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iapennell

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  • Gender
    Male
  • Location
    Alston, Cumbria
  • Interests
    Weather observing and prediction, Likes extreme weather prediction. Currently studying Accountancy for more money/weekends off!
    Likes walking, photography and visiting friends and family in spare time. A committed Christian with moderate Conservative values.

    Also likes walking, photography, politics and spending time with family.
  • Weather Preferences
    Proper Seasons,lots of frost and snow October to April, hot summers!

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  1. Continued. Whilst a World without convection is out of the question, mainly because the surface and lower atmosphere have a net heat surplus of about 50 Watts per square metre whilst the upper atmosphere loses heat at a rate of 50 Watts per square metre (averaged globally throughout the year), one cannot underplay the importance of deep atmosphere convection in bringing clouds and rainfall across the World. Even in higher latitudes in winter, the deep depressions that bring rain and snow depend (to a considerable degree) on convection to remain healthy. Oceans at higher latitudes cool o
  2. Dear Readers Underpinning depressions (particularly the tropical variety), tall cumulonimbus clouds bringing heavy showers and thunderstorms and even widespread heavy rainfall or snowfalls occurring over hills in high latitudes have one vital ingredient for their occurrence: Convection. Atmospheric convection lies at the root of strongly rising air (or even gently- rising air originating over an ocean surface or moist land) that brings about cloud- formation and rainfall. If the surface of the land were much colder, the oceans frozen and/ or the upper troposphere a good deal warmer
  3. Continued. This Ekman Spiral effect beneath the subtropical jet-stream is only effective in creating the Ferrel Cell (with surface Westerlies in middle latitudes) when four conditions are met: Firstly, that subsidence beneath the subtropical jet-stream subsides subsides at the subtropical high fairly slowly- so that it can drag the air beneath it equatorwards before it impinges upon mountain ranges. If it is rapid the strong flow of air from west to east will hit mountains like the Himalayas and South American Andes before it has had a chance to move equatorwards (over areas the Ear
  4. NORTHERN HEMISPHERE SEVERE WINTER IN ICE-AGE: RELEVANCE OF THE "EKMAN SPIRAL" AFFECT ON ATMOSPHERIC CIRCULATION A further consideration, with regards to the behaviour of the Global Circulation and Global (Westerly) Atmospheric Angular Momentum (GLAAM) sources and sinks is a feature called the Ekman Spiral, which is related to the Coriolis effect- and which affects related not only surface winds and ocean currents, but it also governs how air that is "dragged" along by faster moving air aloft moves. The Ekman Spiral effect explains why surface atmospheric pressure becomes lower polewards
  5. Continued. A 3C warmer Earth with an ice-free Arctic Ocean year-round has profound implications for the Global Westerly Atmospheric Angular Momentum (GLAAM) fluxes. In the absence of an outside force a rotating mass maintains the same total angular momentum, this is the Law of Conservation of Angular Momentum and for the Earth and its atmosphere this does closely approximate to being true (outside forces such as lunar tides and meteorites are miniscule compared to the exchanges in Westerly Atmospheric Angular Momentum (AAM) between the surface of the Earth and the atmosphere. This means t
  6. Dear Readers The impact of increasing global temperatures over the last forty years on Arctic sea-ice cover is clear: There has been a consistent decline in sea-ice extent compared to the long-term normal (see here for an illustration: http://nsidc.org/soac/sea-ice.html#seaice). The possibility of the Arctic Ocean becoming ice-free in summer, then remaining so into the winter is one that is of increasing concern for remote communities on the Arctic coastline and for wildlife. Less appreciated, perhaps is how an Arctic Ocean free of pack-ice year round would impact upon the prevailing (and
  7. Continued. The conventional understanding of the atmospheric sinks and sources of Westerly AAM, so that the Earth Atmosphere System conserves total axial Angular Momentum, does not necessarily hold true in a manner that some meteorologists might expect for strong Global Warming either: Strong Global Warming would lead to melting of all the ice-caps whilst engendering more frequent (and severe) tropical depressions and hurricanes. Depressions in higher latitudes depend, amongst other things, on steep upper atmospheric temperature and pressure gradients between warmth over mid- latitudes an
  8. continued During the summer half-year in the last Ice age there will still have been enough open water over oceans (and indeed warmth over land) south of about 45N to mean that the transfers of Westerly AAM happened in a manner close to how it is conventionally understood today: That is, with Westerly AAM being transferred polewards to furnish depressions (and Westerlies to the south of them) in higher latitudes. However, the zone of Westerlies would have been closer to the Equator- 30 to 45N rather than 40 to 70N (as in summer nowadays). With the Westerlies blowing in latitudes further f
  9. Dear Readers, I would like to explain how a fundamental feature of the Global Circulation, that of the tendency of the atmosphere to rotate with the solid Earth around it's axis of rotation accommodates changing seasons functions. I also discuss how it accommodates some of the extreme conditions deduced by paleo-climatologists to have occurred across a large area of planet Earth during the most severe phase of the last Ice Age. Drought and severe cold seem to have featured heavily in both lower and higher latitudes during the most severe phase of the last Ice Age whilst drought was a feat
  10. continued Even in the absence of mountains in the Northern Hemisphere, if all surfaces and land areas north of 25N were frozen, then the strong North-East Trade winds in the tropics that would result would still pump lots of Westerly AAM into the atmosphere, yet this would still be unlikely to lead to depressions forming in higher latitudes. This is most certain to be the case in winter when extremely frigid conditions with high-pressure would be liable to dominate and prevent any depressions or Westerlies touching the surface. Instead, it is likely that the Westerly AAM would be forced t
  11. continued However, the manner in which Westerly AAM is returned to the Earth's surface varies with the seasons and is also dependent on whether conditions are such at higher latitudes to favour the formation of depressions, upon which strong Westerly winds are dependent. In winter the frictional impact of stronger North East Trade Winds between the cooler sub-tropics and hot, steamy Equatorial zone add Westerly AAM to the atmosphere at a higher rate as these blow over land and oceans, than in summer. However it does not follow that higher latitudes are always the sink for such Westerly AA
  12. Global Atmospheric Angular Momentum (AAM) is a fascinating subject because it is very central to the type of weather that is experienced over much of the Earth's surface, particularly at higher latitudes. In essence, what goes up must come down, so if the atmosphere gains Westerly AAM with respect to the Earth's surface in part of the World, it must lose it elsewhere. Much is made of the fact that the Earth- Atmosphere system as whole must maintain the same level of axial Angular Momentum overall- through rotation of the Earth and atmosphere from west to east- for the Law Conservation of
  13. There has been quite a few high-profile big eruptions in recent months, each of which has led to volcanic dust ejected to over 10,000 metres' elevation: La Soufriére is the latest, with dust reaching over 13,000 metres' elevation. In March there was Sangay in Ecuador (dust reaching over 12,000 metres) and Mount Sinabung (Sumatra) blew its top at the beginning of March , again with dust reaching over 12,000 metres. At the end of November/ early December 2020 two powerful volcanoes (Semeru and Lewotowo in Indonesia) blew their top and each pushed volcanic dust to over 14,000 metres. The impact o
  14. You will find this in the Winter Prediction part of the forum
  15. Early February will likely be cold and frosty, on the strength of the Sudden Stratospheric Warming now predicted for mid-January exteme minima across the English and Welsh lowlands will be somewhere between -5C and -10C, some frost-hollow areas are likely to be a bit colder than this. In the Scottish Highland's frost-hollows (places like Altnaharra and Braemar) the extreme minima are likely to be near -15C. However, don't expect widespread heavy snowfall unless you live near the North East and Yorkshire coasts, in the Pennines or in northern/ eastern Scotland. For temperatures to get belo
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