This is Pete Dunkelberg's Typepad Profile.
Join Typepad and start following Pete Dunkelberg's activity
Pete Dunkelberg
Recent Activity
Rodger, thanks for the methane graph. It's a very good collection of data + presentation to have. A detail though:
"Methane is the second most important greenhouse gas...."
It's so easy to forget water vapor and clouds and NOx but we shouldn't.
November 2011 Open Thread
I've been hibernating more than anticipated (man, I slept good last night!), but luckily there's more than 5 months to go until the start of the melting season. It's still November, so here's this month's open thread. We don't do Antarctic here, but FrankD sent me a couple of images from Pine ...
This paper although not a surprise, may add some clarity to the overall sea ice picture:
Eisenman et al. 2010 Consistent changes in the sea ice seasonal cycle in response to global warming
Abstract
The Northern Hemisphere sea ice cover has diminished rapidly in recent years and is projected to continue to diminish in the future. The year-to-year retreat of Northern Hemisphere sea ice extent is faster in summer than winter, which has been identifed as one of the most striking features of satellite observations as well as of state-of-the-art climate model projections. This is typically understood to imply that the sea ice cover is most sensitive to climate forcing in summertime, and previous studies have explained this by calling on factors such as the surface albedo feedback. However, in the Southern Hemisphere it is the wintertime sea ice extent that retreats fastest in climate model projections. Here, we show that the inter-hemispheric differences in the model projections can be attributed to differences in coastline geometry, which constrain where sea ice can occur. After accounting for coastline geometry, we fnd that the sea ice changes simulated in both hemispheres in most climate models are consistent with sea ice retreat being fastest in winter in the absence of landmasses. These results demonstrate that despite the widely differing rates of ice retreat among climate model projections, the seasonal structure of the sea ice retreat is robust among the models and uniform in both hemispheres.
Yet another broken record
Who says records can only be broken during the melting season? Just a week ago the 12 month rolling average for monthly NSIDC Arctic sea ice extent was at its lowest point on record, and this week it looks very much like global sea ice area (Arctic and Antarctic combined, as calculated by the go...
News flash from the RC cosmic rays & clouds topic:
#55
Jeff Pierce says:
28 Sep 2011 at 6:41 AM
Interesting timing.
It looks like we might be in the middle of a Forbush decrease right now…
http://neutronm.bartol.udel.edu/~pyle/Spectral.png
(note, this updates real time, so you view this in the future, it won’t show the decrease in Cosmic rays near the poles that I see.)
There was a coronal mass ejection that just hit the Earth (http://spaceweather.com/archive.php?view=1&day=26&month=09&year=2011).
muoncounter, you seem to know your stuff in this area. Can you weigh in on this?
SIE 2011 update 21: post mortem
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
While waiting for October here are a couple notes from Alaska:
Observations of Climate Change from Indigenous Alaskans
http://www.usgs.gov/newsroom/article.asp?ID=2931&from=news_side
http://www.startribune.com/blogs/130529403.html
The temp dropped below 32 on Saturday in Barrow, AK for the first time since June 29th. 85-day streak > 32 is longest on record! Previous record 68 days. The average temperature over the streak was 41.9°. The September average temp has been 5.2 degrees above normal.
Average first freeze is September 7th in Fairbanks - have not had a freeze yet. This is the 6th year in a row the first freeze has taken place after September 20th.
SIE 2011 update 21: post mortem
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
The Rabett notes that Eric May has a heavy handed history:
http://rabett.blogspot.com/2011/09/why-doj-dont-love-eric-may.html
So that explains part of it - only part of it.
Arctic scientist suspended
Following a comment in the latest SIE update comment section, I draw attention to this article on the Guardian website: Arctic scientist who exposed climate threat to polar bear is suspended US government conducts 'integrity inquiry' on federal biologist amid lobbying by oil firms for Arctic p...
Bremen falls through the trap door, fat lady recalled for encore?
http://iup.physik.uni-bremen.de:8084/amsr/ice_ext_n.png
Final score: 2011 vs 2007
Now that I've called the minimum, it's time to have a look at the differences between the two years with the lowest minimums in all data sets. This post will be a potpourri of different factors. If we look at the six most important data sets - which IMHO are IJIS extent, NSIDC extent, Cryosphere...
Andrew: For 80N temperatures to be below average, it means that there has been below average exchange or air masses north of 80N and south of 80N. In other words, north of 80N has been more isolated than it generally does.
Well, some pretty chilly air escaped and made it as far as Minnesota.
NSIDC also calls the minimum
Yet another update by the National Snow and Ice Data Center (NSIDC) to announce that the minimum has been reached: Arctic sea ice at minimum extent Arctic sea ice appears to have reached its lowest extent for the year. The minimum ice extent was the second lowest in the satellite record, after ...
dorlomin: "only" "Pliocene\ Miocene type temperatures?"
Summer heat waves would be more than inconvenient. With the faster water cycle, storms even without high wind speeds will be more than inconvenient. With climate disruption disrupting agriculture and ocean acidification disrupting our seafood, the price of a meal will be more than inconvenient.
Neven: Good post. However this fatalism
"The collective consciousness changes at its own pace."
is contrary to the post, and certainly not what the professional deniers think. Nor what you really think, I think.
Understanding changes in the Arctic is very valuable and helpful to the "collective consciousness" as well as to participants here. I thank everyone here for all your Arctic analysis. Keep it up! This will be part of what moves the collective consciousness toward serious emissions reduction sooner.
And now, a word for our sponsors
We are all equally responsible for the melting of the Arctic sea ice. But to paraphrase the pigs in Animal Farm: Some are more responsible than others. Some will do their utmost to make sure the greatest geophysical experiment of all time is conducted to the very end. They are doing everything i...
That's an emissions scenario question. If we run CO2 up to nearly 1000 ppm as some would if they could, survivors will experience a much warmer world and much higher seas than such recent times.
And now, a word for our sponsors
We are all equally responsible for the melting of the Arctic sea ice. But to paraphrase the pigs in Animal Farm: Some are more responsible than others. Some will do their utmost to make sure the greatest geophysical experiment of all time is conducted to the very end. They are doing everything i...
Maltose, too late. Bremen is up again.
http://iup.physik.uni-bremen.de:8084/amsr/ice_ext_n.png
Historical Minimum in Sea Ice Extent
The Arctic sea ice extent index calculated by a University of Bremen research team led by Dr. Georg Heygster reached a new historical low point of 4.24 million km2 on September 8. The previous one-day minimum was 4.27 million km2 on September 17, 2007 (Figure 1). The usual melt season is not yet...
Bremen says extent increased.
http://iup.physik.uni-bremen.de:8084/amsr/ice_ext_n.png
SIE 2011 update 19: the fat lady is humming
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
Bob Wallace, thanks a lot for your remarks and link on Jacobson!
SIE 2011 update 18: ten yard line
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
Bob Wallace, agreed, I had read that, but is it believable? "other factors" hint Rampal
SIE 2011 update 18: ten yard line
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
“It’s hard to predict the future of Arctic sea ice.”
William Crump observed earlier that the demise of multiyear ice creates new territory for first year ice to form in and occupy year after year.
Steele et al. find mostly bottom melt using this model:
"2. Methods
[5] Our main analysis tool is model output from a coupled sea‐ice‐ocean model of the arctic seas, the pan‐Arctic ice ocean
modeling and assimilation system (PIOMAS) of Zhang and Rothrock [2003]."
Does the model overestimate volume and thickness?
Note the investigations of Rampal et al.: http://web.mit.edu/~rampal/rampal_homepage/Publications.html.
Jacobson wants to clean up the transportion sector, and who doesn't? But as for cooling the Arctic, how much can that do vs other factors?
Perhaps after this year's minimum SIE there could be a thread just for analysis of papers. For now, it would nice to have definitive explanation of why Bremen and IJIS show current extent lower/higher than 2007 at this date.
SIE 2011 update 18: ten yard line
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
Janne Tuukkanen: "It sounds like a long shot to connect something born near Cap Verde to Arctic ice, but these systems bring winds with them."
Some surprising corelations turn up. The Naval Graduate School thesis of Megan M. Stone, LONG RANGE FORECASTING OF ARCTIC SEA ICE (pdf) is an example.
Conclusion:
Our results indicate that viable long-range forecasts of October SIC in the Beaufort Sea are possible via the use of Beaufort Sea SIC and Caribbean SSTs at lead times of one to five months. While our results show a definite correlation between these two variables and October SIC in the Beaufort Sea, we suspect that there are additional factors and dynamics that play an important role in the variability of SIC in the Beaufort Sea. Our study is meant to emphasize how advanced data sets and methods can be used to generate skillful long-range forecasts of sea ice amounts in the Arctic for use in operational planning by the U.S. Navy.
SIE 2011 update 18: ten yard line
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
Did Prof Mandia say "statistically overdue?" I suggest that this phrase be reconsidered. Think about it, or look up "exponential waiting time."
SIE 2011 update 17: unfulfilled potential
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
"All in all, a lot of natural" (or anthropogenic) "catastrophes in the past 2 years."
Yes, a couple. Or five comment pages worth for 2010.
For the USA this year, Hurricane Irene hasn't come ashore and may not but if you look at Capital Climate and keep clicking Older posts at the bottom, extremes keep coming longer than you can keep clicking.
Flash melting
I introduced the term 'flash melting' in a recent SIE update. It was a pun on the term 'flash flooding' where lots of rain falls out of the sky in a short amount of time, causing creeks and rivers to flood very fast. I based the concept on the state of large parts of the ice pack in the Beaufort...
Tom Z, are you familiar with the tropicalista Tom Zé? http://en.wikipedia.org/wiki/Tom_Zé
---
I'm not sure this great ice-empiricist blog would be much improved by digging into why various models under-predict the melt. Instead that might bog the blog down. For my part I seem to read a climate paper or a good chunk of one if it's long most days, although I don't start with that intention.
For the Arctic Sea Ice blog, I think keeping up with the ice is the important thing. The new paper by Rampal et al. brings more physics to the Arctic models. This will add understanding of the process. I hope the pdf will be available soon. But now I only want to bring http://chronicle.com/blogs/wiredcampus/the-public-playing-a-molecule-building-game-outperforms-scientists to your attention.
Arctic ice melt could pause in coming decades
First the ice extent had been 50% less during the Holocene Climatic Optimum than it was in September 2007, now we have models saying the ice could expand during some decades just as easily as contract, according to this NSF press release (hat-tip to Noel): Researchers find unexpected results in ...
For a good bit of perspective on models one might look at http://www.realclimate.org/index.php/archives/2011/08/cmip5-simulations/ and follow the link to Schmidt, G.A, 2010: Enhancing the relevance of palaeoclimate model/data comparisons for assessments of future climate change. J. Quaternary Sci., 25, 79-87, doi:10.1002/jqs.1314.
... and the conclusion may be that it is best to keep on watching the ice closely.
Arctic ice melt could pause in coming decades
First the ice extent had been 50% less during the Holocene Climatic Optimum than it was in September 2007, now we have models saying the ice could expand during some decades just as easily as contract, according to this NSF press release (hat-tip to Noel): Researchers find unexpected results in ...
Rampal et al. abstract.
Perhaps the flurry of Arctic models will settle down by 2014. For now this empirical blog is as good a source on the Arctic as any. I encourage you again to look into heat sources including ocean currents and to think about how you might synthesize all that you know into a coherent explanation. Start thinking now; the ice won't last forever, and who better to write its story?
Ten years from now this year's climate, this year's models and this years Arctic will be history.
Arctic ice melt could pause in coming decades
First the ice extent had been 50% less during the Holocene Climatic Optimum than it was in September 2007, now we have models saying the ice could expand during some decades just as easily as contract, according to this NSF press release (hat-tip to Noel): Researchers find unexpected results in ...
Funder et al. 2011 is a wonderful paper and a wonderful addition to this blog. It starts on a wonderfully empirical note:
Driftwood on Greenland’s raised beaches
and shores originates from transocean drift from Asia and America. The voyage takes several years....
and ends with this long paragraph (breaks and bolding inserted by me) arriving at specific significant room for improvement in climate models:
In general, our sea-ice record for North
Greenland follows the Holocene climate development,
with an early warm period followed
by declining temperatures, which were punctuated
by relatively warmer and colder intervals
(17, 25).
The reduction of the HTM sea ice in
northern Greenland fits with the simulated ice
distribution and surface temperature in orbitally
forced ECHAM5/JSBACH/MPI-OM (EJM) and
LOVECLIM general circulation climate model
simulations (3, 4, 10).
A tentative first approximation
of the large-scale changes associated
with the observed ice retreat north of Greenland
can be obtained by selecting among the numerical
experiments performed with the LOVECLIM
model those that are the most similar to our observations
[experiments E3 to E5 (3) and fig. S3].
In this exercise, our records would correspond
in the model to an Arctic Ocean sea-ice cover
in summer at 8 ky B.P. that was less than half
of the record low 2007 level. The general
buildup of sea ice from ~6 ky B.P. agrees with
the LOVECLIM model, showing that summer
sea-ice cover, which reached its Holocene maximum
during the LIA, attained its present (~2000)
extent at ~ 4 ky B.P. (fig. S3).
However, despite
the similarities at large scale and the long-term
trends between model and observations, the complementarity
in sea-ice abundance between East
(Ellesmere) andWest (Greenland), which is seen
especially during the HTM, is not simulated in
the climate models. The largest reduction in the
EJM is indeed seen in the eastern part of the
Arctic in association with an enhanced oceanic
circulation and net northward heat transport (4).
However, there are no signs in the EJM or in
LOVECLIM of a concurrent simulated increase
in the West.
It has been seen in recent years that
there is a strong influence on the sea-ice variability
from the large-scale atmospheric flow anomalies
and associated wind stress (1, 2, 23, 24), and
the importance of wind-stress is also known from
basic sea-ice physics. Thus, it is likely that the
model deficits are related to a too-weak large-
scale AO-type flow response to the orbital forcing
during the HTM. Such troubles in reproducing
past sea-ice variations may also have an impact
on future simulated regional changes using the
same models. Therefore, improved understanding
of these inconsistencies is important.
[breaks and bolding inserted]
Along the way we gain interesting food for thought like
At ~2.5 ky B.P., an
era of dramatic centennial fluctuations in driftwood
abundance and of change of source areas
began.
and also learn more about the famous MWP.
What a great experience for a team with many graduate students (I presume) to collect data along 500 km of wild, cold coast and then publish an important paper in Science! What a refreshing change of pace for this blog, excellent as it is, to look at a much longer perspective than "which way is the wind blowing at this moment."
Arctic 'tipping point' may not be reached
I saw this news item in the blog news feed in the right side bar and thought it was worth a post. From the BBC website: Arctic 'tipping point' may not be reached By Matt McGrath Science reporter, BBC World Service Scientists say that current concerns over a tipping point in the disappearance o...
aha! Lodger that's the one. Thanks again.
Meanwhile back on the ice, this looks like a good time to study pure melting in place. What is known about the import of heat by ocean currents?
SIE 2011 update 13: One step back, two steps...
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
Thanks for those links, Lodger.
I seem to recall something else as well. Sea water keeps getting denser as it cools toward freezing (at nearly 2 kelvins below the freezing temperature of pure water). So the coldest water keeps sinking until there is enough of a stack of very cold water to slow the sinking enough for the upper water to freeze before it sinks.
On the other hand, if the Arctic surface waters became very fresh for some reason, say a collapsing ice sheet, the Arctic sea might freeze as fresh water does, leading to a much greater extent and a severe winter. I hope the chance of this is below .1.
SIE 2011 update 13: One step back, two steps...
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
Thanks Tzupancic1 for posting this reference:
Kinnard, C., Zdanowicz, C.M., Koerner, R.M., and Fisher, D.A. "A changing Arctic seasonal ice zone: Observations from 1870-2003 and possible oceanographic consequences. Geophysical Research Letters 35(2): art. L02507, 2008."
"Notes: Changes in the extent of seasonal ice were investigated using historical and satellite observations for the period 1870-2003. The seasonal ice zone (SIZ) has been gradually expanding since 1870, with a marked acceleration over the past three decades, and has migrated north to encompass all peripheral Arctic seas. The expansion of the SIZ may be increasing the salinity of the upper Arctic Ocean, consistent with recent observations. The migration of the SIZ over continental shelves may also be enhancing the formation rate and salinity of Arctic deep waters, which are subsequently advected to the convective region of the Greenland-Iceland-Norwegian Sea, thereby influencing the formation of North Atlantic deep waters and related global thermohaline circulation."
1. I find no free pdf of this paper. A note from the redoubtable Neven blog would probably motivate the authors to put it online (ditto for other papers).
2. Isn't Arctic salinity now decreasing in some areas due to the de-permafrosting of Siberia? It would not be at all nice if the Arctic sea became fresh enough to freeze from the top down. I believe Lodger once posted a link explaining the freezing process but I can't find it now.
SIE 2011 update 13: One step back, two steps...
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
"Man, this is exciting!"
Perhaps one day when the ice is gone someone will write an epic poem about it in Old Norse. And a scientific book explaining how it went down. Will that be possible? Can you synthesize? It's reported here like a boxing match. ;) What's the scoop on heat import? The roles of melting in place vs blowing away? I don't expect anyone to have all the answers off the top of your head, I just want to plant some thought-questions.
SIE 2011 update 13: One step back, two steps...
During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good ...
More...
Subscribe to Pete Dunkelberg’s Recent Activity