Casey Tide Gauge Data 1996-2007

Brief description

Over time there have been a number of tide gauges deployed at Casey Station, Antarctica. The data download files contain further information about the gauges, but some of the information has been summarised here. Note that this metadata record only describes tide gauge data from 1996 to 2007. More recent data are described elsewhere.

Old Tide Gauge 2 (TG002_Old)
Oldtg02 is a download from the first gauge submerged deployed at Casey in 1992.
This gauge was lost but later recovered standing upright in the mud.
The gauge overwrote its memory and stopped.
The record runs from 02/04/97 to 08/09/99.
It is highly probable that the position of the gauge was stable during this period.
There is data from the same period from gauge TG06.

Tide Gauge 2 (TG002)
These folders contain data downloaded from the redeployed gauge TG02.
TG02 was redeployed in November 2003.
The Record runs from 12/11/03 to 4/3/05.
It is expected that data will be downloaded from this gauge for the next 4-5 years.

This gauge was deployed after the previously deployed gauge ran out of battery energy.
There is therefore a substantial gap in the record prior to 12/11/03.

Tide Gauge 6 (TG006)
Tg06 was deployed at Casey in March 1996.
The battery became exhausted in June 2003.
The gauge was replaced by TG02 in Novenber 2003.
There is therefore a gap in the data between June and November 2003.

Tide Gauges 33, 34 and 36 (TG033, TG034, TGA001, TG036)
There are two wharf pressure sensors at Casey separated vertically by 2.007 m.
There is also a barometer in the wharf hut.
The files in this folder are from the old tide gauge data loggers.
There are three loggers,

TG33 records pressures from lower water pressure gauge as 30 second average values (absolute pressure mbar).
It also records wharf tube water temperatures.
This logger also streams 30sec average pressure.

TG34 records pressures from upper water pressure gauge.
This logger also streams 30sec average values as and 10minute average water pressure data.

TGA01 (and later replaced by TG36) records air pressure as 10 minute average values in mbar.


Further documentation from the old metadata records:
Documentation dated 2001-03-07
Casey Submerged Tide Gauge

The gauge used at Casey was designed in 1991/2 by Platypus Engineering, Hobart, Tasmania.
It was intended to be submerged in about 7 metres of water in a purpose made concrete mooring in the shape of a truncated pyramid.
The gauge measures pressure using a Paroscientific Digiquartz Pressure Transducer with a full scale pressure of 30 psi absolute. The accuracy of the transducer is 1 in 10,000 of full scale over the calibrated temperature.
The overall accuracy of the system is better than +/- 3 mm for a known water density.
Data is retrieved from the gauges by lowering a coil assembly on the end of a cable over a projecting knob on the top of the gauge and by use of an interface unit, a serial connection can be established to the gauge. Time setting and data retrieval can be then achieved.
One of these of these gauges was deployed at Casey in early 1992 in a mooring in Geoffrey Bay.
The mooring was apparently moved by sea ice and was later found, but the gauge is missing.
A new mooring, one which was originally made for Harry Burton for use in one of the Vestfold Hills lakes, was taken by ship to Casey and was placed in Geoffrey Bay using a collection of 200 litre fuel drum to float the mooring into position.
A new gauge was deployed in March 1996.
The gauge was lowered into position with the holding grab wired closed to check that the device fitted in the mooring. The gauge became jammed so was left in situ with the grab preventing access to downloading. In April that year Roger Handsworth attached weights to the floating ropes of the grab to sink them out of the way of the freezing surface water.
Divers located the mooring and gauge in late 1997 and 22 months of tidal records were retrieved.
The gauge was restarted to clear the memory and allow another two years of data to be collected without any problems from a small software bug.
Conversion of raw data to tidal records is done as detailed in document DATAFORMAT1.DOC .

Levelling
In December 1997 a set of water level observations were made by the station leader. These observations have been sent to National Tidal Facility, Flinders University, SA to derive a value for mean sea level.

Documentation dated 2008-10-17
There is one submerged bottom mounted gauge at Casey. (TG02)

The wharf based tide gauge installation at Casey has been upgraded with 2 Campbell Scientific CR1000 dataloggers.
One logger (Main) receives signals from two wharf installed submerged Paroscientific Digiquartz pressure sensors and a barometer. The other logger (Backup) receives signals from only the two submerged sensors.
Pressures are recorded in hPa, temperatures from the Digiquartz sensors in degrees C and temperatures from thermistors in the water column in unscaled A/D values.

The two submerged pressure sensors are separated vertically by 2.007 metre.
The backup logger streams 30 second average pressure values from both submerged sensors.
The main datalogger records 3 pressure and 6 temperatures and controls the water heaters.

Lineage

Progress Code: completed

Statement: See the data download for more details. Each tide gauge typically encountered some problems throughout its life, resulting in data gaps, or poorer quality data. For example, there is a gap from January to June 2000 and from 20-23 November 2003. There will be a large gap in the datset after the time the gauge ceased to function as the gauge was not immediately replaced.

These data have been through an extensive 'clean-up' to improve their quality as much as possible (see the document in the download file).

Notes

Purpose
Measurement of tides and determination of sea levels.