Data Set Characteristics
Area = ~ 10° x 10° lat/long
Image Dimensions = 2 (4800x4800 row/column)
Average File Size = 507 MB
Resolution = 250 meters
Projection = Sinusoidal
Data Format = HDF-EOS
Science Data Sets (SDSs) = 11
Product Description
The MODerate-resolution Imaging Spectroradiometer (MODIS) Vegetation Indices products use, as input, MODIS Aqua surface reflectances (MYD09) corrected for molecular scattering, ozone absorption, and aerosols. Two vegetation index (VI) algorithms are produced globally for land. One is the standard normalized difference vegetation index (NDVI), which is referred to as the "continuity index" to the existing NOAA-AVHRR derived NDVI. The other is an 'enhanced' vegetation index (EVI) with improved sensitivity into high biomass regions and improved vegetation monitoring through a de-coupling of the canopy background signal and a reduction in atmosphere influences. The two VIs compliment each other in global vegetation studies and improve upon the extraction of canopy biophysical parameters. A new compositing scheme that reduces angular, sun-target-sensor variations with an option to use BRDF models is utilized. The gridded vegetation indices include quality assurance (QA) flags with statistical data that indicate the quality of the VI product and input data.
The MYD13Q1 images shown are samples of the MODIS/Aqua Vegetation Indices 16-Day L3 Global 250m SIN Grid. The NDVI and EVI have been pseudo-colored to represent the biomass health of the western United States using tile h08v05 from July 12, 2002. Due to their simplicity, ease of application, and widespread familiarity, vegetation indices have a wide range of usage within the user community. Some of the more common applications may include global biogeochemical and hydrologic modeling, agricultural monitoring and forecasting, land-use planning, land cover characterization, and land cover change detection.
NOTE: These products are still experimental in nature upon their initial release. Investigations are underway to assess the scientific validity of these products.
Each VI product contains 11 parameters, listed below:
SDS
Units
Data Type-bit
Fill Value
Valid Range
Divide by SCALE FACTOR
250m 16 days NDVI
NDVI
16-bit signed integer
-3000
-2000 - 10000
10000
250m 16 days EVI
EVI
16-bit signed integer
-3000
-2000 - 10000
10000
*250m 16 days NDVI Quality
bit field
16-bit unsigned integer
65535
0 - 65535
na
*250m 16 days EVI Quality
bit field
16-bit unsigned integer
65535
0 - 65535
na
250m 16 days red reflectance MODIS Band # 1, 620 - 670 nm
reflectance
16-bit signed integer
-1000
0 - 10000
10000
250m 16 days NIR reflectance MODIS Band # 2, 841- 876 nm
reflectance
16-bit signed integer
-1000
0 - 10000
10000
250m 16 days blue reflectance ^MODIS Band # 3, 459 - 479 nm
reflectance
16-bit signed integer
-1000
0 - 10000
10000
250m 16 days MIR reflectance ^MODIS Band # 7, 2105- 2155 nm
reflectance
16-bit signed integer
-1000
0 - 10000
10000
250m 16 days average view zenith angle View zenith of the chosen pixel
degree
16-bit signed integer
-10000
-9000 - 9000
100
250m 16 days average sun zenith angle Sun zenith of the chosen pixel
degree
16-bit signed integer
-10000
-9000 - 9000
100
250m 16 days average relative azimuth angle Relative Azimuth of the chosen pixel
degree
16-bit signed integer
-4000
-3600 - 3600
10
^Blue and MIR (Bands 3 and 7) are actually resampled to 250m from the original respective 500m bands
LP DAAC User Services
U.S. Geological Survey (USGS)
Earth Resources Observation and Science Center (EROS)
47914 252nd Street
Sioux Falls, SD 57198-0001