Fog and Low Cloud

Contribution of Each Product

Choosing the most useful products for identifying fog and low cloud is very important during the day and overnight. RGB products have been specifically designed to address this need and should be used with confidence when diagnosing cloud types on satellite imagery.

Question 1

Which products were most useful for identifying low-level stratus and stratocumulus? Select all that apply.

All of the choices are correct.

All of these products are very useful. The IR and night microphysics are useful overnight while the visible, day natural colour, and day microphysics products are good after sunrise.

Please make a selection.

Question 2

Which products were most useful for identifying fog?

The correct answers are C and E.

These are best because they clearly show what’s fog and what’s low cloud. The night microphysics RGB does this overnight, while the day natural colours does this after sunrise.

Please make a selection.

Question 3

In general, what information does each product provide that helps you identify fog and low cloud? Select all that apply.

The correct answers are A, D, E, H, and I.

During the day, visible imagery highlights cloud properties such as its texture and thickness, which help to distinguish the various cloud types from one another.

At night, the night microphysical RGB is very good at highlighting areas with fog, and depicts low cloud in a different colour from fog. The day microphysical RGB does the same thing during daylight hours.

The day natural colour RGB is very helpful in distinguishing between thin and thick water cloud. It also provides clues about cloud type based on texture, shadowing, and thickness. This RGB is very useful for seeing where there’s fog/stratus or low cloud after sunrise during the early morning.

Although the IR channels are always available for viewing, it can be difficult to separate warm low-level cloud from the ground, even during the day (depending on the season). Using the cloud top and land surface temperatures, you should be able to slowly identify cloud and land separately.

Please make a selection.