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Detecting Trend and Seasonal Changes in Bathymetry Derived from HICO Imagery: A Case Study of Shark Bay, Western AustraliaThe Hyperspectral Imager for the Coastal Ocean (HICO) aboard the International Space Station has offered for the first time a dedicated space-borne hyperspectral sensor specifically designed for remote sensing of the coastal environment. However, several processing steps are required to convert calibrated top-of-atmosphere radiances to the desired geophysical parameter(s). These steps add various amounts of uncertainty that can cumulatively render the geophysical parameter imprecise and potentially unusable if the objective is to analyze trends and/or seasonal variability. This research presented here has focused on: (1) atmospheric correction of HICO imagery; (2) retrieval of bathymetry using an improved implementation of a shallow water inversion algorithm; (3) propagation of uncertainty due to environmental noise through the bathymetry retrieval process; (4) issues relating to consistent geo-location of HICO imagery necessary for time series analysis, and; (5) tide height corrections of the retrieved bathymetric dataset. The underlying question of whether a temporal change in depth is detectable above uncertainty is also addressed. To this end, nine HICO images spanning November 2011 to August 2012, over the Shark Bay World Heritage Area, Western Australia, were examined. The results presented indicate that precision of the bathymetric retrievals is dependent on the shallow water inversion algorithm used. Within this study, an average of 70% of pixels for the entire HICO-derived bathymetry dataset achieved a relative uncertainty of less than +/-20%. A per-pixel t-test analysis between derived bathymetry images at successive timestamps revealed observable changes in depth to as low as 0.4 m. However, the present geolocation accuracy of HICO is relatively poor and needs further improvements before extensive time series analysis can be performed.
Document ID
20150021876
Document Type
Reprint (Version printed in journal)
Authors
Garcia, Rodrigo A. (Curtin Univ. of Technology Perth, Australia)
Fearns, Peter R. C. S. (Curtin Univ. of Technology Perth, Australia)
Mckinna, Lachlan I. W. (Curtin Univ. of Technology Perth, Australia)
Date Acquired
November 25, 2015
Publication Date
March 30, 2014
Publication Information
Publication: Remote Sensing of Environment
Volume: 147
Subject Category
Oceanography
Earth Resources and Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN22023
Funding Number(s)
CONTRACT_GRANT: NNG06CC03B
Distribution Limits
Public
Copyright
Other
Keywords
coastal marine
seasonal change
bathymetry