Meteorological day - Revision history

Sfws: Resequence so background follows detail

2022-09-21T18:40:11Z

Resequence so background follows detail

Sfws at 15:45, 9 April 2022

2022-04-09T15:45:56Z

← Older revision		Revision as of 15:45, 9 April 2022
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	\| Reported for day starting at 9 a.m.		\| Reported for day starting at 9 a.m.
	\| Reported for day starting at selected rollover time		\| Reported for day starting at selected rollover time
			\|-
	\| Highest wind speed		! scope="row\| Highest wind speed
	\| Reported for day starting at 9 a.m.		\| Reported for day starting at 9 a.m.
	\| Reported for day starting at selected rollover time		\| Reported for day starting at selected rollover time

Sfws: add category

2021-07-26T10:59:18Z

add category

← Older revision		Revision as of 10:59, 26 July 2021
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	{{Version badge Mx}}{{Version badge 1}}This page applies to both the original Cumulus software and MX.		{{Version badge Mx}}{{Version badge 1}}This page applies to both the original Cumulus software and MX.[[Category:Terminology]]

	=Traditionally=		=Traditionally=

Sfws: /* Daily assignment */ Update Snow, moving MX first

2021-07-24T14:52:42Z

Daily assignment: Update Snow, moving MX first

← Older revision		Revision as of 14:52, 24 July 2021
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	Most weather organisations in the world still to some extent remain consistent with the traditional way of working. This means that they report by '''meteorological day'''. Therefore, a key requirement for Steve Loft was to report daily derivatives based on a day that started at 9 a.m. Most weather software can only report daily measurments on a calendar day basis (since midnight).		Most weather organisations in the world still to some extent remain consistent with the traditional way of working. This means that they report by '''meteorological day'''. Therefore, a key requirement for Steve Loft was to report daily derivatives based on a day that started at 9 a.m. Most weather software can only report daily measurments on a calendar day basis (since midnight).

	Steve Loft did make a simplifying assumption that does not align with the practice of most Meteorological Offices, Cumulus ~~implements~~ minimum temperature and rainfall ~~differently~~. The World Meteorological Office (WMO) allows individual nations some flexibility, and does not prescribe total international alignment.		Steve Loft did make a simplifying assumption that does not align with the practice of most Meteorological Offices, Cumulus treats ''all weather station measurements the same'', booking them to the date at start of measuring period (meteorological day). Most official measurements assign minimum temperature, and rainfall, to the date at end of measuring period. The World Meteorological Office (WMO) allows individual nations some flexibility, and does not prescribe total international alignment.

	The following table tries to illustrate the divergence if you choose a rollover time other than midnight:		The following table tries to illustrate the divergence if you choose a rollover time other than midnight:
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	! scope="row"\| Maximum temperature		! scope="row"\| Maximum temperature
	\| The daily maximum temperature in the 12 hours (9 a.m. to 9 p.m.) after the traditional observation time is assigned to the date that applies to both times		\| The daily maximum temperature in the 12 hours (9 a.m. to 9 p.m.) after the traditional observation time is assigned to the date that applies to both times
	\| Reported for day starting at 9 ~~a.m.~~		\| Reported for day starting at rollover time
	\|-		\|-
	! scope="row"\| Average temperature		! scope="row"\| Average temperature
	\| The WMO says that daily temperature average is calculated in ~~different~~ ~~ways~~. ~~Its~~ preference is the average of the minimum in previous 12 hours and maximum in subsequent 12 hours, this ensures consistency with traditional climate statistics.		\| The WMO says that daily temperature average is best calculated in a way that is comparable with historic climatic records, although it accepts there is some divergence between nations. The WMO preference is to report for mean temperature the average, of the minimum in previous 12 hours, and maximum in subsequent 12 hours, this ensures consistency with traditional climate statistics that might be dependent on a single observation of maximum and lowest per day.
	* Prior to automatic recording, some stations would have manual recordings taken a few times a day, and if these were at 0600, 12:00, and 18:00, the mean might be calculated by adding the 3 readings, then adding the last again, and dividing by 4!		* Prior to automatic recording, some stations would have manual recordings taken a few times a day, and if these were at 0600, 12:00, and 18:00, the mean might be calculated by adding the 3 readings, then adding the last again (to compensate for no night-time observations), and dividing by 4!
	* Nations are permitted to use integrated averages for their internal purposes.		* Nations are permitted by WMO to use integrated averages for their internal purposes. (By integrated all automatic measurements that are available, the reported average is a better representation for the entire day).
	\| ~~Cumulus~~ ~~maintains~~ a ~~total and~~ a ~~count~~ ~~for~~ ~~each~~ ~~day.~~ ~~The~~ ~~total~~ is ~~incremented~~ by ~~the~~ ~~actual~~ ~~temperature~~ ~~every~~ ~~time~~ ~~Cumulus~~ ~~processes~~ a ~~measurement~~ ~~(may~~ be ~~every~~ ~~minute~~ ~~for~~ ~~Cumulus~~ 1, ~~and~~ ~~every second for MX)~~. ~~The count is~~ incremented by ~~one~~ ~~each~~ ~~time~~ ~~a measurement is~~ ~~processed~~. The integrated [[Average_temperature\|average]] reported at the end of the day is ~~just~~ the total divided by the count.		\| Every time Cumulus processes a temperature from your weather, after conversion to your units, and any calibration multiplier/offset has been applied, the resulting temperature is added to a total kept in [[today.ini]], incremented the count in the same file. The integrated [[Average_temperature\|average]] reported at the end of the day is a simple calculation, the total is divided by the count.
	\|-		\|-
	! scope="row"\| Rainfall		! scope="row"\| Rainfall
	\| Some nations report the daily rainfall for the 24 hours prior to the 9 a.m. observation time on a particular date. Others, throw their rainfall total back to previous date, i.e. the total for the 24 hours after 9 a.m on the particular date.		\| Some nations report the daily rainfall for the 24 hours prior to the 9 a.m. observation time on a particular date. Others, throw their rainfall total back to previous date, i.e. the total for the 24 hours after 9 a.m on the particular date.
			\| Cumulus checks the current reading from a "count" supplied by weather station, it subtracts from this the count it stored at rollover time. From the count different, converted to required units, and calibrated, Cumulus assigns a rainfall total to the date when the day started.
	\| Cumulus assigns it to the date when the day started.
	\|-		\|-
	! scope="row"\| Sunshine Hours		! scope="row"\| Sunshine Hours
	\| Always reported by calendar day (midnight to 23:59)		\| Always reported by calendar day (midnight to 23:59)
	\| Regardless of which rollover time is selected, Cumulus always reports sunshine hours from one minute past midnight until midnight for any day		\| Regardless of which rollover time is selected, Cumulus always reports sunshine hours from one minute past midnight until midnight for any day. Note, MX does this efficiently, by using [[yesterday.ini]] if necessary; the legacy Cumulus 1 was dependent on internally held counts, so the calculation was wrong if that software was not running continuously.
	\|-		\|-
	! scope="row"\| Snowfall		! scope="row"\| Snowfall
	\| A snow day is reported by calendar day. The snow depth may be only reported at standard observation time of 9 a.m. (or as maximum that day)		\| A snow day is reported by calendar day. The snow depth may be only reported at standard observation time of 9 a.m. (or as maximum that day)
			\| Processing changes by flavour:
	\| For Cumulus 1, you select a particular time ([[Cumulus.ini_(Cumulus_1)#Read-only_parameters_in_the_Station_section\|SnowDepthHour]]) and that is when the date changes, i.e. prior to that snow depth is assigned to yesterday, a snow index is calculated for any longer period (e.g. month or season). Cumulus 1 allows other information to be recorded in the [[Log.xml\|Weather Diary]]. MX implements its [[diary.db]] slightly differently, and reports snow falling and lying as well as depth.
			* [[File:Badge vMx.png]] MX reports snow falling, snow lying, and snow depth, taken from the weather [[diary.db]]. If the hour part of the current clock time is less than [[Cumulus.ini#Data_Logging\|SnowDepthHour]], the diary entry for previous calendar date is sought, for SnowDepthHour onwards it seeks diary entry with current calendar date
			* [[File:Badge v1.png]] The legacy Cumulus reported just snow depth, but it used that to calculate the snow index for a month, year, or season. Again, it checks hour of clock time against [[Cumulus.ini_(Cumulus_1)#Read-only_parameters_in_the_Station_section\|SnowDepthHour]] to decide which date to seek in [[Log.xml\|Weather Diary]]. However, that diary could have any number of entries for any one date, so Cumulus permitted retrieval of any of those, but for snow index only uses last one of any date.
	\|-		\|-
	! scope="row"\| Highest and lowest pressure		! scope="row"\| Highest and lowest pressure
	\| Reported for day starting at 9 a.m.		\| Reported for day starting at 9 a.m.
	\| Reported for day starting at 9 ~~a.m.~~		\| Reported for day starting at selected rollover time
	\|-
	\| Highest wind speed		\| Highest wind speed
	\| Reported for day starting at 9 a.m.		\| Reported for day starting at 9 a.m.
	\| Reported for day starting at 9 ~~a.m.~~		\| Reported for day starting at selected rollover time
	\|}		\|}

Sfws: /* Daily assignment */ accessibility

2021-07-24T14:21:37Z

Daily assignment: accessibility

Sfws: /* Daily assignment */

2021-06-28T08:11:55Z

Daily assignment

← Older revision		Revision as of 08:11, 28 June 2021
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	Steve Loft did make a simplifying assumption that does not align with the practice of most Meteorological Offices, Cumulus implements minimum temperature and rainfall differently. The World Meteorological Office (WMO) allows individual nations some flexibility, and does not prescribe total international alignment.		Steve Loft did make a simplifying assumption that does not align with the practice of most Meteorological Offices, Cumulus implements minimum temperature and rainfall differently. The World Meteorological Office (WMO) allows individual nations some flexibility, and does not prescribe total international alignment.

	The following table tries to illustrate the divergence:		The following table tries to illustrate the divergence if you choose a rollover time other than midnight:
	{\| class="wikitable" border="1"		{\| class="wikitable" border="1"
	\|-		\|-
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	\|-		\|-
	\| Average temperature		\| Average temperature
	\| The WMO daily average is the average of the minimum in previous 12 hours and maximum in subsequent 12 hours, this ensures consistency with traditional climate statistics. ~~Nations are permitted to use integrated averages for their internal purposes~~		\| The WMO says that daily temperature average is calculated in different ways. Its preference is the average of the minimum in previous 12 hours and maximum in subsequent 12 hours, this ensures consistency with traditional climate statistics.
			* Prior to automatic recording, some stations would have manual recordings taken a few times a day, and if these were at 0600, 12:00, and 18:00, the mean might be calculated by adding the 3 readings, then adding the last again, and dividing by 4!
⚫	\| Cumulus maintains a total and a count for each day. The total is incremented by the actual temperature every time Cumulus processes a measurement (may be every minute for Cumulus 1, and every second for MX). The count is incremented by one each time a measurement is processed. The [[Average_temperature\|average]] at the end of the day is just the total divided by the count.
			* Nations are permitted to use integrated averages for their internal purposes.
		⚫	\| Cumulus maintains a total and a count for each day. The total is incremented by the actual temperature every time Cumulus processes a measurement (may be every minute for Cumulus 1, and every second for MX). The count is incremented by one each time a measurement is processed. The integrated [[Average_temperature\|average]] reported at the end of the day is just the total divided by the count.
	\|-		\|-
	\| Rainfall		\| Rainfall
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	\|-		\|-
	\| Sunshine Hours		\| Sunshine Hours
	\| Always reported by calendar day		\| Always reported by calendar day (midnight to 23:59)
	\| Regardless of which rollover time is selected, Cumulus always reports sunshine hours from one minute past midnight until midnight for any day		\| Regardless of which rollover time is selected, Cumulus always reports sunshine hours from one minute past midnight until midnight for any day
	\|-		\|-

Sfws: /* Daily assignment */ added missing cell to table

2021-06-28T08:04:16Z

Daily assignment: added missing cell to table

← Older revision		Revision as of 08:04, 28 June 2021
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	\| Maximum temperature		\| Maximum temperature
	\| The daily maximum temperature in the 12 hours (9 a.m. to 9 p.m.) after the traditional observation time is assigned to the date that applies to both times		\| The daily maximum temperature in the 12 hours (9 a.m. to 9 p.m.) after the traditional observation time is assigned to the date that applies to both times
			\| Reported for day starting at 9 a.m.
	\|-		\|-
	\| Average temperature		\| Average temperature

Sfws: /* Daily assignment */

2021-06-28T08:03:00Z

Daily assignment

← Older revision		Revision as of 08:03, 28 June 2021
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	The following table tries to illustrate the divergence:		The following table tries to illustrate the divergence:
	\| class="wikitable" border="1"		{\| class="wikitable" border="1"
	\|-		\|-
	!style="width:30px" \| Derivative		!style="width:30px" \| Derivative

Sfws at 08:00, 28 June 2021

2021-06-28T08:00:51Z

← Older revision		Revision as of 08:00, 28 June 2021
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	\| Reported for day starting at 9 a.m.		\| Reported for day starting at 9 a.m.
	\|}		\|}

			=Read more=

			[https://cumulus.hosiene.co.uk/viewtopic.php?f=10&t=17925&p=139901#p139901 thunder, rainfall, mean sea level pressure, snow days, fog day, minimum and maximum temperature]

			[https://cumulus.hosiene.co.uk/viewtopic.php?f=4&t=5177 minimum temperature, and rainfall, a day out]

			[https://library.wmo.int/doc_num.php?explnum_id=4166 WMO guidance for climate normals] see table 1 on page 3 where it says " Different methods are in operational use for the calculation of daily mean temperature."

Sfws: Created page with "{{Version badge Mx}}{{Version badge 1}}This page applies to both the original Cumulus software and MX. =Traditionally= The modern Cumulus user tends to forget that computeri..."

2021-06-27T11:17:01Z

Created page with "{{Version badge Mx}}{{Version badge 1}}This page applies to both the original Cumulus software and MX. =Traditionally= The modern Cumulus user tends to forget that computeri..."

New page

{{Version badge Mx}}{{Version badge 1}}This page applies to both the original Cumulus software and MX.

=Traditionally=

The modern Cumulus user tends to forget that computerisation is a fairly recent change (in the last few decades) for weather recording, which has been taking place for at least a century in most nations.

Older people will remember how weather was traditionally recorded. Weather instruments were not directly connected to a computer. Observers would manually read the instruments at least once a day, traditionally at 9 a.m. (one hour later in daylight saving time). Some observers made measurements every hour, or more frequently at places like airports.

Certain instruments, like barographs and sun recorders, did record readings on a continuous process, but they still needed to be manually read and interpreted. For temperature, [[Temperature_(and_humidity)_measurement#James_Six_and_Diurnal_Variation_measurements|James Six]] invented an instrument that could store the highest and lowest temperatures between manual readings.

Measurements were manually logged onto a sheet, or into a notebook, as they were made. Subsequently, longer period derivatives could be calculated from the manual measurements and these might be either phoned to the main weather service, transmitted electronically (e.g. by telex), or entered into an electronic record.

=Modern era=

Towards the end of the 20th century, not only did computers become small enough to be located on a widespread basis, but electronic sensors that could record various weather parameters started to become cheap, reliable, and widely available.

Thus the concept of recording weather in real-time finally became available.

Another change soon followed, in most nations, the concept of relying on a lot of weather stations recording local weather has been abandoned. Just a few stations remain, generally only to serve the needs of pilots, at airports. Instead, most weather observations nowadays rely on satellites to sense the weather, and mathematical models to interpolate to a local variation. A few terriestrial recordings are still made, mostly to provide consistency with past measurments and to inform climatological models over a decade or more.

=Daily assignment=

Steve Loft created Cumulus software, back in 2003, because he owned a weather station and he could not find any software that allowed him to process measurements in the way he wanted. The first public release, allowing other people to use his software, was on 27th January 2004.

Most weather organisations in the world still to some extent remain consistent with the traditional way of working. This means that they report by '''meteorological day'''. Therefore, a key requirement for Steve Loft was to report daily derivatives based on a day that started at 9 a.m. Most weather software can only report daily measurments on a calendar day basis (since midnight).

Steve Loft did make a simplifying assumption that does not align with the practice of most Meteorological Offices, Cumulus implements minimum temperature and rainfall differently. The World Meteorological Office (WMO) allows individual nations some flexibility, and does not prescribe total international alignment.

The following table tries to illustrate the divergence:
| class="wikitable" border="1"
|-
!style="width:30px" | Derivative
!style="width:800px" | Typical national practice
!style="width:800px" | Cumulus approach
|-
| Minimum Temperature
| The daily minimum temperature in the 12 hours (9 p.m. to 9 a.m.) prior to the traditional observation time is assigned to the date of that observation
| The daily minimum temperature in the 24 hours starting at the selected rollover time is assigned to the date of that rollover
|-
| Maximum temperature
| The daily maximum temperature in the 12 hours (9 a.m. to 9 p.m.) after the traditional observation time is assigned to the date that applies to both times
|-
| Average temperature
| The WMO daily average is the average of the minimum in previous 12 hours and maximum in subsequent 12 hours, this ensures consistency with traditional climate statistics. Nations are permitted to use integrated averages for their internal purposes
| Cumulus maintains a total and a count for each day. The total is incremented by the actual temperature every time Cumulus processes a measurement (may be every minute for Cumulus 1, and every second for MX). The count is incremented by one each time a measurement is processed. The [[Average_temperature|average]] at the end of the day is just the total divided by the count.
|-
| Rainfall
| Some nations report the daily rainfall for the 24 hours prior to the 9 a.m. observation time on a particular date. Others, throw their rainfall total back to previous date, i.e. the total for the 24 hours after 9 a.m on the particular date.
| Cumulus assigns it to the date when the day started.
|-
| Sunshine Hours
| Always reported by calendar day
| Regardless of which rollover time is selected, Cumulus always reports sunshine hours from one minute past midnight until midnight for any day
|-
| Snowfall
| A snow day is reported by calendar day. The snow depth may be only reported at standard observation time of 9 a.m. (or as maximum that day)
| For Cumulus 1, you select a particular time ([[Cumulus.ini_(Cumulus_1)#Read-only_parameters_in_the_Station_section|SnowDepthHour]]) and that is when the date changes, i.e. prior to that snow depth is assigned to yesterday, a snow index is calculated for any longer period (e.g. month or season). Cumulus 1 allows other information to be recorded in the [[Log.xml|Weather Diary]]. MX implements its [[diary.db]] slightly differently, and reports snow falling and lying as well as depth.
|-
| Highest and lowest pressure
| Reported for day starting at 9 a.m.
| Reported for day starting at 9 a.m.
|-
| Highest wind speed
| Reported for day starting at 9 a.m.
| Reported for day starting at 9 a.m.
|}

← Older revision		Revision as of 14:21, 24 July 2021
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	!style="width:800px" \| Cumulus approach		!style="width:800px" \| Cumulus approach
	\|-		\|-
	\| Minimum Temperature		! scope="row"\| Minimum Temperature
	\| The daily minimum temperature in the 12 hours (9 p.m. to 9 a.m.) prior to the traditional observation time is assigned to the date of that observation		\| The daily minimum temperature in the 12 hours (9 p.m. to 9 a.m.) prior to the traditional observation time is assigned to the date of that observation
	\| The daily minimum temperature in the 24 hours starting at the selected rollover time is assigned to the date of that rollover		\| The daily minimum temperature in the 24 hours starting at the selected rollover time is assigned to the date of that rollover
	\|-		\|-
	\| Maximum temperature		! scope="row"\| Maximum temperature
	\| The daily maximum temperature in the 12 hours (9 a.m. to 9 p.m.) after the traditional observation time is assigned to the date that applies to both times		\| The daily maximum temperature in the 12 hours (9 a.m. to 9 p.m.) after the traditional observation time is assigned to the date that applies to both times
	\| Reported for day starting at 9 a.m.		\| Reported for day starting at 9 a.m.
	\|-		\|-
	\| Average temperature		! scope="row"\| Average temperature
	\| The WMO says that daily temperature average is calculated in different ways. Its preference is the average of the minimum in previous 12 hours and maximum in subsequent 12 hours, this ensures consistency with traditional climate statistics.		\| The WMO says that daily temperature average is calculated in different ways. Its preference is the average of the minimum in previous 12 hours and maximum in subsequent 12 hours, this ensures consistency with traditional climate statistics.
	* Prior to automatic recording, some stations would have manual recordings taken a few times a day, and if these were at 0600, 12:00, and 18:00, the mean might be calculated by adding the 3 readings, then adding the last again, and dividing by 4!		* Prior to automatic recording, some stations would have manual recordings taken a few times a day, and if these were at 0600, 12:00, and 18:00, the mean might be calculated by adding the 3 readings, then adding the last again, and dividing by 4!
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	\| Cumulus maintains a total and a count for each day. The total is incremented by the actual temperature every time Cumulus processes a measurement (may be every minute for Cumulus 1, and every second for MX). The count is incremented by one each time a measurement is processed. The integrated [[Average_temperature\|average]] reported at the end of the day is just the total divided by the count.		\| Cumulus maintains a total and a count for each day. The total is incremented by the actual temperature every time Cumulus processes a measurement (may be every minute for Cumulus 1, and every second for MX). The count is incremented by one each time a measurement is processed. The integrated [[Average_temperature\|average]] reported at the end of the day is just the total divided by the count.
	\|-		\|-
	\| Rainfall		! scope="row"\| Rainfall
	\| Some nations report the daily rainfall for the 24 hours prior to the 9 a.m. observation time on a particular date. Others, throw their rainfall total back to previous date, i.e. the total for the 24 hours after 9 a.m on the particular date.		\| Some nations report the daily rainfall for the 24 hours prior to the 9 a.m. observation time on a particular date. Others, throw their rainfall total back to previous date, i.e. the total for the 24 hours after 9 a.m on the particular date.
	\| Cumulus assigns it to the date when the day started.		\| Cumulus assigns it to the date when the day started.
	\|-		\|-
	\| Sunshine Hours		! scope="row"\| Sunshine Hours
	\| Always reported by calendar day (midnight to 23:59)		\| Always reported by calendar day (midnight to 23:59)
	\| Regardless of which rollover time is selected, Cumulus always reports sunshine hours from one minute past midnight until midnight for any day		\| Regardless of which rollover time is selected, Cumulus always reports sunshine hours from one minute past midnight until midnight for any day
	\|-		\|-
	\| Snowfall		! scope="row"\| Snowfall
	\| A snow day is reported by calendar day. The snow depth may be only reported at standard observation time of 9 a.m. (or as maximum that day)		\| A snow day is reported by calendar day. The snow depth may be only reported at standard observation time of 9 a.m. (or as maximum that day)
	\| For Cumulus 1, you select a particular time ([[Cumulus.ini_(Cumulus_1)#Read-only_parameters_in_the_Station_section\|SnowDepthHour]]) and that is when the date changes, i.e. prior to that snow depth is assigned to yesterday, a snow index is calculated for any longer period (e.g. month or season). Cumulus 1 allows other information to be recorded in the [[Log.xml\|Weather Diary]]. MX implements its [[diary.db]] slightly differently, and reports snow falling and lying as well as depth.		\| For Cumulus 1, you select a particular time ([[Cumulus.ini_(Cumulus_1)#Read-only_parameters_in_the_Station_section\|SnowDepthHour]]) and that is when the date changes, i.e. prior to that snow depth is assigned to yesterday, a snow index is calculated for any longer period (e.g. month or season). Cumulus 1 allows other information to be recorded in the [[Log.xml\|Weather Diary]]. MX implements its [[diary.db]] slightly differently, and reports snow falling and lying as well as depth.
	\|-		\|-
	\| Highest and lowest pressure		! scope="row"\| Highest and lowest pressure
	\| Reported for day starting at 9 a.m.		\| Reported for day starting at 9 a.m.
	\| Reported for day starting at 9 a.m.		\| Reported for day starting at 9 a.m.