The current health state of plants can be observed with satellites globally and gives very useful information about the regional stress level of plants. This is interesting for environmental and agricultural purposes. meteoblue presently offers the following vegetation observation data:
- Vegetation health (VHP)
|Title||Vegetation health products|
|Theme||NDVI, vegetation, vegetation health|
|Period of Time||1984 to present|
|Update timelag||< 2 months|
|Time-resolution||weekly values (52 values per year)|
|Spatial Type||Plate carrée grid (rectangular projection)|
|Spatial extend||180°E to 180°W / 55°S to 75°N|
|Spatial resolution||4 km, 0.05 degrees|
|Spatial reference system|
|Publisher||NOAA Climate Prediction Center|
|Date First Published||2012|
The Vegetation Health Products (VH) of NOAA consist of gridded weekly global vegetation indices: temperature condition index, vegetation condition index, vegetation health index, Normalized Difference Vegetation Index (NDVI) and brightness temperature (BT). The data is derived from AVHRR GAC orbital satellites for the global area between latitude 55°S to 75°N. The spatial resolution is 0.036° (about 4 km at equator). Noise is minimized by applying the time series smoothing technique and other correction algorithms. The dataset is updated weekly. There is an archive of this dataset for almost every week since 1984.
The VH are indices, which range from 0 to 100 characterizing changes in vegetation conditions from extremely poor (0) to excellent (100). The VH values below 40 are used for identifying vegetation stress, which is an indirect drought indicator. The VH is very useful for early drought detection, assessing drought area coverage, duration, and intensity, and for monitoring drought impacts on vegetation and agricultural crops. The NDVI and BT were filtered in order to eliminate high frequency noise. They were also adjusted for a non-uniformity of the land surface due to climate and ecosystem differences using multi-year NDVI and BT data.
Current dataset issues:
Due to a change of satellite, NDVI values from March 2018 until present are significantly higher than historic values. NOAA is working on the problem and will make calibrated values available later in 2018.