Posted: Oct 21, 2010 4:39 pm
Sea Levels Rising Around South Atlantic's Falkland Islands, 19th-Century Benchmarks Reveal
ScienceDaily (Oct. 20, 2010) — “We have been fortunate in being able to compare modern sea-level measurements obtained from tide gauges and from satellite radar altimeters with historical measurements made at Port Louis in the Falkland Islands in 1842,” explained researcher Prof. Philip Woodworth of the National Oceanography Centre.
“We have been fortunate in being able to compare modern sea-level measurements obtained from tide gauges and from satellite radar altimeters with historical measurements made at Port Louis in the Falkland Islands in 1842,” explained researcher Prof. Philip Woodworth of the National Oceanography Centre.
In 1839, distinguished naval officer and polar explorer James Clark Ross (1800–1862) set off on an expedition to the Southern Ocean with two ships, HMS Erebus and HMS Terror. In April 1842, he stopped at Port Louis, primarily to make magnetic field and other measurements, but also to make repairs to his ships which had been badly damaged in the Drake Passage. Having set up a winter base, he took the opportunity to make careful measurements of sea level relative to two benchmarks cut into the cliffs and marked with brass plaques.
These marks remain in good condition to this day. This fact, along with the apparent good quality of Ross’s data, has allowed Woodworth’s team to compare the sea level records from 1842 with measurements taken at Port Louis using modern instruments in 1981–1982, 1984 and 2009. They also used information from nearby Port Stanley, where a permanent tide gauge was operated in the 1960s and 1970s and where NOC has had an operational gauge since 1992.
...continues...
The 'Ross benchmark' used for sea level measurements at Port Louis.
(Credit: Image courtesy of National Oceanography Centre, Southampton)
