Metadata Report for BODC Series Reference Number 202506


Metadata Summary

Data Description

Data Category Meteorology -radiosonde
Instrument Type
NameCategories
VIZ 1223 Radiosonde  radiosondes
Instrument Mounting research vessel
Originating Country Germany
Originator -
Originating Organization Max Planck Institute for Meteorology
Processing Status banked
Project(s) JASIN
 

Data Identifiers

Originator's Identifier J78M201
BODC Series Reference 202506
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1978-08-22 22:12
End Time (yyyy-mm-dd hh:mm) 1978-08-22 22:45
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 58.98370 N ( 58° 59.0' N )
Longitude 12.48350 W ( 12° 29.0' W )
Positional Uncertainty 0.5 to 1.0 n.miles
Minimum Sensor Depth -12184.0 m
Maximum Sensor Depth 0.0 m
Minimum Sensor Height -
Maximum Sensor Height -
Sea Floor Depth -
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor Depth Datum Mean sea level - Depth expressed relative to mean sea level as defined by the data originator
Sea Floor Depth Datum -
 

Parameters

BODC CODE Rank Units Short Title Title
AADYAA01 1 Days Date(Loch_Day) Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01 1 Days Time(Day_Fract) Time (time between 00:00 UT and timestamp)
AHSLZZ01 1 Metres Height Height above sea level (spatial co-ordinate)
CAPBSS01 1 Millibars AirPress_Z Pressure (spatial co-ordinate) exerted by the atmosphere by aneroid barometer and expressed at measurement altitude
CDTBSS01 1 Degrees Kelvin AirTemp Absolute temperature of the atmosphere by psychrometer dry bulb
CDTSZZ01 1 Degrees Kelvin SD_Air_Temp Absolute temperature standard deviation of the atmosphere by dry bulb thermometer
CHMSZZ01 1 Grams per kilogram SD_SpecHumid Specific humidity standard deviation of the atmosphere
CHUMSS01 1 Grams per kilogram SpecHumid Specific humidity of the atmosphere
ESEWZZ01 1 Metres per second SD_WindVelE Eastward wind velocity standard deviation in the atmosphere
ESNSZZ01 1 Metres per second SD_WindVelN Northward wind velocity standard deviation in the atmosphere
EWEWSS01 1 Metres per second WindVelE Eastward wind velocity in the atmosphere by in-situ anemometer
EWNSSS01 1 Metres per second WindVelN Northward wind velocity in the atmosphere by in-situ anemometer
 

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

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:

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:

  1. 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.
  2. 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.
  3. 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:

  1. 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.

  2. 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