Monthly log files: Difference between revisions

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=== Cumulus Wind Speed Terminology ===
How wind speeds relate to various weather stations is explained in FAQ. Basically there are 3 values storedprocessed by Cumulus:
#Gust - the highest wind speed over a particular period (this period defaults to 10 minutes),
#Average - the moving average of wind speed measurements over a particular period (this period can be set to what suits you, but defaults to 10 minutes),
[[FAQ#What_do_the_various_wind_speeds_in_Cumulus_correspond_to.2C_with_Davis_stations.3F|FAQ: Wind speeds in Cumulus with Davis stations]], the ''EasyWeather'' differences in [[FAQ#What_do_the_various_wind_speeds_in_Cumulus_correspond_to.2C_with_Fine_Offset_stations.3F|FAQ: Wind speeds in Cumulus with Fine Offset stations]] and [[FAQ#How_do_I_set_up_recording_wind_speeds_in_Cumulus.2C_with_Oregon_Scientific_and_La_Crosse_stations| FAQ: Wind speeds with Oregon Scientific and La Crosse stations]]
 
When Cumulus calculatesis therunning monthly/annual/periodnormally, ''averageit windactually speed''stores (as used for 'This ...' screens in '''View''' menu and the NOAA report) by trawling through the monthly logs, summing the values for the individually logged average wind speed (the fifth item ''after'' the date in each entry, column F in a spreadsheet), and dividing by the numberhighest of(moving) entriesaverage forin the requiredperiod calendarsince days.the Itprevious thereforelogger assumes that each entry has equal 'weight', i.e. each one covers the same periodrecord. If your monthly log(s)Cumulus is/are anot mixturerunning, ofit valuesstores storedthe while Cumulus is running and values copiedaverage from the station logger, duringthat periodsis whenthe Cumuluslatest wasreported notmoving running,average. thenFor itthis is possiblereason the twomost loggingaccurate intervalswind havespeed notrecords beenare setachieved toif theCumulus sameis time,running soall theday outputevery valueday. could be skewed for that month/year/period.
Cumulus calculates the monthly/annual/period ''average wind speed'' (as used for 'This ...' screens in '''View''' menu and the NOAA report) by trawling through the monthly logs, summing the values for those individually logged average wind speed, and dividing by the number of entries for the required calendar days. It therefore assumes that each entry has equal 'weight', i.e. each one covers the same period. If your monthly log(s) is/are a mixture of values stored while Cumulus is running and values copied from the station logger during periods when Cumulus was not running, then it is possible the two logging intervals have not been set to the same time, so the output value could be skewed for that month/year/period because of the difference in what was stored and the difference in the logging interval.
 
[[Windrun]] is also calculated from average wind speed measurements, in this case every minute if Cumulus is running, or from the values that are logged (at station logging interval) as average wind speed when Cumulus is restarted and catches up from the station logger.
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