Author Topic: WeatherCat calculation of rainfall data  (Read 72 times)

nicechristmasjumper

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WeatherCat calculation of rainfall data
« on: December 31, 2020, 11:46:33 am »
Hello,

I’d like some help with WeatherCat and the way it collects rain statistics. I have been using WeatherCat for nearly 8 years now collecting data from a Davis Vantage Vue weather station.

I want to do some additional analysis on daily rain data and have exported the data using the WeatherCat tools option “Data Export”.

Here’s an example of the issue. Take the year 2020 (to and including the 27 December).

I use Data Export and select “Export Hourly Data” and “This Year” (i.e. 2020).
I add up everything in the column “Precipitation Total (This Hour)”.
I get the total 818mm.

I use Data Export and select “Export Weather Data At 1440 minute intervals” i.e. once per 24 hours.
I add up everything in the column “Precipitation Total”.
I get the total 794mm.

The WeatherCat “Statistics”, “Year over Year” reports that 770mm of rain has fallen so far.

So, here’s the question. Which one is correct?

I appreciate that measuring “by day” and “by hour” might lead to slightly different figures.

But where does WC get the 770mm that it reports in the year over year statistics?

Furthermore, if I add up all 1440 minute interval rainfall totals it gives a total of 3530mm. If I add up the yearly totals from the WC “Year over Year” “Statistics” it gives a total of 4722mm. That is a large discrepancy!

Any help would be much appreciated on resolving this would be much appreciated.

Regards,

Giles.

xairbusdriver

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Re: WeatherCat calculation of rainfall data
« Reply #1 on: December 31, 2020, 04:38:52 pm »
Have you changed the default "Rain Season" date (January or July)?

How does an Annual NOAA Style Reports (Tools Menu) "Precipitation" section compare to those exported values?

Searching The Manual is a great way to spend some time during a "lock down". [computer] [lol]

nicechristmasjumper

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Re: WeatherCat calculation of rainfall data
« Reply #2 on: January 03, 2021, 04:28:42 pm »
Thanks for the reply.

The default rain season is set to January.

The NOAA precipitation report for 2020 shows 770mm for the year. The same as the WeatherCat statistics "year on year" report.

I've consulted the manual but can find no joy.

I'm running WeatherCat 3.1.1 BTW.

elagache

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Now that year is over? (Re: WeatherCat calculation of rainfall data)
« Reply #3 on: January 04, 2021, 10:58:04 pm »
Dear Giles, X-Air, and WeatherCat troubleshooters,

Unfortunately, I'm in catch-up mode, but I see that these were the first 2 postings you've made, so let me welcome you to the WeatherCat forum! 

Unfortunately, I was puzzled by your initial posting and I haven't found anything to explain your puzzling observations.  My only suggestion is to repeat your tests now that 2020 is over.  Do you still get the same discrepancies?

Cheers, Edouard