tirsdag, december 13, 2011

Predictions II

So, it's been nine days since I reflected on atmospheric pressure observations some 4 km aloft, which indicated predictive skills: possibly as much as 14 days in advance.

Meanwhile I've reached a few conclusions: It seems to me, that it is indeed possible to predict, at least in sketch, stormtrack behaviour from examining lofty pressure. I believe the limit is probably 10 days. Since the data is published 5 days late of it's conception, that might give me a lead of 5 days. It's very difficult however to say anything precise about the behaviour on the ground: low pressure systems can easily develop below the high pressure umbrella.

However, there may be a theme to those developments: they seem to cause more wind than precipitation and they die quickly. Why exactly, that would be, if it is true, I don't know, but I can venture a guess: If low pressure systems cannot send winds aloft due to higher pressure above it would inhibit the adiabatic lapse rate. That is: expansion is limited by the inhibited ability to condense water wapour by ascend to higher altitude. The air is recycled lower in the atmosphere and remains moist. This may result in higher wind speeds, lower precipitation rates and higher temperature - though I might be wrong about this.

About predictive skills, I'll try to give an example:

Several things from the animation above should be noticed: First the movement of high pressure into the scandinavian area; remember that this is in a height of 4 km and would not be emmediately felt on the ground (this is the predictive skill foundation). Second thing to notice is the low pressure area emmanating from the labrador sea (NE America). Normally in a NAO+ scenario (which we have), this would move towards iceland, but is deflected by the pressure cell aloft in the North Atlantic towards Southern Europe and North Africa.

This is classic NAO- behaviour, but it is not reflected on the ground (not yet). This low pressure deflection aloft happened between the 1st and the 9th of december. now let's look at ECMWF model for the comming week. These are the start conditions (note: these pick will change every twelve hours and soon be outdated):

The deflection may not yet seem apparent, but there is an opportunistic component to this: As low pressure systems are spawned by the evaporating ocean low in the atmosphere, they  prey on preexisting low pressure conditions higher in the atmosphere to grow by condensing water wapour aloft. This is what we call jetstreams.

By cooling the oceans through evaporation the atmosphere grows warmer and expands due to condensation, and these hotspots of condensation cirkulates the globe doing work on other airmasses, while they penetrate high into the atmosphere draining themselves of water. Probably this convective process of cooling is what renders the greenhouse effect almost mute, because it does not rely on radiation, but mecanical work: any co2 effect simply becomes part of the convective forces and speeds them up by a tiny fraction.

Later the model seems to pick up on the opportunities and lacks thereof provided by the upper atmosphere:

This is about a week from events aloft. There is discrepancy in latitude by maybe as much as 10 degrees or even beyond. I suspect, that implies the faster movement of air aloft, which schews the atmospheric vertical column.

In the Norwegian Sea and Scandinavia low pressure conditions at low altitude is still prevalant and may stay so, since SST's are anomalously high:

Also the high altitude high pressure block seems to be fading fast, and it's possibly these high SST's, that are wasting it. Never the less: at very high altitude, it's much colder than normal:

As warmth gradually moves out of the Scandinavian region into Siberia, colder conditions may descend on the region and gradually cool those SST's. This would cause snowfall, but I think mostly in the Norwegian mountains.

Thus far, above scandinavia, low pressure has been dominant with prevalant intermitant high pressure and occasional storminess. This seems to agree with the scenario framework outlined above. Colder conditions may descend on Scandinavia within the month. This could either mean more storms or more winter - I'm guessing: a little bit of both.


søndag, december 04, 2011


Today I noticed something for real, which I was probably only dimly aware of - if at all. Maybe it's nothing, maybe it's significant... I don't pretend to know.

The animation to the left is part of an MJO predictor toolbox provided by NOAA. I have long studied it with curiosity, since it is usefull for understanding the polar vortex behaviour.

Now I've noticed something, which truely intriques me. I will first provide you with still images from a Java Animation (Bottom screen), which displays the beginning and end images of an ECMWF model run from 4th of December to 8th of December:

Notice the rather steady low pressure over Scandinavia... Now study this model state on the 11th December:

This is called blocking or an Arctic breakout. It's still not NAO- for a host of reasons, which are irrelevant to this discussion. What is relevant however: Look to the date on the NOAA tool (Fig. 1); it ends on the 30th of November, but it clearly shows the blocking move in the North Atlantic. This, however, is 14 days prior to the actual event as weather on the ground - that is: if we trust the ECMWF model, which in this case I think I do. It will play out differently from current predictions, but the breakout will happen.

I'll be making more comparisons between NOAA's observations of the atmosphere and the model predictions in the future. I mean: this could be a powerfull predictive tool. DMI now locally predict -10 degrees C in Copenhagen around December 13th, but this was not in the cards 48 hours ago. It will possibly turn out to be overestimation by 2 - 3 degrees C. That would be typical of this model: first it underestimates (24 hours ago), and then it overestimates, accuracy is never achieved beyond 72 hours. By the same token precipitation estimates can only be described as weird.

Last year pretty much the same cirkulation (Eastern Siberia & North America heating up) resulted in some 30 cm of snow and -9 degrees for christmas, which is a very rare event here. If this keeps happening - it hasn't been a regular phenomena for 20 years, now - I'll take it as a sign of a cooling North Atlantic in response to the negativ PDO.


mandag, november 07, 2011

State of climate - an update

It's been some time since I wrote my piece on the state of climate and I've hopefully grown wiser ever since. I would like to share some simple observations first.

In the state of climate article I showed you this sketch from a National Geographic article from the mid 70's (I don't trust the modern products all too much, so it's nice with some counterbalance from a time, when people still had respect for 'objective' science).

I've now superimposed my graph of solar cycle length on that sketch (That would be the red line). And you may notice that they seem somewhat in tune. Now have a look at this graph:

If you click on the images you'll get an enlargement. Please note the dates of polynomic intersection between the AMO (North Atlantic) and the PDO (North Pasific). I get 1934, 1968 and 1998. I also believe, that if the data had reached further back in time you would have been able to locate an intersection around 1900-1910. 

There's some history to this: The Titanic sunk by ice berg 1915, 1934 warmest year in the US thermal record, 1976 marked the year of the great pacific climate shift (changing PDO), the great El Nino of that previous year made 1998 the hottest year on the global record, and scared the easily scared alarmists out of their wits. Compare with the modern global temperature scare product (on the left) and viola, how could anybody miss these striking 'coincidences'. Well the answer is: it takes an enormous amount of bias.  Compare the steep climb of late thermometer record with the satellites gentle hump:

Check also the previously mentioned years of AMO/PDO intersections with some Arctic history: 

Warming Arctic Climate Melting Glaciers Faster, Raising Ocean Level, Scientist Says - “A mysterious warming of the climate is slowly manifesting itself in the Arctic, engendering a “serious international problem,” Dr. Hans Ahlmann, noted Swedish geophysicist, said today. - New York Times, May 30, 1937

“The United States and the Soviet Union are mounting large-scale investigations to determine why the Arctic climate is becoming more frigid, why parts of the Arctic sea ice have recently become ominously thicker and whether the extent of that ice cover contributes to the onset of ice ages.” - New York Times, July 18, 1970  

Arctic warming has become so dramatic that the North Pole may melt this summer (2008), report scientists studying the effects of climate change in the field. “We’re actually projecting this year that the North Pole may be free of ice for the first time [in history],” David Barber, of the University of Manitoba, told National Geographic News aboard the C.C.G.S. Amundsen, a Canadian research icebreaker. - National Geographic News, June 20, 2008 

Of course the North Pole is not melting catastrofically and it is now reported, that sea ice has been refreezing at 40% the average rate (Sat history rate that is) during  this October.

Idealised sketch showing typical areas of low pressure 
thermal expansion, as well as high pressure migration routes 
out of the arctic.

As the pole heats up due to the warmer waters arriving in the region (forced by solar insolation in the tropics and possibly modulated by cloud and galactic cosmic rays), convective expansion pushes cold airmasses to the south over the continents (colder winters warmer summers in the interior). Eventually the cooler drier northern airmasses reaches tropical waters as they move south east where they fascilitate an enhanced Hadley circulation and upwelling regime. The northern warming cools the southern regions. As the south gets colder so, eventualy, do the hot waters which are pushed to the poles at the western plate boundaries. Eventually the north cools. Possibly solar forcing and magnetic fields (both the Suns and the Earths) modulate the polar atmosphere in various ways: cloud, moisture, temps.

The water temperature in the four regions marked in red  determines the level of thermal expansion around the region. In combination with the state of the polar cells pressure/temperature this determines where Arctic breakouts happen (blue arrows) and how intense the events. The PDO and AMO patterns are characteristics of this combined ocean/atmosphere behaviour and is actually an expression of a comprehensive northern hemosphere climate state which modulates the route of the northern jet stream. It defines the polar vortex and the meandering of high pressure systems. As this system feeds back on itself it oscillates between the phases shown in figure 2. The keen observer may notice, that the AMO seems to warm and cool with the cycles of the sun. While the PDO seems to respond to the AMO. And the PDO seems to 'regulate' global temperature. So there's a delay of about 15 years from the warming AMO until the Pasific starts cooling 'way down', which in turn starts cooling the AMO. The 'global' cooling is setting in right about now.

The danish meterological institute has a Java animation (Bottom of the page) simulating atmospheric circulation for the next week. Running this regularly, you can study the high pressure migration, and  the thermal expansion (low pressure) areas and the interaction between them. 
As the North Atlantic atmosperic thermal expansion becomes stronger than the Pasific thermal expansion cold air is pushed between them and the Atlantic wins: the tropical Pasific cools because cooler drier anticyclones enhances Hadley circulation and cold water upwelling. This drives hot water masses north (and south) at the west Pasific plate boundaries: the North Pasific warms. Eventualy the North Pasific will start pushing cold air masses into the North Atlantic creating blocking and cooling. The two oceans move in phase. During the next 20 years a warming North Pasific will graduately cool the North Atlantic.

Obviously this is a highly idealised schematic: a multitude of parameters most of them probably unknown modulate the highly complex climate system. Nothing is for sure!

Ocean temperature anomalies presented by NOAA as of October 26, 2011. 
Showing a cold PDO and a positive NAO.

As I see it, we seem to be in a somewhat simular situation as around World War II, where Hitlers armies perished in Russia due to extremely cold winters, and Scandinavia was hit by severe ice winters. While at the same time the Arctic was melting.

When we look at solar cycle length, it would seem that the recent warming in the 90's was somewhat stronger than the warming in the 30's. However, the present solar cycle lengths should provide a strong cooling effect... all in all we will probably be somewhere near 70's temperatures in roughly 25 years - somewhere around 2035. A cycle length of 60 years. By then we should have a good grasp on what the real effect of co2 looks like.

Oh I should mention, the colder, drier polar airmasses moving on the tropics should generate a lot of downpour. This would spell true in the North as well, as the thermal expansion areas (d)rain away. All this work will remove heat from the oceans, cool the planet and grow the glaciers by a small amount.


onsdag, oktober 26, 2011

Denne kniv er enestående

Jeg hørte engang historien om ekspedienten der hamrede en kniv i en træplade, stillede den i et tomt udstillingsvindue og hængte et skilt over med skriften: Denne kniv er enestående!

Hvilket minder mig om denne artikel i Berlingske:

(...) han [Svante Björck] når frem til, at dagens ændringer er de eneste med global udbredelse i 20.000 år.

Jordens klima har ændret sig mange gange, men Svante Björck har ikke fundet data, der afslører at tidligere ændringer har haft global omfang. Koldere og varmere perioder har derimod været regionale fænomener, lyder det fra den svenske forsker fra universitetet i Lund.

Konklusionen: at dagens ændringer er de eneste med global udbredelse i 20.000 år, baserer sig på den implicite tanketorsk, at det 20. århundredes opvarmning foregik ensartet overalt på kloden. Men det gjorde den naturligvis ikke: ligesom Svante Bjørck korrekt kan konstatere, at ingen opvarmning (eller nedkøling for den sags skyld) i fortiden er forekommet ensartet og øjeblikkelig fra den ene ende af verden til den anden, så gælder det naturligvis heller ikke for den moderne opvarmning.

Vi ved fx på baggrund af satellit-data, at den sydlige halvkugle er blevet varmere siden 1978. Til gengæld ved vi også, at den geografiske sydpol TOTALT SET er blevet en smule køligere, og vi ved ligeledes, at områder på Antarktis er blevet varmere, mens andre er blevet køligere. Hvilket helt naturligt afspejler den rige lokale variation.

Og dermed er argumentet faldet til jorden.

Jeg skal gerne skære det ud i pap:

(...) men Svante Björck har ikke fundet data, der afslører at tidligere ændringer har haft global omfang

Altså lige bortset fra, at alt ved klimaet har ændret sig globalt på de bemeldte 20.000 år (adskillige gange endda), og at de mange lokale ændringer som man kan iagttage både i fortiden og i nutiden naturligvis til sammen udgør den over tid endelige og totale klimatiske forandring vi lever med. Hvilket betyder, at planeten totalt set (altså: globalt) er endog væsentligt varmere end den var for 20.000 år siden.

Alle temperaturer er lokale fænomener, men det gennemsnitlige globale produkt over de bemeldte 20.000 år vidner om global opvarmning – færdig basta... Havde emnet været de sidste 6.000 år, så havde vi talt om global nedkøling.

Svante Bjørck kan altså umuligt rationelt nå frem til, at dagens ændringer er de eneste med global udbredelse i 20.000 år. Det er jo en komplet kortslutning: en benægtelse af elementære fakta og en misforståelse af, hvad en global middeltemperatur er for noget: en abstraktion!

At tage Svante Bjørcks “argumentation” alvorligt som den står formuleret i Berlingske er videnskabeligt livsfarligt! Det eneste der sådan set er demonstreret er, at man i de fleste kredse simpelthen ikke forstår klimatisk abstraktion: hverken hvad angår geografisk afgrænsning eller tidshorisont. Dette er naturligvis uheldigt, når man så samtidigt vedholdende insisterer på at propagandere for et helt bestemt synspunkt og kalder det videnskabeligt.

Det mest besynderlige ved Svantes argumentation bliver imidlertid, at han tilsyneladende ikke længere kan argumentere for at tidligere tiders temperaturstigning skyldtes co2, i det det jo bliver påstanden, at den moderne co2 opvarmning er historisk unik ved at være global, mens alle andre klimaforandringer de sidste 20.000 år adskiller sig derfra ved at være regionale, og således ikke kan være forårsaget af co2, der jo forårsager en global opvarmning.

Go'dav mand økseskaft...