.8 2.0 2.0 2.0 99.0 99.0 9.0 130.0 809.4 -3.4 -4.5 92.3 6.2 -6.0 8.7 314.1 4.4 -104.142 44.068 1.1 193.7 1818.8 2.0 99.0 99.0 99.0 99.0 99.0 Data Type: 10 Second Class Sounding Project ID: UMRBPP Release Site Type/Site ID: North Site Custer Crossing CUS Release Location (lon,lat,alt): 103 38.94'W, 44 12.30'N, -103.65, 44.20, 1652.0 UTC Release Time (y,m,d,h,m,s): 1999, 04, 07, 23:11:14 Radiosonde Manufacturer: VAISALA RS80-15LH 0, 0, 401.925 Winds Type/Processor/Smoothing: LORAN-C, ANI-7000, 60 SECONDS Met Processor/Met Smoothing: NCAR RS80 PROCESSOR, 10 SECONDS System Operator/Comments: FRED, LH sonde, clear sky, nice boundary layer Input File: x4072311.cus.gz / UTC Release Time (y,m,d,h,m,s): 1999, 04, 07, 23:11:14 Time Press Temp Dewpt RH Ucmp Vcmp spd dir Wcmp Lon Lat Ele Azim Alt Qp Qt Qrh 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 ------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- ------- ----- ----- ------- ---- ---- ---- ---- ---- ---- -30.0 827.7 13.2 -4.4 29.1 2.8 1.6 3.2 239.9 999.0 -103.649 44.205 0.0 0.0 1652.0 2.0 2.0 2.0 99.0 99.0 9.0 90.0 825.7 12.8 -7.8 23.0 2.4 0.9 2.6 250.3 999.0 -103.645 44.216 1.2 15.0 1672.8 3.0 2.0 2.0 99.0 99.0 9.0 100.0 819.4 12.1 -9.0 21.9 3.9 1.5 4.2 249.6 6.4 -103.645 44.216 1.2 16.2 1736.9 3.0 99.0 99.0 99.0 99.0 99.0 5.0 Quality Control Processing This dataset underwent an automated QC process which included a procedure checking total wind speed and direction and internal consistency checks. The wind checking procedure included rate-of-change checks on total wind speed and each wind component and checking these against their 120 second running mean. The internal consistency checks included two types of checks, gross limit checks on all parameters and rate-of-change checks on temperature, pressure and ascension rate. 5.1 Wind Checking Procedure Every wind speed value including the U and V wind components underwent a checking procedure which entailed a rate-of-change check and a check against a 120 second running mean. The rate of change in wind shear was used in-order to identify likely questionable and bad wind values. Any flagged wind values are excluded from any 120 second interval used in the following check where values are compared against a 120 second running mean. The rate-of-change checks were started at the lowest level of the sounding and compared neighboring data points. In the table U = U wind component, V = V wind component, B = bad, and Q = questionable. If one component satisfied a flag criterion, then both components were given that QC flag. Similarly if the total wind speed satisfied a flag check then both wind components were flagged as well. Parameter(s) Flag Parameter Rate of shear Check Flagged Applied _____________________________________________________________________ Wind Speed > 1 m/s or < -1 m/s U,V B Wind Speed > 0.5 m/s or < -0.5 m/s U,V Q U or V Wind Comp > 1 m/s or < -1 m/s U,V B U or V Wind Comp > 0.5 m/s or < -0.5 m/s U,V Q After the above rate-of-change check is performed, a running 120 second mean and variance is calculated for every point within the sounding excluding the first and last 30 seconds (approximately). Note: The size of the intervals at the beginning and end of the sounding not examined by this check depends upon the initial time for the first valid data point , the sounding's temporal resolution, and whether the resolution remained constant or varied. In theory if a sounding's first valid data begins at some initial time and the temporal resolution remains constant, say 10 seconds, then the first point checked will be at a point at least 30 seconds after the initial time and the last point will be at a point at least 30 seconds before the final time. The calculated mean and variance are centered for every point excluding the first and last minute. In the first 30 to 60 seconds, the mean uses 30 seconds of data before and 90 seconds after the data point under examination. In the last 60 to 30 seconds, this situation is reversed, i.e 30 seconds after and 90 seconds before the point under examination. Each wind speed and U and V component is compared against its 120 second running mean and using the 120 second running variance, the standard deviation is calculated. The standard deviation is then used to flag the point appropriately. Only points not previously flagged by the rate-of-change check and points containing non-missing data were used when calculating the 120 second running mean. If less than 75% of the points within a particular 120 second interval satisfied the above stipulation then the running mean was not calculated and this check was not applied to that point. Parameter(s) Flag Parameter Standard Deviation Flagged Applied _____________________________________________________________________ Wind Speed > 1.425 or < -1.425 U,V B Wind Speed > 0.95 or < -0.95 U,V Q U or V Wind Comp > 2.25 or < -2.25 U,V B U or V Wind Comp > 1.5 or < -1.5 U,V Q 5.2 "Buddy Check" In many instances, a sufficient number of points above and/or below the point under examination had been flagged previously by the rate-of-change in wind shear check or deviated far enough from the calculated 120 second running mean that too few "good" points remained within the point under examination's 120 second interval for this check to ensue. In order to check these points, a simple scheme was devised: the buddy check, which entails checking the points immediately preceding and following the point under examination. If these points were flagged bad or questionable, it was highly likely the point under examination was either bad or questionable. A careful visual inspection of the points flagged by this check verified this assumption. The point under examination received the least worst flag of the two points examined and both points had to contain non-missing values. 5.3 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 UMRBPP 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 _________________________________________________________________ 5.4 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 6-sec data points (except at pressures less than 100 mb where 30-sec average values were used. 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 _____________________________________________________________________ 6.0 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. NWS, 1991: Micro-ART Observation and Rework Programs Technical Document, National Weather Service, National Oceanic and Atmospheric Administration, Washington, D.C., March 1991. Wade, C. G., 1995: Calibration and data reduction problems affecting National Weather Service radiosonde humidity measurements. Preprints, Ninth Symposium on Meteorological Observations and Instrumentation, Charlotte, NC, Amer. Meteor. Soc., 37-42. Williams, S. F., C. G. Wade, and C. Morel, 1993: A comparison of high resolution radiosonde winds: 6-second Micro-ART winds versus 10-second CLASS LORAN winds. Preprints, Eighth Symposium on Meteorological Observations and Instrumentation, Anaheim, California, Amer. Meteor. Soc., 60-65. Williams, S. F., S. M. Loehrer, and D. R. Gallant, 1998: Computation of high-resolution National Weather Service rawinsonde winds. Preprints, Tenth Symposium on Meteorological Observations and Instrumentation, Phoenix, AZ, Amer. Meteor. Soc., 387-391.