Vegetation Index and Phenology (VIP) daily NDVI data from the VIP01 product across the globe, Aug 30, 2014.
View full-size imageThe 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 VIP01 VI data product is a daily global file at 0.05 degree (5600 meter (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 VIP01 VI product contains 11 Science Datasets (SDS), which includes the calculated VIs (NDVI and EVI2) as well as information on the 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. A low resolution browse image showing NDVI as a color map is also available.
| Characteristic | Description |
|---|---|
| Collection | MEaSUREs VIP |
| DOI | 10.5067/MEaSUREs/VIP/VIP01.004 |
| File Size | ~90 MB |
| Temporal Resolution | Daily |
| Temporal Extent | 1981-01-01 to 2014-12-31 |
| Spatial Extent | Global |
| Coordinate System | Geographic Latitude and Longitude |
| Datum | World Geodetic System (WGS84) |
| File Format | HDF-EOS |
| Geographic Dimensions | Global |
| Characteristic | Description |
|---|---|
| Number of Science Dataset (SDS) Layers | 11 |
| Columns/Rows | 7200 x 3600 |
| Pixel Size | 5600 m |
| SDS Name | Description | Units | Data Type | Fill Value | No Data Value | Valid Range | Scale Factor |
|---|---|---|---|---|---|---|---|
| CMG 0.05 Deg Daily NDVI | Climate Modeling Grid (CMG) 0.05 Degrees resolution Daily NDVI | NDVI | 16-bit signed integer | -12000,-13000,-14000,-15000 | N/A | -10000 to 10000 | 0.0001 |
| CMG 0.05 Deg Daily EVI2 | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily Modified EVI2 | EVI2 | 16-bit signed integer | -12000,-13000,-14000,-15000 | N/A | -10000 to 10000 | 0.0001 |
| CMG 0.05 Deg Daily VI Quality | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily VI Quality | Bit Field | 16-bit unsigned integer | 65535 | N/A | 0 to 65534 | N/A |
| CMG 0.05 Deg Daily Pixel Reliability¹ | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily Pixel Reliability | Rank | 8-bit signed integer | -4 to -1 | N/A | 0 to 11 | N/A |
| CMG 0.05 Deg Daily RED reflectance | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily Red Reflectance (Band 1) | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| CMG 0.05 Deg Daily NIR reflectance | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily NIR (Band 2) | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| CMG 0.05 Deg Daily BLUE reflectance² | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily Blue Reflectance (Band 3) | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| CMG 0.05 Deg Daily MIR reflectance² | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily Middle Infrared Reflectance (Band 7) | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| CMG 0.05 Deg Daily Solar Zenith Angle | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily Solar Zenith Angle | Degree | 16-bit signed integer | 0 | N/A | 0 to 18000 | 0.01 |
| CMG 0.05 Deg Daily View Zenith Angle | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily View Zenith Angle | Degree | 16-bit signed integer | 0 | N/A | 0 to 18000 | 0.01 |
| CMG 0.05 Deg Daily Relative Azimuth Angle³ | Climate Modeling Grid (CMG) 0.05 Degree resolution Daily Relative Azimuth Angle | Degree | 16-bit signed integer | 0 | N/A | -18000 to 18000 | 0.01 |
¹Fill/No Data Value and Valid Range are listed in the Pixel Reliability table.
²BLUE 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.
³The Relative Azimuth Angle is passed along from the input data.
| Value | Description |
|---|---|
| -12000 | No Data - High Latitude |
| -13000 | No Data |
| -14000 | Antarctica |
| -15000 | Water |
| Value | Description |
|---|---|
| 0 | Excellent |
| 1 | Good |
| 2 | Acceptable |
| 3 | Marginal |
| 4 | Pass |
| 5 | Questionable |
| 6 | Poor |
| 7 | Cloud Shadow |
| 8 | Snow |
| 9 | Cloud |
| 10 | Estimated |
| 11 | Long Term Average |
| -1 | No Data |
| -2 | No Data - High Latitude |
| -3 | Antarctica |
| -4 | Water |
See the Algorithm Theoretical Basis Document (ATBD) and User Guide Section 4.5 for Quality Assurance information.
The Relative Azimuth Angle (RAA) for the input MODIS data is computed based on absolute values of the finer resolution pixels resulting in positive values and has minor usefulness.
The RAA for the input AVHRR data contain values in the -360° to 360° range. The routine to restrict the values in the -180° to 180° range was accidentally missed and can be corrected using the following routine described in Section 4.2.1 of the User Guide and Algorithm Theoretical Basis Document:
SinRelativeAz=sin(RAA)
CosRelativeAz=cos(RAA)
Correct-RAA = atan2(SinRelativeAz,CosRelativeAz)