Tropical air circulation drives fall warming on Antarctic Peninsula
The eastern side of the Antarctic Peninsula, a finger of the southern polar continent that juts toward South America, has experienced summer warming of perhaps a half-degree per decade – a greater rate than possibly anywhere else on Earth – in the last 50 years, and that warming is largely attributed to human causes.
But new University of Washington research shows that the Southern Hemisphere’s fall months – March, April and May – are the only time when there has been extensive warming over the entire peninsula, and that is largely governed by atmospheric circulation patterns originating in the tropics.
The autumn warming also brings a notable reduction in sea ice cover in the Bellingshausen Sea off the peninsula’s west coast, and more open water leads to warmer temperatures on nearby land in winter and spring (June through November), said Qinghua Ding, a UW research associate in Earth and space sciences. In fact, the most significant warming on the west side of the peninsula in recent decades has occurred during the winter.
“Local northerly wind pushes warmer air from midlatitudes of the Southern Ocean to the peninsula, and the northern wind favors warming of the land and sea ice reduction,” said Ding.
He is the lead author of a paper explaining the findings, published online this month in the Journal of Climate. Eric Steig, a UW professor of Earth and space sciences, is co-author. The work was funded by the National Science Foundation.
The scientists analyzed temperature data gathered from 1979 through 2009 at eight stations on the Antarctic Peninsula. The stations were selected because each has reliable monthly data for at least 95 percent of the study period. They also used two different sets of data, one from Europe and the other from NASA, that combine surface observations, satellite temperature data and modeling.
A German research vessel, Polarstern, is shown off the Rothera station on the west coast of the Antarctic Peninsula. Rothera is one of eight stations that provided temperature data for this research.
The researchers concluded that the nonsummer Antarctic Peninsula warming is being driven by large-scale atmospheric circulation originating in the equatorial Pacific Ocean. There, the warm sea surface generates an atmospheric phenomenon called a Rossby wave train, which reaches the Antarctic Peninsula and alters the local circulation to warm the region.
The sea-surface temperature trend in the tropical Pacific is related to natural phenomena such as the El Niño Southern Oscillation (El Niño and La Niña) and cycles that occur on longer timescales, sometimes decades. But it is not clear whether human causes play a role in that trend.
“We still lack a very clear understanding of the tropical natural variability, of what that dynamic is,” Ding said.
He said that in the next two or three decades it is quite possible that natural variability and forcing from human factors will play equivalent roles in temperature changes on the Antarctic Peninsula, but after that the forcing from human causes will likely play a larger role.
“If these trends continue, we will continue to see warming in the peninsular region, there is no doubt,” Ding said.
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David wrote –
“Now calculate the average flow of heat through the crust at average ocean depth, and this, with more volcanoes per sq K then on land due to thinner crust, and add in the residence time of said thermal heat, (meaning if said heat takes x years to reach the surface”
In 2005 I presented a mechanism which combined the 26 miles spherical deviation of the planet with crustal motion/evolution based on an uneven rotational gradient between equatorial and polar latitudes known commonly as differential rotation.By 2007 the wider community got wind of this rotational mechanism but instead of outlining the proper reasons using fluid dynamics of the interior they created a Frankenstein’s monster of a thing based on chanting voodoo.The point is that the stationary Earth,thermal driven ‘convection cells’ concept is dead as a concept whether you know it or not.
It is the way they grafted in the Earth’s rotation as a mechanism as an ongoing process to replace ‘convection cells’ in the space of a few years that I find astonishing just as ‘global warming’ altered to ‘climate change’ in the same sleight of hand way but that is how academics behave nowadays.
I don’t mind,sooner or later to explain plate tectonics using an uneven rotational gradient of the fluid interior they will run into the 26 mile spherical deviation between equatorial and polar latitudes hence it is not possible to stumble your way to a rotational mechanism,the answer is already embedded in the Earth’s shape and surface features.
This is the money paragraph:
“He said that in the next two or three decades it is quite possible that natural variability and forcing from human factors will play equivalent roles in temperature changes on the Antarctic Peninsula, but after that the forcing from human causes will likely play a larger role”.
There are no stations in the East Antarctic Peninsula — see http://upload.wikimedia.org/wikipedia/commons/f/f6/Antpen-en.png . Why is that? Because it’s too cold for our intrepid scientists. So now they say that it’s the fastest-warming place on Earth, yeah, right, no penguin will disagree. It’s yet another disgraceful episode of Climate Science.
It’s because we live on a slowly tilting planet. (Apologies to Madeleine L’Engle.) Earth’s axis is tilting towards vertical (or its theorized minimum angle) and as it inexorably trends that way, the overall climate will grow more temperate. There’s less polar surface area that is continuously in light or darkness some part of the year than there was any time in recorded history, and that area will continue to shrink for several thousand years to come. I wouldn’t be surprised if much of the polar ice does melt when the axis reaches whatever its minimum angle will be.
Where does much of the storm activity in the polar regions happen? Around the Arctic and Antarctic circles. What’s been happening to those circles for thousands of years? They’ve been moving polewards. The storm belts move with their respective arctic circles. The circles have moved polewards quite a ways during recorded history. Has anyone yet bothered to examine the effect of that factual happening on the climate?
Ignoring the influence of changes in Earth’s axial tilt on the climate is just as stupid as ignoring the fluctuations in total Solar radiation influx. “But it’s only a small amount.” Aye, but it’s a small amount over a very large surface. It adds up to a rather huge number.
One can apply all the math they want to calculating Earth’s min/max axial tilt. It’s still only a theory until it reaches one extreme or the other and some person with the ability to measure the angle is there to do it, which has never yet happened in recorded history. Nobody knows but Earth might skip right on past “minimum” axial tilt and go straight on to straight up, human calculations be damned. None of us now living will be here to see it. Calculations = theory. Direct observation and measurement = fact. When the measurements don’t agree with the theory, the theory is wrong, but when the chance to take the measurements only come around every 40,000 years (so theory says) theory is all we have.
Wobble, wobble http://www.michaelmandeville.com/earthmonitor/polarmotion/2006_wobble_anomaly.htm