GSD Sounding data format The official GSD data format is similar to the format used by the National Severe Storms Forecast Center (NSSFC) in Kansas City. The first 4 lines of the sounding are identification and information lines. All additional lines are data lines. An entry of 32767 (original format) or 99999 (new format) indicates that the information is either missing, not reported, or not applicable. NOTE: For AMDAR data, there is an additional line at the top of each sounding that looks something like this: A: DEN AC# 533 U/D -1 N: 29 B: 125 R: 150 Secs 931472580 DT: 2 "A:" identifies this as an AMDAR sounding. "DEN" is the airport. "AC# 533" is the Aircraft Number (GSD's own aircraft ID scheme) "U/D -1" indicates this is a descent sounding (1 for ascent); "N: 29" indicates there are 29 levels in the sounding "B: 125 R: 150" indicates that the highest data point had a bearing and range from the airport of 125 degrees and 150 nautical miles. "Secs 931472580" indicates that this sounding left (or reached) the ground this many seconds after 0000 UTC on 1/1/70. "DT: 2" indicates the "data type" pf the aircraft, as follows 0 - measures wind and temperature only 1 - measures vertical acceleration, wind and temperature 2 - measures eddy dissipation rate, wind and temperature 3 - measures dewpoint, wind, and temperature In addition, for AMDAR and RAOB data lines, there are 3 additional columns (8-10) that display hour/minute, bearing, and range from the airport or launch site. ---COLUMN NUMBER--- 1 2 3 4 5 6 7 8 9 10 LINTYP header lines TYPE HOUR DAY MONTH YEAR (blank) (blank) 1 WBAN# WMO# LAT LON ELEV RTIME 2 HYDRO MXWD TROPL LINES TINDEX SOURCE 3 (blank) STAID (blank) (blank) SONDE WSUNITS data lines 9 PRESSURE HEIGHT TEMP DEWPT WIND DIR WIND SPD HHMM BEARING RANGE 4 5 6 7 8 LEGEND LINTYP: type of identification line TYPE = indicates the type of sounding RAOB, Model-name, ACARS, RADIO, etc. 1 = station identification line 2 = sounding checks line 3 = station identifier and other indicators line 4 = mandatory level 5 = significant level 6 = wind level (PPBB) (GTS or merged data) 7 = tropopause level (GTS or merged data) 8 = maximum wind level (GTS or merged data) 9 = surface level HOUR: time of report in UTC LAT: latitude in degrees and hundredths LON: longitude in degrees and hundredths ELEV: elevation from station history in meters RTIME: is the actual release time of radiosonde from TTBB. Appears in GTS data only. HYDRO: the pressure of the level to where the sounding passes the hydrostatic check (see section 4.3).** MXWD: the pressure of the level having the maximum wind in the sounding. If within the body of the sounding there is no "8" level then MXWN is estimated (see section 3.2). TROPL: the pressure of the level containing the tropopause. If within the body of the sounding there is no "7" level, then TROPL is estimated (see section 3.3)** LINES: number of levels in the sounding, including the 4 identification lines. TINDEX: indicator for estimated tropopause. A "7" indicates that sufficient data was available to attempt the estimation; 11 indicates that data terminated and that tropopause is a "suspected" tropopause. SOURCE: 0 = National Climatic Data Center (NCDC) 1 = Atmospheric Environment Service (AES), Canada 2 = National Severe Storms Forecast Center (NSSFC) 3 = GTS or GSD GTS data only 4 = merge of NCDC and GTS data (sources 2,3 merged into sources 0,1) SONDE: type of radiosonde code from TTBB. Only reported with GTS data 10 = VIZ "A" type radiosonde 11 = VIZ "B" type radiosonde 12 = Space data corp.(SDC) radiosonde. WSUNITS:wind speed units (selected upon output) ms = tenths of meters per second kt = knots PRESSURE: in whole millibars (original format) in tenths of millibars (new format) HEIGHT: height in meters (m) TEMP: temperature in tenths of degrees Celsius DEWPT: dew point temperature in tenths of a degree Celsius WIND DIR: wind direction in degrees WIND SPD: wind speed in knots HHMM: hour and minute (UTC) that this data line was taken (for RAOBS, estimated by assuming a 5 m/s ascent rate). BEARING: Bearing from the ground point for this level RANGE: Range (nautical miles) from the ground point for this level. An example of fortran format statements necessary to read output rawinsonde data, according to LINTYP, is as follows: LINTYP 254 (3i7,6x,a4,i7) 1 (3i7,2f7.2,2i7) 2 (7i7) 3 (i7,10x,a4,14x,i7,5x,a2) 4,5,6,7,8,9 (10i7) **- section of noaa tech memo on the data base (in print) TECHNICAL INFORMATION: Schwartz, B.E., and M. Govett, 1992: "A hydrostatically consistent North American Radiosonde Data Base at the forecast Systems Laboratory, 1946-present." NOAA Technical Memorandum ERL FSL-4. Available from NOAA/ERL/FSL 325 Broadway, Boulder, CO 80303.
Prepared by Mark Govett,
and Bill Moninger
Last modified: Thu Aug 16 13:29:06 DST 2007