One third of Arctic ice cap now missing; Midwestern floods; tropical update

By: Dr. Jeff Masters , 12:46 PM GMT on August 24, 2007

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Sea ice in the Arctic continues its record decline, thanks to unusually cloud-free conditions and above-average temperatures. For August 21, the National Snow and Ice Data Center estimated that fully one third of the Arctic ice cap was missing, compared to the average levels observed on that date from 1979-2000. Sea ice extent was 4.92 million square kilometers on August 21, and the 1979-2000 average for the date was about 7.3 million square kilometers. Arctic sea ice has fallen below the record low absolute minimum of 4.92 million square kilometers set in 2005 by about 8%, with another 3-5 weeks of the melting season still remaining. Reliable records of sea ice coverage go back to 1979.


Figure 1. Extent of the polar sea ice on August 21, compared to the average for the date from the 1979-2000 period (pink line). Image credit: National Snow and Ice Data Center.

With one third of the Arctic ice cap already gone, and another month of melting to go, we need to consider what effect this will have on weather, climate, and sea level rise. Well, we don't need to worry about sea level rise, since the polar sea ice is already in the ocean, and won't appreciably change sea level when it melts. However, the remarkable melting of the ice cap will likely lead to unusual weather patterns this fall and winter. The lack of sea ice will put much more heat and moisture into the polar atmosphere, affecting the path of the jet stream and the resultant storm tracks. Expect a much-delayed arrival of winter to the Northern Hemisphere again this year, which may lead to further accelerated melting of the ice cap in future years.

Last week, I remarked that the most recent images from the North Pole webcam show plenty of melt water and rainy conditions near the Pole. It turns out that was misleading, since the webcam is on a ship that was headed towards the pole, but had not reached it. There have been rainy conditions at the Pole this summer, and there is some open water there, but this is not uncommon in summer. Shifting ice frequently opens up leads (cracks) with open sea water at the Pole. It was one of these open leads that British swimmer Lewis Gordon Pugh swam in for 18 minutes this July to draw attention to global climate change.


Figure 2. Total rainfall from August 10-22 as estimated by NASA's TRMM satellite.

Midwest flooding
To get an idea of the magnitude of the flooding that has hit the Midwestern U.S. during the past ten days, take a look at the total amount of rain from August 10-22 (Figure 2). We can blame Tropical Storm Erin for the rain in Texas and Oklahoma (up to 11 inches), and for the nine flooding deaths that occurred in those states. However, the unbelievable rain amounts in excess of 20 inches in Minnesota and Wisconsin were primarily due to a frontal system--with the help of some copious moisture pumped northwards by the counter-clockwise circulation around Erin while it spun over Oklahoma.

Tropical update
There are no threat areas in the Atlantic to discuss. Two of our four reliable forecast models, the NOGAPS and ECMWF, are predicting that a tropical depression could form off the coast of Nicaragua on Sunday. The models forecast that this system would move inland over Nicaragua and Honduras by Monday.

I'll have an update on Saturday morning.
Jeff Masters

After Hurricane Dean (sprinter)
Bulldozer trying to clear sand and debris from Norman Manley Highway(Airport Road)
After Hurricane Dean
Findlay Ohio flood (prairieview)
The flood is over, now the cleanup
Findlay Ohio flood

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196. PensacolaDoug
5:08 PM GMT on August 24, 2007
Where do you find a daily forcast for the North Pole?
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195. bswigg
5:08 PM GMT on August 24, 2007
hey nash...is that 2 systems forming on the gfs or just one at the 168 something hr??
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193. mobilebayrat
12:11 PM CDT on August 24, 2007
nola70119, I guess I am trying to say that you can't really comapre apples and oranges. NOLA is below sea level, and the levees broke. In Mississippi so many people thought the would be safe because their home had survived Camille, but Katrina wasn't Camille, she had her own plans!
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191. nola70119
5:08 PM GMT on August 24, 2007
Mexico is not 15 feet under sea level.
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190. extreme236
5:08 PM GMT on August 24, 2007
i heard that there is a low pressure stationary near bermuda. is that the low pressure of interest?
Member Since: August 2, 2007 Posts: 19 Comments: 19234
189. icepilot
11:02 AM CST on August 24, 2007
Posted By: texascanecaster1 at 10:44 AM CST on August 24, 2007.

jp it would be the same regardless. Ice even when its frozen displaces water. However it doesnt quite work that way with the icecaps themsleves.....when they melt water level rises. but in a glass it would be raised regradles. Now if you mean water level alon then it would be higher in the warm one(duh).

Where did you study physics? There might be a difference after the ice melted but it would be too small to measure with the naked eye
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188. mobilebayrat
12:04 PM CDT on August 24, 2007
thanks bonedog, that's what I thought. I was just reading the Mexico v. NOLA debate and that was the thought that popped in my mind. Yes, a lot of people chose not to go, but some just had no way out. I keep thinking about all those school buses sitting flloded in the parking lot. If you choose not ot go and you end up in a bad situation, your fault. if you have now way to get out, well, that's another story.
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187. extreme236
5:06 PM GMT on August 24, 2007
also i heard there is a low pressure in the atlantic, i heard it is non tropical but if it gains tropical characteristics it might develop
Member Since: August 2, 2007 Posts: 19 Comments: 19234
186. nash28
5:05 PM GMT on August 24, 2007
Well, the 12z GFS is showing development off the African coast next weekend.
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185. extreme236
5:02 PM GMT on August 24, 2007
anything promising out there for development? I know there is some sort of wave about to come off africa. I did hear that two models forecast development near nicaragua though.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
184. DallasGumby
4:59 PM GMT on August 24, 2007
Posted By: groundswell at 4:48 PM GMT on August 24, 2007.

Just my .02 cents on GW-you can argue for it or against it, but I believe that we (the world) are pumping enormous amounts of toxic chemicals into the air/water/land....you just know that can't be good, so I do believe we must change our ways-look at the atmosphere-it's really a thin layer.


Almost no one on either side of the GW debate is arguing about "pumping enormous amounts of toxic chemicals". The debate is about carbon dioxide, hardly a toxic chemical.
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183. icepilot
10:56 AM CST on August 24, 2007
I said greenish cast - ie from a distance - When and where were u in GL - me Thule in 84 & 91 in 91 we sailed around from Thule over to to Norway then on to about 300 miles from the NP
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182. Bonedog
12:58 PM EDT on August 24, 2007
mobile they activate the military and evac folks out of remote areas.
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181. DallasGumby
4:58 PM GMT on August 24, 2007
Posted By: HurricaneMyles at 4:41 PM GMT on August 24, 2007.

LOL, very vigirous.

Also, DallasGumby - you got WUmail.


Myles, back at you!
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180. austxanne
4:58 PM GMT on August 24, 2007
hard to imagine...me right.
well, that perks me up today!
thanks!
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179. Tazmanian
4:58 PM GMT on August 24, 2007
A 1009 MB LOW
NEAR 32N48W SW ALONG 29N57W THEN NW TO 30N61W BECOMING
STATIONARY CONTINUING ACROSS BERMUDA
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178. HurricaneMyles
4:56 PM GMT on August 24, 2007
austxanna...You're right. I misspoke. Ice on land will riase sea level.
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177. mobilebayrat
11:52 AM CDT on August 24, 2007
I may be fixing to put my foot in it, but in Mexico, does the government move people out of the areas in the danger zone if they can't (don't have a vehicle, no money) or won't go? Just curious.
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175. austxanne
4:43 PM GMT on August 24, 2007
I didn't think that it was sea ice melting that changed the levels, but ice on land melting that contributed. I would have to read more on thermal expansion of oceans being nil compared to contribution by ice, but thank you for that.

by the way, i didn't add astrophysicists to add credibility to what I said, though they would know more than me...but obviously not scientists studying these topics..

still learning and thank you all for information and directions to sites that help facilitate the learning....
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174. icepilot
10:21 AM CST on August 24, 2007
Greenland was called Greenland to lure settlers.
The coast has a greenish cast to it in the summer time - Lichen growing on the rocks.

In 1983, while on a research cruise in Antarctica, one of the projects was measurements of currents, salinity and Temp of the waters under the Ross Iceshelf. The lead Researcher Mr. Stanley S. Jacobs (Doherty Senior Research Scientist - LDEO-Ocean and Climate Physics - Earth Institute Affiliate: Lamont-Doherty Earth Observatory (LDEO) and I were talking about Ice melt. I remember the conversation because he made a statement that astounded me. He asked if I knew how long it took for the North American Ice coverage took to retreat from its greatest extent during the last Ice Age to about where it was in Canada in 1983. I guessed several 100 years – He smiled and said no, just about 75 years, one persons life time.

I have no data to back this up, but he had no reason to joke…

Also in 1984 and 92 or 93 the day time air temp in Jan/Feb just off the Ross Ice Shelf reach 40 deg F several times - we were outside with short sleave shirts

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173. Bonedog
12:45 PM EDT on August 24, 2007
exactly JP. My family has mini GO bags in their cars. Your not always home when a disaster strikes. Plus we also have a family disaster plan in place with friends and family out of state. We all know what to do and where to go and who to contact. I work 50 miles from home so I would be the last to reach it and dont want to worry about who is where.

My personal GO bag in my truck even has a gas mask in it because I work in an industrial area with alot of toxic chemicals.
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172. groundswell
4:43 PM GMT on August 24, 2007
Just my .02 cents on GW-you can argue for it or against it, but I believe that we (the world) are pumping enormous amounts of toxic chemicals into the air/water/land....you just know that can't be good, so I do believe we must change our ways-look at the atmosphere-it's really a thin layer.
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169. franck
4:35 PM GMT on August 24, 2007
The common misconception about Greenland has to do with mapping. Nordic explorers originally used memory and spoken instructions for sailing. The land masses to their northwest were of great interest to them, but when the original maps were created, the land mass which was green much of the year was confused with the land mass which was frozen. So Greenland was falsely named Iceland, and Iceland was falsely named Greenland. At least that is what I was told on tour in Iceland about twenty-five years ago.
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168. Tazmanian
4:43 PM GMT on August 24, 2007
get your votes in if you have not done some yet
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167. Bonedog
12:42 PM EDT on August 24, 2007
heheh Mr.Wizard. That was a great show too bad its not on anymore
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163. HurricaneMyles
4:41 PM GMT on August 24, 2007
Austxanne...The rise in sea level by thermal expansion is almost nil compared to the rise that would happen if sea ice melts.
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162. Weather456
4:36 PM GMT on August 24, 2007
Please dont put ur hopes too high with this wave so early....its ok to watch but watch for persistance.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
160. HurricaneMyles
4:40 PM GMT on August 24, 2007
LOL, very vigirous.

Also, DallasGumby - you got WUmail.
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159. Bonedog
12:31 PM EDT on August 24, 2007
exactly LLJ thats my point. noone prepares anymore.

I dont even live near the coast.. hell my home sits at 1443 feet above sealevel... yet I have GO bags, well bins, already set for my family and I even included the pets in those bins.

NOAA radios.. one in each room, including bathroom, plus one in each vehicle.

I am one of the few folks that does it right, yes there are many many out there that do the same but looking at the whole picture we are the small minority.

Just like folks should have at least a flashlight and a multi tool in their cars instead of the cell to call AAA.
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158. austxanne
4:35 PM GMT on August 24, 2007
re: sea levels....i was told by 2 astrophysicists that the warming of the oceans will raise the levels...water expands as it warms..
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156. mississippiwx23
4:23 PM GMT on August 24, 2007
chilliam at 4:13 PM GMT on August 24, 2007.

"I remarked that the most recent images from the North Pole webcam show plenty of melt water and rainy conditions near the Pole. It turns out that was misleading, since the webcam is on a ship that was headed towards the pole, but had not reached it."

Umm, that's not misleading, that's just plain wrong. If a non-global-warming person had posted a picture of massive ice from Antarctica and claimed it was the North Pole, you'd be crying foul.



Yes, it was wrong...but he corrected his statement. I remember looking at the photos and thinking they didnt seem stationary...but then I realized I didnt know anything about the North Pole and didnt question. At least he came out and told the truth, which some people never do.

Oh, and as for Antarctic ice, no statistical significant change in the ice has been found to this point. As said earlier, we do not have a long enough record to truely make a statement about it. All we do know is that has increased recently.
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155. Tazmanian
4:34 PM GMT on August 24, 2007
: HurricaneMyles i need your vote its a yes or no ?


i put you down has a no vote for now be come i was not sure what your vote was
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154. nash28
4:34 PM GMT on August 24, 2007
Oh boy....

We need a vigorous wave or SFC ow to watch, because this GW discussion is a beating.

Like watching water wiggle.
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153. franck
4:21 PM GMT on August 24, 2007
No..not a troll, just have a theory that global warming is approaching the apex of an exponential acceleration, and the predicted 2-5 degrees fahrenheit increases in a decade or two will actually be 4-25 degrees. This should melt the northern cap in five years or so. Of course, at its thickest there will be some ice remaining, sort of like the snowman which still partially stands two weeks after the snow has melted.
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152. HurricaneMyles
4:28 PM GMT on August 24, 2007
jp...While I don't know the reliabilty of reason Greenland was named that, it could also be a mistranslation from Gruntland, which was in reference to the many shallow bays.

Also, in the south, Greenland is acutally green in the summer, and probably would have been more so in the Vikings time.
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151. GaleWeathers
4:31 PM GMT on August 24, 2007
OT: I'm looking for a small 'current conditions' box for the side bar of a website I'm working on. I was hoping to use one from WUnderground, but it does not seem that they have one available. Can someone e-mail me if they have any suggestions? A free one would be preferred. Thanks!

Nevermind...I found the 'Weather Stickers' on WU =)
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150. sullivanweather
4:28 PM GMT on August 24, 2007
DallasGumby,

My point about Antarctic sea-ice is that the trend is too small to discern whether or not there's actually a trend or an oscillation.

As far at the arctic is concerned there's definately a trend because of the large percentage decrease in the sea-ice there.

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148. kmanislander
4:28 PM GMT on August 24, 2007
ok fixed now thanks
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147. GaleWeathers
4:28 PM GMT on August 24, 2007
OT: I'm looking for a small 'current conditions' box for the side bar of a website I'm working on. I was hoping to use one from WUnderground, but it does not seem that they have one available. Can someone e-mail me if they have any suggestions? A free one would be preferred. Thanks!
Member Since: Posts: Comments:

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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.