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iapennell

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    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.
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    Proper Seasons,lots of frost and snow October to April, hot summers!

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  1. Just to add that sea surface temperatures in higher latitudes are modified- over time- by the prevailing weather-patterns over them. If the warmer-than-usual seas cause low-pressure polewards and prevailing mild Westerlies that lock out very cold Arctic (or Antarctic) airmasses and these warm seas cloudy up frigid Arctic airstreams flowing over them minimising surface radiative heat loss, all this in turn helps to keep sea-surface temperatures from dropping, though a month of 100 Watt per square metre cooling of a 400 metre deep layer of ocean leads to just 0.13C of cooling (below 400 metres almost all deep water in high latitudes is near or slightly below 4C) ! So, cold-air advection be needed too, and it would need to be persistent, with winds pushing back any warm ocean-currents from lower latitudes so the ocean cools over a season for a significant impact such that further cold incursions are encouraged (with higher pressure to the poleward encouraged) and are severe and without blanketing cloudy convection preventing night-time radiative cooling over affected mid-latitude islands. And, of course, the entire process can be undone- and more- by the Summer Sun, with clear skies (and high-pressure) more likely over cooler seas. Ocean surfaces have a low albedo when the Sun is high. Thus, unless something major climatic happens (like a quiet Sun with a Grand Solar Minima, or a massive volcano reducing Solar input into the oceans), it means that under current climatic conditions with rising CO2 levels higher mid-latitude oceans will stay well above freezing. This means that middle-latitude islands will continue to be protected from fierce Arctic (or Antarctic) cold in the coming winters- that is unless some pretty extreme set of high-latitude blocking weather-patterns occurs and persists over two or three winters overcoming the ability of the Summer Sun to warm the oceans!
  2. The National Snow and Ice Data Centre so sea-ice limits close to normal positions for mid-October just east of Greenland and in the north of the Davis Strait- even though the Davis Strait remains ice-free. With the Greenland ice-cap also cooling rapidly along with NE Canada, would not the warmer-than-normal surface of the North Atlantic would support stronger baroclinicity in the far North Atlantic going forwards? NSIDC map here:
  3. Continued Once the cold Arctic (or Antarctic) airmass reaches the island mid-latitude region it is likely to be infused with considerable cloud-cover, with cloud of considerable depth about 2 km above the surface. This cloud-cover, in winter, ameliorates the very cold conditions likely to be experienced at the surface because cloud-cover acts as a blanket, greatly reducing night-time radiative heat loss. This means that air-temperatures seldom drop more than a few degrees below the generl temperature of the cold airmass a few hundred metres above the surface. Even if the cold-air advection from high latitudes is accompanied by high-pressure moving in and subsidence up to 500 metres a day, with moisture entering the air from the warm sea-surface at a rate of 1 cm a day (especially likely if the cold airstream is accompanied by strong wind), the replacement of the lowest 2 to 3 km of the atmosphere with dry air at a rate of 20% a day is hardly likely to ensure the cloud-cover disperses. Thus, only very strong subsidence (with some warming of the upper-air to bring the inversion nearer the ground) will bring the clear skies needed for radiation cooling at the surface- a situation that must involve amelioration of the cold temperature of the air some 2 km above the surface so that the airmass is alittle less cold anyway. So, in this second way, warm seas protect mid-latitude islands from fierce high-latitude cold. The third significant manner in which warm seas in higher latitudes protect mid-latitude islands from great cold is by modifying surface atmospheric-pressure polewards of the locations to be affected in a manner that makes those very cold Arctic (or Antarctic) outbreaks less likely in the first place. Upper-air (above 3,000 metres) is invariably extremely cold polwards of 50N (or 50S) in winter, partly as a consequence of Westerly Atmospheric Angular Momentum (created by easterly Trade Winds' interaction with the surface in the tropics and sub-tropics) leading to strong Westerlies- and a resultant limitation in the penetration polewards of warmer air- aloft. Very cold air aloft and warmer air below (as it invariably is over warm sea-surfaces) results in rather lower atmospheric-pressure near the surface. This entire process limits the potential of high-pressure to form and persist poleward of the middle-latitude islands where it could direct frigid high-latitude air towards them. Of course, with sea-surface temperatures in higher latitudes warmer as a result of global warming, this rather limits the scope for frigid high-latitude airstreams to even reach the UK, or to reach Ireland or New Zealand. Warmer seas also limit the scope for these very cold airstreams to then bring clear night skies and extremely low temperatures in winter.
  4. Dear fellow Weather Observers In middle latidude islands and some continental areas in various parts of the World hundreds of miles of warm seas with average temperatures well above 0C in the coldest months separate the region from any source regions from which extremely cold airmasses (with a mean temperature well below 0C at sea-level) may originate. Such areas of the World include the UK, but also Ireland, various Mediterranean islands, southern Japan, Bermuda, New Zealand and Tasmania. Also included are southern Argentina/ Chile as well as southern Australia and South Africa because the continents to which they are attached are only large in latitudes too low to support serious continental cooling and so Antarctica is the only real source region for frigid air- meaning advection across the Southern Ocean is required for this air to reach these continental localtions- so for the purposes of the dynamics of very cold airstreams the southern tips of the Southern Hemisphere continents are included. Quite apart from the modifying influence of much warmer sea-surfaces in warming very cold airmasses passing over them: An airmass of 3 km depth in the lower atmosphere is warmed by roughly 10C in 24 hours if the temperature differential between it and the ocean surface is 20C to begin with because a temperatre differential of 15C leads to a 300 Watts per square metre net heating of the air by the warmer ocean (and the warming will be more than that to begin with), thouh in winter this is offset (to a rather smaller extent) by net radiative heating of the lower atmosphere. In addition, there will be a significant amount of heat (latent heat of condensation) as the water vapour pressure from the warm sea surface greatly exceeds that from the cold atmosphere above- with the result that moisture enters the atmosphere and vigorous convection soon results in cumulonimbus and showers of rain or snow. Thus, you end up with a situation whereby an airmass that starts off at -10C and spends 24 hours over a sea-surface of +10C is likely to be about 2C in the lowest layers after 24 hours. This is why a frigid Siberian airmass, crossing Scandinavia at a temperature of -20C in the lowest layers in winter, is hardly ever likely to be below -5C at sea-level by the time it reaches the coast of eastern Scotland and North East England after its passage across the northern North Sea, the surface of which in January is typically about 8C. But this obvious warming is not the only way warm, ice-free high-latitude seas protect middle-latitude regions from the fiercest onslaughts of Arctic, Siberian or Antarcic cold: It is very clear that the vapour-pressure of warm sea-surfaces compared to a very cold airmass over-running it pumps large amounts of moisture into the air. A strong dry and icy wind at -10C over a sea-surface of 10C can extract over 1cm of water-equivalent, which is more than sufficient to result in deep cloud-cover in an airmass at (say) -5C in the lowest layers and -30C at 3,000 metres (the air would warm more near the surface though less quickly aloft and that would encourage strong convection currents in the still-frigid air). Much of the moisture would freeze out in cloudy convection resulting in sharp snow-showers, which are a feature of very cold airsreams over warm seas, but not all of it. With the moisture chiefly freezing out at higher levels the higher-level air (at 2 to 3 km) warms quite rapidly so after 24 hours this reduces the atmospheric temperature gradient to the extent that convection then proceeds at a lower rate. However, cloud-cover at 2-3 km would act as a stronger surface from which radiative heat-loss maintains the middle-level air at a low-enough temperature to ensure convection continues. Continued below
  5. Hi, been rather busy so not been on here recently. My money is on a slightly milder-than-normal winter in 2022-2023 after a mild blustery autumn overall. Global warming meaning temperatures over a wide area are over 0.5C above long-term normal, Westerly QBO high over the Equator returning just in time to influence winter circulation. Sea-surface temperature anomalies in the North Atlantic of +2C as I speak combined with pack-ice nearer normal around and nw of Greenland indicate greater baroclinicity over North Atlantic (with deeper depressions). Strong La Nina in tropical Pacific that would otherwise lead to less energy entering the Northern Hemisphere circulation (and which would increase the change of blocking/ cold spells) outweighed by the other factors, though a few short cold snaps (from the north/NW) still likely. Ian Pennell
  6. @Roger J Smith The idea of pumping sea-water onto Canadian glaciers in winter- so that the water freezes and increases the surface mass balance- and (hopefully) reduces sea-levels- and also building new glaciers in this way that reflect away the Sun's heat in order to keep the Earth cool are certainly achievable- with sufficient resources and enough pumps. Northern Canada does have large freshwater lakes which can be used in stead of sea-water as the melting point is higher (as is the albedo of pure ice). I agree with the point about the quiet Sun for the next 30 years having a cooling influence that counterracts the effect of rising sea-levels, so it might not be essential to resort to such drastic measures to prevent major tipping points arising until such times. Damming the Bering Straight is certainly doable- a large floating barrier would stop warm currents from the Pacific melting the Arctic ice. Building a real barrier- a wall would require much more in the way of resources, and would certainly stretch the technical capabilities that man possesses today. In the meantime, it is encouraging that COP 26 has produced more agreement from more countries- including India- on the need to reduce CO2 emissions rapidly. Unfortunately, places like Britain- on the west sides of continents in higher middle latitudes- are already suffering from the effects of storms, coastal erosion and greater flooding, some kind of north-south barrier in the North Atlantic or, if more practical, building a massive wind-farm in the North Atlantic west of Scotland both to generate more renewable energy and to slow down the strong winter south-westerlies ought to be considered in the next decade or so to protect our coastal communities and stop them falling into the North Atlantic. An alternative measure might be to invest ££ billions more into strengthening coastal defences and dredging rivers to cope with the storms that will come because of the global warming we already have. Mediterranean lands and countries like Israel already suffer from excessive droughts more than they used to- helping them with water desalination and more reservoirs would be enormously appreciated by these countries. If other readers of this forum have other ideas for Geo-engineering that are practically possible and leave minimal side- effects in terms of pollution, please feel free to share them.
  7. @knocker As the upper warming over the tropics with modest global warming would appear to be the more dominant influence this does tie in with IPCC predictions that higher latitudes will be warmer and wetter in winter with more intense storms as a result of global warming. The reduction in the frequency of prolonged high-latitude blocking bringing bitterly cold northerlies and easterlies for long periods in the UK in winter in recent years does bear this out. The earlier global warming of the 1920's and 1930's was accompanied with few severe winters (1928-29 excepted), and more frequent strong westerlies and heavy rains; the 0.5C global cooling from 1940 to 1970 brought about more frequent blocking and some noteworthy severe winters to the UK, of which 1946-47 and 1962-63 were the most extreme manifestations. For more recent decades, with the exception of December 2010, there has not been a CET with a mean temperature below 0C since January 1987. In the 1980's both February 1986 and January 1987 had a mean CET below 0C- and December 1981 was within three-tenths of a degree of being another month with a mean CET below 0C, as was January 1985. Severe night frosts in April and October were not unknown in the 1980's, but have been virtualy unknown in lowland England in the last eighteen years. All of which suggests that, at least during the winter half-year, high-latitude blocking has been decreasing as the North has got warmer. Other factors help explain why the Circumpolar Vortex and storms should become stronger in winter as the Northern Hemisphere warms- in spite of the Arctic warming faster. One is that a warmer North Atlantic and warmer North Pacific can furnish more moisture (and more latent heat energy to power stronger storms) in a warmer world. The other is to do with the mean latitude of the Westerlies shifting polewards (following the retreating edge of Arctic ice-cover and attendant zones of strong baroclinicity), as the Westerlies shift polewards they have to blow harder to act as a sink for Westerly Atmospheric Angular Momentum put into the atmosphere in the tropics by surface tropical easterlies, that is because the Westerlies blow closer to the axis of the Earth's rotation. A warmer World also means hotter air containing more moisture in the zone of hot rising air near the Equator, which would fuel stronger thunder-storm type convection there, this is something that readily becomes apparent during strong El Niños. More vigorously rising air near the Intertropical Convergence Zone supports stronger NE and SE Trade Winds, and stronger Westerlies aloft in an invigorated Hadley Circulation and greater transfer of Westerly AAM to higher latitudes. Stronger convection near the Equator would lead to greater latent heat transfer aloft and a consequent latent-heat induced warming of the upper air over the tropics, consistent with the article referred to above. This is all consistent with greater Westerly AAM transport to higher latitudes, stronger Westerlies reaching the UK and deeper depressions passing to the north: Strong Westerlies at the surface and aloft tend to preclude high-latitude blocking patterns. If, however, the Arctic basin became very much warmer in winter, perhaps as a result of further climatic warming leading to a complete thaw of the pack-ice and then warm southerly winds from the Atlantic associated with frequent depressions helping to prevent the re-freezing of the Arctic Ocean well into the winter blocking patterns could increase rapidly: The the low atmosphere over the Arctic could be over 20C warmer, which would be enough to greatly reduce baroclinic temperature gradients that fuel the North Atlantic (and North Pacific) depressions- leading to a weakening of the Westerlies. The sinks for Westerly AAM would be pushed into lower latitudes (associated with troughs in a weaker Circumpolar Vortex), as well as the Arctic interior becoming a sink for Westerly AAM associated with depressions. Were that to happen, intense blocking highs over northern Europe could become very frequent- with major implications for winter weather in the UK.
  8. Dear Readers This is a thread which, I hope that fellow members of this great forum can discuss practical geo-engineering solutions to fight Global Warming and to arrest some of the egregious regional climatic trends- heatwaves, drought, floods and storms, coastal erosion, etc.,- that have become more apparent in recent years. Whether one believes we are soon to face Apocalypse or that CO2- induced warming will be cancelled out by natural trends in the next thirty years- temperatures globally- and averaged throughout the year- have undoubtedly risen byjust over 1C since the end of the 19th Century: More severe droughts and wild-fires in the sub-tropics and Mediterranean latitudes and more devastating floods and storms in higher latitudes certainly have the potential to not only destroy habitats but also cause great economic hardship, destroy homes and offices and displace significant numbers of people. And, at this time, with China and Russia staying away it looks like COP26 will end up being little more than a jolly of G20 World leaders: If China, Russia and (likely) India will not countenance really cutting down coal production and burning (these are by far the biggest CO2 polluters), what hope is there for curbing CO2 increases to stop global mean temperatures getting above the 1.5C threshold whereby unstoppable feedbacks set in causing sea-levels to rise precipitously? In the light of all this, and the huge economically-damaging costs of Net Zero, forcing people to go electric by a certain date, putting higher costs and taxes on businesses and home-owners in Britain (and potentially bankrupting the country), I think the Government could abolish the Climate change Act (2008) and strike down the legal commitments to make Britain carbon-neutral by 2050 (costs of this in excess of £1 Trillion are conservative estimates). If the Chinese and Indians are not going to bankrupt their economies to persue Net Zero, then why should Britain when it is not going to have much effect? A different approach is needed. Firstly, Britain should incentivise business and companies to go green using tax breaks. There are still over £20 billion of stakes in part-nationalised banks still on the Government's books, these could be sold and the proceeds used to cut taxes on green products- economic growth and the revenues from the increased "Green Economy" will help make these tax breaks self financing. Secondly, rising CO2 levels, Global Warming and some of the unpleasant side effects (like increased drought in the Med and coastal erosion from more winter storms in high latitudes) need completely different, new approaches to tackle them. Again, R & D funds can be directed at the scientific community to develop real solutions to Global Warming, funded more by (perhaps) cutting the size of Quangoes. And talking of real solutions, please feel free to discuss practical, but effective solutions to reducing global temperatures- and dealing with some of the now- apparent unpleasant side-effects of a warmer World. Some ideas I have seen around, that could be economically feasible and practical (but with limited side effects) are as follows. These might need a Coalition of the Willing countries to just do (getting full Global Agreement for anything these days seems to be nigh-on impossible!): 1) Spraying sea-water into the troposphere over tropical oceans (with pumps from the sea-surface supported by large balloons (hot air balloons or filled with helium, whichever is most practical). The fine salt solutions sprayed into the atmosphere leads to moisture and condensation nuclei causing the ready development of more cloud. The increased cloud over tropical oceans would reflect more heat from the Sun back to space and help keep the Earth cool. The costs of a few thousand large balloons and pumps- and some helium should not be more than a few £ billions. 2) A fleet of suitably-modified high-flying jets could spray milions of tonnes of suplhur dioxide into the stratosphere around the Equator- above the altitude where it will be rained onto the surface from rain and high-altitude snowfall. Half a metre thickness of sulphur-dioxide above 20 km would have a dramatic effect in shielding the Earth from the Sun's rays whilst the settling of this sulphur dioxide is likely to be sufficiently gradual as to cause minimal damage to ecosystems, the environment and communities at the Earth's surface. Relatively cheap and practical to do, but likely to be great resistance from Environmentalists. 3) Salt extracted from sea-water. Billions of tonnes of powdered salt could be carried up to the edge of Space by thousands of specially- constructed Earth- orbiting rockets. These rockets would fly west-to-east around the Equator (and other low latitudes) releasing the powdered Salt- which would remain in orbit around the Earth- a man-made Earth ring (like Saturn's). The Earth-ring of powdered salt rotating around Earth at the edge of space would reflect the Sun's rays back into space and help keep the Earth cooler. At a cost of a few ££ billions, this could buy time for global markets to work on CO2-neutral energy and transport solutions. 4) Pump large amounts of purified sea-water (or fresh water from glacial rivers/ lakes) using giant pumps and large pipes to the top of the Antarctic Pleateau and the top of the Greenland Ice Cap (in their respective autumns and winters) where it would freeze in the very low temperatures. The release of latent heat as vast quantities of water freeze would reduce the atmospheric temperature and pressure gradients (that is what meteorologists call the atmospheric baroclinicity) that drive powerful storms at higher mid-latitudes- helping to stem some of the heavy rain, flooding and coastal erosion in places like Britain, western Norway and western Canada. The freezing of water onto the ice sheets would help build up the ice-sheets and (in the process) help to reduce sea-level rises. This process could be taken further by spraying and freezing water onto large parts of northern Canada (with their permission) in the winter, over a designated a new ice-sheet. If ten metres' thickness of ice can be built up over a large part of Northwest Territories the ice would not melt away the following summer and the new ice-sheet would reflect away the Sun's heat. Thereafter the new ice-sheet could be built up the following winter by being hosed from some of Canada's many tundra lakes- the water would freeze and build up the ice-sheet and the release of latent heat would weaken the baroclinicity downstream- meaning less damaging winter storms heading towards Britain. This is practical, the costs are likely to be just a few £ billion (which rather compares favourably with over £1 Trillion for Net Zero!). 5) Cause a mild "Nuclear Winter" (or "H-Bomb Winter") to fight Global Warming by dropping a couple of powerful H-bombs on an evacuated desert island. Hydrogen bombs dont cause nuclear fall-out but (if powerful) they could send enough dust and ash into the Stratosphere to reflect heat from the Sun to but more time as the World moves towards CO2-free energy and transport solutions. A variation of this might be to try and bomb a normally- explosive volcano in a remote area to provoke it into exploding and releasing vast amounts of dust into the Stratosphere. This is probably the cheapest option, but would be very much a last resort! As this is intended to be a thread to discuss Geo-engineering solutions you are welcome to propose your own, different, ideas. If you think the above are non-starters what do you think might work? Should Western Nations bankrupt their respective economies and impoverish their populations for a vain cause (which it will be if China and India keep belching out CO2 and refuse to reduce emissions)? Ian Pennell
  9. @ ANYWEATHER A wall up to 4,000 metres (just over 13,000 feet) built north to south from 60N to 35N- just off the Canada and USA coast would be a challenge but, I don't think, completely impossible if there was the will to do it. The seas around Britain are already prolifering with wind-farms galore and- in the past- large oil rigs were constructed and put into position in the North Sea. Huge concerete blocks could be manufactured elsewhere and moved into position with the help of some large ships and a few cranes- and moved into place with the assistance of underwater cameras. It would be just offshore- so still on the continental shelf where the sea depth is no more than 150 metres. The wall would need to be 500 metres thick to withstand the forces it would be subjected to, particularly waves and strong winds. And at 4,000 metres' elevation the wall will be consistently exposed to strong 100 mph Westerly winds between October and April - associated with the Circumpolar Vortex- hence the reason for building it: The plan would be to construct a major sink for Westerly AAM- so that the Westerly AAM does not bring strong Westerlies and damaging storms downstream- i.e., over northern Europe, to stop storms that often bring warmth to the Arctic interior too where thy accelerate the loss of that all- important high-albedo ice-cover. Certainly, the floating mirrors on the equatorial Pacific and Atlantic would be a far more feasible option for achieving the same result: Weaker North East and South East Trade winds feeding into a weaker zone of hot rising air near the Equator and- as a by- product- weaker Westerlies and less "Warm sector conveyer belts" bringing ice- destoying heat to the Arctic (and coastal Antarctic). If giant wind-farms can be constructed at sea, large floating mirrors with a single anchor to the sea-bed are certainly doable. Bit this is a point to consider: If NO Geoengineering schemes are EVER to be considered then the World is left entirely at the mercy of China, Russia and India- where rapidly-growing populations and pro-growth governments will not voluntarily impose measures that impose hardship on their populations in order to reduce CO2 emissions (look who is not going to be at Cop 26!). Should Britain and other Western countries impose Net Zero and other economically- harmful Green policies whilst China and Russia laugh at us? There is nothing that Britain can do to prevent significant further Global Warming without their cooperation, and really a proper Conservative Government would (sensibly, in my view) tear up the Climate Change Act (2008) and Net Zero legislation in view of this, especially as Britain is on the verge of Stagflation! Yet Global Warming is real, even if it is not as great as some of the Environmentlists and the IPCC might suppose with rising CO2 levels. Britain's coastlines are precious, coastal communities deserve effective measures to protect them (and I don't mean ever-greater sums spent on coastal defences in the face of winter storms and floods that could smash these like match-sticks). Bugs and pests are spreading and- unkilled by winter frosts- will lead to ever more disease and pestilence. Farmers suffer increasingly from bugs and pests blighting their crops in warm, damp autumns (I have a nice crop of Brussels sprouts at home, but all full of weavils!!). And carbon capture and planting millions of trees is not going to be enough to arrest this change without 100% Global Co-operation (which is about as likely as the Sun going out tomorrow).
  10. The huge expense in trying to combat Global Warmng- through taxes on Carbon, Net Zero- thus helping to stop the higher-latitude Westerlies "Getting out of hand" and causing irreparable coastal erosion in Britain and other parts of northern Europe- is likely to be in vain if we cannot get China and india to curb their CO2 emissions. But at a fraction of the cost, Britain and other countries working together might find another means of taming (and perhaps even reversing) Global Warming by implementing geo-engineering measures that weaken the Westerlies, reduce the number and intensity of strong "warm-front conveyers" associated with depressions that push a little too much heat and wind into high latitudes! If we can reduce the number and intensity of depressions and strong south-west (and southerly) winds moving into the Arctic basin you help preserve the ice there (it may hopefully recover) and that ice then reflects heat from the Sun as it persists through the summer- keeping the Earth cooler. Some measures to do this include the following: 1) Building a 4,000 metre-high wall (500 metres thick); running north to south from northern Quebec to Atlanta (it can be built just off-shore to avoid it going over valuable farmland and communities). This would be a huge undertaking costing $$100 billions but it would be cheaper than all the huge efforts to combat Global Warming running into $$ Trillions. A 4 km-high wall would be effective at intercepting the Westerlies where they are stronger- the force of the wind against this high wall would be a very effective sink for Westerly AAM- leading to weaker Westerlies downstream. The high wall would also create an upper trough (with depressions and associated Westerlies blowing further south) downstream, bringing rain to the parched Mediterranean and Israel whilst relieving Britain of damaging storms and coastal erosion (and brining about colder, drier winters in Britain, too). The Arctic would get a chance to cool, as would Siberia. That will preserve reflective ice-cover and prevent the Siberian permafrost thawing (and all that entails). 2) A cheaper, more practically feasible option (one that will require International Agreement) is to cover 2 million square miles of the Equatorial Atlantic and Pacific with floating mirrors- perhaps attached to the sea-bed by long chains so that they can't drift over fishing lanes, shipping areas or troucle coastal island communities. The mirrors would reflect away the Sun's heat (helping to keep the Earth cool) and the cooling of Equatorial waters would help weaken the zone of hot-rising air in the deep tropics. This would, in turn, weaken the converging North East and South East Trade Winds, reduce the addition of Westerly AAM to the global circulation and, thus, weaken the Westerly AAM available to furnish depressions and Westerlies in higher latitudes. Weaker Westerlies and depressions in the North means less "warm front conveyer belts", less Winter storminess and the Arctic being allowed to cool. That in turn means more reflective ice there (and also around Antarctica), which could be enormously effective at countering the greenhouse effects of rising CO2 levels. The Med and Israel will get much-needed rain, Britain and northern Europe will benefit from hard winter frosts to kill the bugs and from less coastal erosion. There will also be more decent summers in northern Europe. However, as far as Climate Change is going, the Clock is Ticking and there is perhaps just forty years to prevent serious Global Warming and all that entails! At the moment a Quiet Sun is helping, by counterring the CO2 warming effect, in forty years time the strong Solar Sunspot Cycles will be back and the Sun will amplify Global Warming. It does not look like we can rely on China.
  11. So, almost all year round in both the Northern and Southern Hemispheres, there are no strong Westerlies over an extensive area between 36.9 degrees South and 36.9 degrees North, at leas not that impact the Earth's surface. This has been the case fairly consistently over the last decade. It means that Westerly AAM is generated over half the planet- in low latitudes where the Easterlies are most effective at adding Westerly AAM to the atmosphere by surface friction (or by easterlies blowing against mountains causing a mountain torque) as they blow far from the axis of Earth's rotation (think of sitting away from the centre of a see-saw). The surface Westerlies, which act as a sink for Westerly AAM all blow appreciably closer to the axis of Earth's rotation given they are restricted to the 40% most poleward sea and land surfaces of the Earth- and therefore they have to blow extra hard! This explains why the Westerlies have to blow stronger and more consistently in the North. And the warmer seas and oceans and retreated margins of Arctic ice help furnish stronger depressions that move in higher latitudes- and that, too, is consistent with the stronger Westerlies that blight our recent winters with so much rain, wind and mildness for those who like "Proper Winters". Hotter, steamier conditions near the Equator add fuel to the rising air and thunderstorms that dominate the low- pressure areas there. That is expected with rising CO2 levels. Faster rising air near the Equator helps strengthen the North-East and South-East Trade Winds that converge on it- and hotter summers in whichever tropical areas are getting summer strengthens the Equatorial Easterly Jet-stream (about 5,000 metres above sea-level and able to blow against Kilimanjaro, the northern Andes and the mountains of Papua New Guinea). That, in turn means stronger sources of Westerly AAM extensively across the Tropics and sub-tropics- and a need for more persistent and strong Westerlies in higher Northern and Southern latitudes. And the strong Westerlies in higher latitudes of the Southern Hemisphere, both at the surface and aloft explain the unusual extreme cold over interior Antarctica and the re-emergence of the Ozone Hole: These strong Westerlies, associated with deep depressions that encircle Antarctica (some below 930 millibars at the centre) form a barrier stopping frigid air leaking out towards Argentina, South Africa or Australia but they keep the frigid air over Antarctica pure- with little warmer air from lower latitudes getting through. The very frigid air continues to cool in the sunless winter over interior Antarctica (where skies are often clear and maximising heat-loss from the ice surfaces)- and so the extremely low winter temperatures (even lower than normal) at the South Pole are explained. Aloft, the tight vortex of circumpolar Westerlies intensifies during the Antarctic winter (helped by conditions below) and- in the absence of any sunlight- the Stratosphere over interior Antarctica gets intensely cold, that is, below -78C. This is cold enough for minute ice-crystals to form- which facilitate chemical reactions that destroy ozone in the presence of minute amounts of other pollutants (chlorine- based)- these happen when the Sun returns to the interior Antarctic stratosphere (August- September). With strong Stratospheric Westerlies encircling Antarctica ozone-rich upper air from lower latitudes cannot penetrate: Thus you have an Ozone Hole. This concentration of the Westerlies in higher latitudes and mainly just Easterlies in the Tropics and sub-tropics, both in the Northern Hemisphere and Southern Hemisphere is associated with persistent high-pressure near 35 degrees North and 35 degrees South. So whilst Israel and California suffer droughts and summer heatwave, Britain has (mainly) wet mild autumns and winters and frequent flooding and storms, warm airmasses penetrate as far as Siberia even in winter and bring thaws (unheard of in the 1980's) but Antarctica suffers very extreme winter cold (average winter temperature in 2021 at the South Pole was -63C) and an Ozone Hole. Strong south-west winds from the Atlantic have penetrated right up towards the North Pole on occasion- raising the potential for complete ice-loss.
  12. Dear Readers, Rising CO2 levels in the atmosphere has undeniably had a warming impact on the Earth's climate, with the planet as a whole having a mean temperature during 2020 just over 1.0C above pre-industrial averages. The warming impact has undeniably been greater in recent years in Russia, Canada, and northern Europe where- in the winter months the mean warming has been over 2.0C above pre-industrial averages for the season. Some of this warming may be related to the Earth coming out of the Little Ice Age- but some of the effect is undoubtedly due to CO2 levels since we are entering a period of quiet Sun (weaker sunspot cycles with slightly weaker Solar output) which, all else being equal ought to bring a cooling back to the conditions of the 19th Century: Plainly that is not the case. But why do middle latitudes and higher latitudes in winter warm more? The exception is interior Antarctica that has got colder in recent winters, and winter 2021 (June-August) was one of the coldest on record at the South Pole. The Antarctic Ozone Hole in the Antarctic stratosphere has also made a bit of a come-back in 2021 (during the Southern winter). Is that also in some way related to warmer, wetter winters in most middle and high latitude areas? The answer is a definitive "Yes". Most meteorologists appreciate the impact of something called the Law of Conservation of Angular Momentum on the Earth's global weather-pattern: In layman's terms, the Earth's rotation and the virtual absence of outside forces (gravitational tidal influences from the Sun and Moon, the effects of meteorites and bursts of super-charged plasma from the Sun following coronal mass ejections are largely negligible over just a few years) means that the atmosphere as a whole has to rotate with the Earth. From this, the frictional and pressure impacts of Easterlies at low latitudes and near the poles are counterbalanced by the frictional and pressure impacts of Westerlies in middle latitudes. This applies to both the Northern Hemisphere and the Southern Hemisphere and largely dictate the existence of the Westerlies in higher latitudes, but not necessarily where they occur or how strong they are. However, global weather- patterns are also (and primarily) controlled by the heat input to the Earth-Atmosphere system, how much heat there is and where it is on the Earth. It is also dependent on moisture and atmospheric temperature gradients. A warmer Earth not only means more moisture in the atmosphere but, with the edges of polar ice-caps (seasonal and year-round) retreated polewards it means that the Westerlies- intensified and largely fixed by atmospheric and near- surface temperature gradients (what meteorologists call baroclinicity) as the depressions that drive these depressions also need these zones of baroclinicity. Now, the areas of the Earth where easterlies are at the surface are called sources of Westerly Atmospheric Angular Momentum (AAM) or simply Global Atmospheric Angular Momentum (GLAAM). This arises because Easterly winds, blowing in a direction opposite to the Earth's rotation result in the Earth losing a bit of it's eastwards rotation to the atmosphere- in other words these areas with surface Easterly winds are sources of Westerly AAM (or GLAAM). Since, at least under current climatic conditions, the winds aloft do not start blowing 1,000's of miles an hour from the West and remain fairly constant in speed at the height of the winter (seldom more than 200 mph at 10,000 metres' elevation) it follows that other areas are sinks for Westerly AAM (or GLAAM). These areas are in higher latitudes where often -strong Westerly winds blowing over the sea or against hills result in a frictional force at the surface slowing the Westerlies down- and helping to speed the Earth's rotation up. The fact that the Length of Day remains fairly constant throughout the year- and from year to year (though the Length of Day is very slowly increasing by a millisecond a decade mainly due to the effects of marine tidal friction due to the Moon)- means that Westerly AAM is imparted to the rotating Earth as much as it is removed via tropical and Polar Easterlies. Now, for some interesting observations of global weather maps by a seasoned meteorologist (myself): For almost all the year the Westerlies seem to be concentrated at the highest latitude 40% of the Earth's surface (sin-1(1-0.4)=36.9 degrees, so that is Westerlies restricted to North of 36.9 degrees North and South of 36.9 degrees South). Of course, there still are some occasions with Westerlies in lower latitudes, strong Westerlies occur on the equatorwide of hurricanes and tropical depressions when these occur but these are counterbalanced by just as strong violent easterlies on the other side of these tropical storms. South-Westerlies blow over India and adjacent parts of southern Asia during the Summer Monsoon- which will help reduce some of the need for strong Westerlies at higher latitudes of the Southern Hemisphere in the winter there, so this will not help weaken Westerlies in high Northern latitudes. Often the Tibetan Plateau gets Westerly winds in winter, but these have seldom been strong and they are restricted to those areas north of 30 degrees North. (Continued below)
  13. 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 only gradually with the season whilst prevailing westerly winds keep the western continental margins furnished with surface air that is just above freezing- point. Aloft, the air is extremely cold (-60C at 10,000 metres above the surface). The air temperature drop with height is thus just over 6C per 1,000 metres' elevation and moist air rising in a depression- and condensing it's moisture content as it goes- cools at a rate of almost exactly 6C per 1,000 metres- as the moisture condensed and frozen out gives up a lot of latent heat in the process of freezing out. Thus the air stays marginally warmer than the air around it as it rises, causing the air to rise faster because being a little warmer it is lighter. So the air rises faster and provides energy and impetus to the depression. If our Winter depression then moves into Russia and entrains air that is below -10C at sea- level, then with the air at 10,000 metres still at -60C the lapse rate drops to 5C per 1,000 metres. Rising air in the depression still cools at 6C per 1,000 metres- and in rising higher becomes colder (and relatively denser) than the atmosphere around it. Thus convection stops, the colder air in the low elevations of the depression can no longer rise effectively- and our Winter depression quickly fills. This is why depressions penetrating the Central Arctic in February quickly run out of steam and fill and why deep depressions are normal in the Southern Ocean around Antarctica but you rarely, if ever, get a deep depression over the South Pole in any season. Even in the deep tropics, areas of cooler sea- surface temperatures or warmer than normal conditions in the high atmosphere can sharply weaken convection and the rain- bearing thunder-storms that depend on it. The Intertropical Convergence Zone (ITCZ), where hot steamy air in low latitudes rises and fuels spectacular thunderstorms, is largely driven not by converging Trade Winds from the Northern and Southern Hemisphere but by the vigorous up-draughts of a myriad of thunderstorms which pump large amounts of latent heat into the upper atmosphere causing atmospheric divergence aloft and a fall in surface- pressure below. It is the powerful convection currents of thousands of thunderstorms that fuels the ITCZ and that, in turn draws in the Trade Winds below- sending Westerly Atmospheric Angular Momentum (AAM) through the frictional interaction of the easterly Trade Winds with the underlying surface. And that Westerly AAM, under current climatic conditions also helps to fuel depressions in higher latitudes with the attendant surface Westerlies acting as a sink for Westerly AAM. Without the cloudy thunder-storm convection of a myriad thunderstorms along the ITCZ the entire house of cards of the global weather- machine would collapse. If the surface of the lands and oceans near the Equator were 5C colder than nowadays, but the upper-air is the same temperature almost all of the convection driving the ITCZ would collapse because the temperature drop with height would be such that rising parcels of air would become cooler than the surrounding air before much moisture could condense out. Relatively dry air at temperatures typical of the low atmosphere in the tropics cools at a rate of 10C per 1,000 metres, so convection would quickly run out of steam before condensation (and latent heat release) of warm moisture- carrying air reduces the effective lapse rate to 5C per 1,000 metres (which is what fuels deep thunder-storm convection). So an Equatorial zone just a few degrees cooler than today at the surface would scarcely maintain an ITCZ, the Trade Winds converging from north and south of the Equator would be very weak and, without the transfer of Westerly AAM into the global atmospheric circulation there would be very little Westerly AAM transferred to higher latitudes- for which read, means no Circumpolar Vortex, no extra-tropical depressions and no Westerlies in higher latitudes. And that would be all for the want of vigorous thundery convection in the deep tropics! The effectiveness in cooler- than- usual surface conditions in killing convection (and thus rainfall) in the tropics can be seen from low rainfall amounts on the coast of Ecuador and Peru- where the cool Humboldt current effectively kills convection and leads to semi desert conditions just inland.
  14. 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 convection could not occur- anywhere, even in areas where the atmosphere rises because of convergence into the region (and rising air in the hot, steamy tropics and in the vicinity of deep mid-latitude depressions largely depends upon convection and the release of latent heat in the rising cooling air to fuel up-draughts). The situation with an atmosphere without convection means that the areas of rising air would invariably cool faster than the surrounding air- and become denser in the process: Thus the convection currents would be still-born (and probably before the moisture contained in the rising air- parcels cool to the point where the moisture condenses out). The Earth's Hydrologic Cycle would be much weaker, and it would be largely restricted to the oceans- because rainfall over land requires moist air to be pulled inland by areas of vigorously- rising air associated with depressions (and, of which, convection, condensation and the release of latent heat as moisture condenses in rising air is a major part). If the oceans were frozen, very little evaporation could happen in any case but- without mixing with air above it, the atmosphere in a fairly shallow layer over the surface (no more than 500 metres with strong winds, below 50 metres with light winds) would soon reach saturation during periods of nocturnal cooling leading to widespread dense fog (or freezing fog) out of which fine water droplets or ice-crystals would fall back to the surface. This process would balance the net evaporation rate from a frozen/ cold ocean surface. If convection cannot occur and rising air gets colder than the air around it (and no warmer than air up to 500 metres above it), that shallow layer of moist air is not going to go very far and even mixing with the air above is greatly limited by the air not been warmer than that above it- in the same way that today any rising moist air in the upper troposphere mixes very little with air higher up in the Stratosphere because of the very temperature profile of the atmosphere there. It follows, therefore that the only moist layers of air would be shallow layers of air over the oceans if there could be no atmospheric convection on Earth: These shallow layers of air over the oceans would be at or very close to saturation all the time- with the result being that the world's oceans would be largely shrouded in fog- particularly at higher latitudes and over parts of the oceans in low latitudes that had come through a night of radiative cooling. With so much of the watery 70% of planet Earth shrouded in sunlight- reflecting fog the planetary albedo would be well above 40% resulting in sharply lower global temperatures (with the oceans freezing at higher latitudes). Over the continents the lack of moisture and rainfall would quickly turn vast areas into desert: And bright deserts reflect more heat than dark vegetated land-surfaces and the very dry atmosphere above would assist in bringing about greater radiative heat loss- all of which would help keep the Earth even colder. Continued below.
  15. 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 Earth rotates faster) and lose its "Westerliness". If the subtropical jet-stream descends fairly quickly it also pushes air eastwards lower down in the atmosphere before it itself moves equatorwards- and the lower altitude air would still have a considerable component from the west (as well as from higher latitudes) on hitting more extensive upland areas. Secondly, the subtropical jet-stream needs to be polewards of 25N and 25S, in latitudes where the Coriolis force is sufficient to cause an effective Ekman Spiral effect. During the coldest winters in the last Ice Age the subtropical jet-stream would have been strong above 25N, where the Coriolis Force is little over two thirds what it is at 35N. A much colder, denser (and shallower) troposphere polewards of 25N, especially over the continents would have also intensified the pressure- gradients at the top of the troposphere further strengthening the subtropical jet-stream but the Coriolis/ Ekman effect on the air beneath with the strong Westerly sub-tropical jet-stream itself not being deflected equator-wards as much. Winds over the subtropics would- thus- have regularly have maintained a strong Westerly component even down to elevations as low as 3,000 metres (and that is with subtropical-high atmospheric subsidence rates similar to today). An equator-wards- positioned subtropical jet-stream would have meant more low- latitude mountains were the sink of Westerly GLAAM. Thirdly, extreme cold over middle and high latitudes during the severest of Ice Age winters would have precluded the mid- latitude Westerly Ferrel Cell over large areas, particularly over the continents in the Northern Hemisphere. The situation would have been analogous to the situation over Asiatic Russia and Mongolia in winter today where intense cold and high-pressure are normal. If the lowest 3,000 metres of the atmosphere were 30C colder than today, but conditions aloft are little colder that increases the density of 30% of the atmosphere by 15%- which equates to a rise in sea- level pressure by 45 millibars- even assuming the Ekman Spiral effect beneath the subtropical jet-stream is trying to reduce surface barometric pressure in higher latitudes as it is today . The sinks for Westerly GLAAM would clearly be displaced from the entire region- upwards and equator-wards. The shallower troposphere over mid- latitudes that would ensue (5 to 6 km depth, not 9 km as nowadays) would enhance the baroclinic temperature and pressure gradients in the upper- air near the subtropical jet-stream, much colder air seeping from higher latitudes near the surface in the subtropics would intensify the subtropical high- pressure belts and precipitate more rapid descent of air in and beneath the subtropical jet-stream (the mountains beneath which would become major sinks of the Westerly AAM unable to make landfall in frigid high-pressure areas in higher latitudes). With no Ferrel Cell aloft over middle latitudes there's no return flow from higher latitudes aloft to slow down the subtropical jet-stream either- the strong Westerly subtropical jet-stream maintains its speed on descent until it hits something else to slow it down (like the Himalayas and Tibet). Finally, during the coldest winters at the height of the last Ice Age the surface and lower atmosphere- with expanded pack-ice, deserts in low latitudes and ice-sheets in middle and high latitudes reflecting away the Sun's energy there would have been reduced temperature contrasts between a chilly surface and frigid Stratosphere. This would have applied almost everywhere on the planet and the result would have been a general decrease in the thickness of the troposphere by up to 1,000 metres compared to today (but a sharper decrease in its thickness in middle latitudes). This the strong sub-tropical Westerly jet-stream would have blown at a lower elevation and would have had less distance to descend before hitting extensive mountain areas. For all these reasons, during severe Ice Age winters in the Northern Hemisphere the transfers of GLAAM and Westerly AAM are radically altered from one where Westerly AAM is transferred from low latitudes and the highest latitudes to middle latitudes- to a budget of GLAAM whereby Westerly AAM is transferred from low-lying lands and seas in all latitudes to high mountain areas in all latitudes (except right on the Equator where weaker Easterlies blow). The change to full Winter Ice age conditions would involve a permanent shift to stronger Westerlies aloft (over the Earth as a whole), more extensive Easterlies below and a slight reduction in the speed of the Earth's rotation (increasing the Length of Day by a few milliseconds). This is not inconsistent with the Law of Conservation of Angular Momentum since there need not be a net change in the axial Angular Momentum of the Earth- Atmosphere system for the above to happen. The existence of the mid- latitude Ferrel Cell- with surface Westerlies angling in from lower latitudes to bring warmth and moisture and returning to the subtropics aloft- is sensitive to a number of factors coming together. Even today, there are times and places in higher latitudes where it is not found at the surface: Asiatic Russia in winter being a good example, as here early winter snowfalls encourage rapid surface cooling and the development of very cold high-pressure areas that displace the Westerlies upwards- and away from that region. This process would get underway earlier in the season and cover a much wider area during an Ice age. The Coriolis effect today acts on the subtropical jet-stream and the air below pulled along by the subtropical jet-stream: With current climatic conditions- with a deep troposphere and slow subsidence beneath the sub-tropical jet-stream and that subtropical jet-stream being far enough from the Equator the Coriolis forces can bring about a return of considerable depth of atmosphere towards the Equator- and helped by ice-free seas and oceans in higher latitudes- results in sharply lower pressure in high latitudes: So the Ekman Spiral effect helps to create the mild moist conditions that bring warmth and moisture to the North, but that happens under current climatic conditions.
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