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 |