Reanalysis of Woody Encroachment of US Drylands with Finer Resolution MODIS LST
Abstract
USDA recently issued a Sustainable Agricultural Systems call of $10 million per grantee with a milestone of increasing agricultural production by 2% annually. However, globally, extensive water-limited agricultural systems, i.e., Drylands have exhibited a "greening effect" or an increasing trend in net primary productivity (NPP) since the early 1980's. This increase in productivity that exceeds the 2% per annum, includes US Drylands, has been monitored using time series of remotely sensed 1 and 8 -km pixel resolution NPP from the Advanced Very High Resolution Radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS). We found that reductions in the US livestock herd due to western droughts is a likely driver of this increase, but this may also be a function of woody encroachment at the national scale. We tested the encroachment hypothesis using MODIS's version 5, 1-km pixel resolution Land Surface Temperature (LST) product as a surrogate for woody plants and found decreasing trends in LST suggestive of woody encroachment. We present here a reanalysis of this study using version 6 an "improved for Drylands" MODIS LST product. We confirmed the decreasing trend in LST with the improved data set indicating that a driver of increased productivity for Drylands is woody encroachment.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B44A..14W
- Keywords:
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- 0480 Remote sensing;
- BIOGEOSCIENCESDE: 1640 Remote sensing;
- GLOBAL CHANGE