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Short_description: MODIS 500m Level 3 Surface Reflectance product.

Data Policy:

These data products are being distributed free of charge.  Recipients have a
responsibility to acknowledge the University of New Hampshire, EOS-WEBSTER
Earth Science Information Partner (ESIP) as the data source.


Data Summary:

This dataset represents spatial aggregates of the MODIS/Terra Surface
Reflectance 8-Day L3 Global 500m SIN Grid (MOD09A1), as provided by the EROS
Data Center (EDC).

The University of New Hampshire's (UNH) Earth Science Information Partner
(ESIP), EOS-WEBSTER (http://eos-webster.sr.unh.edu), has created this MODIS
surface reflectance aggregate product from MOD09A1 8-day 500m surface
reflectance tiles. MOD09A1 data are provided every 8 days as a gridded
level-3 product in the Sinusoidal projection.  UNH has aggregated multiple
tiles to create a large-region surface reflectance product, which can be
spatially subset within the EOS-WEBSTER Search & Retrieve data ordering tool.
Our system has also reprojected these data from the original Sinusoidal
projection at 500 meters to Geographic, with a pixel resolution of 15 arc
seconds using the nearest neighbor algorithm.

The aggregate products contain all the layers from the original input
products plus an additional layer created by EOS-WEBSTER, which provides a
lookup code to map each pixel in the aggregate back to its original input tile.

These aggregate products allow the users of EOS-WEBSTER to subset MODIS 8-day
surface reflectance data across tile boundaries and to customize the spatial
region of interest using an online GUI interface.  EOS-WEBSTER has broken the
original 12 layers in the input tiles into 2 logical holdings so that a user
may order either of the band sets (see below).  For instance, the user may
only wish to order the 7 reflectance bands and not all the other supporting
data which are provided with the original data.  This significantly cuts down
on the data volume.

Version 5 input products were used to create these output files.

This MODIS surface reflectance product may be used to generate land-related
products or used as input to global and regional climate models and surface
energy balance models.  These data also may be used for land cover
characterization.


Data Attributes:
Temporal Resolution = 8-day composite
Projection = Geographic
Latitude Resolution = 0.004166667 degrees
Longitude Resolution = 0.004166667 degrees

500m Surface Reflectance Bands 1-7 
	Units: Reflectance
	Bit Type: 16-bit signed integer
	Fill Value: -16164
	Valid Range: -100 - 16000
	Scale Factor: 0.0001
500m Reflectance Band Quality
	Units: Bit Field
	Bit Type: 32-bit unsigned integer
	Fill Value: 1106247679
        Valid Range: 0 - 4294966531
	Scale Factor: NA
Solar Zenith Angle
	Units: Degree
	Bit Type: 16-bit signed integer
	Fill Value: 0
	Valid Range: 0 - 18000
	Scale Factor: 0.01
View Zenith Angle
	Units: Degree
        Bit Type: 16-bit signed integer
        Fill Value: 0
        Valid Range: 0 - 18000
        Scale Factor: 0.01
Relative Azimuth Angle
	Units: Degree
        Bit Type: 16-bit signed integer
        Fill Value: 0
        Valid Range: 0 - 18000
        Scale Factor: 0.01
500m State Flags
	Units: Bit Field
        Bit Type: 16-bit unsigned integer
        Fill Value: 16223
        Valid Range: 0 - 57343
        Scale Factor: NA
Day of Year
	Units: Julian Day
	Bit Type: 16-bit unsigned integer
	Fill Value: 16223
	Valid Range: 1-366
	Scale Factor NA
Input Tile Code
	Units: Tile id
	Bit Type: 8-bit unsigned integer
	Fill Value: 0
	Valid Range: 0 - 18
	Scale Factor: NA

Data are available for the  Continental US, 48.5 N to 24.5 N latitude and
125 W to 66.5 W longitude.

MODIS data are originally stored as 10 x 10 degree tiles. The tile coordinate
system starts at (0,0) (horizontal tile number, vertical tile number) in the
upper left corner of the globe and proceeds rightward (horizontal) and
downward (vertical). The tile in the bottom left corner is (35, 17).  These
products were made by aggregating the following tiles into single, regional
coverages:

Vertical tiles 4 - 6
Horizontal tiles 8 - 13

Some input tiles within this range do not exist for certain MODIS products.
In these cases EOS-WEBSTER uses a fill value.

For more information about the MODIS tile system:
http://modis-250m.nascom.nasa.gov/developers/is_tiles/is_grid.html

Band Sets Available:
	Surface Reflectance b1-b7:
		500m Surface Reflectance Band 1 (620-670 nm)
		500m Surface Reflectance Band 2 (841-876 nm)
		500m Surface Reflectance Band 3 (459-479 nm)
		500m Surface Reflectance Band 4 (545-565 nm)
		500m Surface Reflectance Band 5 (1230-1250 nm)
		500m Surface Reflectance Band 6 (1628-1652 nm)
		500m Surface Reflectance Band 7 (2105-2155 nm)
	Surface Reflectance supplemental:
		500m Reflectance Band Quality
		Solar Zenith Angle
		View Zenith Angle
		Relative Azimuth Angle
		500m State Flags
		Day of Year
		Input Tile Code

Browse Image Information:
	Geographic Projection
	image spatial subset corners (lat/lon):
	UL:  49.25 -125.00 
	UR:  49.25 -66.50 
	LL:  24.25 -125.00  
	LR:  24.25 -66.50

References:

MOD09A1 Product Description:
MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid V005
http://edcdaac.usgs.gov/modis/mod09a1v5.asp
 
MODIS Home Page
http://modis.gsfc.nasa.gov/

EOS-WEBSTER_URL:
http://eos-webster.sr.unh.edu

EOS-WEBSTER_Contact_Info:
     EOS-WEBSTER User Support
     Complex Systems Research Center
     Morse Hall
     8 College Road
     University of New Hampshire
     Durham, NH 03824
     Phone: 1-877-589-4909 (toll free)
     Fax: 603-862-0188
     E-mail: support@eos-webster.sr.unh.edu

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