Trace amounts of rain

[serowe]

No doubt, heavy dew would register in these stations from time to time, particularly if it rains following the dew.

Heavy dew is reported as HEAVY DEW (emphasis because this is exactly what they report in the 9am synops). Similarly, DEW is also reported in a synop (usually 3am or 9am synops) and is used to indicate 'moisture on the ground but nothing recorded in the rain gauge).

You also have to remember that the Bureau still uses human reportable synops - not everywhere is autmated for the simple reason that machine cannot report traces of rain; cloud cover etc.

[DaveNZ]

If anyone modifies a rain gauge to measure this trace amount of rain it calls into quesiton all readings from that gauge.

That's not really making much sense to me at all! If Bob's rain gauge can record 0.1mm of rainfall, then it is not a trace of rainfall at all for his records!

"Trace" rainfall is completely specific to the resolution of your rain gauge. Terry (super-T) down the road from me could call 0.2mm of rain a trace due to his rain gauge resolution, but mine can record 0.2mm, so that would mean I am measuring a trace....

[Gina]

serowe - if a "trace" is defined as "too little to measure" then fair enough.

[serowe]

You are all trying ot read something that isn't there. A trace refers to an amount of rain (drizzle would be more accurate) that cannot readily be measured by 'normal' equipment. You have seen it often yourself and I think I would be right in saying you have questioned, more than once, whether your rain gauge was working - you have seen the ground wet but nothing has been recorded. This is because the amount that fell is simply too small for your equipment and too small for even 'official' equipment to record.

But the bottom line is that those days DID have rain (or drizzle) but if you take the way AWS's and our type of weather stations record it, those days were 'fine' (the official weather definition of 'fine' is 'the lack of precipitation'). But in reality, those days were not fine - they actually had rain but, because you (lets use the Royal You here) didn't record any reportable rain, if you go back in 6, 12 or 60 months time, you would read, from the statistics, that the day was 'fine' and there was no rain whatsoever.

As I tried to say before - if the recorded data can record Tr or Trace as an amount of rain (manually entered - I am not asking for the gauge, station or software to determine this) then the record becomes complete because it indicates that yes, 26 Dec 2010 at my sation DID have some precipitaiton, but the amount was so light, it couldn't register an amunt therefore it didn't add to the annual rainfall total. BUT the number of days in which precipitation did occur has now been increased by one.

If your rain gauge registers any amount then Tr or Trace is simply not required. It is solely for those days when 'nothing' registers. There's nothing mystical or magical about what I am asking Steve about.

[beteljuice]

Let's see if we can clarify this - regardless of definitions or pluviometer resolution limitations.

I think ...
That you want a manual (editable ?) flag to be entered after the non-event that can be recognized by the 'Rain Day Count' or perhaps even a separate 'Trace Rain Count' ?
ie. for record purposes.

Not much point in a <#webtag> for 'ago' (eg. yesterday), and for "so far today" you can always manually write in the 'Current Conditions' <#currcond> eg. "There has been a trace of rain", although using this does mean you need access to Cumulus to update if current conditions change.

[werribee_au]

I'm afraid that BOM do not consider a day with a trace of rain an official rain day.
Sorry, but a fact is a fact!

It is noted here
http://www.bom.gov.au/climate/how/newpr ... _notes.txt

Trace -Less than 0.1mm of precipitation. It is recorded as zero precipitation
for the purposes of longer term totals. A day on which only a trace of
rainfall is reported is not considered to be a rainday.

And here (What is a rain day)
http://reg.bom.gov.au/climate/how/faq-data.shtml

[serowe]

Let's see if we can clarify this - regardless of definitions or pluviometer resolution limitations.

I think ...
That you want a manual (editable ?) flag to be entered after the non-event that can be recognized by the 'Rain Day Count' or perhaps even a separate 'Trace Rain Count' ?
ie. for record purposes.

Not much point in a <#webtag> for 'ago' (eg. yesterday), and for "so far today" you can always manually write in the 'Current Conditions' <#currcond> eg. "There has been a trace of rain", although using this does mean you need access to Cumulus to update if current conditions change.

Cprrect - using Current Conditions is not really a viable option for a number of reasons (you can only really record Trace *after* the event anyway. Webtag not needed - again, same reasoning. This is why I suggested using a value in the rain counter that cannot be achieved eg a high negative value -99, -999 etc but ths would require Cumulus and any graphing packages to recognise this new value.

My belief is that, as explained, both dayfile and the monthly log files would (might in the case of monthly) need to be edited and I think this should be done within Cumulus rather than doing it outside the program - less chance for something (formatting etc) to go wrong plus Cumulus then has control over the value it places in the file.

As for the BoM not 'recognising' Trace (next post) whilst they may not count it as a wet day (note the distinction in the terminology they use) they do receive, use and count these days - it is one of the methods used for determining the number of frost and 'dewey' days (the majority of Tr amounts are received in the 0600 and 0900 SYnops (and, once agin, by manual observers not by AWS's which can't think for themselves).

[PaulMy]

What am I missing

Trace Less than 0.1mm of precipitation. It is recorded as zero precipitation
for the purposes of longer term totals. A day on which only a trace of
rainfall is reported is not considered to be a rainday.

[serowe]

Look - if you want to contiunue argueing - go right ahead.

I asked steve for something specific - he hasn't answered yet on a quite specific request, so if you want to continue to pick holes go right ahead and do so.

I could start on wind vanes that only report on 8 points of the compass (useless pieces of ....), rain gauges that don't record to 0.1mm accurately; pressure sensors that don't record to 0.1 mb or temperature gauges that only record whole degrees. But I accept that some people want to use them - with respect, do the same!

[steve]

Please feel free to create an enhancement request.

[serowe]

steve - before I do - and this is why I was l also asking - is it worth it from your POV? Given the work it would require (which is why I was asking about using a special code) is something you

a) don't feel is necessary at all
b) possibly for C2 only
c) worth it fopr C1 and C2?

[serowe]

steve - so do I take it then your response is option d) or e)?

d) Not interested at all
or
e) Not interested because I brought it up?

[robynfali]

Serowe

Can i ask you something, well, ask you to remember something.

A, This is a free product
B, Steve does this in his own time
C, It's the Holiday Season
D, IT'S A FREE PRODUCT
E, Steve already told you to put it in as an enhancement request, he would not have done this, if he felt it wasn't worth his time doing it


Feel a bit of festive cheer towards others mate, all the best for 2011

[serowe]

Rob,

And can I remind you of something - I asked whether he wanted it as a request for C1 or C2 based on what he knows might need to be done. It wasn't a hard question and, based on the fact he has been answering other queries, it was a perfectly legitimate question to ask.

Iwould have thought steve is adult enough to be able to answer and defend his own stand without someone else answering for him.

[steve]

What is it with you? I've already said you should feel free to raise an enhancement request. It doesn't make any difference whether it's for C1 or C2. Everyone else seems to be able to cope with the concept, why should you get special treatment? As Rob says, it's the holiday season, and I am trying to limit the amount of time I spend here, and I'm prioritising. Stop being a drama queen and behave like all the other reasonable people here.