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Monitoring land surface phenology in near real time by using PhenoMap

Informally Refereed

Abstract

Monitoring vegetation phenology is important for managers at several scales. Across decades, changes in the timing, pattern, and duration of significant life cycle events for plant groups can foreshadow shifts in species assemblages that can affect ecosystem services. In the shorter term, managers need phenological information to time activities such as grazing, ecological restoration plantings, biocontrol of pests, seed collection, and wildlife monitoring. However, tools to deliver timely seasonal development have been limited either spatially (data from a single tower or weather station, or on a single species, or both) or temporally (annually, quarterly, or monthly summaries). We developed another option called PhenoMap. This is a weekly assessment of land surface “greenness” across the continental United States that employs the Normalized Differential Vegetation Index (NDVI) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. Here we present the PhenoMap Web map and its validation by using 54 in situ PhenoCam camera sites representing six vegetation structure types and 31 different ecoregions. We found that PhenoMap effectively tracks phenology on grasslands, shrublands, deciduous broadleaf and mixed forests. Results for evergreen needleleaf sites were poor owing to the low green-up signal relative to the total amount of foliage detected by NDVI. Issues of extent and field of view were critical when assessing remotely sensed data with in situ oblique camera imagery.

Keywords

Phenology, vegetation production, NDVI, MODIS, PhenoMap, PhenoCam.

Citation

Schrader-Patton, Charlie; Grulke, Nancy E.; Ott, Jacqueline. 2020. Monitoring land surface phenology in near real time by using PhenoMap. Gen. Tech. Rep. PNW-GTR-982. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 98 p.
Citations
https://www.fs.usda.gov/research/treesearch/59432