Fusing MODIS with Landsat 8 data to downscale weekly normalized difference vegetation index estimates for central Great Basin rangelands, USA

Abstract

Data fused from distinct but complementary satellite sensors mitigate tradeoffs that researchers make when selecting between spatial and temporal resolutions of remotely sensed data. We integrated data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Terra satellite and the Operational Land Imager sensor aboard the Landsat 8 satellite into four regression-tree models and applied those data to a mapping application. This application produced downscaled maps that utilize the 30-m spatial resolution of Landsat in conjunction with daily acquisitions of MODIS normalized difference vegetation index (NDVI) that are composited and temporally smoothed. We produced four weekly, atmospherically corrected, and nearly cloud-free, downscaled 30-m synthetic MODIS NDVI predictions (maps) built from these models. Model results were strong with R² values ranging from 0.74 to 0.85. The correlation coefficients (r ≥ 0.89) were strong for all predictions when compared to corresponding original MODIS NDVI data. Downscaled products incorporated into independently developed sagebrush ecosystem models yielded mixed results. The visual quality of the downscaled 30-m synthetic MODIS NDVI predictions were remarkable when compared to the original 250-m MODIS NDVI. These 30-m maps improve knowledge of dynamic rangeland seasonal processes in the central Great Basin, United States, and provide land managers improved resource maps.

Keywords:

• downscale
• Landsat
• MODIS NDVI
• rangeland
• resolution

Acknowledgments

Thanks are due to many people for the development of this manuscript. The authors thank Jennifer Rover, Thomas Adamson, and the anonymous journal reviewers for constructive recommendations that made this manuscript better; the US Geological Survey sagebrush ecosystem team for sharing data and for testing the downscaled models’ mapping outputs by incorporating them into the sagebrush ecosystem model; and Kurtis Nelson for providing the Landsat 8 composited tiles.

Disclosure statement

The authors declare no conflicting interests. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US government.

Additional information

Funding

The US Bureau of Land Management and the U.S. Geological Survey Land Change Science program funded this work.