anemometer correction factor

[dtidmore]

In the migration from AW hardware using their ObserverIP box to my Meteobridge over to my new Davis VP2 Plus with a Belfryboy USB logger feeding the MB, I LOST the ability to effect ANY corrections to my anemometer (ObserverIP gave me that ability while I used AW hardware). MB does allow me to correct the wind vane but I am finding that to be pretty much dead on. The Davis Display station does NOT give me a way to enter a correction for the anemometer so I am stuck with raw wind speeds from the Davis hardware going out from the MB. I am aware that Davis units are typically super accurate, but most likely due to siting, my station is running a few MPH low and I really would like a way to enter a correction factor. Not sure if the proper approach is a stretch correction like available on the MB for the barometer, or a simple value to be applied to the raw reading.

Is this something that might be considered in a future release of MB?

Thanks
David

[admin]

In general I am not a friend to tweak wind speed of less optimal seated wind sensors by a factor as we going a bit from measuring to guessing by doing so. But as you are not the first one demanding this I will put it on my todo list.

[dtidmore]

Thanks!
I alway use either the 7 or 14 day CWOP wind analysis to determine how much, if any, correction as I know all too well that chasing short term only introduces errors. My approach is to make a correction that is 1/2 of the indicated error and then track it for a week or more. Thanks again for putting this on your to-do list for a future release.

david

[Mattk]

David, So how do you know if the CWOP wind is actually valid and how far away from our physical site would this analysis be based on? To me it appears you are making an adjustment based on data that is not relevant to your location and not indicative of the actual wind at your site.

[dtidmore]

There is a ASOS station (airport) about 10 miles away, several PWSs within 5 miles and a large # of PWSs within 15 miles. We are outside of the city so winds blow pretty much unperturbed and the area is relatively flat. The errors I am seeing are not dramatic and if you use the rule of thumb of 30% underreporting of wind speed for sitings below the recommended 10meters (mine is at 5 meters), my raw wind speed readings are within reason.

I know that a many people have cast shade on the CWOP error graphs but that data comes directly from NOAA via MADIS and not something that Phillip dreamed up. If there was a lot of variation in the geography of my area, I might be less inclined to put faith into the NOAA/MADIS quality check graphs, but my area is about as homogenous as it gets. There is maybe a 100ft elevation delta over a 20 mile radius and as I said, NO heat island, nor tall buildings to mess with the wind.

david

[Mattk]

I think you are making a lot of assumptions with a lot of irrelevant data myself.

[dtidmore]

As you stated "you think". Everyone is entitled to their opinion of MADIS data and to act, or not, accordingly.