Why does NDVI appear to be generated for night-time data (when there are no valid visible channel data)?
This is also due to the presence of noise in the visible channel data at night. NDVI values are calculated whenever visible channel data are present, and as visible channels are present in the AATSR telemetry at all times, the NDVI is calculated for both day and night data. There is no trap for night-time data. However, at night, the visible channels are dominated by noise, making these NDVI values essentially meaningless. Users are therefore advised to disregard the values in the AATSR NDVI field at night.
Related Questions
- I have uploaded my data, but it is not visible using the iControlDB download software. Was there a problem with the upload?
- Why do pixel exception values and corresponding confidence flags appear to be set in some visible channel data at night?
- Why does NDVI appear to be generated for night-time data (when there are no valid visible channel data)?
