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Average temperature: Difference between revisions
→Cumulus outputs: Expanding re NOAA report annual averages with reference to Cumulus MX builds up to 3067
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== Cumulus outputs == | == Cumulus outputs == | ||
At rollover, the ''AvgTemp'' field in [[yesterday.ini]] holds the final integrated mean calculated by the quotient of '''Total''' over '''Samples''' in the old today.ini and the same average is written to [[dayfile.txt]]. The integrated mean temperature for each day is also output to the monthly NOAA style report. Integrated average temperatures are available as [[webtags]] for today and yesterday. | At rollover, the ''AvgTemp'' field in [[yesterday.ini]] holds the final integrated mean calculated by the quotient of '''Total''' over '''Samples''' in the old today.ini and the same average is written to [[dayfile.txt]]. The integrated mean temperature for each day is also output to the monthly NOAA style report row for the last line (which is yesterday's date). Integrated average temperatures are thus available as [[webtags]] for today and yesterday. For past days they are found in the [[dayfile.txt]]. | ||
The average of these daily intregated means for the whole month is shown at the bottom of the monthly NOAA style report and the lowest, actual, and highest of these | The average of these daily intregated means for the whole month is shown at the bottom of the monthly NOAA style report, and the lowest, actual, and highest of these integrated daily mean for each month are output to the annual NOAA style report. Providing Cumulus is in continuous operation, so the number of measurements in the calculation is the same for every day, the average of integrated daily means over a month is mathematically the same as an integrated mean for the whole month. | ||
The annual averages shown at the bottom of the annual NOAA report do not use these integrated daily means, instead they simply add up the figures in that column. '''Thus, the way that Cumulus 1.9.4 (and Cumulus MX up to and including build 3067) works out all of the annual averages is arithmetrically wrong (the discrepancy varies through the year but is highest in March/April (because February has fewer days). The yearly average is calculated by adding all the months and then dividing by the number of months. Arithmetrically, the most accurate average is from adding all individual readings and dividing by number of readings (this what Cumulus does in the [[today.ini]] file that holds sum and number of readings. The NOAA reports however read from the [[dayfile.txt|daily log]] so a more accurate annual average can be calculated from adding all the daily averages and dividing by number of days (which is what newer CM builds do).''' | |||
== Alternatives == | == Alternatives == | ||