Fabled Northwest Passage begins to re-freeze

By: Dr. Jeff Masters , 2:29 PM GMT on October 12, 2007

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This summer's dramatic loss of Arctic sea ice peaked on September 15, and the polar ice cap is finally beginning to re-freeze, according to a press release issued by the National Snow and Ice Data Center on October 1. Extent of the September polar sea ice fell 39%, compared to the 1979-2000 average. To put this loss in perspective, in one year we lost as much ice as we lost during the previous 28 years. Summertime Arctic sea ice is now at 50% of what it was in the 1950s (Figure 1). One may look at at graph and wonder, but what about sea ice loss in other seasons? It hasn't been nearly so severe. True, but it is the summer ice we care most about, since summer is when the thick, multi-year ice melts, which can then precondition the Arctic for much greater ice loss in future years. As sea ice melts in response to rising temperatures, more of the dark ocean is exposed, allowing it to absorb more of the sun's energy. This further increases air temperatures, ocean temperatures, and ice melt in a process know as the "ice-albedo feedback" (albedo means how much sunlight a surface reflects). There is an excellent chance that the summer of 2007 will be remembered as the "tipping point" for Arctic sea ice, when an irreversible ice-albedo feedback process firmly established itself.



Figure 1. Arctic sea ice extent since 1900, as estimated from satellite and ship reports compiled by Walsh and Chapman (2001). Image credit: University of Illinois cryosphere group.

Northwest Passage opens for the first time in recorded history
Long before the Panama and Suez Canals made commercial trading between the Atlantic and Pacific Oceans economically feasible, ships made the long and perilous trip around the African and South America continents. Explorers, traders, and world leaders looking for faster and less dangerous shipping routes to far-away areas of the world have long eyed two routes through the ice-choked Arctic Ocean--the fabled Northwest Passage, through the cold Arctic waters north of Canada, and the Northeast Passage, extending along the northern coast of Russia. The first recorded attempt to find and sail the Northwest Passage was in 1497, and ended in failure. The thick ice choking the waterways thwarted all attempts at passage for the next four centuries. Finally, in 1905, Roald Amundsen completed the first successful navigation of the Northwest Passage. It took his ship two-and-a-half years to navigate through narrow passages of open water, and his ship spent two cold, dark winters locked in the ice during the feat. More recently, icebreakers and ice-strengthened ships have on occasion battered their way through the ice-blocked route.



Figure 2. The Northwest Passage shipping route (red line) and Northeast Passage (green line) superimposed on an ice coverage map from August 22, 2007. The Northwest Passage was ice-free and navigable for 36 days between August 14 and September 18, 2007. The Northeast Passage was blocked by a narrow strip of ice most of the summer. Image credit: National Snow and Ice Data Center.

Times are changing. In 2001, the Bering Strait, a key portion of both the Northwest and Northeast Passages, was completely ice free. This was followed in 2005 by record-breaking sea-ice melt in the Arctic, leading to the first ever recorded opening of the Northeast Passage. The fabled Northwest Passage remained closed in 2005. Arctic ice recovered a bit in 2006, and both passages remained closed. But the unprecedented melting during the summer of 2007 saw the Northwest Passage become ice-free and navigable along its entire length without the need for an icebreaker as of August 14, 2007. Remarkably, the Northwest Passage remained ice-free for 36 days, finally refreezing over a small section on September 19. The Northeast Passage was blocked by a narrow strip of ice all summer. However, this strip of ice thinned to just 30% coverage on September 25 and 26, making the Northeast Passage passable for ordinary ships on those days.

When is the last time the Northwest Passage was open?
We can be sure the Northwest Passage was never open from 1900 on, as we have detailed ice edge records from ships. It is very unlikely the Passage was open between 1497 and 1900, since this was a cold period in the northern latitudes known as "The Little Ice Age". Ships periodically attempted the Passage and were foiled during this period, and the native Inuit people have no historical tales of the Passage being navigable at any time in the past.

A good candidate for the last previous opening of the Northwest Passage was the period 5,000-7,000 years ago, when the Earth's orbital variations brought more sunlight to the Arctic in summer than at present. Prior to that, the Passage was probably open during the last inter-glacial period, 120,000 years ago. Temperatures then were 2-3 degrees Centigrade higher than present-day temperatures, and sea levels were 4-6 meters higher.

Final thoughts
If we have reached the tipping point for Arctic ice, what are the implications? I'll discuss this more in a future blog. Sea ice is very complicated, and it is not a sure thing that we have reached the tipping point. For more on the complexities of sea ice, read wunderblogger Dr. Ricky Rood's latest blog.

NASA has posted a beautiful satellite image of the Arctic ice cap at the September 15 2007 minimum, showing the open water of the Northwest Passage.

I thank Edalin Michael of the University of Michigan's School of Natural Resources and Robert Grumbine of NOAA's Sea Ice Group for their contributions to this blog.

References
Walsh, J.E and W.L.Chapman, 2001, "Twentieth-century sea ice variations from observational data", Annals of Glaciology, 33, Number 1, January 2001 , pp. 444-448.

Jeff Masters

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1047. IKE
6:39 AM CDT on October 13, 2007
Weather456 6:38 AM CDT on October 13, 2007
I agree h23...first it was wilma, now opal when it reaches..or if it reaches the gulf it will be Katrina


I think folks are talking about a path...not a strength compared to those monsters.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1046. IKE
6:37 AM CDT on October 13, 2007
hurricane23 6:36 AM CDT on October 13, 2007
That mess in the caribbean is not even close to opal or should not even be mentioned in the same sentence.Conditions in the caribbean look ok for some development but its 50/50 as you move into the gulf.


That's why I said "Jr"....the moisture and the path.

Member Since: June 9, 2005 Posts: 23 Comments: 37860
1045. Weather456
7:36 AM AST on October 13, 2007
I agree h23...first it was wilma, now opal when it reaches..or if it reaches the gulf it will be Katrina.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1044. UYA
11:37 AM GMT on October 13, 2007
Those are your thoughts 23.....
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1043. hurricane23
7:35 AM EDT on October 13, 2007
That mess in the caribbean is not even close to opal or should not even be mentioned in the same sentence.Conditions in the caribbean look ok for some development but its 50/50 as you move into the gulf.
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1042. IKE
6:34 AM CDT on October 13, 2007
Lili?

Link
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1041. weatherg8r
6:33 AM EST on October 13, 2007
Thanks Ike...we have a restaurant at the mouth of the Suwannee that does not need to blow away! But rain if needed...lots of it.
1040. IKE
6:32 AM CDT on October 13, 2007
It probably will cross a portion of the Yucatan again...

Member Since: June 9, 2005 Posts: 23 Comments: 37860
1039. gulfcoastdweller
6:31 AM CDT on October 13, 2007
wasn't tropical storm Lilli a late bloomer, I seem to recall tons of rain in late Oct in La............maybe 2003?
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1038. TampaSpin
7:29 AM EDT on October 13, 2007
Ike-
Do you think it will cross the Youc. again or stay in the Carib.
Member Since: September 2, 2007 Posts: 179 Comments: 20448
1037. TampaSpin
7:23 AM EDT on October 13, 2007
Yep..the sleeper is waking up in the Carr.Link
Member Since: September 2, 2007 Posts: 179 Comments: 20448
1036. UYA
11:23 AM GMT on October 13, 2007
Quiet please....I'm trying to get Hanna Montana tix.
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1035. IKE
6:22 AM CDT on October 13, 2007
weatherg8r 6:20 AM CDT on October 13, 2007
Ike...any idea what strength this "moisture" my might be when it gets to the Gulf Coast...Tropical Storm would be nice...anything stronger...not so much


I doubt it would be much stronger...call it Opal Jr.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1034. Weather456
7:20 AM AST on October 13, 2007
94L has reemerged out over the Caribbean sea as a 1005 mb low. Current and forecasted shear looks excellent for development. SSTs are high and water vapor content is high. There is one major exception....no define surface circulation. A quikscat should be out this morning for the NW Caribbean.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
1033. weatherg8r
6:09 AM EST on October 13, 2007
Ike...any idea what strength this "moisture" my might be when it gets to the Gulf Coast...Tropical Storm would be nice...anything stronger...not so much
1032. gulfcoastdweller
6:14 AM CDT on October 13, 2007
yeah some rain would be nice

as far as wishcasting, if I wanted to wishcast, I would wish for snow for 2 days....that would be fun!

though we did get some "southern style snow" that X mas in 04, before Katrina
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1031. Weather456
7:12 AM AST on October 13, 2007
Open Ocean Stratocumulus

Very dry air aloft over moist air is unstable situation and would lead to the formation of clouds. However, an overlying inversion keeps the cloud tops low resulting in formation of stratocumulus and fog like the one the imagery below off the East coast of US.

GOES-East 4 km Fog / Reflectivity Product


GOES-EAST Water Vapor imagery showing a very dry and stable airmass induced by an upper trough pushing down over Eastern US.



The surface air temperature has met its dew point which is 15C.






Member Since: July 24, 2005 Posts: 407 Comments: 19076
1030. TampaSpin
7:13 AM EDT on October 13, 2007
yep we do need the rain
Member Since: September 2, 2007 Posts: 179 Comments: 20448
1029. IKE
6:06 AM CDT on October 13, 2007
gulfcoastdweller 6:04 AM CDT on October 13, 2007
well Ike....... I don't say this to often when it comes to tropical weather but

BRING IT ON!!!
lol


I agree....from everything I've seen it looks like some much needed rain...water temps are still near 80 in the eastern GOM..near the coast.

NOEL?

Wishcasters?
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1028. gulfcoastdweller
6:03 AM CDT on October 13, 2007
well Ike....... I don't say this to often when it comes to tropical weather but

BRING IT ON!!!
lol
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1027. UYA
11:03 AM GMT on October 13, 2007
Right....coffee...Ughh...models.
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1026. IKE
6:02 AM CDT on October 13, 2007
The CMC has some company with the GFS...the NOGAPS...the NAM has the moisture heading in the same area.......
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1025. gulfcoastdweller
5:54 AM CDT on October 13, 2007
UGH that CMC!
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1024. IKE
5:56 AM CDT on October 13, 2007
Click on NCEP fronts on the visible loop...EX94L is over water...1005 mb low.......

Link
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1023. IKE
5:56 AM CDT on October 13, 2007
Your link didn't work TampaSpin....get ya another cup of coffee and give it another shot.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1022. TampaSpin
6:45 AM EDT on October 13, 2007
Good Morning everyone..looks like the sleeping gaint is waking up over the warm Caribe. this morning...i would say not a good thing.Link
Member Since: September 2, 2007 Posts: 179 Comments: 20448
1021. IKE
5:28 AM CDT on October 13, 2007
0Z CMC....

Link


Watch out gulf coast!
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1020. IKE
5:21 AM CDT on October 13, 2007
6Z GFS on EX94L...it's run through 132 hours.......

Link

Looks like it's gonna get pulled back to the north.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1019. UYA
10:13 AM GMT on October 13, 2007
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 AM EDT SAT OCT 13 2007

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A NEARLY STATIONARY AND LARGE AREA OF DISTURBED WEATHER OVER
PORTIONS OF CENTRAL AMERICA...THE NORTHWESTERN CARIBBEAN SEA...CUBA
AND JAMAICA IS ASSOCIATED WITH A BROAD AREA OF LOW PRESSURE. THIS
SYSTEM'S PROXIMITY TO LAND WILL LIKELY INHIBIT TROPICAL CYCLONE
FORMATION DURING THE NEXT COUPLE OF DAYS. HOWEVER...HEAVY RAINS
COULD CONTINUE OVER THIS AREA FOR THE NEXT FEW DAYS...PRIMARILY
OVER PORTIONS OF THE PACIFIC COAST OF CENTRAL AMERICA.
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1018. UYA
10:12 AM GMT on October 13, 2007
Holiday Inn Express?
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1017. underthunder
4:05 AM CST on October 13, 2007
and please ya'll...I was just "funnin" with ya'll...please dont take offense...
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1016. underthunder
4:02 AM CST on October 13, 2007
on the weather subject...has anyone taken a look at the "slumbering big person" this morning...it looks to me as if it might have a split personality..and one of them is creeping back towards the east...any takers on this?
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1015. UYA
10:01 AM GMT on October 13, 2007
Anytime guygee....it was enjoyable.
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1014. guygee
9:57 AM GMT on October 13, 2007
1012. underthunder 9:56 AM GMT on October 13, 2007
"gee...maybe you 2 should get a room..."

LOL, underthunder. I have been trying to keep to a dispassionate discussion, but you are partly right, it is late, and I think I will get a room with my sleeping wife.

Goodnight, and thanks UYA for the discussion.
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1013. UYA
9:57 AM GMT on October 13, 2007
1012. underthunder 9:56 AM GMT on October 13, 2007
gee...maybe you 2 should get a room.....



I've been waiting for that comment.....LOL!
I'm gone.

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1012. underthunder
3:48 AM CST on October 13, 2007
gee...maybe you 2 should get a room.....
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1011. UYA
9:53 AM GMT on October 13, 2007
Yes guygee......that would be true for sure.
So you are telling me your 30 year climate models are that accurate?
Like....could you maybe break that down a little better.........
See what I mean?
LMAO!
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1010. guygee
9:45 AM GMT on October 13, 2007
Re: 1007. UYA 9:44 AM GMT on October 13, 2007

UYA - It is often easier to predict time-averaged trends in a non-stationary process than it is to predict the next "sample". This is the difference between "weather" and "climate". I predict that in Denver, December temperatures will be colder than March temperatures "on average", but that does not mean we cannot have a very warm December day or a March snowstorm.
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1009. UYA
9:46 AM GMT on October 13, 2007
LOL....a Politician was just awarded the Nobel "Peace" prize.......get over it!
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1008. guygee
9:43 AM GMT on October 13, 2007
1003. UYA at 9:26 AM GMT on October 13, 2007 wrote thusly:
"I really thought you were smarter than this guygee.
You like Al and Hillary too?
"

Attack the messenger, then try to introduce politics into a scientific discussion...nice try UYA.
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1007. UYA
9:44 AM GMT on October 13, 2007
I'll break this down really simple.
A computer weather model to me is just a snap of "Might" and possibly happen three days out!
I said "Three" days out.
Only a true fool would believe more than that regarding a weather model.
Yet you ask me to trust climate models for 30 years?
I can't and won't do that.
I see temps where I live as highs near 90 and lows at 73....until a real front makes it this far south.
That's how it is guygee.
And the best part....this is still a normal temp differential!
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1006. guygee
9:29 AM GMT on October 13, 2007
UYA - The heat island effect includes the effects of asphalt in urban areas, so the answer to that part of your question is an unqualified "Yes".

As for "Jet exhaust", it is true that jet airplanes release CO2, and also release H20 into the stratosphere. These effects may not be inconsequential, but surely you are not implying that the heat energy released by aircraft is at all significant compared to the energy received from the sun?

Personally I wish we could return to the days of the "Steam Powered Aero Plane", but very sadly John Hartford died a few years ago of cancer.
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1005. UYA
9:28 AM GMT on October 13, 2007
I won't do a Michael STL here with you guygee. I'm trying to speak plain english so most can understand.
I disagree with everything you have posted regarding increased CONUS temps!
I have previously stated why and that the readings are seriously faulted.
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1004. UYA
9:26 AM GMT on October 13, 2007
and again we cannot make judgments based on a single season.

Yeah, I am not....but you sound like you already have based on faulty science.
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1003. UYA
9:20 AM GMT on October 13, 2007
Guygee....anywhere in there did they allow for Asphalt or Jet exhaust?


a matrix of difference series is formed for a large fraction of all possible combinations of station series pairs in each localized region. The station pool for this pairwise comparison of series includes U.S. HCN stations as well as other U.S. Cooperative Observer Network stations.

Right......so you are personally willing to put your personal butt on the line for this?

I really thought you were smarter than this guygee.
You like Al and Hillary too?
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1002. guygee
9:08 AM GMT on October 13, 2007
UYA - As regards to your observations on 2007 severe weather events:

1) I am thankful that the CONUS tornado and hurricane seasons have not been as severe as in recent years.
2)The state of the art in climate science has just begun to even attempt to address regional changes due to GW...this field of climate prediction is still murky at best.
3)There are a growing number of climate scientists who believe that GW may result in a larger proportion of major hurricanes, but this is still an area of active debate, and in any event such changes must be evaluated globally over decadal timescales, not over a single season.
4)Any possible effect of GW on the frequency and spatial distribution of tornadic events is still a matter of active research, and again we cannot make judgments based on a single season.
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1001. pixeldigger
9:03 AM GMT on October 13, 2007
I made 9 out of 10.
I missed the one about which method measures temperature best.
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1000. guygee
9:08 AM GMT on October 13, 2007
USHCN Version 1 Data Package Description

The data package contains the following four versions of the data set.

1. Raw: the data in this version have been through all quality control but have no data adjustments.

2. TOB: these data have also been subjected to the time-of-observation bias adjustment.

3. Adjusted: these data have been adjusted for the time-of-observation bias, MMTS bias, and station moves, etc.

4. Urban: these data have all adjustments including the urban heat adjustments.

USHCN Version 2 Serial Monthly Dataset


"The USHCN Version 2 homogenization algorithm addresses these and other issues according to the following steps. At present, only temperature series are evaluated for artificial changepoints.

1. First, a series of monthly temperature differences is formed between numerous pairs of station series in a region. The difference series are calculated between each target station series and a number (up to 40) of highly correlated series from nearby stations. In effect, a matrix of difference series is formed for a large fraction of all possible combinations of station series pairs in each localized region. The station pool for this pairwise comparison of series includes U.S. HCN stations as well as other U.S. Cooperative Observer Network stations.
2. Tests for undocumented changepoints are then applied to each paired difference series. A hierarchy of changepoint models is used to distinguish whether the changepoint appears to be a change in mean with no trend (Alexandersson and Moberg, 1997), a change in mean within a general trend (Wang, 2003), or a change in mean coincident with a change in trend (Lund and Reeves, 2002) . Since all difference series are comprised of values from two series, a changepoint date in any one difference series is temporarily attributed to both station series used to calculate the differences. The result is a matrix of potential changepoint dates for each station series.
3. The full matrix of changepoint dates is then "unconfounded" by identifying the series common to multiple paired-difference series that have the same changepoint date. Since each series is paired with a unique set of neighboring series, it is possible to determine whether more than one nearby series share the same changepoint date.
4. The magnitude of each relative changepoint is calculated using the most appropriate two-phase regression model (e.g., a jump in mean with no trend in the series, a jump in mean within a general linear trend, etc.). This magnitude is used to estimate the "window of uncertainty" for each changepoint date since the most probable date of an undocumented changepoint is subject to some sampling uncertainty, the magnitude of which is a function of the size of the changepoint. Any cluster of undocumented changepoint dates that falls within overlapping windows of uncertainty is conflated to a single changepoint date according to (1). a known change date as documented in the target station's history archive (meaning the discontinuity does not appear to be undocumented), or (2). the most common undocumented changepoint date within the uncertainty window (meaning the discontinuity appears to be truly undocumented)
5. Finally, multiple pairwise estimates of relative step change magnitude are re-calculated at all documented and undocumented discontinuities attributed to the target series. The range of the pairwise estimates for each target step change is used to calculate confidence limits for the magnitude of the discontinuity. Adjustments are made to the target series using the estimates for each discontinuity."
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999. UYA
8:59 AM GMT on October 13, 2007
ONE HURRICANE......I think I'm crying now..........
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998. UYA
8:52 AM GMT on October 13, 2007
Let's just throw severe CONUS weather in the mix.
I checked yesterday regarding Tornadic activity this year as opposed to 06 and for the three year average.....07 is still about 150 tornados below last year.
and way below the three year average....so don't start shoveling that severe Global Warming-caused weather this way either.
We had one Hurricane so far that impacted the CONUS.....when so many were supposed to kill us all!
I'll make you cry!
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997. guygee
8:34 AM GMT on October 13, 2007
For anyone who thinks that real climate scientists have not already extensively studied the "heat island effect", please see the United States Historical Climatology Network site. In particular, see the Quality Control, Homogeneity Testing, and Adjustment Procedures link for details. Online documentation describing the UNITED STATES HISTORICAL CLIMATOLOGY NETWORK MONTHLY TEMPERATURE AND PRECIPITATION DATA set is available, and the data, metadata and documentation can be downloaded here.

The "heat island effect" is a tired old argument that may have been once valid, but the dataset above is detrended to account for this effect as well as other errors in the historical record.

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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