Tides are measured using a submerged pressure type gauge secured in a heavy concrete mooring in Nella Fjord in the Larsemann Hills near Zhong Shan station.
Tidal records are retrieved from the gauge using an inductive loop lowered through a hole in the ice hence the gauge has been undisturbed since it was deployed.
Documentation dated 2001-06-12
Zhong Shan Submerged Tide Gauge
The gauge used at Zhong Shan 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 mooring for the Zhong Shan gauge was cast in concrete at Davis and sling loaded by helicopter to Nella Fjord in the Larsemann Hills and deployed through a hole in the ice.
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 range.
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.
Data has been retrieved from this gauge once since deployment. The records are complete since deployment.
Conversion of raw data to tidal records is done as detailed in document: Details of Conversion of Raw Data.
One attempts has been made at establishing an absolute height for this gauge using timed water level measurements.
Documentation dated 2008-10-17
The battery in the submerged gauge at Zhong Shan has probably been exhausted. The gauge will be removed at an opportune time.
The gauge has not recently been download. There will still be some records available.