|
| EDG Data Set Name |
Granule Shortname |
| MODIS/Aqua Vegetation Indices Monthly L3 Global 1km SIN Grid |
MYD13A3 |
| Version |
Acquisition Range |
Science Quality Status |
| V004 |
July 4 2002 (2002185) |
Provisional |
MODIS Level 3 Tile h08v05, July 12 2002
Data Set Characteristics
Area = ~ 10° x 10° lat/long
Image Dimensions = 2 (1200x1200 row/column)
Average File Size = 32 MB
Resolution = 1 km
Projection = Sinusoidal
Data Format = HDF-EOS
Science Data Sets (SDSs) = 11
Product Description
The MYD13A3 image shown is a sample of the MODIS Level 3 monthly composite of Vegetation Indices at 1km resolution that has been pseudo-colored. This product uses, as input, the 16 days MODIS Vegetation Index and composited surface reflectance (MYD13A2 product). All available 16 days MODIS VI products (a maximum of 3) that overlap the calendar month are used. A temporal averaging scheme is used to generate the monthly product. Each 16 day product is weighted by the number of actual days that overlap the month being processed. 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 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.
The compositing method used is a simple temporal averaging scheme adjusted for temporal overlap. The algorithm will produce the monthly surface reflectance first from the sixteen-day composite surface reflectance (red, NIR, blue and MIR) in the MYD13A2 product, then derives the VI (NDVI/EVI) products. No sixteen day VI data is used in this product, only the surface reflectance. A worst case scenario is used to generate the per-pixel quality information. The gridded vegetation indices will include quality assurance (QA) flags with statistical data that indicate the quality of the VI product and input data. Due to their simplicity, ease of application, and widespread familiarity, vegetation indices have a wide range of use 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 |
| 1km monthly NDVI |
NDVI |
16-bit signed integer |
-3000 |
-2000 - 10000 |
10000 |
| 1km monthly EVI |
EVI |
16-bit signed integer |
-3000 |
-2000 - 10000 |
10000 |
| *1km monthly NDVI Quality |
bit field |
16-bit unsigned integer |
65535 |
0 -v65535 |
na |
| *1km monthly EVI Quality |
bit field |
16-bit unsigned integer |
65535 |
0 -v65535 |
na |
1km monthly red reflectance
MODIS Band # 1, 620 - 670 nm |
reflectance |
16-bit signed integer |
-1000 |
0 - 10000 |
10000 |
1km monthly NIR reflectance
MODIS Band # 2, 841- 876 nm |
reflectance |
16-bit signed integer |
-1000 |
0 - 10000 |
10000 |
1km monthly blue reflectance
MODIS Band # 3, 459 - 479 nm |
reflectance |
16-bit signed integer |
-1000 |
0 - 10000 |
10000 |
1km monthly MIR reflectance
MODIS Band # 7, 2105-2155 nm |
reflectance |
16-bit signed integer |
-1000 |
0 - 10000 |
10000 |
1km monthly average view zenith angle
View zenith of the chosen pixel |
degree |
16-bit signed integer |
-10000 |
-9000 - 9000 |
100 |
1km monthly average sun zenith angle
Sun zenith of the chosen pixel |
degree |
16-bit signed integer |
-10000 |
-9000 - 9000 |
100 |
1km monthly average relative azimuth angle
Relative Azimuth of the chosen pixel |
degree |
16-bit signed integer |
-4000 |
-3600 - 3600 |
10 |
*Quality Control Bit Index
| Bit |
Description |
| 0-1 |
NDVI quality |
| |
00 NDVI produced, good quality; |
| |
01 NDVI produced, but check QA |
| |
10 produced but most likely cloudy pixel |
| |
11 pixel not produced due to other reasons than clouds |
| 2-5 |
VI usefulness four bit range 0= highest quality |
| |
13 no atmospheric correction performed |
| |
14 quality too low to be useful |
| |
15 not useful for any other reason |
| 6-7 |
aerosol quantity: |
| |
00 climatology |
| |
01 low |
| |
10 average |
| |
11 high |
| 8 |
1 yes adjacency correction performed |
| |
0 no adjacency correction performed |
| 9 |
1 yes atmosphere BRDF correction performed |
| |
0 no atmosphere BRDF correction performed |
| 10 |
1 yes mixed clouds |
| |
0 no mixed clouds |
| 11-12 |
land/water flag |
| |
00 ocean |
| |
01 coast |
| |
10 wetland |
| |
11 land |
| 13 |
1 yes possible snow/ice |
| |
0 no possible snow/ice |
| 14 |
1 yes possible shadow |
| |
0 no possible shadow |
| 15 |
composite method for NDVI |
| |
0 BRDF model based nadir equivalent VI |
| |
1 CVMVC (constraint view angle maximum value VI) |
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 Retrieve the MYD13A3v4 MODIS product through the LP DAAC Data Pool
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Via FTP Directory: ftp://e0dps01u.ecs.nasa.gov/MOLA/MYD13A3.004/
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EOS Data Gateway Search Tips
| Source: |
Aqua |
| Sensor: |
MODIS |
| Dataset: |
MODIS/Aqua Vegetation Indices Monthly L3 Global 1km SIN Grid |
| Spatial: |
HORIZONTALTILENUMBER Max/Min VERTICALTILENUMBER Max/Min |
| Geographic Extent: |
Type Lat/Long Range or Draw on Map |
| Temporal Extent: |
2002-07-04 to present (V004) |
Product Information
Contact Information
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