Climate variability and coral reef damage from satellite imagery

点击翻译按钮获取中文摘要

The ongoing research on climate change and variability of sea ice and coral damage from remote sensing focuses on two themes: 1/ Interactions between the polar sea ice and climate systems 2/ The impact of climate stress on tropical coral as evident from satellite based remote sensing. Work on topic one has been directed towards analysis of change and variability in the twenty-five year record of sea ice concentration for the Arctic seas derived from passive microwave imagery. Studies of the temporal signal in the polar sea ice by colleagues has been based upon linear temporal relationships for various seas. In some areas, there is some change through time, while there is no change in other areas. Recognizing that there is no a priori reason to assume a linear relationship for a natural system, we have been working on a procedure to determine non-linear temporal signals and relate them to atmospheric variables that may be candidates for explanation of the process forcing. To date, we have given several conference papers that have used wavelet analysis of the principal component fields of sea ice and 850 mb geopotential height to explore the technique and elicit feedback from my colleagues. Work on the coral reef stress (Topic two) has focused upon developing remote sensing procedures to assess the health of the coral reef from satellite data. In the last Discovery grant application we reported on ground-breaking techniques in underwater spectroscopy to determine whether we can distinguish healthy from damaged corals. We have also progressed on this problem using a novel approach based upon change detection. By applying Local Area Operator models, such as the Getis Statistic, on multi-date imagery we have illustrated that we can determine the change in the health of a coral reef through time by applying change detection procedures. The objective is to use satellite or airborne imagery to determine the effects of environmental stress on the reef in a quantitative manner that will allow assessment for management decisions.