Introduction: Crucial to the determination of a jurisdictional wetland is the definition of “growing season”. Satellite imagery is being utilized in other ecological applications, but is lagging in wetland growing season determination. Both cost and temporal limitations historically have restrained use of satellite imagery in assessing the start up of the growing season. Multiple commercial satellites are available that provide high resolution imagery, but the cost are prohibitive for most studies. The National Aeronautics and Space Administration (NASA) and the U.S. Geological Survey (USGS) jointly manage the Landsat and the Moderate-resolution Imaging Spectroradiometer (MODIS) satellite programs. Landsat Enhanced Thematic Mapper Plus images an area every sixteen (16) days. The rapid biological changes indicating the start up of the growing season must be captured more frequently to successfully use satellite imagery for such a time dependent event. In 1999 NASA launched the MODIS program with the Terra satellite and followed with the Aqua satellite in 2000. Terra’s orbit around the Earth is timed so that it passes from north to south across the equator in the morning. Aqua will pass south to north over the equator in the afternoon. This continual, comprehensive coverage allows MODIS to complete an electromagnetic picture of the globe every day. MODIS imagery is available on a daily basis, but the trade-off for the increased speed at which the satellites travel is a lower resolution image when compared to other satellite systems. Research utilizing MODIS for studying vegetation phenology is beginning to emerge, but there is a lack of validation through ground observation for these studies. (Figure 1 and Figure 2)
Malone, Karen; Williams, Hans Michael; Hung, I-Kuai; and Unger, Daniel, "Assessing the Efficacy of MODIS Satellite-derived Start of Growing Season for Jurisdictional Determination of East Texas Bottomland Hardwood Wetlands" (2010). Faculty Publications. Paper 7.
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