This paper was presented at the Art, Science and Applications of Reflectance Spectroscopy Symposium sponsored by ASD Inc. and IEEE GRSS, February 23-25, 2010 in Boulder, Colorado.

Proceedings of ASD and IEEE GRS; Art, Science and Applications of Reflectance Spectroscopy Symposium, Vol. II, 15pp, Boulder, CO, www.asdi.com.

Authors: Arnold G. Dekker¹, Janet M. Anstee¹, Elizabeth J. Botha¹, Young Je Park¹, Paul Daniel¹, Tim J.M. Malthus¹, Stuart R. Phinn², Ian A. Leiper²
Affiliations:
(1) CSIRO Land & Water, Canberra, NSW  Australia
(2) Centre for Remote Sensing and Spatial Information Science, School of Geography, Planning and Environmental Management, The University of Queensland, Brisbane  Australia

Abstract

Significant advances have been made in remote sensing methods that support accurate and repeatable methods for mapping the composition, structure and condition of submerged aquatic habitats. At the forefront of developments in substratum mapping are algorithms which have been developed using spectral reflectance libraries of the substratum and benthic cover types. The spectral libraries are used either to constrain the approach taken or as an input parameterisation tool for mapping specific features. As a water column lies between the substratum, benthos and the air-water interface, any complete shallow aquatic water habitat spectral library also needs to include the apparent optical properties of the water column. Substratum mapping projects using these spectral data sets in a range of environments around the world demonstrate the necessity of appropriate spectral reflectance measurements.

In order to assess the estuarine, coastal, coral reef and marine habitat extent from airborne or satellite imagery parameterized by in situ spectral reflectance libraries, a set of standards for the capture, storage and use of these spectral signature files needs to be established. The shallow water environment creates unique challenges for systematic uniformly made under water or above water spectral reflectance measurements due to variations in solar angle, atmospheric condition, sea surface condition, currents, water column optical properties, etc.. Globally useful spectral field data will need to include complete metadata (what is measured, how, by what instrument, where and by whom and under what conditions).

This paper explains our spectral reflectance data collection methods and demonstrates how these can be applied successfully to map seagrass, macro-algae and coral reef environments. This study reviews the literature, compares results of various benthic habitat related spectral measurement approaches and recommends a systematic way forward.