SAC 2024 EN_ Satellite channel for fog detection

SAC 2024 EN_ Satellite channel for fog detection

от Serge Hitayezu SENYANA -
Количество ответов: 8

The best-believed satellite channel for fog detection at night is any ranging between 3.9 and 10.7 micrometers


В ответ на Serge Hitayezu SENYANA

Re: SAC 2024 EN_ Satellite channel for fog detection

от leonard katwale -
Thanks a lot also i want to know which channel is better to distuingish low clouds and fog?
В ответ на leonard katwale

Re: SAC 2024 EN_ Satellite channel for fog detection

от Vesa Nietosvaara -
Hi, Leonard.

Distinguishing low clouds from fog is challenging by standard satellite imagery alone. Satellite sees the top of the cloud, not the base of the cloud.

There are some novel methods to tackle this problem - they require information on cloud microphysical properties to establish whether the cloud touches the ground. These methods go beyond the scope of this course.
 
Investigating satellite images with overlaid surface visibility observations (if there are any!) is a traditional way to assess the situation, too.

Good way to distinguish fog from elevated stratus is also to use animation and see how the edges of the cloud follow the terrain features, they can give some indication of the cloud base.

Also I use sometimes advanced products such as Cloud Type at NWC SAF viewer to see more about low clouds and very low clouds. This can help a bit in assessing the situation. I attach an image of this morning from East Africa of NWC SAF Cloud Type product at 0830 UTC.


В ответ на Vesa Nietosvaara

Re: SAC 2024 EN_ Satellite channel for fog detection

от Francis Jagero -
Thank you for the channels (3.9 to 10.7) as the best channels for fog identification.
In the imagery is it pink or cyan in appearance? I am getting confused about the colours.
Francis Jagero