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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1147. TampaSpin
9:52 AM EDT on October 13, 2007
1143. Hhunter 9:52 AM EDT on October 13, 2007
baha interesting thought, i definetly think that wave coming west if it moves fast enough could get entrained and add to the situation.

HH- i said the same thing late last nite...its going to just add fuel.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
1146. icmoore
1:50 PM GMT on October 13, 2007
Good Morning all, When I left last night the talk was about the GFS models predicting a FL storm just checking in. Not as cool here this morning.
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1145. BahaHurican
9:49 AM EDT on October 13, 2007
Can somebody point me to whatever it is they are looking at which makes them expect this system to move into the GoM? Right now I'm not seeing that pic. . .
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1144. Sfloridacat5
1:51 PM GMT on October 13, 2007
Dr. Lyons on TWC just mentioned "moisture being pulled up into the GOM this week, but wind shear should be too high for tropical development."

We will wait and see.
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1143. Hhunter
1:50 PM GMT on October 13, 2007
baha interesting thought, i definetly think that wave coming west if it moves fast enough could get entrained and add to the situation.
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1142. IKE
8:51 AM CDT on October 13, 2007
Hhunter 8:49 AM CDT on October 13, 2007
ike it was just my opinion.


I know...it's OK.
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1141. kmanislander
1:49 PM GMT on October 13, 2007
Lots of energy still available in that area

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1140. Hhunter
1:49 PM GMT on October 13, 2007
ike it was just my opinion.
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1139. Sfloridacat5
1:45 PM GMT on October 13, 2007
Local meteorologist mentioned to watch the topics for "moisture" moving up into the GOM later this week.
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1138. TampaSpin
9:44 AM EDT on October 13, 2007
Taz,
Isn't sheer in the GOM expected to relax in 2 days.
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1137. BahaHurican
9:48 AM EDT on October 13, 2007
1125. Tazmanian 9:41 AM EDT on October 13, 2007

that is 90E not 90L


Thanks for the heads-up, Taz.
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1136. IKE
8:48 AM CDT on October 13, 2007
I agree Baha.


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1135. Hhunter
1:47 PM GMT on October 13, 2007

nice info kmanislander..
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1134. BahaHurican
9:41 AM EDT on October 13, 2007
Read this quote about 1996's Hurricane Lili:

A tropical wave moved from Africa to the Atlantic Ocean on 4 October accompanied by a large cyclonic rotation of low clouds and a mid-tropospheric jet. The wave moved westward under an unfavorable strong vertical shear environment and, on 11 October, passed through the Windward Islands where a marked wind shift and large 24-hour pressure changes were observed. It reached the southwestern Caribbean on the 13th, where a pre-existing area of low surface pressure was located.

The system developed a well-defined low-level circulation and became a tropical depression at about 1200 UTC on the 14th, just east of Nicaragua, and began moving northwestward at about eight knots. The track in Fig. 1 and Table 1 begins at this time.


Does this sound like a scenario we are familiar with? That approaching Twave might "wake the sleeping giant" . . .
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1133. kmanislander
1:44 PM GMT on October 13, 2007
Taz

That may be true today but there is an elogated high sitting right over the NW Caribbean and the low we are talking about.

Shear near Roatan is now only 5 to 10 knots which makes for a favourable environment for development in that area. With weak steering anything developing there could hang around long enough and far enough S until the GOM becomes more favourable.

This time of year the systems in the Caribbean are slow movers
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1132. IKE
8:45 AM CDT on October 13, 2007
Hhunter 8:44 AM CDT on October 13, 2007
ike i really did not ask you if you believed it. In fact i really don't care if you do. but we will all know in a few days..



This blog is about opinions on the tropics.

I really don't care if you don't care.
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1131. Hhunter
1:45 PM GMT on October 13, 2007
this was written last night by mr B
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1130. IKE
8:43 AM CDT on October 13, 2007
Tazmanian 8:43 AM CDT on October 13, 2007
you can for get ex 94L wind shear is like 60 to 70kt in the gulf right niw and if it where to get in too the get the wind shear will RIP it a part


TAZ...shear should relax in the GOM.
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1129. Hhunter
1:43 PM GMT on October 13, 2007
ike i really did not ask you if you believed it. In fact i really don't care if you do. but we will all know in a few days..
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1128. beell
1:40 PM GMT on October 13, 2007
No argument there IKE. NCEP has analyzed a low over each of them each time.
I do believe something will escape sooner or later.
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1127. Tazmanian
6:41 AM PDT on October 13, 2007
you can for get ex 94L wind shear is like 60 to 70kt in the gulf right niw and if it where to get in too the get the wind shear will RIP it a part
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1126. IKE
8:39 AM CDT on October 13, 2007
Hhunter...that sounds like it's from yesterday...

I think he's off on his threat area. This from the Mobile,AL. extended discussion....

"A deep surface low
associated with this system brings a front through the forecast area
Friday night.".....

I have a hard time believing a system makes it to Texas..., Wed/Thursday of next week.
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1125. Tazmanian
6:40 AM PDT on October 13, 2007
1120. BahaHurican 6:34 AM PDT on October 13, 2007
BTW,

Anybody else notice 90L in the EPac?



that is 90E not 90L
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1124. ShenValleyFlyFish
9:28 AM EDT on October 13, 2007
1098. StormW 9:03 AM EDT on October 13, 2007
Welcome Shen!

Thank you. Been admiring your work for a while now. Decided to anti up. What I don't know about weather is profound. As Mark Twain supposedly said "Weather and Politics are 2 things everyone wants to talk about but no one wants to do anything about."
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1123. kmanislander
1:40 PM GMT on October 13, 2007
Roatan obs are SSW winds @18 mph
Pressure of 1008
This would confirm a low to it's W ( ex 94L probably )
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1122. Hhunter
1:27 PM GMT on October 13, 2007
from everyones favorite weather guy who's last name starts with a B. Kinda interesting.


Tropics:

I like the idea of the Texas/Lousiana storm threat Wed and Thursday next week and here is why. The UKMET and the Euro, are bullish in tracking this system now coming back over the water east of Belize right up into the western gulf and to the coast for later Wednesday and Thursday. The pattern is ripe to go now and it would not surprise me if this becomes a storm over the weekend before crossing the Yucatan on a northwest course Sunday night and Monday. of course that would mean its in the gulf in a weakened state Monday night but every run now of those two models are getting better defined as to how this looks. The upper pattern is ripe for development and so I think this is a threat for at least a tropical storm wednesday and Thursday. The longer it waits, the greater the chance though for a fade more to the northeast

The wild card in this is coming from the east. I can't tell if it combines, competes, or stays separate. It may even slow and be a second storm over the western Caribbean the middle of next week, but it is alive and kicking with a nice thunderstorm cluster at its center. Its the time of the year for that to develop, the upward motion pulse is coming right into those areas now. The pattern to the north, with troughs going by close enough to take these systems up into the gulf, but far enough away not to shear them, is such that we are in a favorable pattern for development. Of course the fact it will have to cross back through the Yucatan is a problem, but an improving outflow pattern may simply mean a weaker storm is still improving coming across.

So cutting away all the possibilities, I think this is now looking more like we will have to deal with a threat the middle part of next week, perhaps even two if the second system slows and stays separate.

Remember, what we are seeing now goes on in the southwest Pacific before a burst of typhoons, and in fact just happened. 10 days or so before, the southwest Pacific lights up with thunderstorms and competing systems, and then 2 or 3 storms develop as the pulse matures. Obviously, the proximity to land limits this, and of course this is not the southwest Pacific, but it is a La Nina season in the area we look for development.

With the major trough moving through the southern Plains next week, at the least, southerly gales may develop through the western Gulf as the system remains weak and simply gets pulled north into the Plains storm, for that would lower pressures over the western Gulf while the stay higher over the eastern Gulf

TD 15 is the entrained remnant of Karen, another system than named or not is of no consequence to our interests. This was mentioned by TPC.
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1121. IKE
8:31 AM CDT on October 13, 2007
beell 8:30 AM CDT on October 13, 2007
Morning all.
Just an observation.
This is at least the third time/day for x94l to lose a piece of energy off to the NE. So far, shear has not allowed any development of the spinlets and the sfc trof that has been in place since prior to the Invest has dictated movement to the NE


And it's also the third day in a row there's still a low spinning...now it's over water...

There's a high building in..."Meanwhile...high pressure will slowly build into the eastern United
States and Florida Peninsula...resulting in freshening low level
northeast to east winds."....from Key West discussion.

Looks like EX94L will head for the GOM over time.
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1120. BahaHurican
9:31 AM EDT on October 13, 2007
BTW,

Anybody else notice 90E in the EPac?

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1119. TampaSpin
9:28 AM EDT on October 13, 2007
One thing is for certain IMO. We got a system that is getting better organized by the hour currently.
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1118. stormpetrol
1:26 PM GMT on October 13, 2007
Good Morning to everyone.I think I see two spins one around 18N 86W and the other SSW of that one around 16N and 87/88W, I think the the most southern has made it offshore and is basically due West of the Island of Rotan (sp). I think the the most southern spin is ex94L which still has a healthy spin and apparently to me in my opinion is now over water and at a lower Lat.I don't know where it will track but looks all the convection coming that area in the last few days has been tracking ENE, my opinion only.
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1117. beell
1:28 PM GMT on October 13, 2007
Morning all.
Just an observation.
This is at least the third time/day for x94l to lose a piece of energy off to the NE. So far, shear has not allowed any development of the spinlets and the sfc trof that has been in place since prior to the Invest has dictated movement to the NE.
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1116. Hhunter
1:25 PM GMT on October 13, 2007
does look like there maybe two vortices one at around 17 and the other at maybe 18.5. any thoughts on that folks..a little suprised this has not been classified as an investigate..
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1113. Hhunter
1:19 PM GMT on October 13, 2007
what going on with 94l this morning..will be interested in your analysis storm w
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1112. Hhunter
1:15 PM GMT on October 13, 2007
well folks what do we have with old 94L this morning....
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1111. kmanislander
1:17 PM GMT on October 13, 2007
StormW

Took a look with the JSL and see another low further S to the W of Roatan right in the "neck" of the Gulf of Honduras. Two lows at work it seems

I wonder if old 94L managed to just get offshore after all?

Check it out when you get a chance
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1110. kmanislander
1:15 PM GMT on October 13, 2007
gone for coffee
back in a while
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1109. kmanislander
1:13 PM GMT on October 13, 2007
StormW

The QS places it in the general area of 17/18
The SW corner of the low is nearer to 17 I agree
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1108. TerraNova
9:11 AM EDT on October 13, 2007
GFS has been showing consistancy in developing a system in the GOM and taking it up the east coast after crossing Florida....6z has it being absorbed by a low over the southern US after nearly stalling northeast of Florida. CMC developes both ex94L and the wave in the Eastern Caribbean...I can't beleive I'm saying this but the CMC's potential track for ex94L seems plausible...intensity, maybe not as dry air is prevalent in the gulf.
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1105. kmanislander
1:08 PM GMT on October 13, 2007
Adrian

Would you mind putting up the QS pass I posted earlier using image shack so that I can see if it makes any appreciable resolution diff in this new format ?
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1104. TerraNova
9:09 AM EDT on October 13, 2007
Morning StormW!
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1103. BahaHurican
9:05 AM EDT on October 13, 2007
Adrian,

I am lazy about using Imageshack, I have to admit. I have, however, taken to posting only images in which the writing doesn't matter (or which have little / no writing). The oldfashioned method of posting images does mess with the resolution, I admit.
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1102. kmanislander
1:06 PM GMT on October 13, 2007
Hey StormW

Do you see the NW Caribbean low over water at 18/85 ?
Any comments on this ?
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1101. BtnTx
8:02 AM CDT on October 13, 2007
Baha, No annother previous one is a weird 595x394
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1100. kmanislander
1:03 PM GMT on October 13, 2007
Welcome Shen

You are joining at the tail end of the season but it is not over yet.
Still some blogging to do on at least 2 more systems IMO
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1099. kmanislander
1:02 PM GMT on October 13, 2007
H23

When anyone posts an image here I see it as 500x375
I think it has to do with the new blog format
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1097. BahaHurican
9:01 AM EDT on October 13, 2007
Welcome, Shen.

Good time to join the blog, when people will not be so absorbed in what's going on that they won't even see you're there . . .

LOL
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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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