I will pay $500 to the person who can explain the atmospheric physics behind the following phenomena:
If your cup of tea is too hot to drink you can blow across the surface of the liquid to cool it down.
In the trade wind zone, between the equator and 30° of latitude the temperature of the surface of the sea varies inversely with the differential pressure driving the trade winds (negative correlation).
In the zone where the westerly winds blow, between 30° and 60° of latitude, the temperature of the surface of the sea varies directly with the differential pressure driving the westerly winds (positive correlation).
I want to advise that the reward will increase by $1 per day from today, the 16th November 2010 until the physics behind this phenomenon is explained to the satisfaction of both Mr Leif Svalgaard and myself.
Thank you Leif, for agreeing to participate.
I propose to provide a clue about once a week until the matter is resolved.
As Leif says, it should be fun.
Should there be sponsors who desire to elevate the stake I would be delighted to hear. Adding a dollar a day might suit you……..a bunch of flowers…..whatever strikes your fancy.
Update 17th November
Thanks for the contributions thus far.
No correspondence will be entered into in relation to the veracity of this data. That is the concern of the authorities responsible. I thank them for making available a fine database that enables a person to explore the relationship between climatic variables over time. I maintain that our climate system is changing on a daily basis. Without an idea of where and why it changes you can not model it successfully.
Here is the data that supports the statement that sea surface temperature increases with the differential in atmospheric pressure in the latitude band 30-50° where winds with a westerly component dominate. The first figure presents anomalies based on climatology of the record up to today. In other words the data represents the departure from the monthly average for the entire period.
The figure below is very simply derived. The pressure data represents the difference between the sea level pressure at 30-50°N and the sea level pressure at 50-60°N averaged over the four months from June to September. Despite the variable lag, the response in terms of increasing SST to increasing differential pressure is in my view quite striking. Remember that the latitude band chosen is pretty arbitrary, it is not refined according to the position of the wind systems in the summer season and that there will be interference at low latitudes from processes that characterize the trade wind zone.
And here is the winter situation where the connection between the two is even more obvious.
The northern and the southern hemisphere are different kettles of fish. But he relationship between SST and the pressure differential is also pretty tight in the southern hemisphere when viewed as anomalous monthly data. Notice the discrepancy from 1993 that is also apparent in the northern hemisphere data. My guess is that its due to volcanic action. You will see it in the summer and winter figures as well. This data should be compared with data from the stratosphere to explore the relationship. But, that is not my current interest.
The data for southern hemisphere summer is only faintly suggestive of a relationship.
But the data for the winter is much tighter. What causes sea level pressure to fluctuate strongly on short and long time scales? Where does sea surface temperature fluctuate most and how does it affect the differential pressure driving the major wind systems?
And just in case you think that the ocean always cools in the trade wind zone when the differential pressure driving the trade wind increases, look at this.
And to focus on recent years.
Compare the SST response to the pressure decline in 2001-2 to 2003-4 and 2008-9. Why the discrepancy. If you contemplate this for a moment you will realize that evaporation and upwelling of cold waters are not the only factors driving the temperature of the sea in the trade wind zone. The ‘thing’ that drives the temperature of the sea upwards with sea surface pressure in the zone where the westerly winds blow is also probably operating to some extent, and at some times more than others, in the trade wind zone.
Plainly, any explanation of the climate system has to resolve the question of how and why atmospheric pressure changes over time and why sea surface temperature responds on very short (hourly) and long time scales………centuries. It must account for SST declines in some places and concurrent increases in other places. It must also account for the difference in the behavior of two quite different baskets of fish.
There is evidence in both pressure and temperature data that we are dealing with gradual change in both directions, increase and decrease. Any person in their right mind would not suggest that the sudden warming of the tropical ocean in the southern hemisphere from 1978 is due to back-welling radiation. The increase in the temperature of the sea in the southern hemisphere mid latitudes was steep initially and has flattened out since. It seems that the temperature of the sea in northern mid latitudes is currently in decline, having peaked at a value that was last reached in the 1940’s.
I hope that some of this discussion has helped. At this stage I consider my money safe.
Update no 2 on 17th November
Nature. 2004 Nov 18;432(7015):290-1.
Atmospheric Science: Early peak in the Antarctic Oscillation Index
Institute for Coastal Research, GKSS Research Centre, 21502 Geesthacht, Germany. email@example.com
The principal extratropical atmospheric circulation mode in the Southern Hemisphere, the Antarctic oscillation (or Southern Hemisphere annular mode), represents fluctuations in the strength of the circumpolar vortex and has shown a trend towards a positive index in austral summer in recent decades, which has been linked to stratospheric ozone depletion and to increased atmospheric greenhouse-gas concentrations. Here we reconstruct the austral summer (December-January) Antarctic oscillation index from sea-level pressure measurements over the twentieth century and find that large positive values, and positive trends of a similar magnitude to those of past decades, also occurred around 1960, and that strong negative trends occurred afterwards. This positive Antarctic oscillation index and large positive trend during a period before ozone-depleting chemicals were released into the atmosphere and before marked anthropogenic warming, together with the later negative trend, indicate that natural forcing factors or internal mechanisms in the climate system must also strongly influence the state of the Antarctic oscillation.
Update no 3 20th November 2010
I want to revisit the first figure presented above. It explores the relationship between pressure and temperature in the west wind zone of the northern hemisphere. This time I present it as a 12 month moving average of hourly data centered on the seventh month. That removes seasonal influences. Looking at this data you might think that there is an excellent relationship from 1996 to 2004 and the rest is obscure. It is probably most obscure in the period from 1948 through to 1970.
So, lets look at the monthly data for this period. This data is presented as the departure from the monthly average for the particular month concerned, that average computed for the entire period.
There is no doubt about the relationship. When Sea Level pressure rises so does sea surface temperature. This is different to what happens in the trade wind zone where SST falls as the pressure differential increases and the winds blow harder. That is due to the effect of evaporation and cold water upwelling. So, what happens in the west wind zone is the direct opposite of what happens in the trade wind zone.
The next figure shows that the trade wind and westerly pressure differentials move together and of the two, the greater flux is seen in the westerlies.
Consider this satellite derived imagery.
Areas of dense cloud flowing away from the major centres of tropical convection (Amazon, Congo, Maritime continent) close to the surface are moving into colder territory and the tendency will be for cloud density and the heavily shaded surface area to increase as latitude increases. However, the light grey is high level cirrus cloud that is lifted into the upper troposphere in these same centres of of intense tropical convection and also due to uplift associated with mid latitude cyclones. Cirrus tends to flow westward as the low level cloud travels eastward. I suggest that it is this cirrus cloud that lightens off as sea level pressure in the west wind zone increases. It will do so if trace quantities of ozone enter the lower stratosphere/upper troposphere from the polar regions. This occurs as polar pressure falls. It is the fall in polar pressure that allows the westerlies and the trades to gain momentum.
The evidence for this can be seen in the flux in 200hPa temperature here: http://www.cpc.ncep.noaa.gov/products/intraseasonal/z200anim.shtml. If you look frequently at sea surface temperature anomaly maps you will see that the areas that stand out as being highly variable in temperature are closely related. This includes as notable examples, the Arctic and the north west Pacific off Kamchatka.
There is a notion abroad that the presence of cirrus warms the surface. I say, the warming of the surface is related to the disappearance of cirrus cloud. We know the surface warms when atmospheric pressure increases. We know that cloud intensity is directly related to atmospheric pressure (happens in mid latitudes every summer and on a week to week basis with the passage of the pressure systems). Perhaps some smart person can separate these influences and give us the answer as to whether the observed warming of the upper troposphere is related to surface warming. My work in climate science started with the observation that a 1°C increase in SST is related to a 3°C warming at 200hPa.
Again, I point you toward the pole, the enormous flux in atmospheric pressure that occurs at high latitudes, particularly in the south, and the flux in ozone that is closely related.
Here is the flux in the differentials driving the trade winds in millibars:
On the right hand is dTN (differential driving the trades in the northern hemisphere) in summer and the left axis is used for polar pressure. Note the very large difference in the scales. There is a 45mb range on the left and a 4.5mb range on the right.
Here is dTN winter.
dTS (Southern Trades, where the great bulk of the tropical ocean lies) in summer.
dTS in winter.
We see a 1-2 millibar change in the differential driving the trade winds that is associated with a 10-15 mb change in Antarctic pressure.
The change in global pressure relations is part of a planetary system that involves ongoing change in the mass of the atmosphere at all latitudes on inter-decadal and longer time scales.
The change in the mass of the atmosphere is responsible for the surface winds that drive evaporation, upwelling of cold water and associated change in cloud cover, direct drivers of surface temperature.
What is being described here is a natural climate system that explains the cooling of the nineteen seventies, the warming from 1978 to 1998, static temperature thereafter and a swing to La Nina dominance from 2007.
Update no 4 20th November 2010
Here is independent support for my statement that an increase in the strength of the westerly winds (due to a rise in the AO or the AAO representing falling pressure at the pole) that is associated with La Nina type cooling in the tropics (due to concurrent intensified trade winds) is associated with reduced cloud cover and increased sea surface temperature in mid latitudes:
Relationship of the Arctic and Antarctic Oscillation to the Outgoing Longwave Radiation
A. J. Miller, NOAA/NWS/NCEP, Camp Springs, MD; and S. Zhou and S. K. Yang
Utilizing a combined data set of broadband outgoing longwave radiation data derived by NASA, (Wielicki et al., 2001) we show that the relationships of the Arctic and Antarctic Oscillation (AO/AAO) to the outgoing longwave radiation are well defined on the monthly time scale. Recent work by Limpasuvan and Hartmann(2000) (L&H) utilizing the NCEP/NCAR reanalyses indicate that the AO/AAO high phase minus low phase difference depicts downward motion in the mid-latitudes of each hemisphere. While it is usually very difficult to test attributes of the reanalysis, this downward motion suggests that this would be associated with a decrease of clouds and an increase in the outgoing longwave radiation (OLR). Thus, the independent OLR data provide a test of the data and results. Through both correlation analysis and composite analysis we demonstrate that a positive AO/AAO signal is, indeed, strongly associated with an increase in OLR in the mid-latitudes and vice-versa. These results also compare very well with the OLR computed within the reanalyses. This leads to conjecture as to how we may improve the current forecast system at time-scales beyond about a week.
Poster Session 2, Earth Radiation Budget
Tuesday, 4 June 2002, 1:00 PM-3:00 PM
Comment on this research: This research does not assist our understanding of the type of cloud that disappears but the logic (see above under the map) supports the notion that it is high altitude cirrus cloud that is affected by the flux in ozone from the stratosphere. Ozone is a potent absorber of long wave radiation from the earth. Small amounts of ozone are influential in raising air temperature. Downward transport carries the warmed air towards to the surface although it does not always reach it. Downward transport commences when polar pressure increases, as signified by a fall in the AAO or AO respectively. This is a very consistent feature that relates warming of the stratosphere to the change in pressure.
Update no 5 22nd November
Warning: What follows may be, from some points of view, an unorthodox interpretation of the way the world is. Some maintain that any warming of the Antarctic stratosphere is due to planetary waves. I consider that interpretation unphysical. Planetary waves are internally generated and can not explain the variability that is seen, the extent of warming or in the distribution of the air that is warmed. There may be an involvement of planetary wave activity in vortex splitting events that occur when polar air pressure falls to a very low point and the vortex is wholly inactive.
First look at this: http://www.jhu.edu/~dwaugh1/gallery_stratosphere.html
Stratospheric warming is episodic and continuous but most intense in the winter hemisphere where air pressure is at its annual high point. Between seasons you can see it occurring in both hemispheres simultaneously. See the excellent animation at: http://www.cpc.noaa.gov/products/intraseasonal/temp10anim.shtml
I want to describe the process by which cirrus cloud can come and go affecting sea surface temperature in the west wind zone. The diagram below shows very cool air in the eye of the polar vortex over Antarctica. The AAO index is currently (November 17-22, 2010) high which means that sea level atmospheric pressure at 80-90°S is low. The flow through the vortex will be weak and the rate of change in atmospheric constituents like ozone, slight. There will be little air entering the upper stratosphere from the mesosphere and in this circumstance ozone concentrations will rise.The stage is being set for the next warming of the middle and lower stratosphere when the vortex refreshes. At this time of the year pressure is falling away in the south and rising at the northern pole. So the next major warming will be in the north. Humpty Dumpty needs to sit on the wall before he can fall off. If pressure is low it is difficult to reduce it still further. If its high, it can fall more readily.
On November 17th (diagram below) we are looking at the result of a fall in the AAO centred about 7th November denoting higher surface pressure and a more vigorous vortex. As the vortex refreshed with the increase in air pressure , ozone was brought down into the middle stratosphere and mixed with air as far north as the equator, as you can see by the bulge between 120 and 150 west longitude. The nitogen oxides that come from the mesosphere destroy ozone and the eye of the vortex is an ‘ozone hole’. In circumstances where the vortex is weak, ozone concentrations rise in the upper stratosphere (10hPa is about the middle at 30km) and this happened prior to November 7th. The AAO had been high for the preceding three weeks as you can see here:http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/hgt.aao.shtml
If you check that link you will see that a warming of the stratosphere always occurs when the AAO falls.
Looking at the diagram below (which relates to the tropopause, the border between the troposphere and the stratosphere) you can see a region of high temperature (Letter H) between Antarctica and Australia and another close to the junction of the Antarctic Peninsula with South America. Ozone is a very good absorber of long wave radiation from the Earth and it imparts energy to the surrounding molecules of nitrogen and oxygen causing the local temperature to increase. Paradoxically, areas with high ozone levels in the lower stratosphere are usually anomalously cool at the surface. I would ask those who believe that greenhouse gases warm the surface to contemplate that rather awkward fact.
The atmosphere is a convective medium. Local warming promotes the ascent of low density air. Accordingly, ozone descends into the troposphere where the stratospheric air is descending, and that is never ever where the stratosphere is warmest. So, look for the temperature anomalies in the upper troposphere at 200hPa and they will be a mirror image of the temperature anomalies in the stratosphere. Then look at a map of sea surface temperature anomalies and you will see positive anomalies beneath the positive temperature anomalies at the 200hpa level. That is sunlight streaming through a hole in the cirrus cloud. The effect is most readily seen in the southern hemisphere where the flux in stratospheric temperature is slowest and there is a single dominant vortex. By contrast the northern hemisphere is a bucket of worms with strong centres of descending air not only at the pole but also over the Tibetan Plateau, Siberia and Eastern Canada and Greenland and there is much less ocean (which is relatively neutral) than in the southern hemisphere.
All you need to do to lose cloud density is to warm the air a little. Watch the air cross a mountain range and descend on the other side and the point will become obvious.
One last point. The surface warms when cirrus cloud becomes less dense. The notion that the presence of cirrus cloud warms the surface is just an urban myth. The surface warms according to the rate of evaporation in relation to the rate of heat accumulation and the latter is determined by the strength and duration of sunlight on a daily basis. Cloudy days and nights are warmer than clear days and night s because the air that is associated with cloudy conditions comes from a wet and warm place and it is moving into cooler territory.
The climate system is not that complex, but if you are fixated on a central, inappropriate idea it is going to look incredibly complex, inexplicable in fact. Then you start talking about chaos, butterfly wings and so on. But the single most debilitating idea is that it is a closed system where change is determined by internal forces. Then you can fall into the trap of thinking that the Pacific Ocean forces change worldwide and drives the polar vortex, the AAO and determines whether it’s going to rain this winter.
Update December 19th 2010
It looks like this little puzzle is not engaging too many minds. I will close the contest with the following diagrams which provides some of important clues to the physics behind shifts in the atmosphere, the forces driving the wind systems and the resulting warming and cooling of the ocean, in short climate change as it is driven by the solar wind.
The Dst index measures the strength of the electromagnetic fields in the Earth’s atmosphere.The Antarctic Oscillation Index and the Arctic Oscillation Indexes represent the balance of pressure between the mid latitude and the respective pole. Practically speaking these indices represent the flux in polar sea level pressure with the polar index falling as sea level pressure rises.
When the solar wind intensifies the Dst index becomes more negative and it takes a couple of months to fully relax again. In about one half of occasions when it pulses negative both the AO and the AAO move upwards, and on a quarter of occasions it is one or the other only.
As the atmosphere becomes more compact, it does towards solar minimum and in low amplitude solar cycles, the swings in the AO and the AAO become wilder, with a greater range in their activity. In an atmosphere where neutrals and changed particles are more closely associated it takes less energy from the solar wind to bring about the same shift in the mass of the atmsophere.
In the long term the AO and the AAO are locked together but in the short term there can be shifts of atmosphere from one hemisphere to the other due to seasonal influences (pressure at the pole is much higher in winter) and perhaps to the state of the northern hemisphere temperature in winter and the flux of ozone into the stratosphere and troposphere from the stratospheric vortex. Perhaps the solar wind itself can preferentially shift the atmosphere from one hemisphere to the other. Certainly there has been a spectacular decline in pressure in the Antarctic since 1948 which is now bottoming. In the Arctic pressure fell from the 1940’s till the early 1990’s and is now recovering.The recovery is faster in winter. Interestingly, the temperature of northern hemisphere winters is strongly tied to the Arctic Oscillation. When pressure rises during an Arctic winter the westerlies weaken and the polar easterlies descend from their usual habitat in the stratosphere to plunge southwards in what is frequently described as an Arctic Outbreak. The Westerlies retreat south and the hemisphere outside of the Arctic cools. In the Arctic circle and the usual centres of downdraft activity, Siberia and Greenland, the surface warms when that descending air contains ozone from the upper stratosphere. Every interval of slightly increased pressure at the pole results in an increase in geopotential heights as ozone is gathered up from the interaction zone of the stratosphere and the mesosphere by renewed vortex activity, absorbs long wave radiation from the Earth and warms the surrounding atmosphere. The phenomenon is called a sudden stratospheric warming. Ultimately that ozone finds its way into the troposphere in the mid latitudes where it warms the air so reducing cloud density.
Some people have noticed a relationship between the AAO and the Southern oscillation index, a proxy for ENSO and Sea surface temperatures in tropical waters. It’s frequently out of phase however.
Some people have noticed a relationship between the AO and the Southern oscillation index a proxy for ENSO and Sea surface temperatures in tropical waters. It’s frequently out of phase however.
There is nothing sloppy about the relationship between the Antarctic sea level pressure and the differential pressure driving the westerly winds however. The relationship is inverse.
And the same can be said of the AAO and the differential pressure driving the westerlies. The relationship is stronger in the northern hemisphere (not shown)
As the westerly winds strengthen there is an increase in sea surface temperature. One expects evaporation to increase as the surface of the ocean becomes rougher. So, this relationship can only be due to flux in cloud cover.
It is apparent that the flux in sea surface temperature is greater at 30-50N than it is at 30-50S and that the flux is even less at lower latitudes. This conforms to the density of mid and upper level cloud by latitudes and the fact that the northern stratosphere has a higher ozone content and experiences a much greater flux in ozone from the stratospheric vortex than is seen in the southern hemisphere.
Going forward, weaker solar cycles will allow atmospheric mass to return to the poles, the westerlies will weaken, the stratosphere and the upper troposphere will cool, cloud cover will increase and the surface will cool. The SOI has been positive most of the time since 2007 whereas it was highly negative over the previous thirty years since the gross climate shift of 1978 when upper atmosphere temperatures jumped. Since that time upper atmosphere temperatures have been in decline.
What is described here is a mechanism that accounts for the change in the climate of the Earth over short and long periods of time that needs no reference to the supposed influence of carbon dioxide or other ‘greenhouse gases’ of anthropogenic origin.
It is not expected that a better understanding of climate change phenomena will make much difference to the UN driven campaign to control carbon emissions. The ‘science’ of AGW has always been weak. This campaign is driven by an agenda that sees economic growth as unsustainable. Such a view has long been held by a section of the intelligentsia. They hold this view regardless of evidence that man is highly adaptive, technology is advancing at a faster pace than ever before and individual people (even at times nation states) frequently exhibits an unselfish attitude towards those in greater need than himself.