FASTEX Interpolated 5 hPa Vertical Resolution Composite Dataset 1.0 Dataset Overview This dataset is a composite of data from all FASTEX sounding platforms interpolated to a constant vertical resolution of 5 hPa. 2.0 Detailed Dataset Description The `native' resolution data for every sounding were interpolated to 5 hPa vertical reslution files. The surface data point was kept as the initial level in each sounding. The first interpolated data point was at the next lowest pressure evenly divisible by 5 and then every 5 hPa pressure level beyond that point to either 50 hPa or the lowest pressure level reached by the radiosonde, whichever came first. The first 15 lines of each file (the header information) were kept without change. For the interpolation, the software searched for two data points around the desired pressure level. The search was conducted by looking for two valid (i.e. non-missing) data points around the desired pressure level, while also paying attention to the time difference between the two data points as well as their quality control flags. There was a search for the two best possible data points to use in the interpolation. If the desired pressure level was within the original dataset, that data point was used without interpolation. There was first a search for values flagged as good within some time range (50 sec for temperature, humidity, and wind and 100 sec for pressure; hereafter termed the ARANGE) and the interpolated data point was flagged as good. Failing that, it searched for values flagged as estimated within the same time range and the interpolated data point was flagged as estimated. Then the search went for good values within a wider time range (100 sec for temperature, humidity, and wind and 200 sec for pressure; hereafter termed the BRANGE) the flag for the interpolated data point here was then degraded (even though two `good' data points were used there was a significant time difference between them) to questionable. Then, in turn, estimated values within the BRANGE were used (flag set to questionable), questionable values within the BRANGE (flag set to bad), good values greater than the BRANGE apart (flag set to bad), estimated values greater than BRANGE apart (flag set to bad), questionable values greater than BRANGE apart (flag set to bad), finally any bad values (flag set to bad). This search was conducted separately for each interpolated variable (pressure, temperature, relative humidity, and the u and v wind components. Thus for each interpolated data point, the quality control flag was set to the worst case among the data points used in the interpolation, except, for each time range apart, the quality control flag was degraded one level (i.e. good to questionable, etc). The quality control flags should be carefully heeded in these files. While some of the data may look good, it may have been interpolated over large pressure intervals, and thus be suspect. For each interpolated data point the dew point was calculated from the temperature and relative humidity (Bolton 1980) and the total wind speed and direction were calculated from the interpolated u and v component values. Also, the altitude and time were interpolated using the same data points used for the pressure interpolation. The ascension rate was recalculated based on the time and altitude values from the two data points used to interpolate the 5 hPa data point. Thus the ascension rate values do not reflect the values based on the interpolated data. The latitude and longitude values were interpolated using the same data points used in the wind component interpolation. 3.0 JOSS CLASS Format (ASCII text) Description 3.1 Header records The header records (15 total records) contain data type, project ID, site ID, site location, actual release time, nominal release time, and possibly other specialized information. The first 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 data set to data set. The next line (line 12) contains the Nominal date and time of the release. 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 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 UTC Launch Time: Time of release, in format: yyyy, mm, dd, hh:mm:ss 12 UTC Nominal Launch Time: Nominal release time. The launch site type/site ID has the format: site ID (three or four letter code), the full site name, the country code and the WMO code for the site. 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 six 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 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 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. Fields 16 through 21 contain the Quality Control information (flags) generated locally at JOSS. These flags are based on the automated or visual checks made. See Sections 6.0 and 7.0 for further information. 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') ---------------------------------------------------------------------- 3.3 Sample data The following is a sample portion of a JOSS 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: Sounding Project ID: FASTEX class format UKMET high resolution sounding Launch Site Type/Site ID: ABE Aberporth, UK, 03502 Launch Location (lon,lat,alt): 004 34.20'W, 52 7.80'N, -4.57, 52.13, 121.0 GMT Launch Time (y,m,d,h,m,s): 1997, 01, 10, 14:07:00 / / / / / / Nominal Launch Time (y,m,d,h,m,s): 1997, 01, 10, 15:00:00 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 1001.3 0.9 -2.3 79.0 -3.0 5.2 6.0 150.0 999.0 -4.570 52.130 999.0 999.0 121.0 1.0 1.0 1.0 1.0 1.0 99.0 2.0 1000.7 0.9 -2.5 78.0 -3.2 5.7 6.5 151.0 2.0 -4.570 52.130 999.0 999.0 125.0 1.0 1.0 1.0 1.0 1.0 99.0 4.0 1000.4 0.9 -2.7 77.0 -3.2 6.0 6.8 152.0 1.0 -4.570 52.130 999.0 999.0 127.0 1.0 1.0 1.0 1.0 1.0 99.0 4.0 Quality Control Procedures No additional quality control was applied to this dataset. The quality control procedures were conducted on the high resolution data set and the results were applied during the interpolation (see above). 5.0 FASTEX Data Use According to the FASTEX data policy, the use of these data is unrestricted for research and educational purposes. Proper acknowledgements should be given in publications that utilize this data to specific scientists and institutions that made the collection of data possible. Where appropriate, all authors considering publication of FASTEX related research results should offer co-authorship to investigators that had a primary role in the collection of data utilized in the study. 6.0 Upper-Air Sounding Data Providers FASTEX Land-Based Upper-Air Sounding Data Providers Country Name Address -------- ---------------- -------------------------------------------------- Canada Dave Steenbergen AES 4905 Dufferin Street Downsview Ontario M3H 5T4 Denmark Klaus Hedegaard DMI Lyngbyveg 100 DK-2100 France Michel Rochas Meteo-France Instrumentation Dept. 7,rue Teisserenc de Bort BP202 78195 Trappes Iceland Flosi Sigurosson Meteorological Office Technical and Obs. Dept Bustadavegur 9 IS-140 Reykjavik Ireland Liam Burke Meteorological Office Instrumentation and Environmental Division Glasnevin Hill Dublin 9 Portugal Renato Carvalho INMG Rua C. Aeroporto de Lisboa 1700 Lisboa Spain Cesar Belandia INM Servicio de Observacion, Camino de la Moreras s/n Ciudad Universitaria 28071 MADRID United John Stancombe UK Met Office Upper Air Network Kingdom London Road Bracknell, Berkshire RG12 2SZ USA Robert Thomas NOAA W/OSO14 SSMC/2 1325 East West Highway Silver Spring,MD 20910 FASTEX Aircraft Dropsonde Data Providers Aircraft Name Address -------- -------------- ---------------------------------- LEAR36 Dean Lauritsen NCAR/ATD P.O. Box 300 Boulder,CO 80307 USA (lauritsn@ucar.edu) US-C1307 Jon Talbot 53rd Weather Reconnaissance Squadron, US-C1308 Keelser Air Force Base Mississippi, USA (info@hurricanehunters.com) NOAA-GIV John Daugherty NOAA/NSSL 325 Broadway Boulder,CO 80303 USA (johnd@ncar.ucar.edu) NOAA-P3 David Jorgensen NOAA/NSSL 325 Broadway Boulder,CO 80303 USA (davej@ncar.ucar.edu) UK-C130 Sid Clough Joint Centre for Mesoscale Meteorology (JCMM) Department of Meteorology, University of Reading PO Box 243 Earley Gate Reading Berkshire RG6 6BB UK (saclough@meto.gov.uk) FASTEX Principal Investigators and Data Providers for the FASTEX Ships Ships Name Address -------- ------------------ -------------------------------------- AEGIR Alain Joly Meteo-France/CNRM 42 Av.G.Coriolis 31057 Toulouse Cedex France (alain.joly@meteo.fr) V.BUGAEV Pierre Bessemoulin Meteo-France/CNRM 42 Av.G.Coriolis 31057 Toulouse Cedex France (pierre.bessemoulin@meteo.fr) KNORR Ola Persson NOAA/ETL CIRES, Univ. of Colorado Campus Box 216 Boulder, CO 80309 USA (pogp@etl.noaa.gov) SUROIT Alain Joly Meteo-France/CNRM 42 Av.G.Coriolis 31057 Toulouse Cedex France (alain.joly@meteo.fr) The FASTEX enhanced radiosounding program was supported by AES (Canada), CNRS/INSU (France), DMI (Denmark), the Icelandic Met. Office, Meteo-France, Met Eireann (Ireland), NCAR/MMM (USA), the UK Met. Office, WMO/COSNA. The FASTEX ships were supported by CNRS/INSU (France), The European Commission, IFREMER (France), Meteo-France, NOAA (USA), NSF (USA). 7.0 Composite Sounding Platforms The sites included within the 5 hPa sounding composite include: Site Country or Platform ---------------------------------------- Aberporth United Kingdom Aegir FASTEX Ship Angmagssalik Greenland Bermuda Bermuda Bordeaux France Boulmer United Kingdom Brest France Victor Bugaev FASTEX Ship Camborne United Kingdom Charleston United States Chatham United States Douce France ASAP Ship Egedessminde Greenland Fort Desaix ASAP Ship Fort Fleur D' Eppe ASAP Ship Fort Royal ASAP Ship Funchal Portugal Godafoss ASAP Ship Goose Bay Canada Gulfstream G-IV Dropsondes Hemsby United Kingdom Hillsborough United Kingdom Irena Arctica ASAP Ship Keflavic Iceland Knorr FASTEX Ship Kuujjuaq Canada La Coruna Spain Lajes Portugal Lear Lear Dropsondes Lerwick United Kingdom Lisbon Portugal Narssarssuaq Greenland NOAA P-3 NOAA P-3 Dropsondes Nuca Arctica ASAP Ship Sable Island Canada Scoresbysund Greenland St. Johns Canada Stornoway United Kingdom Le Suroit FASTEX Ship Thorshavn Faroe Island Trappes France UK C-130 United Kingdom C-130 Dropsondes US C-130 United States C-130 Dropsondes Valentia Ireland Wallops Island United States --------------------------- 8.0 Reference Bolton, D., 1980: The Computation of Equivalent Potential Temperature. Mon. Wea. Rev., 108, 171-180.