Topic: Positioning and height about roof line for anemometer?

[ggsteve]

Replacing my LaCrosse WS with a Davis VP+ w/FA.  I live among tall pines on all four sides, so I know my wind data will be suspect at best, but I want it to be as accurate as possible.  The anemometer I have now hardly moves in it's current location (left of picture).  I plan on mounting the Davis anemometer above the gable at one end of the roof (N or S).  Or I could mount it near the chimney on the center of the roof.  Questions:

Which location would be most accurate?

How high above the roof peak should it be for reasonably accurate readings?

I plan on mounting the solar and UV sensors on the anemometer pole. 

Any thoughts for positioning the rain gauge and temp sensor array would be welcome too.

[geofb13]

Is the relative direction of the wind that does make it to your house coming from a specific direction normally like from the back of the house to the front, or from a side to side or diagonally?  You want to measure it where it is as far from obstructions as possible which you know and for the most part I'd say you'd want it on your roof or in a location that is the most centralized from the tree walls. That might not be possible but at least it's something to get started thinking about.

For height above the roof peak I'd say as much as you can get without putting yourself in a situation where the anemometer isn't accessible. But you need to place it as high as you can to remove any effect from the roof or your home.

As far as the rain gage, in a perfect world it would also be in the location as far from any effect from the house or trees as possible and on or in the ground. But that's rarely if ever possible for these type of stations or locations. Temperature sensor is again best placed as far away from anything as possible. With that said and not being able to tell if the picture is being taken from right next to a tree line that grass patch in the driveway is actually probably a good location for both the temp and rain gage.

Sorry for all of the extra nonsense but I hope that this will be able to help you some.

[ggsteve]

Thank you!  That information is helpful.  The prevailing wind would normally come from the left in the picture (North).  Thunderstorms typically come from the WSW, the front of the house in the picture.  It sounds like your saying higher is better above the roof.  I think 10 feet above the peak will be easy, 20 feet may be possible.  Don't know about more than that.  I considered the circle in the driveway, issues with this location:

I would have to be able to mount a tall pole for the anemometer too.

That is actually an oriental lily garden mowed down for winter, but I don't think the lilies would have much effect.

I throw a lot of snow on this island in the winter, often over head high, that could definitely affect temp readings.

No way to get power to a rain gauge heater.

May not pass the WAF (Wife Approval Factor).  However, this will be a problem with any site.

EDIT: How about this:  If I mount the Rain/temp array on the railing of the front porch (over the edge of the front lawn), I can run cables up to the roof and anchor the solar, UV and anemometer pole to the chimney?

[geofb13]

Understandable and I caught myself thinking about the snow issue after I posted haha.  For the anemometer, if you're prevailing wind and thunderstorms are coming from those directions I'd move it to the front left facing corner of the house because then you'd catch both occurrences without as much problems. Unless you can move it to the peak or above for that matter but I feel like those would fall heavily in WAF category! It would give you the longest amount of fetch though for unimpeded wind.

I'll have to rethink for the rain gage and temp sensor siting though.

[George Richardson]

ggsteve

First, download this: http://www.smlweather.com/downloads/CWOP_Guide.pdf

Read and study. Remember, you will NOT be able to do what it suggests, but it is a goal. From what I can see of your house, I would place the anemometer at the paek of the south facing garage wall, run the 40' cable down the roof line to the front corner and then down to a #6332 mounted at a convenient height for maintenance on the south facing wall. Then mount the ISS whereever the Boss allows. That is very forgiving, only needing to be on a 5' pole away from everything. Oh, height above roofline. I think I have seen that 6' is sufficient.

FWIW

George

[ggsteve]

ggsteve

First, download this: http://www.smlweather.com/downloads/CWOP_Guide.pdf

Read and study.
George

Do I have to remember all the words to "It's Raining Men" by the Weathergirls?

[George Richardson]

"Do I have to remember all the words to "It's Raining Men" by the Weathergirls?"

Only if you don't already know it 

[ggsteve]

Ok, it's time to fish or cut bait.  I have changed directions and a Rainwise Mk III should be here by the end of the week instead of the planned Davis 6163.  This greatly simplifies installation since the unit is all-in-one, but offers new challenges regarding the best location to site it.  Here is a new picture of the house:



The prevailing wind still comes from the NNE (left).  Tree walls all around.  My two planned sites are on a Rainwise Monopole:

1) attached to the right peak of the garage-side, good for wind and the solar panel, but it puts the temp sensor above the center of the roof.

2) attached to the far right peak of the house, ok for temp sensor since it will be a little bit away from the roof, but above a south facing wall.  This location would not be as good for wind as it would be about 15-20' from trees blocking a Southerly wind.

Please offer your thoughts as to the best positioning.  I'd like to mount it this week so I can have my contractor mount a cleat where I will put the monopole.

The North peak on the left end of the house is out because it is too close to the trees and I don't have a ladder that will reach up there for maintenance.  I want to stay away from the chimney because exhaust gases could affect temp readings.  Anything on the ground and I will get almost no wind readings at all, unless I figure out how to mount it in the middle of my one acre swamp.

[Scalphunter]

Your minature mountain range going to have a lot of burbles with all those peaks and valleys on that roof line. Not knowing where prevailing winds are from I go with out in the middle of your 1 acre.

John

[ggsteve]

Your minature mountain range going to have a lot of burbles with all those peaks and valleys on that roof line. Not knowing where prevailing winds are from I go with out in the middle of your 1 acre.

John

Thanks, but the middle of the swamp was a joke (sort of).  I don't know how I would anchor a post in the mud, I could only service it by kayak in the summer and in the winter I would worry about it disappearing as it would be closer to a main road than the house.  Plus, I think the distance would be taxing the unit's range.  I think it's going to have to go on the roof, just not sure which peak.