SINKS FOR WESTERLY AAM PACKED INTO TOP FORTY PERCENT SURFACE OF EARTH MEANS WARMTH AND RAIN IN THE NORTH

[iapennell]

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. 

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[iapennell]

Just now, iapennell said:

 

(Continued below)        

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.       

   

[iapennell]

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.          

[ANYWEATHER]

Please can I ask what would a 15000 foot wall which would be impossible to construct alter the weather??? 

[iapennell]

18 hours ago, ANYWEATHER said:

Please can I ask what would a 15000 foot wall which would be impossible to construct alter the weather??? 

@ 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).      

Edited October 24, 2021 by iapennell