More data...

[steve]

The latest beta build adds a few more items to the log files, realtime.txt and web tags. As promised, I want to add still more. So rather than use the enhancement request section, this thread is for suggestions for new items. Please try to be as explicit as possible about what you would like to see, and please try not to let your imaginations run too wild, and keep to the more important meteorological data which is currently missing from Cumulus.

[6719jason]

Hi Steve,

Is there anyway of having a calculated/estimated 'Wet Bulb' Temperature for stations which do not supply or support this?

Probably not but I thought I would ask anyway

Thanks Steve - Excellent work so far and I am so pleased to be using Cumulus

[steve]

Is there anyway of having a calculated/estimated 'Wet Bulb' Temperature for stations which do not supply or support this?

There may well be a formula based on humidity/dew point and ambient temperature; I'll see what I can find.

[beteljuice]

Hi Steve,

Is there anyway of having a calculated/estimated 'Wet Bulb' Temperature for stations which do not supply or support this? ....

Here's some Javascript I put together to work out agricultural spraying conditions, there is only one additional line (toward the end) to calculating wetbulb

Code: Select all

// ------ Calculate delta T --------------------------------------------------------
// needs tempC, dewpointC, pressureABS, (baro_offset is YOUR difference to ASL)

element = document.getElementById("delta_T");

if(element){
			
	temp = parseFloat(temp);
	dewpoint = parseFloat(dewpoint);
	baro = parseFloat(baro);
			
	if(pressunit == "inHg") {
		MBpressure = parseFloat(convertinHGtomb(baro)) - parseFloat(convertinHGtomb(baro_offset));
	} else {
		MBpressure = baro - baro_offset;
	}
			
				
tempunit = tempunit.substr(5);
	if (tempunit == "F") {
		Ctemp = parseFloat(convertFtoC(temp));
		Cdewpoint = parseFloat(convertFtoC(dewpoint));
	} else {
		Ctemp = temp;
		Cdewpoint = dewpoint;
	}
			
	E1 = parseFloat(esubx(Cdewpoint));
			
	Twguess = Cdewpoint;
	incr = 10;
	previoussign = 1;
	Edifference = 1;
			
	wetbulb = calcwetbulb(Edifference,Twguess,Ctemp,MBpressure,E1,previoussign,incr);
// NB - you've got a wet bulb (C) temp ;-)
	delT = roundOff(temp - wetbulb)
	element.innerHTML = delT;
							
}	// END calculate delta T



function esubx(temp) {
	var Ex;
	Ex = 6.112 * Math.exp((17.67 * temp) / (temp + 243.5));
	return Ex;
}    // END

			
function calcwetbulb(Edifference,Twguess,Ctemp,MBpressure,E,previoussign,incr) {
	outerloop:
	while (Math.abs(Edifference) > 0.05) {
		Ewguess = 6.112 * Math.exp((17.67 * Twguess) / (Twguess + 243.5));
		Eguess = Ewguess - MBpressure * (Ctemp - Twguess) * 0.00066 * (1 + (0.00115 * Twguess));
		Edifference = E - Eguess;
					
		if (Edifference == 0) {
			break outerloop;
		} else {
			if (Edifference < 0) {
				cursign = -1;
				if (cursign != previoussign) {
					previoussign = cursign;
					incr = incr/10;
				} else {
					incr = incr;
				}
			} else {
				cursign = 1;
				if (cursign != previoussign) {
					previoussign = cursign;
					incr = incr/10;
				} else {
					incr = incr;
				}
			}
		}
		if (Math.abs(Edifference) <= 0.05) {
			break outerloop;
		} else {
			 Twguess = Twguess + incr * previoussign;
		} 
	}
	wetbulb = Twguess;
	return wetbulb;
}	// END
			
			
							
function RH(E,Es) {
   var RH;
   RH = 100 * E/Es;
   return RH;
}


function roundOff(value) {
	value = Math.round(100*value)/100;
	return value;
}    // END

[steve]

Brilliant - thanks, bj

[captzero]

Hi Steve,

Love the new graphs. I'd like to see yesterdays high and low humidity readings. This would compliment the new today high, low and record webtags for humidity.

Thanks

[steve]

I'd like to see yesterdays high and low humidity readings.

There are web tags for these; I use them on the new yesterday page - http://sanday.org.uk/weather/yesterday.htm but I've forgotten to include them in the list of new ones! I'll remedy that...

[captzero]

No Probs. I had a play around and worked it out.

[captzero]

Any chance of daily and all time records for cloudbase and longest and shortest windrun days?

Cheers

[steve]

Any chance of daily and all time records for cloudbase and longest and shortest windrun days?

Cheers

Hmmm... cloudbase...

Windrun, yes, definitely.

[wd40]

Number of days since the last rain.

We are in another drought so the number of days without rain become more important. The graphs of course display that information so it might not be useful.

I would think it should be settable like only count rain over 1 or 2 cm.

Randy

[steve]

Number of days since the last rain.

Ah, yes. And the number of days since it didn't last rain.

I would think it should be settable like only count rain over 1 or 2 cm.

In the UK, the official amount for a 'rain day' is 0.2 mm, but I can make it configurable. 1 or 2 cm is quite a lot of rain in one day and would count as a rain day in most people's view!

[wd40]

Here is another version.
I did not know there were definitions for a rain day until your post Steve. Interesting as always.

http://earlywarning.usgs.gov/usraindry/rdreadme.php

Here is an abbreviated list of their products

Rain" Day or Dry Day Threshold Criteria
Number of Rain Days >= 0.04 in. (1 mm)
Maximum Consecutive Dry Days < 0.04 in. (1 mm)
Number of Days Since Last Rain >= 0.04 in. (1 mm)

[captzero]

Hi Steve,

Viewing the yearly Averages and Extremes data in Cumulus, shows, amongst other things, total wind run for the year, No. of rain days and total gale days, etc. I'd like to use some of the yearly data on my site somewhere (might need more than 10 FTP slots though). Any chance of some webtags do display yearly data?

Cheers

[steve]

Any chance of some webtags do display yearly data?

Yes, some yearly (and monthly etc.) tags would be good. It'll take some thinking about, though, because as things stand they would have to be determined on the fly every time from the logs, which is why there currently aren't any. It needs some temporary storage for the accumulated data.