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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347. moonlightcowboy
6:46 PM GMT on October 12, 2007
lol, beell, no. It's an audio file from a podcast, that I'd like to link to and post here. Having trouble though.

--btw, haven't had a chance "due to the man" to get back with you on WUmail, but I think your post in the blog probably nailed it. We'll see.
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346. weatherg8r
6:39 PM GMT on October 12, 2007
LakeShadow
yeah, NEwxguy...gotta watch out for shrinkage



LOL


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345. beell
6:45 PM GMT on October 12, 2007
make a video w/the lens cap on?
Member Since: September 11, 2007 Posts: 144 Comments: 16862
344. LakeShadow
6:44 PM GMT on October 12, 2007
and he's gone...
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343. moonlightcowboy
6:42 PM GMT on October 12, 2007
Lottsa miles!

My youtube upload failed "wrong file format" -- any other suggestions anyone? TIA
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341. NEwxguy
6:42 PM GMT on October 12, 2007
mlc,ain't that the truth
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340. SamTeam
1:40 PM CDT on October 12, 2007
Gosh, missed all the Rockford files due to the fact that I used my ignore button yesterday.....get that guy outta here
Member Since: September 22, 2007 Posts: 0 Comments: 213
339. moonlightcowboy
6:40 PM GMT on October 12, 2007
It's not the age, it's the miles.
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337. NEwxguy
6:39 PM GMT on October 12, 2007
334. moonlightcowboy 6:38 PM GMT on October 12, 2007
Jim, go find Angel, he'll tell you the tropics aren't done yet. And, btw, Doc posts that kind of stuff in July

Lol,you showing your age
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336. tampabayfish
6:37 PM GMT on October 12, 2007
JimR... The fact that you speak in absolutes demonstrates a naive scientific background. I'm not saying the season is over or not...until its over, water temps drop... This is only the first cold front to get FL this year, and its weak and wavering.
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335. CaneAddict
6:37 PM GMT on October 12, 2007
The season is not over untill November 31st.
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334. moonlightcowboy
6:36 PM GMT on October 12, 2007
Jim, go find Angel and he'll tell you the tropics aren't done yet. And, btw, Doc posts that kind of stuff in July!
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333. JUSTCOASTING
6:36 PM GMT on October 12, 2007
Rockford why do you come on this blog just to start people up .You would think you have better things to do on a friday afternoon
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332. LakeShadow
6:36 PM GMT on October 12, 2007
yeah, NEwxguy...gotta watch out for shrinkage!
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330. NEwxguy
6:34 PM GMT on October 12, 2007
hey,shadow,just a thought,but that blow dryer probably isn't a good thing near saran wrap!
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328. LakeShadow
6:33 PM GMT on October 12, 2007
LOL! You and everyone else!
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327. mit5000
6:32 PM GMT on October 12, 2007
any 1 reckoning 97l will be another hurricane vince?
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326. NEwxguy
6:32 PM GMT on October 12, 2007
floodman,thats been the story all season,timing. And its been bad timing for these systems,or should I say good timing,(don't want to be accused of wishcasting)
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325. nrtiwlnvragn
6:29 PM GMT on October 12, 2007
Appears to me the low over Guatemala is still the dominate low. Loop
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324. beell
6:29 PM GMT on October 12, 2007
307. beell 6:20 PM GMT on October 12, 2007
299. nrtiwlnvragn 6:04 PM GMT on October 12, 2007

We are talking about the new low correct?
Member Since: September 11, 2007 Posts: 144 Comments: 16862
322. mit5000
6:31 PM GMT on October 12, 2007


15l looks like a hurricane....

wtf is going on there?
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321. LakeShadow
6:31 PM GMT on October 12, 2007
good point, floodman!
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320. LakeShadow
6:29 PM GMT on October 12, 2007
either way jp, its not going to be pretty! LOL
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319. CaneAddict
6:28 PM GMT on October 12, 2007
Good afternoon all! It looks like 94l's remnants will reemerge over the carribean and possibly meander around the region for while. If it does make it back over water i expect a depression to form shortly after reemerging.
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318. Floodman
6:22 PM GMT on October 12, 2007
307. beell 6:20 PM GMT on October 12, 2007
299. nrtiwlnvragn 6:04 PM GMT on October 12, 2007
Seems to be a pretty fair assesment from this post nrt. Sfc trof is pinching off in the FL straits so WSW flow may be in the works. Still have some broad CCW flow around the Yucatan that would keep this in the BOC. That's just from a steering standpoint. Add shear and dry air and we get pretty close to an academic discussion. Sfc low would survive I think.



Timing, beell, it's all about the timing...the shear begins to retreat in 48 hours (per projections); it's a small inroad, but at 60-72 hours we see the shear down to 10-15knts from the Straits to about 24N across the GOMEX; at 90 hours the entire GOMEX is under less than 15knts, with the exception of the Texas coast from around Galveston to Port Aransas, and ditto the Florida coast from P'cola to Tampa...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
317. mit5000
6:25 PM GMT on October 12, 2007
current adt for 15l:
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 12 OCT 2007 Time : 171500 UTC
Lat : 30:06:39 N Lon : 49:02:09 W


CI# /Pressure/ Vmax
2.5 /1005.0mb/ 35.0kt


6hr-Avg T# 3hr-Avg T# Adj T# Raw T#
2.3 2.4 2.1 2.1

Latitude bias adjustment to MSLP : +0.0mb

Center Temp : +16.9C Cloud Region Temp : 9.0C

Scene Type : SHEAR (0.88^ TO DG)

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : OFF
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316. NEwxguy
6:26 PM GMT on October 12, 2007
sounds like an attempt to get on utube
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314. NEwxguy
6:23 PM GMT on October 12, 2007
while we're on the subject of naked swirls,TD15 is really losing its convection and is going to be swallowed up
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313. LakeShadow
6:22 PM GMT on October 12, 2007
details!!!
*sheesh!*
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312. tropicofcancer
2:22 PM EDT on October 12, 2007
300. LakeShadow 2:05 PM EDT on October 12, 2007
I wanted to go as a naked swirl for halloween but the other parents in the neighboorhood complained... LOL!
May I suggest you dress as 'The Remnant of Karen'.
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311. Floodman
6:21 PM GMT on October 12, 2007
Going to be a bit cold in your neck of the woods for saran wrap and glitter, you think? LOL
Member Since: August 2, 2006 Posts: 10 Comments: 9922
310. jpritch
6:20 PM GMT on October 12, 2007
I think that costume might need just a hint of convection in a few key sectors.
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307. beell
6:18 PM GMT on October 12, 2007
299. nrtiwlnvragn 6:04 PM GMT on October 12, 2007
Seems to be a pretty fair assesment from this post nrt. Sfc trof is pinching off in the FL straits so WSW flow may be in the works. Still have some broad CCW flow around the Yucatan that would keep this in the BOC. That's just from a steering standpoint. Add shear and dry air and we get pretty close to an academic discussion. Sfc low would survive I think.
Member Since: September 11, 2007 Posts: 144 Comments: 16862
306. Weather456
6:18 PM GMT on October 12, 2007
RSMC- The Regional Specialized Meteorological Center

Each region has one or two of these centers. The Atlantic and E PAC east of 140W the RSMC is the National Hurricane Center.

U also have

Central Pacific
The Central Pacific Hurricane Center (CPC)

Western Pacific
The Japan Meteorological Agency (JMA)
Philippine Atmospheric, Geophysical and Astronomical Services Administration
And many others

SW Indian Ocean
La Reunion-Tropical Cyclone Centre/Meteo-France

North Indian Ocean (Arabian Sea and Bay of Bengal)
Tropical Cyclones New Delhi/India Meteorological Department (IMD)

SE Indian Ocean
TCWC-Perth/Bureau of Meteorology

Northern Australia
TCWC-Darwin/Bureau of Meteorology

SW Pacific Near Eastern Australia
TCWC-Brisbane/Bureau of Meteorology

SW Pacific
Nadi-Tropical Cyclone Centre, Fiji Meteorological Service


More Info
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304. Floodman
6:12 PM GMT on October 12, 2007
Lakeshadow, I have an image working of your "naked swirl" costume, as the neighbors look on...and they were calling me the Imagist the other day LOL
Member Since: August 2, 2006 Posts: 10 Comments: 9922
303. latitude25
2:10 PM EDT on October 12, 2007
It's uncanny!

Link

Link

ok, just poking some fun, it's a joke.
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302. moonlightcowboy
6:00 PM GMT on October 12, 2007
What site can I use to upload an audio file, similarly to what we do with imageshack or photobucket? I'd like to reference a link like that! TIA
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301. Weather456
6:00 PM GMT on October 12, 2007
According to the RSMC of the SW Indian Ocean 91S will soon be upgraded to TD 01R. If the JTWC (which the navy uses) upgrade it then it would be TD 02S...as 01S formed July this year but was classified as a Tropical depression by the JTWC but not by RSMC of the SW Indian Ocean.
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299. nrtiwlnvragn
6:03 PM GMT on October 12, 2007
Marine Weather Discussion

Weak high press ridge over the northern gulf of mexico with light n to ne winds over most area. The models differ some on the movement of the low pres currently over the nw caribbean. Overall the gfs differs the most then the other models...a it brings the low across the yucatan peninsula into the eastern bay of campeche mon night and into the central portion of the sw gulf mon afternoon and se of the mouth of the mississippi tue and into the florida panhandle wed. The other models are a little more similar bringing the low across the yucatan peninsula into the bay of campeche mon but keep it in the sw gulf through wed. Either way in the sort term winds should increase across the eastern gulf will increase with the low to the s and ridge to the n tighten the gradient.
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298. brazocane
1:01 PM CDT on October 12, 2007
So it looks like the CMC and UKMET want to bring former 94l towards the Texas coast. Although odd for October, we are not supposed to get another cold front pushing through Texas until the 21st.
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297. NoNamePub
5:58 PM GMT on October 12, 2007
456 ...Yes!
Thats the one!

Thanks!
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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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