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Non-linear motions of Australian geodetic stations induced by non-tidal ocean loading and the passage of tropical cyclones


Memin, A and Watson, C and Haigh, ID and MacPherson, L and Tregoning, P, Non-linear motions of Australian geodetic stations induced by non-tidal ocean loading and the passage of tropical cyclones, Journal of Geodesy, 88, (10) pp. 927-940. ISSN 0949-7714 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 Springer-Verlag Berlin Heidelberg

DOI: doi:10.1007/s00190-014-0734-8


We investigate daily and sub-daily non-tidal oceanic and atmospheric loading (NTOAL) in the Australian region and put an upper bound on potential site motion examining the effects of tropical cyclone Yasi that crossed the Australian coast in January/February 2011. The dynamic nature of the ocean is important, particularly for northern Australia where the long-term scatter due to daily and sub-daily oceanic changes increases by 2055 % compared to that estimated using the inverted barometer (IB) assumption. Correcting the daily Global Positioning System (GPS) time series for NTOAL employing either a dynamic ocean model or the IB assumption leads to a reduction of up to 52 % in the weighted scatter of daily coordinate estimates. Differences between the approaches are obscured by seasonal variations in the GPS precision along the northern coast. Two compensating signals during the cyclone require modelling at high spatial and temporal resolution: uplift induced by the atmospheric depression, and subsidence induced by storm surge. The latter dominates (>135 %) the combined net effect that reaches a maximum of 14 mm, and 10 mm near the closest GPS site TOW2. Here, 96 % of the displacement is reached within 15 h due to the rapid transit of cyclones and the quasi-linear nature of the coastline. Consequently, estimating sub-daily NTOAL is necessary to properly account for such a signal that can be 3.5 times larger than its daily-averaged value. We were unable to detect the deformation signal in 2-hourly GPS processing and show that seasonal noise in the Austral summer dominates and precludes GPS detection of the cyclone-related subsidence.

Item Details

Item Type:Refereed Article
Keywords:non-tidal ocean loading, storm surge loading, global positioning system, Australia
Research Division:Earth Sciences
Research Group:Geophysics
Research Field:Geodesy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Memin, A (Mr Anthony Memin)
UTAS Author:Watson, C (Dr Christopher Watson)
ID Code:92731
Year Published:2014
Web of Science® Times Cited:4
Deposited By:Mathematics and Physics
Deposited On:2014-06-26
Last Modified:2017-11-01

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