The Many Hazards of Trend Evaluation

Thursday, 18 December 2014: 8:00 AM
Geoffrey M Henebry1, Kirsten de Beurs2, Xiaoyang Zhang1, John S Kimball3 and Chris Small4, (1)South Dakota State University, Brookings, SD, United States, (2)University of Oklahoma, Geography and Environmental Sustainability, Norman, OK, United States, (3)The University of Montana, Flathead Lake Biological Station, Polson, MT, United States, (4)Columbia University of New York, Lamont Doherty Earth Observatory, Palisades, NY, United States
Given the awareness in the scientific community of global scale drivers such as population growth, globalization, and climatic variation and change, many studies seek to identify temporal patterns in data that may be plausibly related to one or more aspect of global change. Here we explore two questions: “What constitutes a trend in a time series?” and “How can a trend be misinterpreted?” There are manifold hazards—both methodological and psychological—in detecting a trend, quantifying its magnitude, assessing its significance, identifying probable causes, and evaluating the implications of the trend. These hazards can combine to elevate the risk of misinterpreting the trend. In contrast, evaluation of multiple trends within a biogeophysical framework can attenuate the risk of misinterpretation. We review and illustrate these hazards and demonstrate the efficacy of an approach using multiple indicators detecting significant trends (MIDST) applied to time series of remote sensing data products.