| Level 3 Binning Operator |
|
The spatial data-day approach has been introduced in the frame of the GlobColour project. It is used to spatially and
temporally filter observed pixels during the L3 creation process. This shall avoid mixing pixels with observation
times that are too far apart.
This type of filtering increases the duration of a day to include data from the previous and next day. This
extension
allows to select pixels with the lowest temporal discrepancy for the same spatial area.
More detailed information can be found in the
GlobColour Product User Guide in section 3.4 'The GlobColour data-day approach'
As parametrisation in SNAP the minDataHour needs to be specified. This value is sensor dependent. In the GlobColour PUG this value is named the crossing nodal time (CNT). This CNT value is equal to the equator crossing time (ECT) which is more commonly used.
Values for some sensors are provided in the table below. For other sensors the ECT value can be looked up from the sensor specification pages.
| Instrument | MODIS (Aqua) VIIRS (NPP) |
SeaWiFS (SeaStar) | MERIS (Envisat) OLCI (Sentinel-3) |
|---|---|---|---|
| CNT/ECT | 13.5 | 12.0 | 10.0 |