Metadata Report for BODC Series Reference Number 201515
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags
Metadata Summary
Data Description |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Data Identifiers |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Time Co-ordinates(UT) |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Spatial Co-ordinates | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parameters |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Problem Reports
No Problem Report Found in the Database
Data Access Policy
Public domain data
These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.
The recommended acknowledgment is
"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."
Narrative Documents
JASIN Radiosonde Data
Radiosondes were released from the ships MV Gardline Endurer, HMS Helca, RV Meteor and RRS John Murray. The ships were stationed at the northwest, northeast and south corners of a triangle of sides approximately 200km. During Phase 2 (20 August to 5 September) of the measurement programme a fourth ship was located at the centre of the triangle. The approximate positions were:
Ship | Position |
---|---|
MV Gardline Endurer | 60° 15' N 14° 30' W |
HMS Hecla | 60° 15' N 10° 30' W (not between 29 July and 9 August) |
RRS John Murray | 60° 15' N 10° 30' W (between 30 July and 9 August) |
RV Meteor | 59° 00' N 12° 30' W |
RRS John Murray | 59° 58' N 12° 30' W (between 20 and 30 August) |
The absolute position of each radiosonde ship was known to ±1km at the beginning of each radiosonde ascent. A position fix was taken every 30 minutes during the intensive radiosonde periods.
VIZ 1223 radiosondes were used, in which the rod thermistor, carbon hygristor and aneroid pressure sensor were sampled sequentially every 0.8seconds. Winds were measured by tracking the balloon with the use of LORAN-C signals retransmitted by the radiosonde. Balloons were filled with helium so as to give a rate of ascent of 5 to 6 m/s. Four radiosonde flight rigs were used:
- B single balloon tracked until burst
- T single balloon tracked until tropopause
- TC as T, but cut down at 200mbar
- P single balloon with 500mbar release and parachute, tracked during ascent and descent
Great care was taken to minimise systematic differences between ships. All radiosondes used were obtained from a single batch and the factory calibrations were used to avoid any systematic biases in the shipboard calibrations performed before launch.
Accuracy of Radiosonde Sensors
Variable | Sensor | Factory Specified Accuracy |
---|---|---|
Temperature | VIZ 1366-211 | ±0.1K (rms) |
Relative Humidity | VIZ 1386-060 | ±2% (rms) |
Pressure | VIZ 1292-213 | within 1mbar |
All data were recorded onto magnetic tape, with similar Beukers W-3 system LO-CATE ground equipment on each ship and post-experiment processing was performed at a single site.
Intercomparisons were carried out on 22 July, 23 July, 28 July, 9 August, 20 August and 5 September. Where possible each intercomparison flight was tracked by each of the ships. Unfortunately equipment failures and tracking problems resulted in the loss of much intercomparision data during Phase 1 (22 July to 9 August), particularly in the first inter- comparison period. The flight data were processed using the standard JASIN radiosonde processing system and comparisions limited to cases of ships tracking the same radiosonde.
Temperature and humidity data were corrupted by signal breakup at low transmitted modulation frequencies from the radiosonde. This corresponds to humidities above about 80 per cent and temperatures of below -40 °C. This was caused by an unexpected change in the design of the radiosondes by VIZ which resulted in different signal characteristics from those of the sample sondes tested prior to the experiment. This prevented some radiosonde tracking and all of the sets had to be retuned. Those on Hecla and Gardline Endurer were retuned at the start of Phase 1 and all sets were retuned in Glasgow between Phases 1 and 2. No corrections have been made for the temperatures. A correction procedure was developed for the Phase 2 humidities based on the fact that signal breakup was negligible for Hecla for Phase 2. Thus Hecla data have been used as a standard to which the other data have been corrected. Application of these corrections to Phase 1 data shows that further correction is needed. Corrections for Hecla are difficult to evaluate since for most of the flights a parallel resistance was incorporated into the hygristor circuit to prevent signal breakup, however this was not done at the intercomparisons.
The main conclusions of the intercomparison exercise are summarised below:
- Errors due to the reception, recording and processing of the radiosonde data are 0.05 ±0.04m/s for each wind component, less than 0.05K for temperature and less than 1 per cent for humidity after corrections applied.
- The standard deviation of the differences between individual 5mb values was about 0.5m/s for winds, less than 0.1K for temperature and 5 per cent for relative humidity after correction.
- The true accuracy of all variables will be affected by errors not included in these figures. Only Phase 2 humidity values have been corrected.
The launch number for each ship is of the form j78snnn, where s is a ship code as follows:
C = MV Gardline Endurer
M = RV Meteor
H = HMS Hecla
J = RRS John Murray
and nnn = flight sequence of numbers starting with 001 at the start of the JASIN programme.
Project Information
Joint Air Sea Interaction Experiment (JASIN)
The JASIN Project was designed to study the interaction of the atmospheric and oceanic boundary layers with the larger scale motions of the sea and the air.
The primary aims may be summarized as follows:
-
To observe and distinguish between the physical processes causing mixing in the atmospheric and oceanic boundary layers and relate them to the mean properties of the layers.
-
To examine and quantify aspects of the momentum and heat budgets in the atmospheric and oceanic boundary layers and fluxes across and between them.
The multiplicity of processes to be sampled necessitated a large experiment and JASIN involved 14 ships and 3 aircraft with more than 50 teams of investigators from 9 countries. Altogether 35 mooring systems were deployed.
The experiment lasted for 2 months from mid-July to mid-September 1978 and comprised 2 intensive measuring periods preceded by a preparatory test period. The project took place in the north Rockall Trough, an area of deep water (1000m - 2000m) several hundred kilometres off the west coast of Scotland.
Data Activity or Cruise Information
Cruise
Cruise Name | MT49 |
Departure Date | 1978-07-05 |
Arrival Date | 1978-09-11 |
Principal Scientist(s) | E Augstein (Max Planck Institute for Meteorology) |
Ship | FS Meteor |
Complete Cruise Metadata Report is available here
Fixed Station Information
No Fixed Station Information held for the Series
BODC Quality Control Flags
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
Flag | Description |
---|---|
Blank | Unqualified |
< | Below detection limit |
> | In excess of quoted value |
A | Taxonomic flag for affinis (aff.) |
B | Beginning of CTD Down/Up Cast |
C | Taxonomic flag for confer (cf.) |
D | Thermometric depth |
E | End of CTD Down/Up Cast |
G | Non-taxonomic biological characteristic uncertainty |
H | Extrapolated value |
I | Taxonomic flag for single species (sp.) |
K | Improbable value - unknown quality control source |
L | Improbable value - originator's quality control |
M | Improbable value - BODC quality control |
N | Null value |
O | Improbable value - user quality control |
P | Trace/calm |
Q | Indeterminate |
R | Replacement value |
S | Estimated value |
T | Interpolated value |
U | Uncalibrated |
W | Control value |
X | Excessive difference |
SeaDataNet Quality Control Flags
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
Flag | Description |
---|---|
0 | no quality control |
1 | good value |
2 | probably good value |
3 | probably bad value |
4 | bad value |
5 | changed value |
6 | value below detection |
7 | value in excess |
8 | interpolated value |
9 | missing value |
A | value phenomenon uncertain |
B | nominal value |
Q | value below limit of quantification |