This is one of the upper air data sets developed for the Dynamics of the Madden-Julian Oscillation (DYNAMO) 2011-2012 project. This preliminary data set includes 1068 high vertical resolution (2-sec) soundings from the Atmospheric Radiation Measurement (ARM) M1 Airport (Addu Atoll), Gan Island, Maldives site, collected during the DYNAMO field campaign from 22 September 2011 through 9 February 2012. There are typically eight soundings per day at 00, 03, 06, 09, 12, 15, 18, and 21 UTC. This preliminary version of the data set contains data from 22 September 2011 to 9 February 2012. There may be corrections applied to these data at a later point. If you order this data set now you will be notified when additional and/or corrected data becomes available. After 9 February 2012 the Maldivian Meteorological Service continued to conduct releases once or twice per day through the end of the DYNAMO field phase. Those data will be part of a separate data set. This station used Vaisala RS92-SGP radiosondes with GPS windfinding during the DYNAMO field campaign.
Scot Loehrer
NCAR/EOL
loehrer@ucar.edu
Location: beside the Gan MMS offices on Gan airport grounds, within 100 feet or so same location as normal MMS sondes launches occur. Lat/Long: -0.6905967, 73.1498967
Sondes used are RS-92 using Digicora V3.64 software. This software includes proprietary daytime dry bias correction for RH and applies the Vaisala smoothing algorithm. The details of these algorithms are proprietary to Vaisala. All sondes prepped using a GC25 unit inside an air-conditioned van. Balloons use helium gas with the sonde package set on an open-air, non-forced-air-aspirated shelf during balloon filling prior to launch.
Surface data entered in to the Digicora software come from AMF-1 met system, using forced-air aspirated Vaisala HMP45 combined T/RH probe located about 50 feet from balloon filling station. Generally good agreement between these met measurements and sonde values at launch time.
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 |
| 7 | ||
| 8 | ||
| 9 | ||
| 10 | ||
| 11 | ||
| 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 |
|---|---|---|---|---|---|
| 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 | Ascent 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 | Elevation Angle | Degrees | 999.0 |
| 14 | 5 | F5.1 | Azimuth Angle | Degrees | 999.0 |
| 15 | 7 | F7.1 | Altitude | Meters | 99999.0 |
| 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:
| 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") |
The following is a sample record of DYNAMO Gan ARM 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: ARM AMF Radiosonde/Ascending Project ID: DYNAMO Release Site Type/Site ID: M1: Airport (Addu Atoll), Gan Island, Maldives Release Location (lon,lat,alt): 073 09.00'E, 00 41.40'S, 73.150, -0.690, 1.0 UTC Release Time (y,m,d,h,m,s): 2011, 09, 22, 06:01:00 Sonde Id/Sonde Type: G0220143/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 10.0 1006.7 27.7 23.2 76.5 3.0 -0.6 3.1 282.0 4.0 73.150 -0.690 999.0 999.0 40.8 99.0 99.0 99.0 99.0 99.0 99.0 12.0 1006.0 27.6 23.3 77.4 3.2 -0.7 3.3 282.0 3.8 73.150 -0.690 999.0 999.0 46.7 99.0 99.0 99.0 99.0 99.0 99.0 14.0 1005.4 27.6 23.6 78.5 3.3 -0.8 3.4 283.0 3.7 73.150 -0.690 999.0 999.0 52.4 99.0 99.0 99.0 99.0 99.0 99.0 16.0 1004.8 27.6 23.6 79.0 3.5 -0.8 3.6 283.0 3.6 73.150 -0.690 999.0 999.0 57.9 99.0 99.0 99.0 99.0 99.0 99.0 18.0 1004.1 27.5 23.5 78.8 3.6 -0.9 3.7 284.0 3.5 73.150 -0.690 999.0 999.0 64.1 99.0 99.0 99.0 99.0 99.0 99.0 20.0 1003.4 27.4 23.4 78.9 3.7 -1.0 3.8 285.0 3.5 73.151 -0.690 999.0 999.0 70.0 99.0 99.0 99.0 99.0 99.0 99.0 22.0 1002.7 27.4 23.4 79.2 3.8 -1.0 3.9 285.0 3.4 73.151 -0.690 999.0 999.0 75.9 99.0 99.0 99.0 99.0 99.0 99.0 24.0 1002.0 27.3 23.5 79.6 3.8 -1.1 4.0 286.0 3.4 73.151 -0.690 999.0 999.0 82.5 99.0 99.0 99.0 99.0 99.0 99.0 26.0 1001.2 27.2 23.5 79.9 3.8 -1.2 4.0 287.0 3.4 73.151 -0.690 999.0 999.0 89.7 99.0 99.0 99.0 99.0 99.0 99.0 28.0 1000.4 27.2 23.5 80.1 3.9 -1.2 4.1 287.0 3.4 73.151 -0.690 999.0 999.0 96.7 99.0 99.0 99.0 99.0 99.0 99.0 30.0 999.6 27.1 23.5 80.7 4.0 -1.3 4.2 288.0 3.4 73.151 -0.690 999.0 999.0 104.0 99.0 99.0 99.0 99.0 99.0 99.0 32.0 998.7 27.0 23.6 81.3 4.1 -1.3 4.3 288.0 3.3 73.151 -0.690 999.0 999.0 111.5 99.0 99.0 99.0 99.0 99.0 99.0 34.0 997.8 26.9 23.5 81.4 4.1 -1.4 4.3 289.0 3.3 73.151 -0.690 999.0 999.0 119.4 99.0 99.0 99.0 99.0 99.0 99.0 36.0 997.1 26.9 23.5 81.8 4.2 -1.4 4.4 289.0 3.3 73.151 -0.690 999.0 999.0 126.3 99.0 99.0 99.0 99.0 99.0 99.0 38.0 996.3 26.8 23.5 82.1 4.3 -1.5 4.5 289.0 3.3 73.151 -0.690 999.0 999.0 133.0 99.0 99.0 99.0 99.0 99.0 99.0 40.0 995.5 26.7 23.5 82.4 4.3 -1.5 4.5 289.0 3.3 73.151 -0.690 999.0 999.0 140.3 99.0 99.0 99.0 99.0 99.0 99.0 42.0 994.7 26.7 23.5 82.5 4.3 -1.5 4.6 289.0 3.4 73.151 -0.690 999.0 999.0 147.7 99.0 99.0 99.0 99.0 99.0 99.0 44.0 993.8 26.6 23.4 82.4 4.4 -1.4 4.6 288.0 3.4 73.151 -0.690 999.0 999.0 155.8 99.0 99.0 99.0 99.0 99.0 99.0 46.0 992.8 26.5 23.4 82.8 4.5 -1.5 4.7 288.0 3.5 73.151 -0.690 999.0 999.0 164.4 99.0 99.0 99.0 99.0 99.0 99.0 48.0 991.8 26.4 23.4 83.4 4.5 -1.5 4.7 288.0 3.6 73.152 -0.690 999.0 999.0 173.0 99.0 99.0 99.0 99.0 99.0 99.0 50.0 990.9 26.3 23.4 83.8 4.5 -1.5 4.7 288.0 3.7 73.152 -0.690 999.0 999.0 181.1 99.0 99.0 99.0 99.0 99.0 99.0 52.0 990.0 26.2 23.3 83.8 4.5 -1.4 4.7 287.0 3.8 73.152 -0.690 999.0 999.0 189.3 99.0 99.0 99.0 99.0 99.0 99.0 54.0 989.1 26.2 23.1 83.3 4.6 -1.4 4.8 287.0 3.8 73.152 -0.691 999.0 999.0 197.7 99.0 99.0 99.0 99.0 99.0 99.0
| ID | SITE | LONG | LAT | ELEV (m) |
|---|---|---|---|---|
| Gan_ARM | 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 ARM 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 > Temperature |
RH T, RH | Q Q |
| Relative Humidity | < 0% or > 100% | RH | B |
| 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, 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 | 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 |
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.
Some soundings exhibit seeming oscillations in the RH data. This sometimes occurs during periods of slow (< 3m/s) balloon ascent due to the cycling of the dual VRS92 humidity sensors. Examples can be seen in the following soundings:
201110040834 201110141135 201110142337 201110240837 201111182037 201111222035 201111222334 201111241735 201111262337 201112100235 201201250537
A few soundings had bad surface temperature or RH values:
201110122038 201111050836 201201270835
One sounding had a problem temperature sensor during a substantial period of the flight:
201112180846
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.