Not sure if this is the correct forum for this, but anyways...
My VP2 anemometer is mounted on the east gable of a long, steep, WNW-ESE oriented roof, at only about 3.5' above peak roof level. W, WNW and NW winds are usually recorded on my anemometer as being quite variable, and gusts are often "missed". Wind data from these directions is generally quite poor. I live near the bottom of a steep valley with high tree density, so I used to think that being in the valley or having trees around the yard had more to do with my poor wind obs from certain directions than the roof, but the winds that blow through the yard and hit the house just don't seem to match those on the anemometer when the wind is from W, WNW, or NW. Often, gusts will cause the anemometer to spin around 360 degrees and show lessened wind speeds- for ex; a gust estimated around ~25 mph from the WNW in the trees will be variable and peak at around 15 mph on the anemometer.
So, I was wondering- is my roof the culprit of my poor wind obs from those important directions of W, WNW, and NW
? If it's not the roof, it would have to be the terrain (see topo map/anemometer pic below to compare). Winds from perpendicular directions to the roof, such as SW and NE (the front of the house faces due SW, the back due NE) are very consistant with regards to direction and speed, and often seem to give a very "true" representation of wind. The same is true for N winds, which don't have to contend with the spine of the roof. E, SE, and S winds seem to be okay, but almost never occur here, so I don't have a good sampling of data from those directions.
Here is the anemometer in a picture I took facing towards the SW. The roofline goes on to the right of the picture for quite a long distance- it is a very long, steep roof.
Here is a topo map with my location represented by the red dot in the right-center:
I won't be able to change my setup on this house, I'm afraid, but I may be moving in the not-too-distant future. If you guys think the roof is the problem here, I'll make sure to get the anemometer on the potential new house at least ~7' above the roofline.