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V005 MYD17A2 Changes (abbreviated Points of Interest below)
V005 MYD17A2 Science Data Sets (specifications for data layers)
V005 MYD17A2 Quality Information

Users are advised to consider improved products at ntsg.umt.edu

MYD17A2 Gross Primary Productivity	MYD17A2 Net Photosynthesis
Data Characteristics Area: ~10 degrees x 10 degrees lat/long Dimensions: 1200 x 1200 rows/columns File Size: ~1 MB compressed Resolution: 1 kilometer Projection: Sinusoidal Data Format: HDF-EOS Science Data Sets (SDS HDF Layers): 3	These images are examples of the GPP and PSN values reported in the MYD17A2 product with data acquired June 10-17, 2005 in tile h08v05 over the western US. Values are low in the desert Southwest, increasing towards the more vegetated coastline.

V005 Change Points of Interest:

• Data Set Name change to emphasize Gross Primary Production over Net Photosynthesis
• Modification of parameters in Biome Property Look-Up Table (BPLUT) to agree with GPP derived from measurements at eddy flux towers and synthesized NPP
• Spatially non-linear interpolation of coarse resolution meteorological data into 1-km MODIS pixel level, instead of nearest neighbor sampling, to increase the accuracy of meteorological data input at pixel level
• Reduced file volume by using internal compression

V005 Limitations:

• BPLUT may be subject to change if LAI/FPAR or meteorological inputs have large changes
• 8-day data are subject to incorrect estimates caused by contaminated LAI/FPAR , and require special processing. Users are encouraged to consider the "clean" products available from ntsg.umt.edu .

Product Description
The MODerate-resolution Imaging Spectroradiometer (MODIS) Gross Primary Productivity (GPP) product (MYD17A2) is a cumulative composite of GPP values based on the radiation use efficiency concept that may be used as inputs to data models for calculating terrestrial energy, carbon, water cycle processes, and biogeochemistry of vegetation. MYD17A2 is an 8-day composite at 1-kilometer spatial resolution provided as a gridded level-4 product in the Sinusoidal projection.

Version-5 MODIS/Aqua GPP products are validated through the LAI/FPAR product (MYD15A2) to Validated Stage 1, meaning that accuracy has been estimated using a small number of independent measurements obtained from selected locations and time periods and ground-truth/field program efforts. Although there may be later improved versions, these data are ready for use in scientific publications.

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Retrieve the MYD17A2.5 MODIS product through the LP DAAC Data Pool
Via Search Tool: http://e4eil01u.ecs.nasa.gov:22000/WebAccess/drill?attrib=esdt&esdt=MYD17A2.5&group=MOLA
Via FTP Directory: ftp://e4ftl01u.ecs.nasa.gov/MOLA/MYD17A2.005/

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(http://edcimswww.cr.usgs.gov/pub/imswelcome/)

EOS Data Gateway Search Tips

Data Center:	LPDAAC
Sensor:	MODIS
Dataset:	MODIS/Aqua Gross Primary Productivity 8-Day L4 Global 1km SIN Grid V005
Spatial:	HORIZONTALTILENUMBER Max/Min VERTICALTILENUMBER Max/Min
Geographic Extent:	Type Lat/Long Range or Draw on Map
Temporal Extent:	2002-07-04 to present

Product Information

Product Description http://modis-land.gsfc.nasa.gov/npp.htm

User Guide http://www.ntsg.umt.edu/modis/MOD17UsersGuide.pdf

Algorithm Theoretical Basis Document (ATBD) http://modis.gsfc.nasa.gov/data/atbd/atbd_mod16.pdf

MODIS Standard Data Products Catalog http://modis.gsfc.nasa.gov/data/dataprod/index.php

EOS Data Products Handbook Volume 1 (2000) http://eospso.gsfc.nasa.gov/eos_homepage/for_scientists/data_products/vol1.php

Contact Information

LP DAAC User Services U.S. Geological Survey (USGS) Earth Resources Observation and Science Center (EROS) 47914 252nd Street Sioux Falls, SD 57198-0001
Phone:	605-594-6116
Toll Free:	866-573-3222
	866-LPE-DAAC
Fax:	605-594-6963
Email:	LPDAAC@eos.nasa.gov
Web:	http://LPDAAC.usgs.gov

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