This is one of the upper air data sets developed for the Dynamics of the Madden-Julian Oscillation (DYNAMO) 2011-2012 project. This data set includes 184 high vertical resolution (2-sec) soundings from the Addu Atoll, Gan Island, Maldives site, collected before and towards the end of the DYNAMO field campaign by the Maldives Meteorological Service (MMS). MMS conducted the releases from this site before the field phase daily at 12 UTC nominal time from 15 June to 30 September 2011. Also after the Maldivian political crisis the MMS conducted the soundings after ARM personnel departed from the site. Releases were daily at the 12 UTC nominal time from 12 February to 5 March 2012 and twice daily (00 and 12 UTC) from 6-30 March and then back to daily at 12 UTC from 1-8 April 2012. The soundings taken by ARM personnel from 22 September 2011 to 9 February 2012 are included in a separate data set. This station used Vaisala RS92-SGP radiosondes with GPS windfinding.
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.
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:
|Line||Label (padded to 35 char)||Contents|
|1||Data Type:||Description of type and resolution of data.|
|2||Project ID:||Id of weather project.|
|3||Release Site Type/Site ID:||Description of the release site.|
|4||Release Location (lon,lat,alt):||Position of release site in the format described below.|
|5||UTC 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.
|Line||Label (padded to 35 char)||Contents|
|6||Sonde Id/Sonde Type:||G0220143/Vaisala RS92-SGP with GPS windfinding|
|12||Nominal Release Time (y,m,d,h,m,s):||Nominal time of release, in the format: yyyy, mm, dd, hh:mm:ss|
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.||Width||Format||Parameter||Units||Missing Value|
|3||5||F5.1||Dry-bulb Temperature||Degrees C||999.0|
|4||5||F5.1||Dew Point Temperature||Degrees C||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|
|10||5||F5.1||Ascent Rate||Meters / Second||999.0|
|16||4||F4.1||QC for Pressure||Code (see below)||99.0|
|17||4||F4.1||QC for Temperature||Code (see below)||99.0|
|18||4||F4.1||QC for Humidity||Code (see below)||99.0|
|19||4||F4.1||QC for U Wind Component||Code (see below)||99.0|
|20||4||F4.1||QC for V Wind Component||Code (see below)||99.0|
|21||4||F4.1||QC for Ascension Rate||Code (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:
|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")|
The following is a sample record of DYNAMO Gan MMS high resolution sounding 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: MMS Radiosonde/Ascending Project ID: DYNAMO Release Site Type/Site ID: M1: Airport (Addu Atoll), Gan Island, Maldives/43599 Release Location (lon,lat,alt): 073 09.00'E, 00 41.40'S, 73.150, -0.690, 2.0 UTC Release Time (y,m,d,h,m,s): 2011, 06, 15, 07:17:00 Sonde Id/Sonde Type: E5340033/Vaisala RS92-SGP with GPS windfinding / / / / / Nominal Release Time (y,m,d,h,m,s):2011, 09, 22, 06:00:00 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 ------ ------ ----- ----- ----- ------ ------ ----- ----- ----- -------- ------- ----- ----- ------- ---- ---- ---- ---- ---- ---- 0.0 1011.2 29.0 24.2 75.3 3.6 0.0 3.6 270.0 0.0 73.150 -0.690 999.0 999.0 1.0 99.0 99.0 99.0 99.0 99.0 99.0 2.0 1010.1 28.3 23.3 74.2 2.1 -0.4 2.1 280.0 5.0 73.150 -0.690 999.0 999.0 11.0 99.0 99.0 99.0 99.0 99.0 99.0 4.0 1009.1 28.1 23.3 75.0 2.2 -0.4 2.2 281.0 4.7 73.150 -0.690 999.0 999.0 19.7 99.0 99.0 99.0 99.0 99.0 99.0 6.0 1008.2 28.0 23.2 75.2 2.6 -0.5 2.6 281.0 4.4 73.150 -0.690 999.0 999.0 27.4 99.0 99.0 99.0 99.0 99.0 99.0 8.0 1007.4 27.8 23.1 75.6 2.7 -0.5 2.8 281.0 4.2 73.150 -0.690 999.0 999.0 34.3 99.0 99.0 99.0 99.0 99.0 99.0
|Gan_MMS||M1 Airport, Gan Island, Maldives||73.150||-0.690||1.0|
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).
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 DYNAMO Gan MMS 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.
|Parameter||Gross Limit Check||Parameter(s) Flagged||Flag Applied|
|Pressure||< 0 mb or > 1050 mb||P||B|
|Altitude||< 0 m or > 40000 m||P, T, RH||Q|
|Temperature||< -90 °C or > 45 °C||T||T|
|Dew Point||< -99.9 °C or > 33 °C
|Relative Humidity||< 0% or > 100%||RH||B|
|Wind Speed||< 0 m/s or > 100 m/s
> 150 m/s
|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, V||B|
|Ascent Rate||< -10 m/s or > 10 m/s||P, T, RH||Q|
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 Consitency Check||Parameter(s) Flagged||Flag Applied|
|Time||decreasing / equal||None||None|
|Altitude||decreasing / equal||P, T, RH||Q|
|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 < 2 50 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
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.
A few soundings had bad surface temperature or RH values:
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.