rain ofset

Hi every one and body.

Every one know that wind influences greatly the accuracy of rain fall readings. More the wind less the rain fall.

Therefore, would it be possible to set an ofset :slight_smile: relative to the windspeed by determining an initial ratio.
Ex;

Wind == 10 Kts ==> ofset * 1.1
Wind == 20 Kts ==> ofset * 1.2

Why do I ask this… A bunch of visitors of my website that live in the same village as I are informing very often times that rainfall displayed on my site is way lower than their manual raincollector.

Maybe a good job for Brian.

You all have a great day.

-= Guy =-

How high off the ground do you have the raingauge mounted?

Typically it is not a good comparison to use a manual gauge that is not right next to your tipping gauge.
Rain can vary greatly from spot to spot.

Also, what type of manual rain gauge are your neighbors using?
If it’s not something like this: Rainguage

Then their readings could be suspect.

Not even sure how you could measure how much is lost the stronger the wind is

But like Looney2ns says, there are many factors involved, but, if there are numerous
peoples reporting higher then there is something a miss, for one thing, they must
have the same wind speeds as you so would be loosing similar amounts, whats it like
when there is little wind?

How is your bucket mounted, is it in a sheltered spot, is it high up?

Hi thanks looney2ns and Bashy for the fast answers.

To reply to you both:

My Davis rain bucket is located about 20inches from the webcam that you may see at: http://www.meteoturbie.fr/turbiecam.php

You see it is a slopy mountain side faced to dominant east winds that since the begining of this year went up several times to 100Km/h.
In these cases rain bucket looses quite a lot of the rain overflying it. To looney2ns, yes manual rainguages are similar to yours. At least mine, located in a wind protected area (same garden) and readings are quite different. I can unfortunately (for wireless reasons) install tha Davis station close to the manual gauge, further more UV & solar rads would be impaired.

I understand my suggestion may be weird but if not getting 100% accuracy, it would a least improve it. I will not here enter the wind factor impact discutions but they may be found as you know on the net and differences are quite impressive windwise.

So my suggestion of creating a rain ofset related to wind speed may not be so stupid and could be set after a few readings and making an average.

When winds at my location, are close to 60miles/h (100Km/h) readings go from simple to double, that is huge.

Have a good day guys.

-= Guy =-

Ah, Davis, you are not the 1st person i have heard with a Davis under reporting rain, i believe Brian has
about 30% under reading, so it may not be a wind issue after all???

@meteo: Sounds to me like it would be worth to try the new Aero Cone for the Davis. It is designed to perform better in windy conditions.

Hi niko,

Well I have confirmation that my concerns were not out of bounds.

Thanks so lot for the collector cone info. It will be ordered in the coming minutes.

We will see what happens after.

Kind regards.

-= Guy =-

It’s a well known issue with all types of precipitation gauge, especially when collecting snow.