PLOWS 2008-2009 Sounding Composite Highest Resolution Upper-Air Data Set

1.0 General Description

This dataset contains the highest possible resolution (i.e. the 'native' resolution) upper-air sounding data in the National Center for Atmospheric Research (NCAR) Earth Observing Laboratory (EOL) Sounding Composite Format from stations in the following networks in the Profiling of Winter Storms 2008-2009 (PLOWS 2008-2009) domain:

Data for the PLOWS 2008-2009 domain (37°N to 46°N latitude and 88°W to 99°W are contained within this dataset. The dataset covers the time period 1 February 2009 through 31 March 2009. This PLOWS 2008-2009 Sounding Composite Highest Resolution Upper-Air Dataset contains 979 soundings from 3 platforms.

Data from the NWS stations are typically available every 12 hours (00 and 12 UTC) with occasional special releases. The NCAR MISS data are available at variable intervals during PLOWS 2008-2009 IOP-3 (26 February) and IOP-4 (8 March). The University of Missouri data are available at variable intervals during PLOWS 2008-2009 IOP-1 (11-12 February), IOP-2 (18 February), and IOP-5 (28-29 March).

Section 2.1 contains a detailed description of the format of the composite dataset. See Section 3.0 below for the quality control processing performed by NCAR/EOL on this dataset. Section 4.0 contains references.

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 (ESC) format. 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, 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:

LineLabel (padded to 35 char)Contents
1Data Type:Description of type and resolution of data.
2Project ID:Project name.
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'W where ddd is the number of degrees from True North (with leading zeros if necessary), 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 nonstandard 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 three nonstandard header lines.

LineLabel (padded to 35 char)Contents
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
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
135F5.1Elevation AngleDegrees999.0
145F5.1Azimuth AngleDegrees999.0
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 Sounding Composite Format codes:

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 a PLOWS 2008-2009 high resolution rawinsonde data in EOL Sounding Composite 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:                         GAUS SOUNDING DATA/Ascending
Project ID:                        PLOWS_2008-2009
Release Site Type/Site ID:         IOP 3
Release Location (lon,lat,alt):    090 29.58'W, 44 01.32'N, -90.493, 44.022, 305.3
UTC Release Time (y,m,d,h,m,s):    2009, 02, 26, 19:07:08
Sonde Id/Sonde Type:               082033957/Vaisala RS92-SGP (ccGPS)
Reference Launch Data Source/Time: Campbell Scientific CR10/19:07:26.00
System Operator/Comments:          lou/lost everything at approx 675mb, No PTH
Post Processing Comments:          Aspen Version, Configuration upsonde-1s
Nominal Release Time (y,m,d,h,m,s):2009, 02, 26, 19:07:08
 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  973.7   2.4  -3.2  66.5   -2.2   -0.9   2.4  68.0 999.0  -90.493  44.022 999.0 999.0   310.9  1.0  1.0  1.0  1.0  1.0  9.0
   0.0  973.4 999.0 999.0  66.8   -2.7   -1.0   2.9  69.7   4.4  -90.493  44.022 999.0 999.0   313.8  1.0  9.0  1.0  1.0  1.0 99.0
   1.0  972.8   2.3  -3.2  66.9   -3.4   -1.1   3.6  71.9   4.8  -90.493  44.022 999.0 999.0   318.4  1.0  1.0  1.0  1.0  1.0 99.0
   2.0  972.2   2.2  -3.3  67.1   -4.0   -1.2   4.2  73.4   5.3  -90.493  44.022 999.0 999.0   323.6  1.0  1.0  1.0  1.0  1.0 99.0

2.2 Station List

ID SITE STATE LONG LAT ELEV (m) Radiosonde Type Windfinding Vertical Resolution # Soundings
MISS Mobile Mobile Mobile Mobile Mobile Vaisala RS92-SGP GPS 1 sec 14
UMO Mobile Mobile Mobile Mobile Mobile IMET1 AB GPS 10 sec 27
KABR Aberdeen (NWS) SD -98.414 45.455 398.0 Sippican Mark IIA GPS 1 sec 119
KDVN Davenport (NWS) IA -90.582 41.612 230.0 Sippican Mark IIA GPS 1 sec 118
KGRB Green Bay (NWS) WI -88.112 44.498 209.0 Sippican Mark IIA GPS 1 sec 118
KILX Lincoln (NWS) IL -89.338 40.151 179.0 Sippican Mark IIA GPS 1 sec 120
KMPX Chanhassen (NWS) MN -93.565 44.849 290.0 Sippican Mark IIA GPS 1 sec 117
KOAX Omaha/Valley (NWS) NE -96.366 41.320 351.0 Sippican Mark IIA GPS 1 sec 118
KSGF Springfield (NWS) MO -93.402 37.236 391.0 Sippican Mark IIA GPS 1 sec 119
KTOP Topeka (NWS) KS -95.600 39.100 270.0 Vaisala RS80-57H Radiotheodolite 6 sec 109

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 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. EOL conducted the following gross limit checks on the T-REX sounding datasets. 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
Relative Humidity < 0% or > 100% RHB
Wind Speed < 0 m/s or > 100 m/s
> 150 m/s
U, V
U, V
U Wind Component < 0 m/s or > 100 m/s
> 150 m/s
V Wind Component < 0 m/s or > 100 m/s
> 150 m/s
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.

Parameter Vertical Consistency Check Parameter(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
Temperature < -15 °C/km
< -30 °C/km
> 50 °C/km (not applied at p < 250 Mb)
>100 °C/km (not applied at p < 250 Mb)
P, T, RH
P, T, RH
P, T, RH
P, T, RH
Ascent Rate change of > 3 m/s or & lt; -3 m/s
change of > 5 m/s or < -5 m/s

3.3 Data Quality Issues

Complete information on the processing and data quality of each network can be found in their respective documentation files:

University of Missouri


National Weather Service

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.

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.