2009 Arctic Sea Ice Extent exceeds 2005 for this date
21 09 2009
Those that have been watching the IARC-JAXA Arctic sea ice plot, and noting the slope of gain, rather expected this to happen. Today it did.
Here’s the current IARC-JAXA Sea Ice Extent plot:
source: http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
And here is the plot magnified and annotated to show the crossing:
While 2009 minimum on 09/13 of 5,249, 844 was just 65, 312 sq km below 2005 in minimum extent, which occurred on 9/22/2005 with 5,315,156 sq km, it has now rebounded quickly and is higher by 38,438 sq km, just 2 days before the 9/22/05 minimum. On 9/22/2009 it may very well be close to 60-80,000 sq km higher than the minimum on the same date in 2005.
While by itself this event isn’t all that significant, it does illustrate the continued rebound for the second year. The fact that we only missed the 2005 minimum by 65, 312, which is about one days worth of melt during many days of the melt season is also noteworthy.
NOAA NEWS - The July 2009 temperature for the contiguous United States was below the long-term average, based on records going back to 1895, The July 2009 temperature for the contiguous United States was below the long-term average, based on records going back to 1895, according to a preliminary analysis by NOAA's National Climatic Data Center in Asheville, N.C. The average July temperature of 73.5 degrees F was 0.8 degrees F below the 20th century average. Precipitation across the contiguous United States in July averaged 2.90 inches, which is 0.14 inches above the 1901-2000 average.
Hadley Monthly Anomalies in rose, UAH MSU in blue, CO2 monthly seasonally adjusted from ESRL.
Arctic Sea Ice Extent
Arctic Ice 2007 vs. 2008
Antarctica Warming? An evolution of viewpoint.
Above: Mt Erebus, Antarctica
picture by Sean Brocklesby
A press release today by the University of Washington makes a claim that Antarctica is warming and has been for the last 50 years:
“The study found that warming in West Antarctica exceeded one-tenth of a degree Celsius per decade for the last 50 years and more than offset the cooling in East Antarctica.”
…
“The researchers devised a statistical technique that uses data from satellites and from Antarctic weather stations to make a new estimate of temperature trends.”
…
“People were calculating with their heads instead of actually doing the math,” Steig said. “What we did is interpolate carefully instead of just using the back of an envelope. While other interpolations had been done previously, no one had really taken advantage of the satellite data, which provide crucial information about spatial patterns of temperature change.”Satellites calculate the surface temperature by measuring the intensity of infrared light radiated by the snowpack, and they have the advantage of covering the entire continent. However, they have only been in operation for 25 years. On the other hand, a number of Antarctic weather stations have been in place since 1957, the International Geophysical Year, but virtually all of them are within a short distance of the coast and so provide no direct information about conditions in the continent’s interior.
The scientists found temperature measurements from weather stations corresponded closely with satellite data for overlapping time periods. That allowed them to use the satellite data as a guide to deduce temperatures in areas of the continent without weather stations.
…
Co-authors of the paper are David Schneider of the National Center for Atmospheric Research in Boulder, Colo., a former student of Steig’s; Scott Rutherford of Roger Williams University in Bristol, R.I.; Michael Mann of Pennsylvania State University;Josefino Comiso of NASA’s Goddard Space Flight Center in Greenbelt, Md.; and Drew Shindell of NASA’s Goddard Institute for Space Studies in New York City. The work was supported by grants from the National Science Foundation.
Anytime Michael Mann gets involved in a paper and something is “deduced” it makes me wary of the veracity of the methodology. Why? Mann can’t even correct simple faults like latitude-longitude errors in data used in previous papers he’s written.
But that’s not the focus of the moment. In that press release they cite NASA satellite imagery. Let’s take a look at how the imagery has changed in 5 years.
NASA’s viewpoint – 2004
Click for larger image
NASA’s Viewpoint 2007 (added 1/22)
NASA’s viewpoint – 2009
Click for larger image Earth’s viewpoint – map of Antarctic volcanoes
Click for larger image From the UW paper again:
“West Antarctica is a very different place than East Antarctica, and there is a physical barrier, the Transantarctic Mountains, that separates the two,” said Steig, lead author of a paper documenting the warming published in the Jan. 22 edition of Nature.
But no, it just couldn’t possibly have anything at all to do with the fact that the entire western side of the Antarctic continent and peninsula is dotted with volcanoes. Recent discovery of new volcanic activity isn’t mentioned in the paper at all.
From January 2008, the first evidence of a volcanic eruption from beneath Antarctica’s ice sheet has been discovered by members of the British Antarctic Survey.
The volcano on the West Antarctic Ice Sheet began erupting some 2,000 years ago and remains active to this day. Using airborne ice-sounding radar, scientists discovered a layer of ash produced by a ’subglacial’ volcano. It extends across an area larger than Wales. The volcano is located beneath the West Antarctic ice sheet in the Hudson Mountains at latitude 74.6°South, longitude 97°West.
UPDATE 1/22
In response to questions and challenges in comments, I’ve added imagery above and have a desire to further explain why this paper is problematic in my view.
The author of the paper himself (Steig) mentions the subglacial heat source in a response from “tallbloke” in comments. My issue is that they don’t even consider or investigate the possibility. Science is about testing and if possible, excluding all potential candidates that challenge your hypothesis, and given the geographic correlation between their output map and the volcanic map, it seems a reasonable theory to investigate. They didn’t.
But let’s put the volcanoes aside for a moment. Let’s look at the data error band. The UAH trend for Antarctica since 1978 is -0.77 degrees/century.
In a 2007 press release on Antarctica, NASA’s describes their measurement error at 2-3 degrees, making Steig’s conclusion of .25 degrees Celsius over 25 years statistically meaningless.
“Instead, the team checked the satellite records against ground-based weather station data to inter-calibrate them and make the 26-year satellite record. The scientists estimate the level of uncertainty in the measurements is between 2-3 degrees Celsius.”
That is from this 2007 NASA press release, third paragraph.
http://earthobservatory.nasa.gov/IOTD/view.php?id=8239
Also in that PR, NASA shows yet another satellite derived depiction which differs from the ones above. I’ve added it.
Saying you have a .25 deviation over 25 years (based on one-tenth of a degree Celsius per decade per Steig) with a previously established measurement uncertainty of 2-3 degrees means that the “deduced” value Steig obtained is not greater than the error bands previously cited on 2007, which would render it statistically meaningless.
In an AP story Kenneth Trenberth has the quote of the day:
http://news.yahoo.com/s/ap/20090121/ap_on_sc/sci_antarctica
“This looks like a pretty good analysis, but I have to say I remain somewhat skeptical,” Kevin Trenberth, climate analysis chief at the National Center for Atmospheric Research, said in an e-mail. “It is hard to make data where none exist.”
The Ice Caps are Growing
By David J. Ameling
There is very little precise data when it comes to climate change. Are the Ice Caps growing or are they diminishing? Accurate measurements are hard to obtain. The International Earth Rotation and Reference Systems Service (IERS) provides very precise data that can answer this question. The IERS calculates leap seconds. Just like leap years add days to keep our calendar in sync with the actual amount of time it takes for the Earth to orbit the Sun, leap seconds are used to keep highly accurate atomic clocks in sync with clocks based on the Earth’s rotation. The Earth’s rotation has slowed down. To keep the clocks in sync leap seconds will have to be added at a constant rate. If the Earth’s rotation continues to slow down leap seconds will need to be added at an increasing rate. The IERS determines the rotation of the Earth. Data only exists from 1972 to the present. From 1972 thru 1998 (26 years) 21 leap seconds were added. From 1999 to the present (9 years) only 1 leap second has been added. This means since 1999 to the present the Earth’s rate of rotation has increased. There are two possible (but not mutually exclusive) causes for this. 1. Some of the Earth’s mass has moved closer to the Earth’s axis of rotation similar to a spinning skater bringing his arms closer to his sides, and thus spinning faster. For the Earth this would occur when some of its ocean water is moved to the polar ice caps to form snow and ice. Satellite data shows the Earth’s atmosphere has been cooling since 1998. This would cause a build up of snow and ice at the polar ice caps and thus increase the Earth’s rate of rotation. The time lines for the increase in the Earth’s rotation and the atmosphere’s cooling match. The Ice Caps are growing. Mass could also have been moved closer to Earth’s axis of rotation by geological methods, but these would require more time. 2. An electromagnetic force that would slow down the Earth’s rotation is lessening. When a conductor is passed through a magnetic field an Electromotive Force (EMF) is created. If this EMF results in a current; the magnetic field created by the current opposes the motion of the conductor through the magnetic field. This will slow the motion of the conductor unless additional force is applied. The Earth rotates within the Sun’s magnetic field. The Earth’s oceans and atmosphere are conductors. The resulting eddy currents slow down the Earth’s rotation. The Sun’s resultant magnetic field (a summation of polar and toroidal magnetic fields) has been decreasing since the 1990s. This results in a reduction in the created EMF. This results in a reduction of eddy currents, which reduces the electromagnetic force that would slow the Earth’s rotation. This reduction in the electromagnetic force that would slow the Earth’s rotation rate is far too small to account for the increase in the Earth’s rotation rate. It would only complement the effects described in cause 1. The Ice Caps are growing.
Antarctic temperatures disagree with climate model predictions
COLUMBUS , Ohio – A new report on climate over the world’s southernmost continent shows that temperatures during the late 20th century did not climb as had been predicted by many global climate models.
This comes soon after the latest report by the Intergovernmental Panel on Climate Change that strongly supports the conclusion that the Earth’s climate as a whole is warming, largely due to human activity.
It also follows a similar finding from last summer by the same research group that showed no increase in precipitation over Antarctica in the last 50 years. Most models predict that both precipitation and temperature will increase over Antarctica with a warming of the planet.
David Bromwich, professor of professor of atmospheric sciences in the Department of Geography, and researcher with the Byrd Polar Research Center at Ohio State University, reported on this work at the annual meeting of the American Association for the Advancement of Science at San Francisco.
“It’s hard to see a global warming signal from the mainland of Antarctica right now,” he said. “Part of the reason is that there is a lot of variability there. It’s very hard in these polar latitudes to demonstrate a global warming signal. This is in marked contrast to the northern tip of the Antarctic Peninsula that is one of the most rapidly warming parts of the Earth.”
Bromwich says that the problem rises from several complications. The continent is vast, as large as the United States and Mexico combined. Only a small amount of detailed data is available – there are perhaps only 100 weather stations on that continent compared to the thousands spread across the U.S. and Europe . And the records that we have only date back a half-century.
“The best we can say right now is that the climate models are somewhat inconsistent with the evidence that we have for the last 50 years from continental Antarctica .
“We’re looking for a small signal that represents the impact of human activity and it is hard to find it at the moment,” he said.
Last year, Bromwich’s research group reported in the journal Science that Antarctic snowfall hadn’t increased in the last 50 years. “What we see now is that the temperature regime is broadly similar to what we saw before with snowfall. In the last decade or so, both have gone down,” he said.
In addition to the new temperature records and earlier precipitation records, Bromwich’s team also looked at the behavior of the circumpolar westerlies, the broad system of winds that surround the Antarctic continent.
“The westerlies have intensified over the last four decades of so, increasing in strength by as much as perhaps 10 to 20 percent,” he said. “This is a huge amount of ocean north of Antarctica and we’re only now understanding just how important the winds are for things like mixing in the Southern Ocean.” The ocean mixing both dissipates heat and absorbs carbon dioxide, one of the key greenhouse gases linked to global warming.
Some researchers are suggesting that the strengthening of the westerlies may be playing a role in the collapse of ice shelves along the Antarctic Peninsula.
“The peninsula is the most northern point of Antarctica and it sticks out into the westerlies,” Bromwich says. “If there is an increase in the westerly winds, it will have a warming impact on that part of the continent, thus helping to break up the ice shelves, he said.
“Farther south, the impact would be modest, or even non-existent.”
Bromwich said that the increase in the ozone hole above the central Antarctic continent may also be affecting temperatures on the mainland. “If you have less ozone, there’s less absorption of the ultraviolet light and the stratosphere doesn’t warm as much.”
That would mean that winter-like conditions would remain later in the spring than normal, lowering temperatures.
“In some sense, we might have competing effects going on in Antarctica where there is low-level CO2 warming but that may be swamped by the effects of ozone depletion,” he said. “The year 2006 was the all-time maximum for ozone depletion over the Antarctic.”
Bromwich said the disagreement between climate model predictions and the snowfall and temperature records doesn’t necessarily mean that the models are wrong.
“It isn’t surprising that these models are not doing as well in these remote parts of the world. These are global models and shouldn’t be expected to be equally exact for all locations,” he said.
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Contact: David Bromwich (614) 292-6692; Bromwich.1@osu.edu
