NOAA P-3 Flight Level Data for TOGA-COARE
1.0 Site Information
Location: Variable
Station Elevation: Variable
Typical Launch Times: Variable
Dates Available: 2 Nov 1992 - 22 Feb 1993
Total Launches Available
in `Native Resolution': 303
Total Launches Available
in GTS Format Only: 0
2.0 Radiosonde Information
Radiosonde Type: Not Applicable
Radiation Correction Applied?: Not Applicable
Ground Equipment: Not Applicable
Windfinding System: Not Applicable
Windfinding Equipment: Not Applicable
Resolution of Raw Data: 1 s
3.0 Parameters in Raw Dataset
3.1 Native Resolution Files
Parameters Units
-----------------------------------------------------------
Time Hour, Minute, Second
Latitude Degrees, Minutes
Longitude Degrees, Minutes
Static pressure Millibars
Ambient temperature Degrees C
Downward-looking CO2 radiometer Degrees C
Side-looking CO2 radiometer Degrees C
Ground speed Meters/Second
True airspeed Meters/Second
Track angle (North relative) Degrees
Heading angle (North relative) Degrees
Pitch angle (positive up) Degrees
Roll angle (positive right wing down) Degrees
J-W cloud liquid water Gram/Meter^3
Dew point temperature Degrees C
Upward-looking radiometer Degrees C
Geopotential altitude Meters
Pressure altitude Meters
Wind speed Meters/Second
Wind direction Degrees
INE #1 vertical accelerometer Meters/Second^2
INE #2 vertical accelerometer Meters/Second^2
Vertical ground speed Meters/Second
Vertical air speed Meters/Second
Vertical wind Meters/Second
-----------------------------------------------------------
4.0 Conversion to OFPS CLASS
4.1 The OFPS definition of a flight sounding includes the
specifications:
4.1.1 Must span at least 900 m in the vertical.
4.1.2 Must not be a break of more than 5 min in the
upward/downward motion in a(n) upward/downward
sounding.
4.1.3 During any break in the upward/downward motion
in a(n) upward/downward sounding, the sounding
cannot drift more than 30 m in the opposite
direction.
4.2 The OFPS flight level soundings do not include any
of the data during the breaks in the overall motion
in a sounding. No portion of the upward (downward)
motion data is used in a(n) downward (upward) sounding.
Hence, the OFPS data set is not always a 1 sec vertical
resolution data set.
4.3 The geopotential altitude is NOT used in this dataset.
The geopotential altitude had some apparent problems,
hence, OFPS used the pressure altitude data instead.
4.4 The ascension rate was calculated for each data point
(excluding the surface, where it was given a missing
value) based on the altitude and time at two levels,
the current level and the previous level. If
any time or altitude values were missing, at either of
the levels, the ascension rate was not calculated at
the current level and it was flagged as missing.
4.5 Relative humidity values were calculated via the
equations from Bolton (1980).
4.6 The U and V wind components were calculated based on the
wind speed and direction at a level.
4.7 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 estimated.
4.8 The position data in this data set was corrected by the
National Oceanic and Atmospheric Administration in
conjunction with the National Center for Atmospheric
Research using GPS data.
5.0 Automatic Quality Control Procedures
Internal quality control procedures were applied to each
sounding individually. These checks included two general
types: `Reasonable limit' checks on all parameters and
`Rate-of-Change' checks on pressure, temperature, and
ascension rate. These checks led to the development of
automatically generated quality control flags in the OFPS
CLASS format file. Also, files were generated that contain
descriptions of the problems found in each sounding. Due
to the relative high frequency of this dataset (6 s) and
the noise often found above 100 mb, the error messages
developed by the routine in its basic state became very
large. In order to cut down on the large number of error
messages and still flag the major problem areas, a slightly
different version of the routine was used than is described
in the documentation. The checks are all the same,
however, rather than check each data point versus the
previous data point, we used 30 sec averaging intervals at
pressure levels above 100 mb. This allowed for much fewer
error messages, while still capturing the problem areas.
Below 100 mb the routine was unchanged. For further
information on the more general version of the OFPS
automatic quality control procedures used for the TOGA-COARE
project see Loehrer et al. (1996).
-----------------NOTE------------------NOTE------------------
Due to the nature of these soundings, no automatic QC was
applied.
-----------------NOTE------------------NOTE------------------
6.0 Visual Quality Control Procedures
Each sounding was then visually examined for problems that
are not able to be captured via the automatic checks
described in item 5.0 above. These problems typically
included oddities in the dew point and wind profiles. These
two parameters can be highly variable, and hence, the
automatic checking is more difficult. The visual checking
procedure has two main purposes: First, as a check on the
results provided by the automatic checks, and second, as a
more stringent check on the more variable parameters. For
further information on this procedure, see Loehrer et al
(1996).
7.0 Spatial Quality Control Procedures
Basic statistics are generated indicating whether a given
station performed consistently with respect to its
neighbors and the network as a whole. The first set of
statistics are level-by-level checks versus neighboring
stations. The neighbors are those stations in a constricted
latitude band. The general methodology used by OFPS is
a simple distance weighted averaging scheme comparing the
observed values to those expected by the averaging scheme.
Tests are applied to altitude, temperature, dew point, wind
speed and direction at 14 standard pressure levels.
The second set of statistics are level-by-level checks versus
network-wide averages. For these all of the data from the
network at a particular level and time is averaged and each
site is compared to the average.
For more information on the procedures used for the spatial
consistency checks see Loehrer et al (1996). For general
findings from the spatial QC see the OFPS spatial QC
overview and findings document. The statistics from both
checks are also available online.
-----------------NOTE------------------NOTE------------------
Due to the nature of this dataset, no spatial QC procedures
will be applied.
-----------------NOTE------------------NOTE------------------
8.0 Derived Sounding Parameters
The NCAR SUDS (System for User-editing and Display of
Soundings; Burghart 1993) software was used to calculate
common wind, thermodynamic and stability parameters using
the procedures of Weisman and Klemp (1982). Any data points
flagged as BAD by the automatic or visual checks are not
used in the calculation of these parameters. These
parameters will be online, with a separate file for each
sounding. The parameters calculated by this routine
include:
SUDS Derived Parameters
----------------------------------------------
Surface Potential Temperature
Surface Virtual Potential Temperature
Surface Mixing Ratio
500 mb Potential Temperature
500 mb Virtual Temperature
500 mb Virtual Potential Temperature
Lifted Condensation Level (LCL)
Lifted Index
Level of Free Convection (LFC)
Positive Area Below the LFC
Negative Area Below the LFC
Convective Available Potential Energy (CAPE)
Negative Area Above the LFC
Shear over the Lowest 6 km
Bulk Richardson Number (Ri)
Mean Layer Vector Wind between 1000 and 700 mb
----------------------------------------------
-----------------NOTE------------------NOTE------------------
Due to the nature of these soundings, no sounding parameter
files were created.
-----------------NOTE------------------NOTE------------------
9.0 JOSS CLASS Format (ASCII text) Description
9.1 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
later in this section.
9.2 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.
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')
----------------------------------------------------------------------
9.3 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:
Project ID: NOAA P3 native resolution soundings.
Release Site Type/Site ID: NOAA-P3, 42RF
Release Location (lon,lat,alt): 159 55.80'E, 09 22.80'S, 159.93, -9.38, 1102.0
UTC Release Time (y,m,d,h,m,s): 1993, 02, 22, 01:03:40
Comment: NOAA/NSSL Processed TOGA/COARE P-3 Flight Level
Data
/
/
/
/
/
Nominal Release Time (y,m,d,h,m,s):1993, 02, 22, 01:03:40
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
------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- -------
----- ----- ------- ---- ---- ---- ---- ---- ----
0.0 887.7 19.0 17.5 91.0 17.4 0.0 17.4 270.0 999.0 159.925 -9.378
999.0 999.0 1102.0 1.0 1.0 1.0 1.0 1.0 9.0
26.0 887.9 19.1 17.2 88.7 18.2 1.0 18.2 267.0 -0.1 159.942 -9.393
999.0 999.0 1100.0 1.0 1.0 1.0 1.0 1.0 99.0
27.0 888.3 19.1 17.2 88.7 18.3 1.0 18.3 267.0 -4.0 159.942 -9.393
999.0 999.0 1096.0 1.0 1.0 1.0 1.0 1.0 99.0
10.0 Usage of GTS Messages
No GTS messages were available for the flight level data.
11.0 Dataset Availability
Datasets Available Online
----------------------------------------------------------------
Quality Controlled Data File in Native Resolution
(available in Bufr, EBufr, and OFPS QCF (ASCII) formats)
Statistics generated from the Horizontal Checks
(see item 7.0 above)
Derived Sounding Parameters (see item 8.0 above)
Interpolated 5 mb Vertical Resolution Files (see item 9.0 above)
Site-by-site processing and QC documentation (including special
spatial QC and general QC documents)
----------------------------------------------------------------
Datasets Available Offline
----------------------------------------------------------------
Non-Quality Controlled, Raw Format File in Native Resolution
Automatically generated Error Files (see item 5.0 above)
----------------------------------------------------------------
12.0 Dataset Remarks
No remarks.
13.0 References
Bolton, D., 1980: The Computation of Equivalent Potential
Temperature. Mon. Wea. Rev., 108, 171-180.
Burghart, C., 1993: SUDS: The system for user-editing and
display of soundings. Research Data Program, National Center
for Atmospheric Research, Boulder, CO.
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.
Weisman, M.L., and J.B. Klemp, 1982: The dependence of
numerically simulated convective storms on vertical wind shear
and buoyancy. Mon. Wea. Rev., 110, 504-520.