Snow cover dataset

I’m trying to use data from the GlobSnow fractional snow cover product included in the data cube. I’m encountering an issue where where there are no values for January at latitudes > 65oN (see image below). From February onwards data are then available up to 77.5oN and finally, the full product extent is reached (85oN) in April. This seems to persist even between different years.

I can’t tell if this is an issue with the underlying dataset itself (e.g. lots of cloud so no observations), or to do with ingestion in the cube. If anyone can shed an light on this this would be greatly appreciated!

From what I understand from skimming the description of the algorithm, this is based on a passive optical sensor and this can’t detect anything in the polar night.