VIP15: Vegetation Index and Phenology (VIP) Vegetation Indices 15Days Global 0.05Deg CMG V004
VIP15. NDVI. First composite period in the month of August, beginning August 1 and ending August 15, 2014. South America.
The NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) Vegetation Index and Phenology (VIP) global datasets were created using Advanced Very High Resolution Radiometer (AVHRR) N07, N09, N11, and N14 datasets (1981 - 1999) and Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra MOD09 surface reflectance data (2000 - 2014). The VIP Vegetation Index (VI) product was developed to provide consistent measurements of the Normalized Difference Vegetation Index (NDVI) and modified Enhanced Vegetation Index (EVI2) spanning more than 30 years of data from multiple sensors. The EVI2 is a backward extension of AVHRR. Vegetation indices such as NDVI and EVI2 are useful for assessing the biophysical properties of the land surface, and are used to characterize vegetation phenology. Phenology tracks the seasonal life cycle of vegetation, and provides information on the biotic response to environmental changes.
The VIP15 VI data product is provided twice monthly at 0.05 degree (5600 meters (m)) spatial resolution in geographic (Lat/Lon) grid format. The data are stored in Hierarchical Data Format-Earth Observing System (HDF-EOS) file format. The VIP15 VI product contains 12 Science Datasets (SDS) which include the calculated VIs (NDVI and EVI2) as well as quality assurance/pixel reliability, the input Visible/Near Infrared (VNIR) surface reflectance data, and viewing geometry. The Blue and Middle Infrared (MIR) surface reflectance data are only available for the MODIS era (2000 - 2014). Gaps in the daily product are filled using long term mean VI records derived from the more than 30 year time series of data, and are indicated as gap-filled in the Pixel Reliability SDS.
The VIP15 dataset includes two composites per month. The first composite is generated from day 1 to 15, and the second composite includes the remaining days of the month. This dataset consists of 24 files per year.
Citation
PI Name: Kamel Didan
DOI: 10.5067/MEaSUREs/VIP/VIP15.004
Collection
| Characteristic | Description |
|---|---|
| Temporal Granularity | Twice a month |
| Temporal Extent | 1981 - 2014 |
| Spatial Extent | Global |
| File Size | |
| Coordinate System | Geographic Latitude and Longitude |
| Datum | WGS84 |
| File Format | HDF-EOS |
| Geographic Dimensions | Global |
Granule
| Characteristic | Description |
|---|---|
| Number of Science Dataset (SDS) Layers | 12 |
| Columns/Rows | 7200 x 3600 |
| Pixel Size | 5600 m |
Data Layer Characteristics
| SDS Name | Description | Units | Data Type | Fill Value | Valid Range | Scale Factor |
|---|---|---|---|---|---|---|
| CMG 0.05 Deg 15Days NDVI |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days NDVI |
NDVI | Int16 |
-15000 |
-10000 to 10000 |
10000 |
| CMG 0.05 Deg 15Days EVI2 |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days EVI2 |
EVI2 | Int16 |
-15000 |
-10000 to 10000 |
10000 |
| CMG 0.05 Deg 15Days VI Quality |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days VI Quality |
Bits | UInt16 |
65535 |
0,65534 |
N/A |
| CMG 0.05 Deg 15Days Pixel Reliability |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days Pixel Reliability |
Rank | Int8 |
-4 |
-4 to 11 |
1 |
| CMG 0.05 Deg 15Days Composite Day of the Year |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days Composite Day of the Year |
Day of the Year | Int16 |
-1 |
1 to 366 |
1 |
| CMG 0.05 Deg 15Days RED reflectance |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days Red Reflectance |
Reflectance | Int16 |
-28672 |
-100 to 16000 |
10000 |
| CMG 0.05 Deg 15Days NIR reflectance |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days Near Infrared Reflectance |
Reflectance | Int16 |
-28672 |
-100 to 16000 |
10000 |
| CMG 0.05 Deg 15Days BLUE reflectance* |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days Blue Reflectance |
Reflectance | Int16 |
-28672 |
-100 to 16000 |
10000 |
| CMG 0.05 Deg 15Days MIR reflectance* |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days Middle Infrared Reflectance |
Reflectance | Int16 |
-28672 |
-100 to 16000 |
10000 |
| CMG 0.05 Deg 15Days Solar Zenith Angle |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days Solar Zenith Angle |
Degree | Int16 |
0 |
0 to 18000 |
100 |
| CMG 0.05 Deg 15Days View Zenith Angle |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days View Zenith Angle |
Degree | Int16 |
0 |
0 to 18000 |
100 |
| CMG 0.05 Deg 15Days Relative Azimuth Angle** |
Climate Modeling Grid (CMG) 0.05 Degree resolution 15 Days Relative Azimuth Angle |
Degree | Int16 |
0 |
-18000 to 18000 |
100 |
*BLUE and MIR SDS are only available for MODIS (2000-2014). The Middle Infrared reflectance data used for AVHRR was generated using a MODIS based model that correlates the Red and NIR with the MIR band. The model is then applied to AVHRR Red/NIR to generate false MIR reflectance data useful for image generation.
From the NASA MEaSUREs VIP ATBD/User Guide: While only a single Fill_Value is listed,in practice there are multiple Fill Values to separate between the different reasons of missing data. For example, the Pixel Reliability has 4 different value for Fill depending of where the pixel is located (-1 over land, -2 over high latitude, -3 over Antarctica, and -4 over Water/Ocean).
Product Quality
See the NASA MEaSUREs VIP ATBD/User Guide Table 6.
Known Issues
**The Relative Azimuth Angle (RAA) from the MOIS era, which is simply passed along from the MODIS data, was computed based on an absolute value of all the finer resolution pixels, resulting in only positive values and minor usefulness. For AVHRR data relative Azimuth Angle, which is also passed along in our processing from Input provided by the LTDR group, has an issue with the valid range. The actual range is [-360° to 360°] and it should have been [-180° to 180°]. To correct the range users can convert the value using the following simple routine (http://ltdr.nascom.nasa.gov/ltdr/docs/AVHRR_LTDR_V4_Document.pdf):
SinRelativeAz=sin(RAA)
CosRelativeAz=cos(RAA)
Correct-RAA = atan2(SinRelativeAz,CosRelativeAz)
E-Learning
There are no E-Learning items for this Product.
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