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Comparison of TOPEX/Jason-1 and ERS-2 tropospheric xenith wet delay measurements with estimates from offshore GPS data

Lookup NU author(s): Professor Stuart Edwards, Professor Philip Moore, Professor Matt King


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The accuracy of estimated atmospheric path delay due to water vapour derived from GPS data is often assessed by comparing GPS estimates with those derived from other sensors including radiosondes and ground based Microwave Radiometers (MRs). However, this is not always a convenient or cost effective approach. In this work we adopt an alternative approach utilising data from the MRs present on the altimetric satellites ERS-2, ENVISAT, TOPEX and JASON-1, which pass almost directly overhead a number of continuously recording GPS receivers located on oil platforms in the northern North Sea. This coincidence removes the main obstacle preventing such studes over land; namely background surface heat emissions which contaminate the MR tropospheric delay measurement. We use the GIPSY/OASIS II GPS processing software with a tuned tropospheric delay estimation strategy to process daily solutions and estimate tropospheric Zenith Wet Delay (ZWD) at 5 minute intervals as a random-walk parameter. PreciseZWD estimates, at the time of satallite overpass of the oil platforms, are derived at the repeat period of the altimetric satellites. Early results from 40 ERS-2 overpasses spanning a four year period show good agreement between GPS and MR, with a mean fit of <10mm.

Publication metadata

Author(s): Edwards SJ, Moore P, King MA

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: 2003 AGU Fall Meeting

Year of Conference: 2003

Pages: Abstract G51B-0028

Publisher: Eos Transactions: American Geophysical Union