Metadata Report for BODC Series Reference Number 51116


Metadata Summary

Data Description

Data Category Multiple data types -tethered balloon
Instrument Type Unspecified Instrumentation
Instrument Mounting research vessel
Originating Country United Kingdom
Originator -
Originating Organization UK Meteorological Office
Processing Status banked
Project(s) JASIN
 

Data Identifiers

Originator's Identifier TB7808232155
BODC Series Reference 51116
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1978-08-23 21:55
End Time (yyyy-mm-dd hh:mm) 1978-08-24 00:27
Nominal Cycle Interval 102.0 seconds
 

Spatial Co-ordinates

Latitude 60.25000 N ( 60° 15.0' N )
Longitude 10.50000 W ( 10° 30.0' W )
Positional Uncertainty 0.5 to 1.0 n.miles
Minimum Sensor Depth -180.0 m
Maximum Sensor Depth -180.0 m
Minimum Sensor Height -
Maximum Sensor Height -
Sea Floor Depth -
Sensor Distribution Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed for the duration of the series
Sensor Depth Datum Unspecified -
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)
CAPHAL01 1 Millibars Air_press Pressure (measured variable) 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
ESSASS01 1 Metres per second WindSpd Wind speed in the atmosphere by in-situ anemometer
ESSSZZ01 1 Metres per second SD_WindSpd Wind speed standard deviation in the atmosphere
ESZASS01 1 Metres per second UpWindVel Upward air velocity in the atmosphere by in-situ anemometer
ESZSZZ01 1 Metres per second SD_UpWindVel Upward air velocity standard deviation in the atmosphere
 

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

Data Processing Notes

Data Originator Comment that Run 7 produced good data.

Average height of instrument package Run 7 180m
Axis rotation to force vertical velocity to zero Run 7 0.240 radians

BODC Comment that inspection of the time series plot shows that the pressure values have not attained a steady value for data cycles 1 to 2; this appears to have affected the other parameters. These data cycles should be treated with caution.

JASIN Tethered Balloon Data collected by HMS Hecla

Introduction

H M S Hecla was located at 60° 15' N, 10° 3' W between 16 and 28 July (Phase 1) and 22 August and 05 September 1978 (Phase 2) . A tethered balloon was flown from the aft of the ship during this period. Turbulence probes from the UK Meteorological Office Porton Group were instrumented with a miniature cup anemometer for wind speed, dry and wet bulb platinum sensors, a hot wire inclinometer and an aneroid capsule. These were mounted on a vane clamped to a captive balloon cable and an electronics box mounted beneath telemetered FM data of wind speed, wind inclination, dry and wet bulb temperatures and pressure to be recorded on an analogue tape recorder. The tapes were then played through filters and digitised at 10Hz. Raw data were then transferred to the Meteorological Office computer at Bracknell and spectra and fluxes were calculated.

Instrumentation

The following sensors were included in the package.

Sensor Parameter Measured Accuracy Sampling Frequency
Cup anemometer Mean wind speed 2 per cent Continuous
Magnetic compass Horizontal wind direction 3 degrees 20Hz
Dual V hot wire inclinometer Inclination of wind to horizontal 1 degree Continuous
Platinum resistance thermometer Dry and wet bulb temperatures 0.2 °C Continuous
Aneroid capsule Atmospheric pressure - -

Continuous data recorded continuously in analogue form but digitized at 10Hz.

Calibrations

Sensors were calibrated in the laboratory before and after the experiment. Field calibrations were limited to checks of the sensitivities of the electronic signal processing circuits, by substitution of dummy sensors.

Before averaging checks on the time derivatives of horizontal and vertical windspeeds and temperatures were performed to remove spikes (mainly a problem with wind speeds). Data were then averaged over 102.4 seconds. The time value associated with each data cycle is the mid-point of each 102.4 second averaging period. Wind speeds have not been corrected for ship motion. The standard deviation of the wind speeds is seriously affected by the action of waves on the ship.

To calculate the specta and co-spectra the mean vertical velocity was forced to zero by applying an axis rotation. The rotation has not been performed, but the rotation angles have been supplied for each series. Phase 1 of JASIN was used mainly as a proving phase and measurements were severely limited by problems with the balloon system and instrumentation. The hydraulic gear which automatically pulled in and paid out the balloon cable to compensate for ship motion, designed for (and used successfully in) the GARP Atlantic Tropical Experiment, was not able to cope with the heavy seas encountered in JASIN.

During Phase 2 the balloon was raised on 22 August 1978 (after strong winds had abated sufficiently) and remained aloft until 05 September 1978. In all some 160 hours of data were recorded during Phase 2 made up of about 100 runs when the probe was at a constant height between 50m and 450m. Measurements were made by day and by night using one turbulence probe.

Data from 36 runs, totalling approximately 65 hours, are held by BODC.

Note: The first specific humidity data cycle (and associated standard deviation) on each series is probably not a valid data value.

Reference

S. Nicholls et. al. 1983
The structure of the turbulent atmospheric boundary layer. Phil. Trans. Roy. Soc. London A Volume 308 pp 291 - 309.


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 HECLA_JASIN78
Departure Date 1978-07-14
Arrival Date 1978-09-05
Principal Scientist(s)Unknown (Unknown)
Ship HMS Hecla

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