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Earth Trends Modeler (ETM)


Over the past 30 years there has been a veritable explosion of earth observation image time series such as monthly global sea surface temperature and vegetation index imagery. The Earth Trends Modeler (ETM) is a ground-breaking tool for the analysis of such data. With ETM, one can map long term trends, trends in seasonality (such as vegetation phenology) and search for recurrent patterns over time, over space or over space-time. Additionally, ETMís pattern seeking tools are particularly adept at looking for coupled patterns across multiple image series. For example, the patterns associated with ENSO (the El Nino Southern Oscillation) in oceanic, tropospheric and stratospheric temperatures are related, but different in space and lagged in time. ETM has the tools to discover such patterns and much more, including:

 Earth Trends Modeler


The Earth Trends Modeler (ETM) is specially designed for the analysis of earth observation image time series. In this illustration, a series of 348 global images of monthly NDVI vegetation index data were analyzed for the presence of trends in seasonality. Pixels colored gray (which are almost absent) indicate a stable seasonality. All other colors represent trends. ETM provides an interactive legend (lower left) to interpret the trend for any area chosen either by a vector boundary or a circular area of interest (the area in eastern Alabama and western Georgia in this case). The green curve represents the beginning of the series (1982) while the red one represents the end (2010). The X axis is time and the Y axis is NDVI. As can be seen, NDVI has generally increased with a growing bimodality. Spring is coming a bit earlier (11 days) and the autumn is extending longer (almost 30 days).