Climate variability and coral reef damage from satellite imagery

正在进行的关于气候变化和海冰变异性以及遥感对珊瑚的损害的研究侧重于两个主题：1极地海冰与气候系统之间的相互作用2卫星遥感显示的气候压力对热带珊瑚的影响。关于专题一的工作是针对被动微波图像得出的北极海海冰密集度二十五年记录的变化和可变性进行分析。同事们对极地海冰的时间信号的研究是以各种海洋的线性时间关系为基础的。在某些领域，随着时间的推移有一些变化，而在其他领域则没有变化。认识到没有一个先验的理由来假设一个自然系统的线性关系，我们一直在努力的程序，以确定非线性的时间信号，并将它们与大气变量，可能是候选人的过程强迫的解释。到目前为止，我们已经给出了几个会议论文，使用小波分析的海冰和850毫巴的地球位势高度的主成分场，探索技术，并从我的同事们那里得到反馈。关于珊瑚礁压力的工作（专题二）侧重于开发遥感程序，以便根据卫星数据评估珊瑚礁的健康状况。在上一次的发现资助申请中，我们报告了水下光谱学的突破性技术，以确定我们是否可以区分健康的珊瑚和受损的珊瑚。我们也已经在这个问题上取得了进展，使用一种新的方法，基于变化检测。通过应用局部区域运营商模型，如Getis统计，对多日期的图像，我们已经说明了，我们可以通过应用变化检测程序来确定珊瑚礁的健康变化。其目的是利用卫星或航空图像，以定量的方式确定环境压力对珊瑚礁的影响，以便评估管理决策。

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.