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RainFall OFFSET

Posted: Mon 09 Jan 2012 9:16 am
by CrasHBoneS
Hi all, I have a PCE-FWS20 produced by Fine Offset Electronics Co. LTD (Honk Kong), also known as:
Fine Offset WH1080/WH1081,
Watson W-8681/WX-2008,
National Geographic: 265 NE,
Elecsa 6975/6976,
Ambient Weather WS-1080/WS-1090/WS-2080,
Tycon TP1080WC

I have a question:
almost every day the station measures 0.3 mm rainfall, probably caused by "moisture" in the rain gauge
example:
Today
Rainfall max. 0,3 mm at 08.06
Yesterday
Rainfall max. 0,3 mm at 08.08

This "apparent" rainfall, If I don't correct the value with Cumulus, produces wrong trends, wrong "day count with rain", wrong total rainfall, etc etc

My question is:
-Coul be added a new "offset parameter" related to rainfall (like pressure, temp. hum.) so I can set to -0.3 mm?
The actual rainfall multiplier is not suitable for my problem.
-There is a workaround?
Thank You very much.

Re: RainFall OFFSET

Posted: Mon 09 Jan 2012 9:36 am
by steve
You can change the threshold that Cumulus uses to record a 'rain day', by stopping it and editing Cumulus.ini. Add a line to the [Station] section

RainDayThreshold=0.4

Cumulus will then only record a 'rain day' when two tips of the gauge have occurred.

It is possible that in future I may add an offset so the amount doesn't get included in the total for that day.

Edit: You may need to make that

RainDayThreshold=0,4

I can't remember whether Windows uses regional settings for decimals in ini files - it probably does, just use whatever the existing settings use.

Re: RainFall OFFSET

Posted: Mon 09 Jan 2012 9:53 am
by CrasHBoneS
steve wrote:You can change the threshold that Cumulus uses to record a 'rain day', by stopping it and editing Cumulus.ini. Add a line to the [Station] section

RainDayThreshold=0.4
......................
...................
I just read it in the Wiki;
steve wrote: It is possible that in future I may add an offset so the amount doesn't get included in the total for that day.
I'll be waiting for next release to solve this "problem"
Thank You

Re: RainFall OFFSET

Posted: Mon 09 Jan 2012 11:02 pm
by Spider-Vice
Well I don't really see this as a problem, as, theorically, dew is precipitation and I think it should be counted ;)

Re: RainFall OFFSET

Posted: Tue 10 Jan 2012 8:13 am
by geoffp
This 0.3mm may also be the wind vibrating the pole to which the instruments are attached I had this problem until I moved the rain collector to a firm base. :bash:

Re: RainFall OFFSET

Posted: Wed 11 Jan 2012 9:56 am
by CrasHBoneS
Spider-Vice wrote:Well I don't really see this as a problem, as, theorically, dew is precipitation and I think it should be counted ;)
Thank You for Your suggestion
The 4 weather station (1 LaCrosse, 3 Davis www.bellarameteo.it) near to mine (http://meteobellaria.altervista.org) do not misure anything

I think:
1)"cold air" is "trapped" inside rain gauge and the air over the gauge is heated by the sun rising.
2)"cold air" "trapped" inside rain gauge cause the moisture on the air heatred by the sun rising
Image
geoffp wrote:This 0.3mm may also be the wind vibrating the pole to which the instruments are attached I had this problem until I moved the rain collector to a firm base. :bash:
The time the station register rain fall the wind speed is about 8 km/h, if the cause is the wind, I should register rainfall many times during the day but it is not my situation.

This is my rain gauge modded to avoid loss of rain due to low "wall" of the rain gauge
Image