The tidal corrections are applied automatically by the gravity meter
and their small residuum is then removed within the instrument drift corrections.
On both expeditions, he used a gravity meter
in the Wright Valley and the Koettlitz Glacier region both to delineate geological structure (a rock fault) and to determine glacier thicknesses.
The relative gravity meter
Scintrex CG-3M has a standard resolution of 1 [mu]Gal-a (1 uGal = 10-8 ms-2) with a standard deviation smaller than 5 [mu]Gal-a.
"Instead of measuring the distance an atom falls in a certain amount of time," Chu explained, "our atomic gravity meter
measures the change in velocity during a given time by measuring the Doppler shift of a very well-known atomic frequency." The researchers expect to push the technique to 1 part in 10 billion in the near future, making the technique about 1000 times more accurate than any other, Chu said.
Realizing that winds on Earth could potentially have the same effect, Kobayashi alerted Kazunari Nawa, a seismologist at Nagoya University who was studying records from an extremely sensitive gravity meter
stationed at the South Pole.
This obviously depends on the accuracy of the instrument, the reading methods and, mainly, on the quality of the determination and stability of the coefficient of the gravity meter
They theorized that a previously unrecognized force -- acting over distances of tens to thousands of meters -- had altered the attraction between the gravity meter
and the rock around the shaft.
Roger Bilham and his colleagues at the University of Colorado in Boulder will measure distances between horizontal points with the satellite-based Global Positioning System (GPS), and vertical elevations with an xtremely accurate gravity meter
. By comparing sets of measurements collected several years apart in the same locations, the researchers hope to gauge how quickly the land surface warps under tectonic stresses as India and Asia collide at a rate of about 5 centimeters a year.
The Air Force team had originally set out to detect the controversial fifth force by making precise measurements with a gravity meter
on and around a 2,000-foot television tower in Garner, N.C.
Ducarme of the Observetoire Royal de Belgique in Brussels published the results of their studies on changes in the local gravity field as measured by a superconducting gravimeter, which is at least 100 times more sensitive than a conventional gravity meter
. Melchior and Ducarme reported that following two large, deep earthquakes in 1983 and 1984, they detected slow waves in the local gravity field that had periods of 13 to 15 hours.
For example, they will "season" or stretch the wire line, which will hold the gravity meter
, many times before the experiment and will calibrate its absolute length in an Idaho silver mine both before and after their experiment.