Cumulus Support

Hi,
I have just added a bigger funnel to my W-8681 rain gauge, and now I need to know what the multiplier should be.
My funnel has a diameter of 18cm, so I have worked out the area is 283cm squared. How would I go about working out the new multiplier?

Thanks,
Mark

The area of the original rain gauge is 55 sq. cm. so the correction is 55 divided by your new funnel area.

Diameter = 18cm Radius = 9cm r2 = 81 - multiply this by Pi (3.142) gives 254.5 sq. cm. So the ratio is 4.627 (254.5/55) and the correction factor (multiplier) is the inverse of this = 0.216. Actually 55/254.5 ie. old/new catchment area.

Thanks alot for that Gina. I never would have worked that out.

Mark19 wrote:Thanks alot for that Gina. I never would have worked that out.

Maths was one of my best subjects at school