Author Topic: Vue rain count in high wind  (Read 3761 times)

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Offline 4wd

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Vue rain count in high wind
« on: April 05, 2010, 10:03:21 AM »
Had an illustration of the predicted slight shortcoming caused by all-in-one unit this morning as we had about 5mm of rain through stand alone Oregon gauge but the Vue on a pole only counted 3.6mm.
They have generally been neck and neck so I'm putting this own to the wind averaging 20mph with gusts to 28mph.
The Oregon gauge is relatively sheltered at ground level, but with rain driving near horizontal at times clearly the Vue could not catch almost 25% of it.
This must be a fairly predictable calculation which some clever software could compensate for!

Offline dalecoy

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Re: Vue rain count in high wind
« Reply #1 on: April 05, 2010, 10:28:52 AM »

This must be a fairly predictable calculation which some clever software could compensate for!


...not until we have a way to measure the size of the raindrops, as well as the vertical components of wind direction and speed.

Offline killwilly

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Re: Vue rain count in high wind
« Reply #2 on: April 06, 2010, 01:40:08 AM »
Had an illustration of the predicted slight shortcoming caused by all-in-one unit this morning as we had about 5mm of rain through stand alone Oregon gauge but the Vue on a pole only counted 3.6mm.
They have generally been neck and neck so I'm putting this own to the wind averaging 20mph with gusts to 28mph.
The Oregon gauge is relatively sheltered at ground level, but with rain driving near horizontal at times clearly the Vue could not catch almost 25% of it.
This must be a fairly predictable calculation which some clever software could compensate for!


I too have noticed this with my Vue during high winds, probably something we shall have to live with.

Alan.
Alan

Offline Weather Display

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Re: Vue rain count in high wind
« Reply #3 on: April 06, 2010, 04:47:35 AM »
this problem I posted about as a potential problem when I first saw the Vue when it first was revealed by Davis ...
Brian
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Offline johnd

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Re: Vue rain count in high wind
« Reply #4 on: April 06, 2010, 05:52:08 AM »
There's nothing unexpected in this though. Any rain gauge that's not mounted on the ground will tend to under-record rainfall when there's any significant wind blowing. And the higher it's mounted - and hence the stronger any wind gusts - the more it will under-record. Up to 20-25% shortfall, depending on height, is to be expected.

The Vue is not dissimilar to other all-in-one sensor assemblies such as the Weatherhawk. And its all-in-one design doesn't mean that it can't do a good job for certain groups of user, a couple of examples being:

1. There are many buyers of weather stations who use them in specific applications and not necessarily for all-round weather monitoring. In other words, not all users have an equal interest in every weather parameter.

Sailing clubs are primarily interested in wind speed and direction, with rainfall amounts being of low priority. So they would tend to use a Vue and mount it high up.

OTOH, farmers are interested in rainfall but to the extent that they are interested in wind data, may need speed readings at say 6-8 feet height where it will help manage spraying operations. So mounting a Vue lower down eg on a Davis tripod would fit in with their needs better.

2. Some users are interested in learning the principles of weather measurement but know that they have to accept some compromise in sensor siting. Schools are a common case here. Hardly any school (in the UK at least) is comfortable mounting sensors at ground level because of the risk of vandalism. Nearly always some area like a flat roof is called into use as a mounting point because access can be controlled. It's recognised that the readings will be compromised to a degree, but there's often no other choice. So a Vue would do no worse than any other station in this scenario.

So there is a substantial market for Vue-type sensor assemblies even though it's obviously not the ideal choice for users interested in accurate, all-round weather measurement.
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Offline utahweatherbear

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Re: Vue rain count in high wind
« Reply #5 on: August 30, 2010, 01:39:36 PM »
have had several storms, seems to run about 10-15% low on rainfall compared to my 4" gauge and WS-3610 tipping bucket. main difference...vue is roof mounted and gets more wind, other 2 are not on roof and pretty much wind protected most of the time. had a fairly light wind rain event overnight, 4" gauge had .22, 3610 recorded .20, and the vue reported .19 ... have yet to use the console rain correction... instead am using the rain tweak in WUHU, which is nice because you can tweak the rain after the fact, and it will correct and send updated rainfall to the servers. the vue correction only applies as the rain falls, not for past rain. anyway, not a huge issue IMHO, and since it is likely due to wind more than an inaccurate rain gauge, will continue to tweak as needed. if I can get a reliable correction over the passage of time, probably should just go ahead and use the console correction. anyone else having rainfall issues?

Offline William Grimsley

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Re: Vue rain count in high wind
« Reply #6 on: April 29, 2012, 09:30:21 AM »
Hello There, I have a Vantage Vue Weather Station which is about 5 or 6 meters high and a Oregon Gauge witch is on the ground. One Day it rained and my vue said 19mm and my oregon 20mm. Why is my vue underrecording? Plus it was quite windy during the day!

Will
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Offline SlowModem

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Re: Vue rain count in high wind
« Reply #7 on: April 29, 2012, 10:59:12 AM »
Hello There, I have a Vantage Vue Weather Station which is about 5 or 6 meters high and a Oregon Gauge witch is on the ground. One Day it rained and my vue said 19mm and my oregon 20mm. Why is my vue underrecording? Plus it was quite windy during the day!

Will

Wind and height both make a difference in readings.
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Offline christophercawley

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Re: Vue rain count in high wind
« Reply #8 on: May 02, 2012, 02:09:03 PM »
I am a member of CoCoRaHS, and the CoCo gauge and Vue gauge are usually within 0.01 of each other.  The CoCo gauge is about 4 feet up, the Vue is about 10 feet up.  During Irene last year, of course my CoCo outstripped the Vue, as we had a persistent 40-60 mph wind over the course of about 5 hours.  In fact I'm not so sure my CoCo had a truly "accurate" reading....