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The dynamical principles of the seasons

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Old September 4th 18, 09:59 AM posted to sci.astro.amateur
Gerald Kelleher
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Default The dynamical principles of the seasons

Recently a narrative has emerged that introduces a disruptive notion of astronomical seasons vs meteorological seasons, a notion that disrupts appreciation of planetary climate and the actual seasons created by the daily and annual motions of the planet.

I can't argue against the vapid dichotomy as it is throwing good information after bad so that leaves the actual principles as a benchmark in a clear and concise way.

The warmest part of the 24 hour day, bearing any atmospheric variables, is generally towards 3 PM rather than noon without having to explain why this is so -


There is no astronomical noon vs meteorological noon based on when temperatures rise and subside as it respects the mechanism which causes the variations in the first place.

In hemispherical/seasonal terms it is not much different. Astronomical noon and midnight occurs on the June and September Solstices with temperatures getting progressively warmer or colder for a number of months after the Solstices until polar sunrise and polar sunset on the Equinoxes. This normal and reasonable narrative relies on recognizing the rotational cause behind the polar day/night cycle so that midsummer and midwinter fall on the solstices. Either side of this event sees May as the beginning of Summer and August as the beginning of Autumn/Fall.

The annual sea extent graph serves the same principle as materials during the 24 hour day/night cycle insofar as there is a lag between polar noon and the greatest level of sea ice melting and its recovery that normally takes place around this week -


The meteorologists are presently having a ball talking about the end of meteorological summer for Western Europe while the Americans don't recognise it until the September Equinox hence an unnecessary train wreck that demonstrates poor understanding of planetary temperature variations, the seasons, climate, the motions of the Earth behind the changes and all those things experts are supposed to know.

Just like terms sunrise and sunset are much loved observations and people in Northern Europe tend to base the seasons on length of daylight/darkness rather than temperature markers of the USA, it is important to completely understand both the daily and hemispherical day/night cycles in terms of cause and effect. The British/ Irish meteorologists created a hybrid description that serves nobody and especially not the astronomical underpinnings of planetary climate.

Old September 5th 18, 07:50 AM posted to sci.astro.amateur
Gerald Kelleher
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Posts: 1,528
Default The dynamical principles of the seasons

The polar day/night cycle is an expanded version of the 24 hour day/night cycle with its noon/midnight markers on the June/December Solstices and sunrise/sunset on the March/September Equinoxes.

The South pole location turns parallel to the orbital plane so the Sun has yet to come into view even though it has been constant dawn for a number of weeks. On the Equinox, the Sun will come into view for the first time in 6 months affirming what reasonable people should know - that when daily rotation and all its effects are subtracted, the entire surface of the planet will still turn once to the Sun each year.


That event is like no other sunrise as it affirms the Earth also turns parallel to the orbital plane with the North and South poles acting like beacons for that rotation.


Remove the unsightly 'pole' and up the use of images of other planets,graphics and illustrations to demonstrate that seasonal variations are much more intricate than the normal 'tilting pole' explanation.

I don't exist in a no-man's land between academics and the wider population because that is a hopeless position which suggests an attempt to impress people. Astronomy is a shared experience with its own individual talents and social responsibilities but at its centre is a more intimate connection between observer and creation including the experienced changes of a moving Earth in a solar system structure. It is not intelligence but kindness that is required along with courage that will open up the faculties which make astronomy such a joy in so many ways.


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