CLOSED as IMPLEMENTED: Feels Like (from 3.6.10) and Humidex (from 3.7.0)

[sfws]

It is early days of looking at the new tag, and I'm spending more time in the garden than watching the changes on my web page showing this derivative. So far the new feels like web tag is giving me a better indication of how I feel when out in my garden than the apparent temperature which tends to suggest a lower temperature by around a degree or two. Recently Wind Chill has stayed equal to air temperature, because it has been warm and there has been little wind. I can't pretend to have studied the theory and calculation of all these different approaches of varying the air temperature for effect on humans.

I don't know what others want, but I think it would be good to get highest and lowest feels like for each day with associated times, going into dayfile. With those 4 extras consequently also going into my daily summary table, I could easily work out max and min for month or any other period.

If you do plan to extend feels like then I think you should also extend humidity index (humidex), because that too only has a web tag forCurrent Conditions, adding the highest/lowest and times into dayfile would be useful I'm sure. Steve had extending it in that way on his "to do" list for Cumulus 1, but never actually did it.

EDITS: simply updating subject to reflect when these were available for daily, monthly, yearly and all-time.

[mcrossley]

I'll see about extending the Feels Like into a "fully supported" variable. It is quite a lot of work to do this though due to the way the variables are implemented.

This is now two (three if you include me) votes for keeping and extending Feels Like.

If if do extend it, I have a question about what to do about MYSQL, add it to the standard tables and inserts or not? Adding to the log files is fine, they have been extended many times

The Apparent temp seems to be a predominantly Australian thing, and Humidex is predominately Canadian. Feels like seems to be more used in UK and USA, I'm not sure about Europe.

[sfws]

now two (three if you include me) votes

I did react to

Thumbs up from me for adding <#feelslike> I have always preferred that calculation.

I want to complicate it now.. can it be added to the dayfile insertion? high/low feelslike and the time of the high/low? As well as tags for it covering day/yesterday/month/year and perhaps LowFeelsLikeRecordSet / HighFeelsLikeRecordSet?

I'm such a wag!

and Freddie's response to that got me posting. If it is as much work as you suggest, I would not worry about month/year. If today can be done, then yesterday should be an easy add on. Those together should suit most people. After all some people have asked for "this day last year", "this day last week" and similar in past, but I have not seen any requests like that for a while.

If if do extend it, I have a question about what to do about MYSQL, add it to the standard tables and inserts or not? Adding to the log files is fine, they have been extended many times

The Apparent temp seems to be a predominantly Australian thing, and Humidex is predominately Canadian. Feels like seems to be more used in UK and USA, I'm not sure about Europe.

I guess those who have voted so far are happy with their own Custom SQL as needed, so that is why I only suggested changing log files, and made no suggestion re standard db schema. The impression I have is that those using the standard SQL uploads don't really care what it contains, what matters is that there is a way to automatically upload without them having to be experts! Certainly from my decades of reading forum comments, I believe most people concentrate on the simple outputs, not all the extra derivatives. As a gardener I find Chill Hours useful, and store a daily total as well as the Cumulative Total in the web tag, but I am not aware of anyone else ever wanting it added to standard database, although there are a couple of others who choose like me to store it in their own.

Given Cumulus is used internationally, I am a firm believer that Apparent Temperature, Humidex, Heat Index, Wind Chill, and Feels Like, indices are all worth having in Cumulus; and I don't think it is fair to give more information on one than another.

I'm not sure about European adoption of Feels Like, it is definitely used in Iceland, and mentioned in USA. Canada hosted the Joint Action Group for temperature Indices (JAG/TI) see https://www3.nd.edu/~nsl/Lectures/mphys ... 20body.pdf when it was discussed, I am unsure if they actually use it (Paul usually helps with Canada weather questions).
The Netherlands mention it at https://nl.wikipedia.org/wiki/Gevoelstemperatuur, and were proposing to adopt it 2 decades ago see https://edepot.wur.nl/324573.

[billy]

I'd vote for anointing "feels like" with a higher status. Incidentally, the Australian bom seems to be using "feels like" rather than AP on many of their pages. Frankly it is a more meaningful term for Joe Blow and actually has some biological relevance. (And as heat is the more common issue here, AP is usually the relevant measure.) The problem is we have different measures - one dealing with hyperthermia and the other with hypothermia - using the same terminology. I not aware of a single "feels like" measure that covers both ends of the extreme? Probably all too hard.

[mcrossley]

The JAG/TI feels like scale effectively uses wind chill below 10C, apparent temp (Steadman not Aus BOM) above 20C, and blends the two values between 10 and 20C.

[billy]

From a quick look at the bom site they use the Steadman AP

[billy]

Coincidentally, this morning was the first day of the year that the temperature dropped below 10C. As you can see in the attached plot, the AT was a couple of degrees below the actual temp (there has been a nice breeze averaging 3 - 5 km/hr) and for us it was chilly . WC is identical to temperature (WC is plotted under the temp line). Options are set to use the VP2's WC which a quick search indicates is only calculated if wind speed is > 5 mph (and I think temperature < 10 C). Cumulus uses a 3 mph limit so that might have picked up a temp-WC difference but I'm guessing it would be marginal. So my question is does the JAG/TI "feels like" do better than these existing measures we have for WC in the "intermediate" range of 5 - 15 C? I guess there is a reference somewhere?

Annotation 2020-04-29 101747.jpg

[sfws]

I'll see about extending the Feels Like into a "fully supported" variable. It is quite a lot of work to do this though due to the way the variables are implemented.

Thanks for implementing Feels Like web tags for all periods.
However, your release announcement does not mention Recent History tags, so I assume these have not been implemented yet. Are you going to implement these? I will add in the wiki how recent history feels like can be worked out from recent history tags that do exist.

Getting more meaningful monthly and annual figures
Since the release is part way through month and year, only today tags were accurate (you are ok, you have had it as beta for a while on your web site), but I am rectifying this by editing dayfile.txt (and the database table I have for daily summary figures), back to when I started recording at my latest home.

Luckily, most days so far this year have had temperatures below 10 Celsius for part of the day, thus the Lowest Feels Like for those days is numerically equal to greatest wind chill. Consequently, I have populated lowest feels like for past days/months in my database tables very easily.

I am now updating all the local files, including the extreme records. I have posted php scripts at viewtopic.php?f=18&t=18096&p=142634 that will recalculate feel like (and other derivatives) for the standard log files and when ExportMySQL monthly has been used to get those into a database table, another script in that same post will update the daily table. Tomorrow I plan to populate the ByMonth tags for past months, based on the daily values I added today.

[mcrossley]

I did all my history calculating feels like for each row in the monthly table - only took a few seconds to do 10+ years. From that I could extract the daily highs/lows into the Dayfile table. From that I could extract all the records and add them into MX.

[water01]

I did all my history calculating feels like for each row in the monthly table - only took a few seconds to do 10+ years. From that I could extract the daily highs/lows into the Dayfile table. From that I could extract all the records and add them into MX.

Was this some SQL calculation you ran through monthly tables and if so is it available to us mortals?

[mcrossley]

OK, I've had to recode it so it is more generally useful for people using units other that mph & C.

First create a function to do the calculation... (Note my version takes the windspeed in mph, and temperature in C - if you use other units you will have to adjust the multiplier to kph)

Code: Select all

DELIMITER $$
CREATE FUNCTION `CalcFeelsLike`(`temp` DECIMAL(4,1), `wind` DECIMAL(4,1), `hum` INT) RETURNS decimal(4,1)
    NO SQL
BEGIN
DECLARE tempC FLOAT(9.6);
DECLARE kph FLOAT(9,6);
DECLARE chill FLOAT(9,6);
DECLARE vaporp FLOAT(9,6);
DECLARE apptemp FLOAT(9,6);
DECLARE A,B FLOAT(9,6);
DECLARE retVal FLOAT(9,6);

-- Convert mph to kph
SET kph = wind * 1.609344;
-- Convert user temp to C, nothing to do for 
SET tempC = temp;
-- SET tempC = (temp - 32) * 5 / 9;

IF kph < 4.828 THEN
    SET chill = tempC;
ELSE
    SET chill = 13.12 + 0.6215 * tempC - 11.37 * Power(kph, 0.16) + 0.3965 * tempC *  Power(kph, 0.16);
END IF;

SET vaporp = ((hum / 100.0) * 6.105 * Exp(17.27 * tempC / (237.7 + tempC))) / 10.0;

SET apptemp = -2.7 + (1.04 * tempC) + (2.0 * vaporp) - (kph * 0.1805553);

IF temp < 10 THEN
    SET retVal = chill;
ELSEIF temp > 20 THEN
    SET retVal = apptemp;
ELSE
    SET A = (tempC - 10) / 10.0;
    SET B = 1 - A;
    SET retVal = (apptemp * A) + (chill * B);
END IF;

-- Convert back to user temp scale, nothing to do for C
-- RETURN ((retVal * 9 / 5) + 32);
RETURN retVal;

END$$
DELIMITER ;

Then update your monthly table...

Code: Select all

UPDATE Monthly SET FeelsLike = CalcFeelsLike(temp, Windspeed, humidity);

[water01]

Code: Select all

CREATE FUNCTION `CalcFeelsLike`(`temp` DECIMAL(4,1), `wind` DECIMAL(4,1), `hum` INT) RETURNS decimal(4,1)
    NO SQL
BEGIN
DECLARE tempC FLOAT(9,6);
DECLARE kph FLOAT(9,6);
DECLARE chill FLOAT(9,6);
DECLARE vaporp FLOAT(9,6);
DECLARE apptemp FLOAT(9,6);
DECLARE A,B FLOAT(9,6);
DECLARE retVal FLOAT(9,6);

-- Convert mph to kph
SET kph = wind * 1.609344;
-- Convert user temp to C, nothing to do for 
SET tempC = temp;
-- SET tempC = (temp - 32) * 5 / 9;

IF kph < 4.828 THEN
    SET chill = tempC;
ELSE
    SET chill = 13.12 + 0.6215 * tempC - 11.37 * Power(kph, 0.16) + 0.3965 * tempC *  Power(kph, 0.16);
END IF;

SET vaporp = ((hum / 100.0) * 6.105 * Exp(17.27 * tempC / (237.7 + tempC))) / 10.0;

SET apptemp = -2.7 + (1.04 * tempC) + (2.0 * vaporp) - (kph * 0.1805553);

IF temp < 10 THEN
    SET retVal = chill;
ELSEIF temp > 20 THEN
    SET retVal = apptemp;
ELSE
    SET A = (tempC - 10) / 10.0;
    SET B = 1 - A;
    SET retVal = (apptemp * A) + (chill * B);
END IF;

-- Convert back to user temp scale, nothing to do for C
-- RETURN ((retVal * 9 / 5) + 32);
RETURN retVal;

END

Thanks Mark. I had to modify your function as there were some errors (I am sure you do this to see if we can fix coding errors!!). Forgot to declare tempC, some of the comments did not have spaces between -- and comment and the retVal in the elseIF did not have an = sign.

Other than that it worked great, now have a fully populated feels like in the monthly table, thank you.

[mcrossley]

Thanks David, I just hacked my function as I knew it would raise more questions from people as everything was hard coded to my units. Fixed my post now too.

[mcrossley]

I leave the extraction of daily highs/lows and their associated times, then extracting all the records as your coding challenge!

[water01]

Yep thought you might say that !!