Author Topic: precipitation per hr  (Read 3491 times)

Randall75

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precipitation per hr
« on: December 05, 2013, 01:25:32 PM »
Hi Stu
 I know that the precipitation per hr estimates what the rain per hour would be if the rain continued at that rate for the hour but has there been a release of WeatherCat that show what the actual rain rate per hour was for the high amount?
 I would like to be able to see what the actual high rate was  for each hour not an estimate high is there a way to do this?


thanks
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wurzelmac

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Re: precipitation per hr
« Reply #1 on: December 05, 2013, 01:40:36 PM »
Hi Randall,
WeatherCat reports all days and months as PDF at the end of a day respective the end of a month. This daily report provides the data you are looking for. On my side the folder is located in Documents > WeatherCatReports. Hope this helps.
Cheers,
Reinhard
Reinhard


Randall75

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Re: precipitation per hr
« Reply #2 on: December 05, 2013, 04:54:18 PM »
Hi Reinhard
 Thanks for the info but i want to be able to come in at any time it is raining to see how much rain it has done in the recent hours I just don't like the estimate rain rate i want to know exactly how much rain it just did in the last hour and so on for example 7am to 8 am the rain rate was .05 inches 8 am to 9 am .05 inches and the total so far should be .10 inches the it rain daily total again at  10 am to 11 am .18 inches  fell now the daily total is .28 inches
thanks


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WCDev

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Re: precipitation per hr
« Reply #3 on: December 05, 2013, 05:33:48 PM »
Go to the Daily Stats view (Tools->Statistics then select the 'Daily' tab) - there you'll get hour by hour min/max rain rate and the cumulative rain for that hour.

Note it's entirely possible to get cumulative rain without a rain rate (where the period between bucket tips exceeds the consoles maximum time between tips to calculate the rate).

xairbusdriver

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Re: precipitation per hr
« Reply #4 on: May 30, 2016, 01:50:46 AM »
This is an inactive thread but comes close to my question, so...
I'd like to display a "Highest Rain Rate" with a date/time in several places on my Stats page. I must have asked about this before but don't see it after a search.

I have a custom email alert if that rate exceeds the highest rate I now have recorded (and I'm not even sure where that 'info' came from!). It uses an "R$" tag. I have a "STAT$RAIN:TOTAL:TODAY$ RAINUNITS$" and a "Rain Rate: CR$" display on my current (today) weather page.

I've unsuccessfully attempted building a STAT$ display with the "ALLTIME" period but it doesn't seem to work. There is a mention in the Manual that different combinations will change the "RAIN" value between 'rain rate' and 'rain totals'. But I haven't been able to decipher the exact tags to use to get the 'all time/highest maximum' value.
Code: [Select]
STAT$ITEM:TYPE:PERIOD$
ITEM can be one of:
       RAIN             Either rain rate or accumulated rain
                        (depending on the query context)

I also have "STAT$DAILYRAIN:MAX:ALLTIME$ RAINUNITS$ on STAT$DAILYRAIN:MAX:ALLTIME:TIME$" that works,

Suggestions? Thanks!
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WCDev

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Re: precipitation per hr
« Reply #5 on: May 30, 2016, 01:48:00 PM »
STAT$RAIN:MAX:ALLTIME$ is where you want to be.

xairbusdriver

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Re: precipitation per hr
« Reply #6 on: May 30, 2016, 04:50:14 PM »
Thanks!

I would have sworn I tried that. But at my age, I try not to depend on my memory that much.

OK, I just deleted a paragraph describing what I assume happens in this rain rate process. I don't really need to know the details of how WC works. It just seems that the "rate" could be changing quite fast and may not be a useful measurement unless the hardware and/or WC does a lot of work involving rate and lengths of time. Anyhow, thanks for the correct formatting! ;)
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xairbusdriver

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Re: precipitation per hr
« Reply #7 on: May 30, 2016, 07:09:59 PM »
STAT$RAIN:MAX:ALLTIME$ is where you want to be.
I'm probably not explaining what I'm looking for. The above 'tag' displays "38.40". That's a wee bit high for a rain rate, unless it is a computed total of how much rain would fall in 24 hours.

What I'm looking for is this info (that I haven't actually found in any data file, yet): "3.16 in/Hr on 23 Dec 2015 1:04 pm". At that rate, it would be close to the "38.40" value at "37.92" the difference might be a conversion from mm to inches plus rounding?

When I added a date/time tag grouping to the original (STAT$RAIN:MAX:ALLTIME$ on STAT$RAIN:MAX:ALLTIME:TIME$) the display is "38.40 on 26 Mar 2015 5:01 PM"

My plan is to convert these inch values back to mm and double check different the precip values on those two dates... after lunch. ;)
THERE ARE TWO TYPES OF COUNTRIES
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And the United States = The Banana system


WCDev

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Re: precipitation per hr
« Reply #8 on: May 30, 2016, 08:08:58 PM »
The 38.4 is the converted value - you have a rain rate of 38.4 inches per hour. Extremely high and probably the result of the bucket tipping twice in fast succession.

xairbusdriver

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Re: precipitation per hr
« Reply #9 on: May 30, 2016, 10:49:51 PM »
OK, I've searched through both the March and December .cat files. I assume those are those are the files I need to examin. Is that correct?

First, the March files are the first I ever got, only installed the ISS last part of the month. I'm thinking I have some bogus info even for he Mar 2015 data. All the lines of data have negative numbers at the first position: "-9581 t:261521 T:20.78 Ti:24.89..."

April data lines are all positive numbers, all except the first and second are increments of 15:
  • 2 t:010002 T:16.56...
  • 15 t:010017 T:16.22...
  • 30 t:010032 T:16.17... until
  • 420 t:010702 T:13.83...
  • 422 t:010704 T:13.83... until
  • 430 t:010712 T:13.94... at which point they increment by 1, ending at
  • 43199 t:302359 T:13.28...

All the other monthly  .cat files I looked at use positive number, but a few also had weird incrementing for the first ~10 entries and then followed the normal +1 procedure.

So, although I did find a 38.40 (975.36mm) value in the March data, I find it a bit hard to believe the bucket is capable of tipping that fast!  :o At least it would be 'water-cooled'!

Second, December presented me with some interesting data, also. And I think it is more reliable, also. The data showed the highest rain rate in December as 9.29 (235.97mm) on the 28th. So, I think my "3.16 in/Hr on 23 Dec 2015 1:04 pm" is also incorrect. That date did have a 4in/hr rain. But the real downpour was a few days later when the rate was over 28mm for 12 minutes!. It peaked at 0735 at 235.97mm!

The Vantage Pro captures data every 2.5 seconds. My final inquiry is the exact definition of the "Ph is hourly precipitation". I'm taking these numbers to actually mean "hourly precipitation rate averaged by the station (or WC) over the last 60 seconds". I guess I'm just having trouble wrapping my brain around the usefulness value like 9+ inches of rain an hour. I don't live in a "Rain Forrest" after all! I don't want to report exaggerated numbers that indicate a need for keeping a boat in the back yard! [lol]

I think I need to delete the March .cat & .cat.hrs files. [banghead]

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« Last Edit: December 30, 2017, 05:45:19 PM by xairbusdriver »
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WCDev

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Re: precipitation per hr
« Reply #10 on: May 30, 2016, 11:18:12 PM »
If I remember correctly, Davis quote 40"/hour is the max on the rain rate, so your 38.4 is valid.

Essentially it's the period between bucket tips (this is probably calculated by the ISS *I'm guessing*) - for example if there was 1 second between tips that'll be 3600 tips per hour. Multiply this out by the bucket resolution to convert to actual inches/hour.

So for a .01" bucket, that'd be 36"/hour maximum. As it's specced at a max of 40"/hour we can say the minimum period between tips it can cope with is 0.9 seconds.

BTW, you can ignore the first column in a WeatherCatData file, it's purely for debug and undocumented - it isn't used by WeatherCat. The t: fields are what it reads as the time - the periods between these are set by your sampling rate in WeatherCat (and they can vary if adaptive sampling is enabled).

[ Edit: correction - Davis quote 96"/hour max on the rain rate for a Vantage - see http://www.davisnet.com/product_documents/weather/spec_sheets/6152_62_53_63_SS.pdf ].

xairbusdriver

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Re: precipitation per hr
« Reply #11 on: May 30, 2016, 11:42:08 PM »
Thanks! I moved the March files out of WC's 'sight' anyway. They only had a couple of weeks worth of data. I'll play with the tags again this week, right now the display is just hard coded.

And thanks for the details on the data files, also.
THERE ARE TWO TYPES OF COUNTRIES
Those that use metric = #1 Measurement system
And the United States = The Banana system