Historical observations of sea level at Port Arthur, Tasmania

Brief description

Contains observations of sea level at Port Arthur, Tasmania during the period 1840 to 1842.

A sea level benchmark was struck on a small cliff on the Isle of the Dead, near Port Arthur, Tasmania by T.J. Lempriere and Captain Clark Ross. Lempriere had previously constructed a tide gauge at Port Arthur where he made observations of the times and heights at approximately high and low water from mid-1837 to at least the end of 1842.

No detailed information about the construction of the tidal gauge appears to have survived and was probably not self recording.

Data includes the date, time and sea level.

Lineage

Maintenance and Update Frequency: notPlanned

Statement: Correction of some obvious errors in the original hardcopy data was performed during this digitisation, which was carried out by Dr. David Pugh, presently Chairperson, Intergovernmental Oceanographic Commission of UNESCO (IOC). They cover the period 1840 to 1842, but are incomplete for 1840.

The exact location of the observations is unknown, but is almost certainly within 1 km of 43 deg 08 min 50 secs South, 147 deg 51 min 10 sec East.

Details of the tide gauge have not survived.

The datum of these sea levels is 1474.2 mm BELOW AHD (Tasmania).

For information on local survey marks, see:

Watson, C.S., 1999. A Contribution to Absolute Sea Level in Tasmania, B. Surv. (Hons.) thesis, 200 pp., University of Tasmania, Hobart, Tasmania, Australia.

Further details of the historic documents and an analysis of the data contained in them are given by:

Pugh, D., Hunter, J., Coleman, R. and Watson, C., 2002. A comparison of historical and recent sea level measurements at Port Arthur, Tasmania, International Hydrographic Review, Vol. 3, No. 3 (New Series), 27-46,

and:

Hunter, J., Coleman, R. and Pugh, D., 2003. The sea level at Port Arthur, Tasmania, from 1841 to the present, Geophysical Research Letters, Vol. 30, No. 7, 54-1 to 54-4, doi:10.1029/2002GL016813.

Data Format
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Each day consists of 4 lines:

MM DD hhmmffii ddd
hhmmffii ddd
hhmmffii ddd
hhmmffii ddd

where:

MM is the month number,
DD is the day number of the month,
hh is the hour of the day (24-hour clock),
mm is the minute of the hour,
ffii is the sea level in feet ("ff") and inches ("ii"), and ddd is the time difference in minutes between this and the previous line ("ddd" was used for diagnostic purposes).

The time zone is believed to be Hobart local time, or UTC + 9 hours 49 minutes.
For a discussion of the probable time zone, see:

Hamon, B., 1985. Early mean sea levels and tides in Tasmania, Search, Vol. 16, No. 9-12, 274-277.



The original datasets are in hardcopy form at the following locations:

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porta40.txt
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Sea level data for 1840, from:

P2472/Item 9

at:

National Archives of Australia,
Hobart Office,
85 Macquarie Street,
Hobart,
Tasmania 7000,
Australia.

---------------------------------

porta41.txt and porta42.txt
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Sea level data for 1841 and 1842, from:

MA59

at:

Royal Society Archives,
The Royal Society,
6-9 Carlton House Terrace,
London SW1Y 5AG,
United Kingdom.

Notes

Purpose
To contribute to the knowledge of past sea level rise in the Southern Hemisphere.