Subject: Wind gradient and height of Tempest
The wind speed is most important to me so I installed my Sky 12m above ground on top of my house. But the surrounding houses slow the wind causing a large wind gradient. Here are comparisons of 3 Skys during the same reasonably constant wind. What I see very clearly is the difference in the average and maximum speeds at the different heights. This first Sky is located about 1m (3ft) above ground in a tiny clearing to measure rainfall surrounded by trees. (Its direction is not facing North, thats another story if you need to know why)
This next Sky is mounted in a tree which seems to be a very solid mount with the wind coming from the direction this photo is looking towards. Its height above ground is effectively reduced by the flatish house up wind.
This Sky is high above the house about 12m above ground:
And as you can see I am also on top of a rounded hill which effectively increases the height and compresses the wind gradient. When I say ‘compresses the wind gradient’ I mean that the wind flowing over a rounded hill will have a compression layer where the wind can be stronger than the wind near the ground and stronger than the higher wind above which is not being compressed.
For more info see this solved topic:
https://community.tempest.earth/t/wind-speed-seems-to-be-reading-low-solved-in-firmware-v103/1510/17
cheers Ian
