VORTEX2 NSSL MGAUS Radiosonde Data Set

1.0 General Description

The Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX) is a project aimed at investigating tornado genesis and examining tornado structure and evolution using a suite of atmostpheric instruments. The VORTEX2 field campaigns included the use of four mobile GPS Advanced Upper_Air Sounding (GAUS) systems. This dataset contains 117 radiosonde soundings collected during the 2009 field campaign (May 11 - June 14, 2009) and 186 radiosonde soundings collected during the 2010 field campaign (May 6 - June 15, 2010) from two of the systems that were operated by the NOAA National Severe Storm Laboratory (NSSL).

1.1 Data Set Contact

Scot Loehrer
NCAR/EOL
loehrer@ucar.edu

2.0 Detailed Data Description

2.1 Detailed Format Description

All upper air soundings were converted to National Center for Atmospheric Research/Earth Observing Laboratory (NCAR/EOL) Sounding Composite Format (ESC). ESC 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, and meteorological and wind data processors. 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:

LineLabel (padded to 35 char)Contents
1Data Type:Description of type and resolution of data.
2Project ID:Id of weather project.
3Release Site Type/Site ID:Description of the release site.
4Release Location (lon,lat,alt):Position of release site in the format described below.
5UTC Release Time (y,m,d,h,m,s):Time of release, in the 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. Records for this dataset include the following non-standard header lines.

LineLabel (padded to 35 char)Contents
6Sonde Id/Sonde Type:083823103/Vaisala RS92-SGP (ccGPS)
7Reference Launch Data Source/Time:Manual Entry/21:52:52.75
8System Operator/Comments:G Bryan/Training test from parking lot of Ramada in Clinton, Good Sounding
9Post Processing Comments:Aspen Version 2.8.1.8, Configuration upsonde-1s
10  
11  
12Nominal Release Time (y,m,d,h,m,s):Nominal time of release, in the format: yyyy, mm, dd, hh:mm:ss

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 No.WidthFormatParameterUnitsMissing Value
16F6.1TimeSeconds9999.0
26F6.1PressureMillibars9999.0
35F5.1Dry-bulb TemperatureDegrees C999.0
45F5.1Dew Point TemperatureDegrees C999.0
55F5.1Relative HumidityPercent999.0
66F6.1U Wind ComponentMeters / Second9999.0
76F6.1V Wind ComponentMeters / Second9999.0
85F5.1Wind SpeedMeters / Second999.0
95F5.1Wind DirectionDegrees999.0
105F5.1Ascent RateMeters / Second999.0
118F8.3LongitudeDegrees9999.0
127F7.3LatitudeDegrees999.0
135F5.1Elevation AngleDegrees999.0
145F5.1Azimuth AngleDegrees999.0
157F7.1AltitudeMeters99999.0
164F4.1QC for PressureCode (see below)99.0
174F4.1QC for TemperatureCode (see below)99.0
184F4.1QC for HumidityCode (see below)99.0
194F4.1QC for U Wind ComponentCode (see below)99.0
204F4.1QC for V Wind ComponentCode (see below)99.0
214F4.1QC for Ascension RateCode (see below)99.0

Fields 16 through 21 contain the Quality Control information derived at the NCAR Earth Observing Laboratory (NCAR/EOL). Any QC information from the original sounding is replaced by the following EOL codes:

CodeDescription
99.0Unchecked (QC information is "missing.") ("UNCHECKED")
1.0Checked, datum seems physically reasonable. ("GOOD")
2.0Checked, datum seems questionable on physical basis. ("MAYBE")
3.0Checked, datum seems to be in error. ("BAD")
4.0Checked, datum is interpolated. ("ESTIMATED")
9.0Checked, datum was missing in original file. ("MISSING")

Sample Data

The following is a sample record of VORTEX2 NSSL MGAUS high resolution radiosonde data in ESC 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:                         NCAR GAUS/Ascending
Project ID:                        VORTEX2
Release Site Type/Site ID:         20090511/NSSL1
Release Location (lon,lat,alt):    098 59.18'W, 35 30.03'N, -98.986, 35.501, 488.1
UTC Release Time (y,m,d,h,m,s):    2009, 05, 11, 22:01:07
Sonde Id/Sonde Type:               083823103/Vaisala RS92-SGP (ccGPS)
Reference Launch Data Source/Time: Manual Entry/21:52:52.75
System Operator/Comments:          G Bryan/Training test from parking lot of Ramada in Clinton, Good Sounding
Post Processing Comments:          Aspen Version 2.8.1.8, Configuration upsonde-1s
/
/
Nominal Release Time (y,m,d,h,m,s):2009, 05, 11, 22:01:07
 Time  Press  Temp  Dewpt  RH    Ucmp   Vcmp   spd   dir   Wcmp     Lon     Lat    Ele   Azi   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
------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- ------- ----- ----- ------- ---- ---- ---- ---- ---- ----
  -1.0  961.6  14.9  11.1  77.4 9999.0 9999.0 999.0 999.0 999.0  -98.986  35.501 999.0 999.0   493.9 99.0 99.0 99.0  9.0  9.0  9.0
   0.0  961.5  14.1  10.7  79.9   -0.1    0.1   0.1 150.5   3.4  -98.986  35.501 999.0 999.0   494.9 99.0 99.0 99.0 99.0 99.0 99.0
   1.0  961.1  13.7  10.5  80.8   -1.5    0.9   1.7 122.9   4.1  -98.986  35.501 999.0 999.0   498.5 99.0 99.0 99.0 99.0 99.0 99.0
   2.0  960.6  13.5  10.4  81.0   -1.8    1.2   2.1 125.4   4.9  -98.986  35.501 999.0 999.0   503.1 99.0 99.0 99.0 99.0 99.0 99.0
   3.0  959.9  13.4  10.3  81.3   -2.0    1.5   2.5 127.2   5.7  -98.986  35.501 999.0 999.0   508.7 99.0 99.0 99.0 99.0 99.0 99.0
   4.0  959.2  13.3  10.3  81.6   -2.3    1.8   2.9 128.4   6.2  -98.986  35.501 999.0 999.0   515.0 99.0 99.0 99.0 99.0 99.0 99.0
   5.0  958.5  13.3  10.3  81.9   -2.6    2.1   3.3 129.4   6.4  -98.986  35.501 999.0 999.0   521.7 99.0 99.0 99.0 99.0 99.0 99.0
   6.0  957.7  13.2  10.3  82.1   -2.8    2.4   3.7 130.2   6.4  -98.986  35.501 999.0 999.0   528.4 99.0 99.0 99.0 99.0 99.0 99.0
   7.0  957.0  13.2  10.3  82.4   -3.0    2.6   4.0 130.9   6.2  -98.986  35.501 999.0 999.0   534.7 99.0 99.0 99.0 99.0 99.0 99.0
   8.0  956.3  13.1  10.3  82.8   -3.2    2.9   4.3 131.5   6.0  -98.986  35.501 999.0 999.0   540.3 99.0 99.0 99.0 99.0 99.0 99.0    

2.2 Data Remarks

2.3 Station List

ID SITE STATE LONG LAT ELEV (m)
NSSL1 Mobile Mobile Mobile Mobile Mobile
NSSL2 Mobile Mobile Mobile Mobile Mobile

3.0 Quality Control Processing

This dataset underwent an 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 NCAR/EOL can be found in Loehrer et al. (1996) and Loehrer et al. (1998).

3.1 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. NCAR/EOL conducted the following gross limit checks on the VORTEX2 NSSL MGAUS 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.

ParameterGross Limit CheckParameter(s) FlaggedFlag Applied
Pressure < 0 mb or > 1050 mb PB
Altitude < 0 m or > 40000 m P, T, RHQ
Temperature < -90 °C or > 45 °C TT
Dew Point < -99.9 °C or > 33 °C
> Temperature
RH
T, RH
Q
Q
Relative Humidity < 0% or > 100% RHB
Wind Speed < 0 m/s or > 100 m/s
> 150 m/s
U, V
U, V
Q
B
U Wind Component < 0 m/s or > 100 m/s
> 150 m/s
U
U
Q
B
V Wind Component < 0 m/s or > 100 m/s
> 150 m/s
V
V
Q
B
Wind Direction < 0° or > 360° U, VB
Ascent Rate < -10 m/s or > 10 m/s P, T, RHQ

3.2 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 2-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.

ParameterVertical Consitency CheckParameter(s) FlaggedFlag Applied
Time decreasing / equal NoneNone
Altitude decreasing / equal P, T, RHQ
Pressure increasing / equal
> 1 mb/s or < -1 mb/s
> 2 mb/s or < -2 mb/s
P, T, RH
P, T, RH
P, T, RH
Q
Q
B
Temperature < -15 °C/km
< -30 °C/km
> 50 °C/km (not applied at p < 250 mb)
>100 °C/km (not applied at p < 2 50 mb)
P, T, RH
P, T, RH
P, T, RH
P, T, RH
Q
B
Q
B
Ascent Rate change of > 3 m/s or & lt; -3 m/s
change of > 5 m/s or < -5 m/s
P
P
Q
B

3.3 Visual Quality Checks

Each sounding was visually examined for data quality issues. Any issues found were flagged in the data file and/or noted in Section 3.4.

3.4 Data Quality Issues

Please check the documentation files created by the NCAR/EOL GAUS radiosonde QC team for details on data quality issues: VORTEX2 2009 GAUS QC documentation

VORTEX2 2010 GAUS QC documentation

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.