Topic: Anemometer Settings - Differences / Purpose

[Mattk]

What is the understanding between the three (3) anemometer selection settings: Small / Large / Other (Vue) and especially in regard the difference between the Vue and the VP2 both of which would appear to be classed as a standard wind cup anemometer?

[johnd]

Isn't this just for the secondary corrections that are applied to raw wind speed readings. So:

1. Small: Essentially obsolete now - can't remember the last time I saw small wind cups;

2. Large: For the standard 6410 anemometer where the default LUT provides secondary speed corrections for wind coming from different directions relative to the body of the anemometer.

3. Vue/Other: Don't know for sure, but guessing that there are no secondary corrections applied at all. The Vue cups are up essentially clear of the mounting pole and the ISS body so speed should measure equally from all directions, at least in theory. 'Other' is presumably just a setting for compatible but non-Davis anemometers where the secondary corrections will depend on the specific anemometer and therefore unknown in the general case. Simplest answer here therefore is to apply no secondary corrections, ie as per Vue.

[Mattk]

Ok then so it's to do with obstructions like the (VP2) anemometer arm on the wind flow where as the Vue cups being on top are in clean air? An Ultrasonic anemometer then would imitate a Vue or Other setting?

[johnd]

Ok then so it's to do with obstructions like the (VP2) anemometer arm on the wind flow where as the Vue cups being on top are in clean air? An Ultrasonic anemometer then would imitate a Vue or Other setting?

Yep, that's what I would do. I think the different settings only make a slight difference, at least at moderate wind speeds. But might as well get it as accurate as possible.