Hurricane Sandy's huge size: freak of nature or climate change?

By: Dr. Jeff Masters , 1:10 PM GMT on November 13, 2012

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Hurricane Sandy was truly astounding in its size and power. At its peak size, twenty hours before landfall, Sandy had tropical storm-force winds that covered an area nearly one-fifth the area of the contiguous United States. Since detailed records of hurricane size began in 1988, only one tropical storm (Olga of 2001) has had a larger area of tropical storm-force winds, and no hurricanes has. Sandy's area of ocean with twelve-foot seas peaked at 1.4 million square miles--nearly one-half the area of the contiguous United States, or 1% of Earth's total ocean area. Most incredibly, ten hours before landfall (9:30 am EDT October 30), the total energy of Sandy's winds of tropical storm-force and higher peaked at 329 terajoules--the highest value for any Atlantic hurricane since at least 1969. This is 2.7 times higher than Katrina's peak energy, and is equivalent to five Hiroshima-sized atomic bombs. At landfall, Sandy's tropical storm-force winds spanned 943 miles of the the U.S. coast. No hurricane on record has been wider; the previous record holder was Hurricane Igor of 2010, which was 863 miles in diameter. Sandy's huge size prompted high wind warnings to be posted from Chicago to Eastern Maine, and from Michigan's Upper Peninsula to Florida's Lake Okeechobee--an area home to 120 million people. Sandy's winds simultaneously caused damage to buildings on the shores of Lake Michigan at Indiana Dunes National Lakeshore, and toppled power lines in Nova Scotia, Canada--locations 1200 miles apart!

Largest Atlantic tropical cyclones for area covered by tropical storm-force winds:

Olga, 2001: 780,000 square miles
Sandy, 2012: 560,000 square miles
Lili, 1996: 550,000 square miles
Igor, 2010: 550,000 square miles
Karl, 2004: 430,000 square miles



Figure 1. Hurricane Sandy’s winds (top), on October 28, 2012, when Sandy was a Category 1 hurricane with top winds of 75 mph (this ocean surface wind data is from a radar scatterometer on the Indian Space Research Organization’s (ISRO) Oceansat-2.) Hurricane Katrina’s winds (bottom) on August 28, 2005, when Katrina was a Category 5 hurricane with top winds of 175 mph (data taken by a radar scatterometer on NASA’s defunct QuickSCAT satellite.) In both maps, wind speeds above 65 kilometers (40 miles) per hour are yellow; above 80 kph (50 mph) are orange; and above 95 kph (60 mph) are dark red. The most noticeable difference is the extent of the strong wind fields. For Katrina, winds over 65 kilometers per hour stretched about 500 kilometers (300 miles) from edge to edge. For Sandy, winds of that intensity spanned an region of ocean three times as great--1,500 kilometers (900 miles). Katrina was able to generate a record-height storm surge over a small area of the Mississippi coast. Sandy generated a lower but highly destructive storm surge over a much larger area, due to the storm's weaker winds but much larger size. Image credit: NASA.

How did Sandy get so big?
We understand fairly well what controls the peak strength of a hurricane's winds, but have a poor understanding of why some hurricanes get large and others stay small. A number of factors probably worked together to create a "prefect storm" situation that allowed Sandy to grow so large, and we also must acknowledge that climate change could have played a role. Here are some possible reasons why Sandy grew so large:

1) Initial size of the disturbance that became Sandy was large
Sandy formed from an African tropical wave that interacted with a large area of low pressure that covered most of the Central Caribbean. Rotunno and Emanuel (1987) found that hurricanes that form from large initial tropical disturbances like Sandy did tend to end up large in size.


Figure 2. The initial disturbance that spawned Sandy, seen here on October 20, 2012, was quite large.

2) High relative humidity in Sandy's genesis region
The amount of moisture in the atmosphere may play an important role in how large a hurricane gets (Hill and Lackmann, 2009.) Sandy was spawned in the Caribbean in a region where the relative humidity was near 70%. This is the highest humidity we saw during 2012 during the formation of any Atlantic hurricane.

3) Passage over Cuba
Sandy struck Cuba as an intensifying Category 2 hurricane with 110 mph winds. While the core of the storm was over Cuba, it was cut off from the warm ocean waters surrounding Cuba. Most of Sandy's large circulation was still over the ocean, though, and the energy the storm was able to extract from the ocean went into intensifying the spiral bands over water. When Sandy's core re-emerged over water, the hurricane now had spiral bands with heavier thunderstorm activity as a result of the extra energy pumped into the outer portion of the storm during the eye's passage over land. This extra energy in the outer portions of Sandy may have enabled it to expand in size later.

4) Interaction with a trough of low pressure over the Bahamas
As Sandy passed through the Bahamas on October 25, the storm encountered strong upper-level winds associated with a trough of low pressure to the west. These winds created high wind shear that helped weaken Sandy and destroy the eyewall. However, Sandy compensated by spreading out its tropical storm-force winds over a much wider area. Between 15 and 21 UTC on October 25, Sandy's area of tropical storm-force winds increased by more than a factor of two.

5) Leveraging of the Earth's spin
As storms move towards Earth's poles, they acquire more spin, since Earth's rotation works to put more vertical spin into the atmosphere the closer one gets to the pole. This extra spin helps storms grow larger, and we commonly see hurricanes grow in size as they move northwards.

6) Interaction with a trough of low pressure at landfall
As Sandy approached landfall in New Jersey, it encountered an extratropical low pressure system to its west. This extratropical storm began pumping cold air aloft into the hurricane, which converted Sandy into an extratropical low pressure system, or "Nor'easter". The nature of extratropical storms is to have a much larger area with strong winds than a hurricane does, since extratropical storms derive their energy from the atmosphere along a frontal boundary that is typically many hundreds of miles long. Thus, as Sandy made landfall, the hurricane's strongest winds spread out over a larger area, causing damage from Indiana to Nova Scotia.

Are we likely to see more such storms in the future?
Global warming theory (Emanuel, 2005) predicts that a 2°C (3.6°F) increase in ocean temperatures should cause an increase in the peak winds of the strongest hurricanes of about about 10%. Furthermore, warmer ocean temperatures are expected to cause hurricanes to dump 20% more rain in their cores by the year 2100, according to computer modeling studies (Knutson et al., 2010). However, there has been no published work describing how hurricane size may change with warmer oceans in a future climate. We've seen an unusual number of Atlantic hurricanes with large size in recent years, but we currently have no theoretical or computer modeling simulations that can explain why this is so, or if we might see more storms like this in the future. However, we've seen significant and unprecedented changes to our atmosphere in recent decades, due to our emissions of heat-trapping gases like carbon dioxide. The laws of physics demand that the atmosphere must respond. Atmospheric circulation patterns that control extreme weather events must change, and we should expect extreme storms to change in character, frequency, and intensity as a result--and not always in the ways our computer models may predict. We have pushed our climate system to a fundamentally new, higher-energy state where more heat and moisture is available to power stronger storms, and we should be concerned about the possibility that Hurricane Sandy's freak size and power were partially due to human-caused climate change.

References
Emanuel, K. (2005). Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436(7051), 686-688.

Hill, Kevin A., and Gary M. Lackmann (2009), "Influence of environmental humidity on tropical cyclone size," Monthly Weather Review 137.10 (2009): 3294-3315.

Knutson, T. R., McBride, J. L., Chan, J., Emanuel, K., Holland, G., Landsea, C., ... & Sugi, M. (2010). Tropical cyclones and climate change. Nature Geoscience, 3(3), 157-163.

Rotunno, R., & Emanuel, K. A. (1987). An air–sea interaction theory for tropical cyclones. Part II: Evolutionary study using a nonhydrostatic axisymmetric numerical model. J. Atmos. Sci, 44(3), 542-561.

The Atlantic is quiet, but a Nor'easter expected next week
The Atlantic is quiet, with no threat areas to discuss. An area of low pressure is predicted to develop just north of Bermuda on Wednesday, and the GFS model predicts that this low could become a subtropical cyclone as moves north-northeastwards out to sea late in the week.

The long-range models are in increasing agreement that a Nor'easter will develop near the North Carolina coast on Sunday, then move north to northeastwards early next week. High winds, heavy rain, and coastal flooding could affect the mid-Atlantic coast and New England coasts next Monday and Tuesday due to this storm, but it appears likely that the Nor'easter will stay farther out to sea than the last Nor'easter and have less of an impact on the region devastated by Sandy. Ocean temperatures off the coast of North Carolina were cooled by about 4°F (2.2°C) due to the churning action of Hurricane Sandy's winds, but are still warm enough at 22 - 24°C to potentially allow the Nor'easter to acquire some subtropical characteristics. I doubt the storm would be able to become a named subtropical storm, but it could have an unusual amount of heavy rain if it does become partially tropical. The Nor'easter is still a long ways in the future, and there is still a lot of uncertainty on where the storm might go.

Jeff Masters

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Quoting sullivanweather:




I see a rodent...


I think those clouds.. look like clouds.
Member Since: Posts: Comments:
910. Skyepony (Mod)
12ZCMC showing the next low starting subtropical & moving more tropical as it deepens. Click pic to see sst which are kinda cool for all that, 23-25C.



Large with a large blocking high to the north..
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Hi guys...

look at this stunning pic from Australia total eclipse...NASA

i might use it as my desktop picture
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Quoting Naga5000:


Not much of a leap of logic considering. Obviously he is trying to relate the cutting of funding to something, otherwise it's just a pointless statement. Also, nothing else to do than attack someone on a typo. GG.
Didn't attack anyone (but I see you added one to your comment). (edit) That's the first time I've seen the CA "Berkeley" spelled correctly on this board in many a moon. Couldn't even tell you how many or who misspelled it.

Types like you actually keep folks from understanding stuff like that graph. So be it. I see your second illogic and raise you an ignore button.
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Quoting wxmod:
'Airport clouds' covering several states in the eastern USA. MODIS today





I see a rodent...
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Quoting wxgeek723:


Tell me something Kori. Where do you live? Would an earthquake on the West Coast affect you in any direct way?
Louisiana.
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Quoting Naga5000:


Not much of a leap of logic considering. Nice try.
No logic involved. LOLOL. Thanks for the chuckle. LOL. I'm still laughin'.
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Quoting wxgeek723:


Tell me something Kori. Where do you live? Would an earthquake on the West Coast affect you in any direct way?

Let's just say they won't and he has been hit by some bad hurricanes.
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Quoting Barefootontherocks:
How do you get there...from here?


LMAO. Was gonna ask you a question about the graph, Naga5000, but at this point I'll just say thanks for spelling "Berkeley" correctly in your last comment.

Good night, One and All.


Not much of a leap of logic considering. Obviously he is trying to relate the cutting of funding to something, otherwise it's just a pointless statement. Also, nothing else to do than attack someone on a typo. GG.
Member Since: June 1, 2010 Posts: 4 Comments: 3390
Quoting Naga5000:


So you are claiming a professor of physics at UC Berkeley falsified data over a funding cut? What a joke...you don't have much of a clue of how academia works do you?
How do you get there...from here?
Quoting yoboi:


he did the research after watts cut funding.....that's all.. but i think we are both smart enough to see the big picture....


LMAO. Was gonna ask you a question about the graph at comment 855, Naga5000, but at this point I'll just say thanks for spelling "Berkeley" correctly in your last comment.

Good night, One and All.
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Quoting yoboi:




that he did the research after funding was cut...


Meaning what? Why does it matter?
Member Since: June 1, 2010 Posts: 4 Comments: 3390
Quoting KoritheMan:

Speculation = disaster craving?


Tell me something Kori. Where do you live? Would an earthquake on the West Coast affect you in any direct way?
Member Since: Posts: Comments:
Quoting yoboi:




that he did the research after funding was cut...


and that means what? You have a conclusion; spit it out. If you don't, stop with the coy little jibes.
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898. yoboi
Quoting Naga5000:


"he did the research after watts cut funding.....that's all.. but i think we are both smart enough to see the big picture...." - your quote

What is it you are trying to say then? Spit it out.




that he did the research after funding was cut...
Member Since: August 25, 2010 Posts: 7 Comments: 2337
Quoting yoboi:


i never claimed that, you are implying words i never said....


"he did the research after watts cut funding.....that's all.. but i think we are both smart enough to see the big picture...." - your quote

What is it you are trying to say then? Spit it out.
Member Since: June 1, 2010 Posts: 4 Comments: 3390
896. yoboi
Quoting Naga5000:


So you are claiming a professor of physics at UC Berkeley falsified data over a funding cut? What a joke...you don't have much of a clue of how academia works do you?


i never claimed that, you are implying words i never said....
Member Since: August 25, 2010 Posts: 7 Comments: 2337
Quoting yoboi:


he did the research after watts cut funding.....that's all.. but i think we are both smart enough to see the big picture....


So you are claiming a professor of physics at UC Berkeley falsified data over a funding cut? What a joke...you don't have much of a clue of how academia works do you?
Member Since: June 1, 2010 Posts: 4 Comments: 3390
894. wxmod
China and India, aerosol overlay. MODIS satellite image today.


Member Since: October 4, 2011 Posts: 0 Comments: 1758
893. yoboi
Quoting Naga5000:


What do you think that is? Please just get it out.


he did the research after watts cut funding.....that's all.. but i think we are both smart enough to see the big picture....
Member Since: August 25, 2010 Posts: 7 Comments: 2337
Quoting yoboi:


i only asked 1 question.....there is more to the story than your putting out there....


What do you think that is? Please just get it out.
Member Since: June 1, 2010 Posts: 4 Comments: 3390
891. yoboi
Quoting Naga5000:


What are you implying? I really wish you would just say what you are thinking instead of playing 20 questions.


i only asked 1 question.....there is more to the story than your putting out there....
Member Since: August 25, 2010 Posts: 7 Comments: 2337
890. beell
Quoting Astrometeor:


You have this backwards. Eggnog is one of the most delicious drinks out there.


Chickens don't much care for it...
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Quoting yoboi:


i know who funded it was asking was it done after watts cut funding to him...


What are you implying? I really wish you would just say what you are thinking instead of playing 20 questions.
Member Since: June 1, 2010 Posts: 4 Comments: 3390
888. yoboi
Quoting Naga5000:

Read the article, this research was mainly funded by the Koch brothers through UC Berkley.


i know who funded it was asking was it done after watts cut funding to him...
Member Since: August 25, 2010 Posts: 7 Comments: 2337
Quoting yoboi:



did he do this research after watts cut funding off to him???

Read the article, this research was mainly funded by the Koch brothers through UC Berkley.
Member Since: June 1, 2010 Posts: 4 Comments: 3390
Quoting TropicalAnalystwx13:

No, I mean it was absolutely disgusting. Worse than eggnog..


You have this backwards. Eggnog is one of the most delicious drinks out there.
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885. wxmod
'Airport clouds' covering several states in the eastern USA. MODIS today

Member Since: October 4, 2011 Posts: 0 Comments: 1758
884. yoboi
Quoting Naga5000:


%u201CWe tried fitting the shape to simple math functions (exponentials, polynomials), to solar activity and even to rising functions like world population. By far the best match was to the record of atmospheric carbon dioxide, measured from atmospheric samples and air trapped in polar ice.%u201D - Richard Muller, ex climate change denier turned supporter after he did the research himself. Link



did he do this research after watts cut funding off to him???
Member Since: August 25, 2010 Posts: 7 Comments: 2337
Quoting KoritheMan:

Correction: they are releasing it tomorrow.

I can wait..
Quoting KoritheMan:

You mean it was too good for you? I know.

No that is not it, it can't be good.
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Quoting KoritheMan:

You mean it was too good for you? I know.

No, I mean it was absolutely disgusting. Worse than eggnog..
Member Since: July 6, 2010 Posts: 113 Comments: 32078

Quoting TropicalAnalystwx13:

I tasted the Kori flavor. It was disgusting..
You mean it was too good for you? I know.
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Quoting wxchaser97:

Why have I not seen it when I go to Walmart then?
Correction: they are releasing it tomorrow.
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quake doom monitor

The earth has the DT's everyday, some days more than others

Link
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Quoting TomballTXPride:

My experience on here tells me that if it's not 100% burning of the fossil fuels fault, then it ain't being bought. Never mind the sun or any of the other dozen reasons that could explain it. Even de-forestation which is man-made. Forget it. It's not fossil fuels.

I think some would be better off just accepting the fact that they are likely not going away anytime soon, whether or not it's having an impact on the climate or not.


%u201CWe tried fitting the shape to simple math functions (exponentials, polynomials), to solar activity and even to rising functions like world population. By far the best match was to the record of atmospheric carbon dioxide, measured from atmospheric samples and air trapped in polar ice.%u201D - Richard Muller, ex climate change denier turned supporter after he did the research himself. Link
Member Since: June 1, 2010 Posts: 4 Comments: 3390
877. yoboi
Quoting Xulonn:
Yoboi - I added the caption to the graph with the year of publication - 2011.



if the graph holds true we should see a drop coming soon...
Member Since: August 25, 2010 Posts: 7 Comments: 2337
Quoting TropicalAnalystwx13:

I tasted the Kori flavor. It had an awful taste....


Cold.... xD
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875. yoboi
Quoting Xulonn:
Yoboi - I added the caption to the graph with the year of publication - 2011.



thanks did not see it...
Member Since: August 25, 2010 Posts: 7 Comments: 2337
Quoting pottery:

"Eternity"....

that's what I heard anyway.

I thought that was a perfume
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Quoting KoritheMan:

The "Kori" flavor, my very own brand. Home office agreed to start mass producing it worldwide.

I tasted the Kori flavor. It was disgusting..
Member Since: July 6, 2010 Posts: 113 Comments: 32078
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1026 PM AST WED NOV 14 2012

.UPDATE...SATELLITE IMAGERY SHOWS VARIABLY CLOUDY SKIES OVER
PUERTO RICO AND USVI THIS EVENING. DOPPLER RADAR HAS SHOWN SPOTTY
SHOWERS BEING CARRIED IN ON THE TRADES...MAINLY ACROSS THE LOCAL
WATERS. LATEST SURFACE ANALYSIS AS WELL AS THE CIMMS-MIMIC PWAT
ANALYSIS SHOWED A WEAK TROUGH OVER THE NORTHERN LEEWARD ISLANDS
MOVING EAST AT AROUND 15 KTS. THIS SURFACE TROUGH AND ITS ASSOCIATED
DEEP MOISTURE WILL ENCOMPASS THE LOCAL REGION OVERNIGHT. 18Z GFS
MOVES THIS WEAK SFC TROUGH OVER THE LOCAL CARIBBEAN WATERS DURING
THE NEXT 24 HOURS. AS A RESULT...EXPECT SCATTERED SHOWERS AFFECTING
THE USVI AND THE EASTERN THIRD OF PR EARLY THURSDAY MORNING...
FOLLOWED BY AFTERNOON CONVECTION DEVELOPING ACROSS THE WEST AND
SOUTH SECTIONS OF PR. CHANGES WERE DONE TO THE PREVIOUS FORECAST
PACKAGE TO INCREASE THE POP`S IN FEW ZONES.
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871. wxmod
Quoting TomballTXPride:

What if I don't have or want kids?


Then you must go to work in the oil fields.
Member Since: October 4, 2011 Posts: 0 Comments: 1758
Yoboi - I added the caption to the graph with the year of publication - 2011.
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Quoting KoritheMan:
Since the Atlantic seems like it wants to quit (finally), I suppose I'll resume work on my TCRs tonight, starting with Beryl (I only did the actual storm histories, not the more intricate aspects like intensity and pressure). Still a long ways to go!*

*Also not gonna paraphrase the TCRs the NHC has already done like I did last year.

I am doing a spin-off of TCR's this year, called TCS's(Tropical Cyclone Summaries). It is not like an official TCR but it goes over what happened and why. Mine will be finished hopefully after winter break, if I do heavy work during my breaks. Most likely they will be done in January or February.
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868. wxmod
Quoting wxgeek723:
Hate to break it to you disaster-hungry folk, but I think the 7.7 in BC during Hurricane Sandy was 'the event' for the west coast of North America for the time being.


I'm not "hungry" for disaster. I suggest that everyone on the west coast should at least have a flashlight, a few gallons of water and a few snack bars.
Member Since: October 4, 2011 Posts: 0 Comments: 1758
867. yoboi
Quoting KoritheMan:

The "Kori" flavor, my very own brand. Home office agreed to start mass producing it worldwide.



sure it will be made in china....
Member Since: August 25, 2010 Posts: 7 Comments: 2337
Quoting AttackOfTheRevenge:
Sometimes, I like to sit in my refrigerator and pretend I'm Milk.


Suddenly thirsty, ....
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Quoting KoritheMan:

The "Kori" flavor, my very own brand. Home office agreed to start mass producing it worldwide.

Why have I not seen it when I go to Walmart then?
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Quoting Bluestorm5:
Yeah, I remember a 5.2 quake from Wabash Vally Fault in Illinois few years ago, but I didn't feel that one. I never felt an quake until the one that shook DC area.


I felt one a couple of years ago that was beneath St. Louis. Woke me up, rattled the windows.

Edit: windows, not winds, been trying to type to fast recently. Not working out to well.
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Since the Atlantic seems like it wants to quit (finally), I suppose I'll resume work on my TCRs tonight, starting with Beryl (I only did the actual storm histories, not the more intricate aspects like intensity and pressure). Still a long ways to go!*

*Also not gonna paraphrase the TCRs the NHC has already done like I did last year.
Member Since: Posts: Comments:

Quoting wxgeek723:
Hate to break it to you disaster-hungry folk
Speculation = disaster craving?
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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.