Subsetting Tools for MODIS Land Products: Time-series data for field sites
Robert
B.
Cook, Environmental Sciences Division, Oak Ridge National Laboratory, cookrb@ornl.gov
(Presenting)
Stephen
M.
Margle, Environmental Sciences Division, Oak Ridge National Laboratory, marglesm@ornl.gov
Suresh
Kumar
Santhana Vannan, Environmental Sciences Division, Oak Ridge National Laboratory, santhanavans@ornl.gov
Susan
K.
Holladay, Environmental Sciences Division, Oak Ridge National Laboratory, holladaysk@ornl.gov
Tammy
W.
Beaty, Environmental Sciences Division, Oak Ridge National Laboratory, beatytw@ornl.gov
Satellite imagery provides a means of extending our understanding of vegetation dynamics from site-specific studies to larger regions. However, preparing time-series of remote sensing products for small areas is computationally challenging.
The ORNL Distributed Active Archive Center (DAAC) has developed two tools to facilitate the use of Moderate Resolution Imaging Spectroradiometer (MODIS) data to examine vegetation dynamics. The first tool provides subsets in ASCII (7 x 7 km) and GeoTIFF (31 x 11 km) formats of 20 MODIS products for 280 sites worldwide. The tool provides an ASCII file of the time series pixel values for the selected product along with quality information. The data can also be viewed in a time-series plot or as an individual composite period. In addition, the GeoTIFF files can be viewed in a WebGIS system, in Sinusoidal projection. For more information see http://daac.ornl.gov/MODIS/modis.html .
The second tool creates subsets in ASCII format for user-selected areas in North America from 1 x 1 km up to 201 x 201 km area and for a user-selected time period during the MODIS record. The tool takes up to 60 minutes to complete the processing for most products, and it will send an email message containing the URL where the output can be accessed. The tool provides time series plots of the measurement, an ASCII file of the time series pixel values for the selected product along with quality information, average and standard deviations for the area selected, and a file that can be imported directly into GIS software. In addition we provide a land cover grid (IGBP classification) of the area, along with an estimate of heterogeneity.For details, please see http://www.modis.ornl.gov/modis/NorthAmerica_Tool/index.cfm .
The ORNL DAAC will offer subsets of MODIS Collection 5 data using both tools, with the second tool expanding to global coverage.