Energy arrives from the sun in the full gamut of wave lengths documented above. It is emitted by the Earth in a relatively narrow range in the infra-red between 1-125 um.
Ozone is made possible by the splitting of the oxygen atom by short wave radiation in the ultraviolet spectrum at wave lengths shorter than 250 nanometres, equivalent to 0.250 um. Once formed ozone can be broken down by wave lengths between 0.3 and 0.4 um in the ultraviolet.
Ozone is a greenhouse gas absorbing some of the very considerable sum of energy emitted by the Earth in the infra-red spectrum instantaneously transmitting that energy to adjacent molecules. But does this absorption in the infra-red contribute to the warmth of the stratosphere? You can survey the literature and find nary a reference to this phenomenon. The literature is dominated by the environmental concerns as to whether ozone is a significant pollutant in the troposphere and secondly, the degree to which its presence in the stratosphere enables the screening out of short wave energy that is harmful to plants and animals. The ‘ozone hole scare’ gave rise to the Montreal Protocol for the elimination of the use of certain gases including the commonly used ‘Freon’. Apart from that, the stratosphere is seen as largely irrelevant to the concerns of man, a place where the atmosphere is relatively static because ‘stratified’ with warmer air above colder air.
Now lets get to grips with the question posed in the heading:
WHY IS THE STRATOSPHERE WARM?
On a website prepared by the US Earth Sciences National Teachers association with the support of NASA we have this statement:
Temperatures rise with increasing altitude in the stratosphere. Ozone molecules in the stratosphere absorb ultraviolet radiation coming from the Sun. The energy from the UV radiation is transformed into heat. The heating is most intense near the top of the stratosphere, so that is where the stratosphere is warmest.
From Wikipedia we have:
Within this layer, temperature increases as altitude increases (see temperature inversion); the top of the stratosphere has a temperature of about 270 K (−3°C or 26.6°F), just slightly below the freezing point of water. The stratosphere is layered in temperature because ozone (O3) here absorbs high energy ultraviolet (UVB and UVC) radiation from the Sun and is broken down into the allotropes of atomic oxygen (O1) and common molecular oxygen (O2). The mid stratosphere has less UV light passing through it; O and O2 are able to combine, and this is where the majority of natural ozone is produced. It is when these two forms of oxygen recombine to form ozone that they release the heat found in the stratosphere. The lower stratosphere receives very low amounts of UVC; thus atomic oxygen is not found here and ozone is not formed (with heat as the by product).
So, the question arises: Is the energy absorbed at short wave lengths that is involved in both the creation and destruction of ozone sufficient to explain the warmth of the stratosphere?
- Well, for a start we can note that the stratosphere is warmest at 1 hPa and not at 30 hPa (the mid stratosphere) where the Wikipedia article suggests that the heat is released in the creation of the ozone molecule.
- Secondly, we can note that the reversal of the lapse rate ( rate of temperature change with elevation) at the tropopause requires heating at and below that elevation to produce the reversal of the lapse rate. There is no way that short wave radiation is responsible for heating the atmosphere at and below the level of the tropopause.
Its obvious therefore that the notion that the heat of the stratosphere is due to interception of short wave radiation or produced as a by product of the formation of ozone is not a very satisfying proposition.
The profile of Earth emitted outgoing long wave radiation as measured by satellites reveals a deficit at 9-10 um due to absorption of part of that energy by the atmosphere. That is outgoing infrared energy lost to ozone. The deficit in outgoing radiation at 9-10 um represents a hole in the energy emitted that is close to the peak of the spectrum carrying the bulk of the energy emitted by the Earth. The energy at these wave lengths is abundant. That energy is absorbed by ozone in the troposphere (the troposphere contains about 10% of total ozone) and the stratosphere. There is absolutely no shortage of energy in the outgoing infra-red wavelengths to warm the stratosphere whereas the energy available in the incoming ultraviolet spectrum is but a tiny portion of that of solar origin.
The effort to map the distribution of ozone in the atmosphere by satellites can utilise the attenuation of radiation in the ultraviolet spectrum OR the infra-red spectrum to infer the presence and concentration of ozone. The Toms satellite utilised the former while more recently the availability of Japanese developed instruments abroad the Gomes satellite enables the measurement of ozone utilising the attenuation of the infra-red spectrum.
The source of this information is the following expert review:
The attenuation by ozone, water vapour and CO2 is graphed:
We see that the attenuation of the energy available in certain wave numbers between 975 and 1100 rises to as much as 50% of the total with considerable energy lost to the atmosphere measured in terms of watts per square centimetre.
There is another consideration that is very important. It is conveyed in the following statement that can be accessed in the original at http://www-ramanathan.ucsd.edu/files/pr24.pdf
This is a very important dynamic that influences how and where the stratosphere absorbs outgoing infra-red. Consider this:
- The amount of radiation absorbed by ozone is pressure dependent.The lower that ozone is present in the atmospheric column the greater its heating capacity.This is of particular interest given the fact that ozone is ubiquitous throughout the atmospheric column in high latitudes and richly so in winter. The closer the poles are approached, the greater is its heating power, helping to explain the velocity of the jet stream that develops at the conjunction of dense ozone deficient air of mesospheric origin and warmer air that is ozone rich on the equatorial side of the polar vortex.
- The greater opacity of ozone in the troposphere, to the point that the troposphere absorbs as much energy as the entire stratosphere goes a long way to explaining the attenuation of the lapse rate at very low altitudes as we approach the poles. See here for lapse rates.
- This phenomenon helps to explain the origin of the energy behind the generation of so called ‘cold core’ cyclones that are in reality cold core only below 500 hPa , the origin of the uplift being an extensive warm core of low density air in the atmosphere manifesting strongly above 500 hPa.
In fact the bulk of short wave ionising UVC radiation with wave lengths shorter than 240 nm is absorbed by nitrogen and oxygen above 1 hPa while only a relatively small portion remains to directly energise oxygen and ozone in the stratosphere. It is reported that wave lengths shorter than 280 nm are required to ionize oxygen. The following table from here details the particular spectra absorbed at various elevations.
According to this table, it is the Herzberg continium between 200 and 242 nm (0.200 um to 0.242 um) that impacts oxygen in the stratosphere. whereas longer wave lengths up to 0.850 um impact ozone.
Accounts are conflicting. Fortunately, observation can settle the matter informing us as to the source of the warmth in the stratosphere.
Source: http://www.esrl.noaa.gov/psd/map/time_plot/ (latest version).
At left we have a hovmoller diagram showing us the evolution of surface temperature from 2005 through till 2011 at 20-40° south latitude. On the right there is another hovmoller showing the evolution of temperature at 10hPa over the same time interval. At 10 hPa the partial pressure of ozone in the air in relation to the other gases peaks. It peaks there in part because it is gathered together in the lower atmosphere in low pressure cells of its own creation and lifted to the top of the atmospheric column. Only 1% of the atmosphere lies above the 10 hPa pressure level. The maths is (10/1000)*100/1 = 1%
10 hPa represents an elevation of 30 km. For surface dwellers that’s just a five hour walk. Fifteen minutes on the free-way. In terms of radiation from the Earth the transit from surface to 10 hPa takes no time at all.
There is plainly a variation in the temperature at 10 hPa associated with the season of the year. There is also an obvious warming above the land masses that radiate strongly in summer. Plainly, the temperature of the stratosphere at 10 hPa responds strongly to variations in emissions of long wave radiation from the Earth.
It apparent that the temperature of the stratosphere is in some part due to the emission of infra-red radiation from the Earth, an entirely different story to that pedalled by NASA, the teachers association and Wikipedia.
Wherever ozone travels, and regardless of its altitude, it becomes a potent means for local heating by day and the night, including the long polar night when ozone partial pressure increases due to the absence of photolysis. Ozone for its very existence depends primarily upon :
- the photolysis of oxygen,
- Diffusion and transport processes,
- Chemical depletion of ozone by NOX, water and other agents,
- The pressure of photolysis of ozone that varies with latitude and season. In winter, low sun angles reduce the pressure of photolysis allowing the seasonal increase in ozone partial pressure. In the polar night there is zero photolysis of oxygen or ozone, neither creation nor destruction .
It is the rate of destruction by photolysis, chemical depletion and transport phenomena that are the critical factors determining ozone partial pressure in high latitudes. It is in the winter hemisphere that we see large variations in the temperature of the stratosphere, air density and consequently winds of extreme velocity. Surface pressures are driven to a planetary low on the margins of Antarctica where ozone partial pressure peaks. In high latitudes the only energy available to ozone in winter is long wave from the Earth itself. But this is more than adequate to drive polar cyclones and also, via a flux of pressure on all time scales, the distribution of atmospheric mass with its associated variations in weather and climate.
Moreover, cloud cover depends upon the flux in the area occupied by high pressure cells, and this determines the rate of accumulation of energy in the global oceans. What ascends to the limits of the atmospheric column gives rise to an equal and opposite descent. The diagram below that shows 200 hPa temperature varying much more widely than the temperature of the surface at 25°-35° south latitude amply reinforces this particular point. The temperature of the air at 200hPa responds to the presence of ozone. At this altitude violent winds redistribute atmospheric constituents in the horizontal domain
There is another way to look at this question of the source of energy that heats the stratosphere and that is in terms of the diurnal range between day (abundant short wave radiation) and night (no short wave radiation from the sun at all).
Siedel et al in a paper that you can access here investigated the diurnal range of temperature at different elevations from the surface through to 10 hPa. The diurnal range at 10 hpa was found to be about half the range of that at the surface and one fifth of the range of actual skin temperature. Plainly, the small diurnal response to the presence of sunlight points towards a large role for outgoing long wave radiation in determining the temperature of the stratosphere. Between day and night there is an ON/OFF relationship between the availability of short wave radiation from the sun. The emission of long wave radiation continues across the 24 hour interval. Siedel et al found a smaller diurnal range of temperature over the ocean than over the land and a larger range in the summer when the diurnal temperature variation at the surface is greater, than in the winter. The timing of the peak in the daily temperature becomes less defined and is more variable as altitude increases. This indicates that the circulation of ozone, as a source of local heating, is more important in determining atmospheric temperature than is the 24 hour rotation of the Earth on its axis and the resulting flux in the availability of short wave solar radiation. It confirms that the warmth of the stratosphere is primarily a direct response to the ability of ozone to intercept outgoing long wave radiation rather than direct heating in the process of photolysis or energy release via recombination phenomena.
Why worry about this you ask? The origin of the energy to heat the stratosphere is a matter of considerable importance because ozone heating in the winter hemisphere is the origin of the variation in surface weather and climate on all time scales. If one is not cognisant of the source of heating that gives rise to the stratosphere it is hard to conceive that the winter stratosphere can play a major role in the evolution of weather and climate. If one imagines that the temperature of the stratosphere is due to incoming short wave radiation alone then the source of the so called ‘coupling of the troposphere and the stratosphere’ becomes a baffling mystery. To be charitable, the misunderstanding of atmospheric processes amongst those who write UNIPCC reports has its roots in misconceptions, a failure to observe and disinterest based upon unshakeable belief patterns. Science thrives on scepticism, curiosity, observation and checking. Dogma is the companion of superstition and fear. Dogma is also the source of inappropriate responses to natural phenomena. It has led to the burning of witches. It has led to the demonization of carbon dioxide, a trace constituent in the atmosphere that represents plant food, a substance at the base of the food chain for which demand is so voracious that it has never been anything but a trace constituent of the atmosphere or the ocean. Today it stands at 400 parts per million in the atmosphere, the advance from 300 ppm leading already to a marked greening of semi arid climates. Give a plant more CO2 and it requires less water.
MORE OBSERVATION: OZONE HEATING AT 200 hPa IN WINTER
The supposed ‘greenhouse effect’ is theoretically due to a downward flow of energy from the atmosphere above to the atmosphere below via back radiation. It is conceived that it occurs in the troposphere where the air is cooler at elevation than it is below. The notion that cooler air can heat warmer air is anti-intuitive but let’s accept for the sake of the argument that it might be possible. How much more influential would back radiation be if the air above were warmer than the air below? Intuitively, that proposition makes more sense.
Uniquely, unlike other greenhouse gases the distribution of ozone is not homogeneous. A tiny fraction of the 10-15 ppm that manifests at 30 hPa is obviously very effective in heating the atmosphere in both the troposphere and the stratosphere. Manifestly it results in the cessation of cooling with increasing altitude and a marked reduction in the lapse rates at pressure levels well below the level of the tropical tropopause in mid and high latitudes.
By virtue of its uneven distribution ozone offers us an opportunity to test the notion that gases that absorb radiation from the Earth produce an increase in the temperature of the atmosphere beneath the level where this gas absorbs energy. In that respect give your best attention to the graph below:
We see that at 30-40° south latitude the temperature of the air above the 200 hPa level is warmer in winter than in summer. Of course the surface is colder in winter. And the incidence of ultraviolet radiation is less in winter. Plainly, the temperature response is due to the enhanced presence of ozone in the winter atmosphere and its ability to gather energy from the Earth itself via absorption of infrared.
Somewhere between the ozone heated portion and the surface we should see the impact of a warmer upper atmosphere via the impact of back radiation. This is plainly not evident at 400 hPa and 500 hPa, let alone the surface. I know of no study that demonstrates that back radiation from the upper troposphere influences the temperature of the lower troposphere as the ozone bearing layers warm in winter. If the supposed ‘greenhouse effect’ were operational we would should see an effect on the lapse rate below 500 hPa. No such effect is observed. Theory is one thing. Demonstration is another thing entirely. If the predicted effect is absent the theory is of no use to man or beast. One instance of failure of prediction based on theory should be enough.
NOTION OF A ‘TROPOPAUSE’
Observe that the pressure level where temperature stops descending with increased elevation at 20-40° south (the diagram above) is 100 hPa. So, above 100 hPa, in fact at 70 hPa the temperature is no different to 100 hPa. Early observers of the stratosphere, unable to observe the temperature above these levels conceived that the stratosphere was ‘isothermal’, with little or no change in temperature with increasing elevation.
If we conceive that the elevation where air temperature no longer falls with elevation marks the start of the stratosphere then 100 hPa is the location of the ‘tropopause’ and the stratosphere is held to start at that point. In consequence we include a region that shows a strong temperature response to the presence of ozone in that part of the atmosphere that we call ‘troposphere’. The Jet stream manifests between 300 hPa and 100 hPa. It is a creature of the variable proportion of ozone in the air between about 300hPa and 70hPa. Meteorologists recognise that the atmosphere beneath the jet stream conforms to the pattern of spatial variation that manifests as waves in the jet stream. They speak of the jet stream ‘steering’ the pattern of high and low pressure cells that define surface weather conditions. By defining a portion of the ozonosphere as ‘troposphere’ climate theorists effectively rule out of contention any notion that ozone is important to surface climate. This is a case of throwing the baby out with the bath water. Silly boys.
It is the heating response to the presence of ozone between 300 hPa and 70 hPa that creates the density differences that give rise to the jet stream. Surface weather on all time scales is driven by the radiative response to ozone between these pressure intervals.
Our failure to understand the origins of surface weather and climate change is a product of this sort of conceptual confusion. Conceptual confusion arises when people are dogma bound.
Greenhouse theory and the concept of ‘radiative forcing’ that is at the core of IPCC reports is no better than armchair speculation uninformed by observation.
The countervailing influence to atmospheric radiation is convection. The heating of the polar troposphere/stratosphere due to enhanced ozone levels results in polar cyclones and result in the lowest surface pressures experienced at any latitude. Historically surface pressure has declined at all latitudes south of 50° south as the temperature of the stratosphere has increased. A warmer stratosphere indicates increasing levels of ozone, in contrast to the ozone hole narrative that gave rise to the Montreal Protocol. This loss of pressure in the high latitudes of the southern hemisphere shifts atmospheric mass to the remainder of the globe altering climates globally via change in cloud cover and the origin of surface air flows.
Can back radiation withstand the countervailing influence of convection in a rising column of air? It’s plainly just not possible.
The atmosphere is never static. Only if it were static could back radiation effectively warm the atmosphere beneath the point where the warming occurs. For greenhouse theorists I see a little problem in logic and some additional problems in understanding the role and efficiency of convection as an agent of energy transfer.
THE MARK OF CLIMATE CHANGE
The 30 hPa level is in the heart of the stratosphere. It is the at the heart of the so called ‘ozone layer’. The diagram above indicates a change in the most influential element in the climate system that governs the evolution of the planetary winds. Why is this basic parameter unrecognized, languishing in obscurity and unrepresented in climate models?
There is a problem in conceptualisation that relates to an inability to connect the dynamics of jet stream establishment and behaviour with the changing concentration of ozone across the year, between years and over time with the pattern of wind and temperature at the surface of the Earth. At the root of this problem is the inability to see that ozone is a potent source of warming of the atmosphere via the absorption of the abundant energy emitted by the Earth itself, that the extent of the warming directly depends upon atmospheric density and is therefore greater at lower elevations than higher, and that ozone manifests at 300 hPa at 20-40° south latitude and lower again as latitude increases. Furthermore, the ozone content of the air depends upon sun angle (rate of photolysis), photolysis rates falling away quite dramatically in winter. Furthermore, atmospheric pressure so far increases at the pole in winter that air from the mesosphere is drawn into the stratosphere inside what is referred to the polar vortex. It is the dynamics so created that are responsible change in the ozone content of the air and with it surface weather.
Gordon Dobson observed back in the 1920’s that total column ozone maps surface pressure. Climate theory, unable to comprehend the importance of that observation is obsessed with unrealities. In common parlance, its off with the fairies.
Practically speaking, the energy generated by the sun is acquired, stored in some mediums better than others but it doesn’t hang about in the atmosphere. The atmosphere is a cooling medium. If the Earth slowed in its rotation so that it experienced the warming radiation from the sun on a 48 hour rather than a 24 hour cycle, then the night side would get very cold regardless of the composition of the atmosphere. If the oceans, a great store of energy, were to evaporate then the night side would become very cold. If one were to double the thickness of the atmosphere and double its greenhouse gas concentration it would not stop the night side cooling. Let’s face it, greenhouse theory is almost universally supported but it exists only in a thought bubble. There is yet to be a demonstration that so called greenhouse gases of anthropogenic origin produce one iota of difference to surface temperature.
The concept of radiative forcing, the basis of UNIPPC climate science, is specious nonsense.
The temperature of the air at the surface is close to the temperature of the surface. If the air at the surface is moving, it is warmer or colder according to the place from which it comes. That is the way the world works.
TABLE OF CONTENTS
There is a body of work that is being presented here, as a blog. Very unusual. It follows a carefully planned logical sequence. You can access all the chapters in this ‘treatise’, in reverse, at: https://reality348.wordpress.com
1 HOW DO WE KNOW THINGS? The virtue of taking in the broadest possible view using our own senses rather than relying on the opinions of others.
2 ASSESSING CLIMATE CHANGE IN YOUR OWN HABITAT Employing reanalysis data and a spreadsheet to take the long view
3 HOW THE EARTH WARMS AND COOLS-NATURALLY. A top down mode of causation is described. This mode of change is capable of explaining variations in both the short and long term in both directions, both warming and cooling. It can explain warming in one place and simultaneous cooling in another. In short it is very well adapted to explain the climate changes that we observe from daily through to centennial time scales ……. and to do so, exclusively and completely.
HERESY AND ORTHODOXY. Some impromptu observations on the inexplicable entanglement of science and politics. On exercising control, suppression of ideas, the nature of propaganda and ‘results oriented behaviour’ that is antagonistic to the interests of humanity in general.
IN THANKS TO STEPHEN WILDE. Some off the cuff comments on the nature of the atmosphere and climate science directed to a man who struggles earnestly in that same field of endeavour.
IT’S SIMPLE SIMON. A brief, impromptu exploration of the nature of the atmosphere.
4 THE GEOGRAPHY OF THE STRATOSPHERE. A re-examination of the nature of the troposphere and the stratosphere via a study of the lapse rate of temperature with elevation as it varies with latitude. Lots of heresy here.
5 THE ENIGMA OF THE COLD CORE POLAR CYCLONE. A cyclone cannot come into existence in the absence of a warm low density core. In short the polar cyclone is cold below and warm above. Ozone kick starts and then accelerates the circulation of the air in a fashion that is more vigorous than is possible anywhere else on the globe. An investigation of the agent that is responsible for natural climate change on all time scales……arguably the only form of climate change that the surface temperature that is consistent with the surface temperature record.
6 THE POVERTY OF CLIMATOLOGY. There is a palpable disconnect between observation and theory. Surface temperature is linked to geopotential height increases that are common from the surface to the 200hPa level in turn linked to change in the ozone content of the air…….as yet unrealized in academic and meteorological circles. Does this represent simply a failure to think things through, or something more sinister? The signature of ozone variability is date stamped into the tropical sea surface temperature record.
7 TEMPERATURE EVOLVES DIFFERENTLY ACCORDING TO LATITUDE. A brief survey that establishes the diversity that exists in the nature of the way temperature changes at different latitudes. On the face it, completely inconsistent with greenhouse theory.
8 VIOLATILITY IN TEMPERATURE. In George Bernard Shaw’s play ‘Pygmalion’ that gave rise to the Lerner and Loewe musical ‘My Fair Lady’, Henry Higgins declares that he can tell where a person comes from according to the accent in their speech. Equally, it is possible to detect the origin of temperature change, natural or otherwise, via a close study of the evolution of temperature over time. This is a critical chapter. It identifies the signature of the mode of natural climate change that is written into the temperature record. It points to origin and causation. Unfortunately, nobody looks.
9 MANKIND IN A CLOUD OF CONFUSION Coming to grips with the true nature of the atmosphere rather than the fairyland version promoted by climate science.
THE ARCTIC STRATOSPHERE SO COLD TODAY. An impromptu investigation of the forces active in the Arctic stratosphere.
10 MANKIND ENCOUNTERS THE STRATOSPHERE The evolution of the planetary winds and temperature at the surface of the Earth is intimately associated with flux in surface pressure wrought by ozone heating in high latitudes.
11 POPULATION, SCARCITY AND THE ORGANIZATION OF SOCIETY. What is the most desirable temperature regime for humanity? What would we prefer?
12 VARIATION IN ENERGY INPUT DUE TO CLOUD COVER. An investigation of the relationship between cloud cover and surface temperature
13 THE PROCESSES BEHIND FLUX IN CLOUD COVER. Change in cloud cover is manifestly a major mode of natural climate variation. This is basic stuff. Here is where the investigation should begin.
14 ORGANIC CLIMATE CHANGE. Focus on natural processes that account for surface temperature change. Heating of the vast land masses of the northern hemisphere in northern summer reduces global cloud cover and as a result the temperature of the Earth peaks in July when the Earth is furthest from the sun. In July solar radiation is 6% weaker than in January. In January the sun is overhead the most extensive stretch of the global oceans, the south Pacific, the Indian, the Atlantic and the enormous Southern Ocean. At this time atmospheric albedo, via cloud cover, peaks. This has not always been the case and nor will it be the case in future.
15 SCIENCE VERSUS PROPAGANDA. If we want to understand the climate system we need to be concerned with both the input and the output side of the energy flows. The singular focus on the output side of the energy equation and the constant promotion of ‘greenhouse theory’ is the result of uni-dimensional thinking that is realms away from the real world. This does not represent rational problem solving behaviour. Some remarks on greenhouse theory and the inappropriate use of a single statistic to monitor a global average temperature.
16 ON BEING RELEVANT AND LOGICAL. When one looks at climate change by latitude there is very marked diversity in the warming/cooling according to the time of year. Here we look at climate change by the decade at different latitudes to escape the gyrations associated with short term oscillations. The interest in this chapter is to ascertain if there is a generalized warming that is like a groundswell, underpinning the whole. That is what would be expected under the greenhouse scenario. The upshot: If it’s there, it’s either insignificant or completely overwhelmed by other influences.
17 WHY IS THE STRATOSPHERE WARM This is a question of fundamental importance. Mainstream climate science says it’s due to the interception of short wave solar radiation. But this cannot explain the warming of ozone rich air in the polar atmosphere during the polar night when contrasting atmospheric density produces the most intense response in terms of wind strength. It can’t explain why the air above Antarctica is warmer than the icy surface below. It can’t explain the strengthened jet stream in winter. It’s inconsistent with the way that the stratosphere drives the generation of polar cyclones and produces the greatest fluctuations in surface temperature across the surface of the globe in the depth of winter.
18 THE OZONE PULSE SURFACE PRESSURE AND WIND Traces the flux of ozone partial pressure by latitude across the annual cycle as it depends upon the uplift of NOx and water from the troposphere and the descent of ozone deficient air from the mesosphere. These inflows determine the ozone content and temperature of the stratosphere against a relatively stable background of short wave ionizing radiation responsible for photolysis and the creation of ozone. Change in surface pressure across the globe results via the variation in the intensity of polar cyclones in the winter hemisphere. These cyclones owe their warm cores to ozone. A broad interactive zone between 8 and 15 km of altitude exhibits extreme variations in air density giving rise to Jet Streams. Meteorologists trace the development of the weather that is so generated at the 250hPa pressure level.