Weather Stations - Measuring Cloud Heights

[.Evan.]

Hey team,

 

Just wondering if anyone knows how the automatic weather stations (such as the one here at the Ballarat Aerodrome) measure the cloud conditions?

 

Is it a kind of upwards radar or sonar-type system?

 

It seems to have been quite accurate during my training, but today it is reporting 0vercast 2800' AMSL, yet VFR pilots are climbing and cruising at 3500'. What might cause that?

 

Thanks in advance,

 

Evan

 

 

[Ultralights]

usually a laser beam pointed straight up, so if there is just 1 cloud in the way, it will report cloud at that height.