[wxqc] Improving Rain Gauge Response Time

[Evan Bookbinder]

Eleanor,

Yes, but the point being made is that due to surface tension on the side 
of gauge, that 0.01 "sticks to the gauge" rather than going down into 
the funnel. If it never rains enough to break the surface tension and 
force this rain into the gauge, it could theoretically evaporate without 
ever measuring.

Instead of Rain-X, I know there are a number of other dry based 
lubricants (silicone, etc..) that should theoretically perform the same 
task and bond to plastic, but I'm drawing a blank on product names.  
I've never thought of this problem before, but it's a valid point!

Evan



Eleanor Linkkila wrote:
> I assumed that it didn't start measuring the rain until it got up to 
> 0.01 which is where I believe my umbrella appears.  Will notice more 
> closely but thought that was the way it was supposed to operate. 
>  
> Eleanor, CW7448
>
> */Paul Grace <paulgrace at lookoutranch.com>/* wrote:
>
>     The bottle my RainX comes in is rotary- blown polyethylene, and my
>     rain guage appears to be styrene , maybe a UV-treated PVC?   Ra
>     in-X will damage headlight covers (Lexan, a polycarbonate) so I
>     think it's risky to use Rain-X on it, it would be likely to harden
>     and crack over time.  But they are easy to replace, so if it lasts
>     in the sun in San Diego next year, then maybe another email to the
>     group would be great!  (You'll need to refinish the RainX anyway)
>     -----Original Message-----
>     From: wxqc-bounces at lists.gladstonefamily.net [
>     mailto:wxqc-bounces at lists.gladstonefamily.net
>     <mailto:wxqc-bounces at lists.gladstonefamily.net> ] On Behalf Of
>     Victor Engel
>     Sent: Friday, March 09, 2007 19:28
>     To: dean at mevis.org; Discussion of weather data quality issues
>     Subject: Re: [wxqc] Improving Rain Gauge Response Time
>     Thanks for asking the question. I was wondering the very same
>     thing some time ago but haven't treated my gauge with Rain-X yet.
>     It reacts negatively with certain things (read the label), so I've
>     been nervous about trying it for that reason. Considering the
>     container it's in, though, I most likely have nothing to fear.
>     Nevertheless, I wanted to do more research before actually trying it.
>     By the way, what is your rain gauge made of? Rain-X, I believe, is
>     designed to bond to glass. Does it even bond to plastic?
>     On 3/9/07, dean at mevis.org <dean at mevis.org> wrote:
>     >
>     >
>     >
>     >
>     > I have noticed, and read others say that there is a delay between
>     when
>     > it actually starts raining and when your rain gage starts to
>     register
>     > some rain.  Apparently the issue is that the initial rain just
>     sits on
>     > the sides of the rain gauge until there is enough rain to break the
>     > surface tension of the water and let it flow down to the
>     tipping-bucket mechanism.
>     >
>     >
>     >
>     > There is a product out on the market called RainX available at Auto
>     > Parts stores.  It is used to keep your automobile windshield clear
>     > during the rain.  I have used it on my car and found that water
>     > immediately beads up and runs off of the windshield.  I don't
>     > understand the chemistry of this product, but it apparently works by
>     > making the water slide more easily off of your windshield.
>     >
>     >
>     >
>     > So it occurs to me that you can apply this product to your rain
>     gauge
>     > and it will make the rain slide right down into your tipping-bucket,
>     > and you will see rain registered sooner.
>     >
>     >
>     >
>     > I have applied this product to my rain gauge.  However, I live in
>     the
>     > San Diego area and it only rains here about 3 times a year, so I
>     have
>     > not been able to see if makes a difference yet.
>     >
>     >
>     >
>     > Does anybody have any experience using this product or a similar
>     > product on their rain gauge?  Does it make a difference?
>     >
>     >
>     >
>     > Is there anyone out there that lives in a rainy part of the country
>     > that can give this a try and see if it makes a difference?
>     >
>     >
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>
>
> Eleanor Linkkila
> Hampton, CT 06247
>  
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