Fabled Northwest Passage begins to re-freeze

By: Dr. Jeff Masters , 12. lokakuuta 2007 klo 14:29 (GMT)

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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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1196. utilaeastwind
13. lokakuuta 2007 klo 15:35 (GMT)
The weather here on Utila (86.5 16.2) is building up. It looks like the COC of 94L is just above us. COOL!
Member Since: 12.10.2007 Posts: 0 Comments: 192
1195. stormpetrol
13. lokakuuta 2007 klo 15:31 (GMT)
I think the spin West of Roatan is getting stronger and better defined by the hour, also to me its definitely offshore now and over water. The seas here in Grand Cayman in Goergetown is starting to get choppy which usually suggest a disturbance to the W/WSW or NW of our area. We sure don't want anything backing up on us from the West , as this is usually the opposite direction of the systems usually approach our area.
Member Since: 29.04.2007 Posts: 0 Comments: 7506
1194. nrtiwlnvragn
13. lokakuuta 2007 klo 15:09 (GMT)
New Blog
Member Since: 23.09.2005 Posts: 13 Comments: 10473
1192. Spetrm
13. lokakuuta 2007 klo 15:00 (GMT)
Baha theres still hope for wishcasters. I mean we had a january cane in 05. LOL (sarcasim)


So who hear thinks Gore deserved his nobel. I know theres a debate about that.
Member Since: 9.06.2007 Posts: 409 Comments: 9857
1191. mit5000
13. lokakuuta 2007 klo 14:58 (GMT)
whats going on?

in epac we have 90e!
1188. TampaSpin
13. lokakuuta 2007 klo 14:47 (GMT)
JFV did my gif file post up.
Member Since: 2.09.2007 Posts: 177 Comments: 20430
1187. beell
13. lokakuuta 2007 klo 14:47 (GMT)
In the newest frame, beell, you can start to see a larger circulation...

I guess I'm back to watch and wait mode jpritch
It all may be a good thing if it can bring some rain to folks that need it.
Member Since: 11.09.2007 Posts: 137 Comments: 15358
1186. jpritch
13. lokakuuta 2007 klo 14:45 (GMT)
Hah! And I see that xKaren is still alive and kicking, though definitely anorexic and underdressed.
Member Since: 28.06.2007 Posts: 0 Comments: 291
1185. TampaSpin
13. lokakuuta 2007 klo 14:43 (GMT)
Gotta go, goin to the USF Bulls game today so no Fighting........lol
Member Since: 2.09.2007 Posts: 177 Comments: 20430
1182. TampaSpin
13. lokakuuta 2007 klo 14:40 (GMT)
1178. JFV 10:34 AM EDT on October 13, 2007
Is my pic visable now. Can someone please reconfirm that for me right now. I would greatly appreciate it.

yep your there
Member Since: 2.09.2007 Posts: 177 Comments: 20430
1181. jpritch
13. lokakuuta 2007 klo 14:40 (GMT)
In the newest frame, beell, you can start to see a larger circulation trying to wrap those two centers into one.
Member Since: 28.06.2007 Posts: 0 Comments: 291
1180. BahaHurican
13. lokakuuta 2007 klo 14:38 (GMT)
1177. LooneyJPdoomcaster 10:33 AM EDT on October 13, 2007
Well the season is coming to a close. What are the wishcasters to do?
Another season where that ideologue Dr Gray is WRONG again. tsk tsk tsk..when will they get rid of Mr Global Warming Doesn't Exist!



Just out of curiousity, what are u talking about?
Member Since: 25.10.2005 Posts: 19 Comments: 20744
1179. beell
13. lokakuuta 2007 klo 14:38 (GMT)
See ya JFV. Dressed up!
Member Since: 11.09.2007 Posts: 137 Comments: 15358
1176. beell
13. lokakuuta 2007 klo 14:31 (GMT)
jpritch-agreement here fwiw. I think it always has been-it has been the secondary low maker for a bit. I think they will put a red L back over it again and remove the one in place now.
Member Since: 11.09.2007 Posts: 137 Comments: 15358
1175. KEEPEROFTHEGATE (Mod)
13. lokakuuta 2007 klo 14:30 (GMT)
looks as if theres a shift starting to happen with that tropical flow over nw carb crossing cay jam cuba bah west atlantic shift to tip of yuc west cuba east gom over fla with copious amounts increasing witin 36 hrs tropical flow will cover intire fla area at the same time system over 4 corners trackin e se e may generate wave over centrl gom and track in tandem with flow movin towards fla as a west flow comes off mex into gulf forced n some where in cen gom to aid in this possble dev of wave
Member Since: 15.07.2006 Posts: 165 Comments: 52406
1174. Hhunter
13. lokakuuta 2007 klo 14:29 (GMT)
Link

starting to wrap around a center...
Member Since: 19.08.2007 Posts: 0 Comments: 2973
1172. Hhunter
13. lokakuuta 2007 klo 14:26 (GMT)
accuweather but not mr B. different guys.
Member Since: 19.08.2007 Posts: 0 Comments: 2973
1171. jpritch
13. lokakuuta 2007 klo 14:24 (GMT)
Swirls all over the place. It looks like the southern one that exited the Belize coast is still the more dominant one though.
Member Since: 28.06.2007 Posts: 0 Comments: 291
1170. BahaHurican
13. lokakuuta 2007 klo 14:22 (GMT)
Lili is the sixth category 3 or higher hurricane in the Atlantic basin in 1996.

I guess we have been fortunate so far this year. 6 of the 9 hurricanes in 1996 were majors. 6 of the 9 hurricanes also made landfall as hurricanes, from Nicaragua to Nova Scotia. Only 3 of the season's 13 storms did not affect land somewhere.

Currently we are at 4 hurricanes, 2 majors, and 7 of 13 storms making landfall. Hopefully the stats will remain in our favour.
Member Since: 25.10.2005 Posts: 19 Comments: 20744
1169. IKE
13. lokakuuta 2007 klo 14:19 (GMT)
From Accuweather...

"Elsewhere in the Atlantic Basin, surface low pressure over Belize and the southern Yucatan is not expected to organize through the weekend. We continue to observe strong, westerly, upper-level shear over the Gulf of Mexico and northern Caribbean north of 20 north. This shear should remain in place over the Gulf of Mexico eastward into the western Atlantic through the weekend. Shear will relax some over the northern Caribbean and southern Gulf of Mexico by early next week, but the upper-level flow will remain strong over the northern Gulf of Mexico. Therefore, even if development is possible in the northern Caribbean or southern Gulf of Mexico, anything trying to move northward will be sheared, at least through early next week. Some computer information is suggesting this low might get drawn northward early next week. So, we will have to maintain watch over this system."
Member Since: 9.06.2005 Posts: 23 Comments: 37858
1168. TCyclone192
13. lokakuuta 2007 klo 14:18 (GMT)
Nevermind i answered that question myself...I looked at visible sat. Well and ways as always im going to go update my blog ill be back in a bit.
1167. TampaSpin
13. lokakuuta 2007 klo 14:17 (GMT)
this will be me if it rains....lol
Member Since: 2.09.2007 Posts: 177 Comments: 20430
1166. beell
13. lokakuuta 2007 klo 14:12 (GMT)
BahaHurican-morning,
Low level easterlies were to move the whatever across the Yucatan and into the BOC. Some evidence of LL flow on vis. If the stalled cold front/trof cannot lift north then NE it is.
If it moves and leaves some energy behind then a new set of rules may apply.
NE would/should be quick.
opinion of course.

Member Since: 11.09.2007 Posts: 137 Comments: 15358
1165. TCyclone192
13. lokakuuta 2007 klo 14:11 (GMT)
The carrib. Tampa? Also im CaneAddict, I made a new name because everytime id post a comment it wouldnt show up and the admin would reply to my emails rehgarding it.
1164. zoomiami
13. lokakuuta 2007 klo 14:09 (GMT)
I thought today was going to be dry, with a little less humidity, and started painting the front door - now I have to run fast and finish before the heavier rain gets here,
Member Since: 13.08.2007 Posts: 10 Comments: 4136
1163. TampaSpin
13. lokakuuta 2007 klo 14:08 (GMT)
1161. TCyclone192 10:02 AM EDT on October 13, 2007
Good Morning all! When is 94L expected to be back over water?

Appears it may already be.
Member Since: 2.09.2007 Posts: 177 Comments: 20430
1162. BahaHurican
13. lokakuuta 2007 klo 14:04 (GMT)
Morning zoo,

Not surprising we are thinking the same way, given the constant rain the last 10 or so days. LOL

I'm still at home because it's been raining here most of the night and morning. Looks like there's a break, though, so I may try to get out of the house for a while . .
Member Since: 25.10.2005 Posts: 19 Comments: 20744
1161. TCyclone192
13. lokakuuta 2007 klo 14:02 (GMT)
Good Morning all! When is 94L expected to be back over water?
1160. TampaSpin
13. lokakuuta 2007 klo 14:02 (GMT)
this is going to be good today.....hehehehehe
Member Since: 2.09.2007 Posts: 177 Comments: 20430
1159. kmanislander
13. lokakuuta 2007 klo 14:02 (GMT)
Steering is very unpredictable from now through the end of the season. Look at all the crazy late season tracks !
Member Since: 19.08.2006 Posts: 0 Comments: 15671
1158. zoomiami
13. lokakuuta 2007 klo 14:01 (GMT)
I will be glad to share some rain, a month ago we wanted it, now it won't go away. The soccer field is squishy this morning -
Member Since: 13.08.2007 Posts: 10 Comments: 4136
1157. Hhunter
13. lokakuuta 2007 klo 14:01 (GMT)
mr b has also been pointing to that fact the last few days most uplift of the season
Member Since: 19.08.2007 Posts: 0 Comments: 2973
1156. zoomiami
13. lokakuuta 2007 klo 14:01 (GMT)
Hi Baha: looks like we are thinking the same way this morning!
Member Since: 13.08.2007 Posts: 10 Comments: 4136
1155. kmanislander
13. lokakuuta 2007 klo 14:00 (GMT)
Well thats my input for the morning. Will head out to do the usual Sat am errands etc. and will check back this afternoon to see how things are going.

Have a nice day everyone
Member Since: 19.08.2006 Posts: 0 Comments: 15671
1154. BahaHurican
13. lokakuuta 2007 klo 14:00 (GMT)
kman,

That supports my view that any movement by 94L is likely to be to the NE as opposed to the NW.

To me, that NEly flow across Cuba, the Bahamas and into the ATL has been established for quite a while. Unless there is a high likely to build up in the next 5 days or so, I just don't see the NW turn. Even with lower shear.
Member Since: 25.10.2005 Posts: 19 Comments: 20744
1153. zoomiami
13. lokakuuta 2007 klo 13:59 (GMT)
Looking at the loops, I'm not sure I see how this is going into the Gulf. If the trough to the south is moving north & west, won't the lows just follow behind?
Member Since: 13.08.2007 Posts: 10 Comments: 4136
1152. tampaENG
13. lokakuuta 2007 klo 13:59 (GMT)
hey StormW - just saw that you are a fellow Palm Harbor resident!
Let wish that the models are right and we get some rain in N county.
All of our holding ponds are lower than they were at the beginning of the "rainy" season.
Member Since: 17.08.2007 Posts: 0 Comments: 97
1151. BahaHurican
13. lokakuuta 2007 klo 13:56 (GMT)
HH, I'd also consider the upswing in MJO to be interesting. It should remain moist here for another 10 to 14 days . . . means instability is likely to continue for a while. . .

Member Since: 25.10.2005 Posts: 19 Comments: 20744
1150. TampaSpin
13. lokakuuta 2007 klo 13:55 (GMT)
1148. Hhunter 9:53 AM EDT on October 13, 2007
the most interesting thing about this deal is the vigorous nature of 94l to survive this long. makes you wonder what could happen if it gets all lined up.

Hopefully lots of rain and little wind.
Member Since: 2.09.2007 Posts: 177 Comments: 20430
1149. kmanislander
13. lokakuuta 2007 klo 13:55 (GMT)
Baha

Here is the current low to mid level steering
Member Since: 19.08.2006 Posts: 0 Comments: 15671
1148. Hhunter
13. lokakuuta 2007 klo 13:53 (GMT)
the most interesting thing about this deal is the vigorous nature of 94l to survive this long. makes you wonder what could happen if it gets all lined up.
Member Since: 19.08.2007 Posts: 0 Comments: 2973
1147. TampaSpin
13. lokakuuta 2007 klo 13:53 (GMT)
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: 2.09.2007 Posts: 177 Comments: 20430

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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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