Assessing the Moment Distance Metric as an Indicator of Spring Green-up Using MODIS NBAR Data and Lilac/Honeysuckle Bloom Dates
Abstract
We present a new metric called the Moment Distance (MD) that characterizes the shape of the reflectance curve in simple geometric operations. We compare 97 lilac and honeysuckle phenophase sequences from 2008 with land surface phenologies described by NDVI and MD time series based on MODIS NBAR 0.05 degree data. The MD metric takes advantage of the seven bands available in the NBAR product and at each composite calculates the moment distances among the bands. Comparison between the NDVI and the MD reveals that MD can provide crisper identification of the timing of phenophase sequences. The disparity in spatial scale between the 0.05 degree MODIS data and the point observations is a source of potential error. However, if clonal plants are to be useful in sentinel networks, then the inference domain of the observations must extend beyond the immediate environmental neighborhood of the ground observations. Results also suggest that the onset of senescence may be clearly delimited due to the inclusion of both the visible and shortwave infrared bands in the MD calculation; however, we do not have ground observations of senescence at this point. We will be pursuing this analysis further with finer spatial resolution datasets.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.B43C0399S
- Keywords:
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- 0430 BIOGEOSCIENCES / Computational methods and data processing;
- 0480 BIOGEOSCIENCES / Remote sensing