Hurricane Sandy's huge size: freak of nature or climate change?
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
Reader Comments
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Gustav, but that was 1.2.3.4.5.6.7. years ago?
you have a lot of what if's; when you get the facts let's debate....
Gustav was a cat 2 at landfall.
wrong wilma 2005...
Oh now don't be so cynical. Surely you realize politics is far more complicated than your statement suggests. I believe the vast majority of people DO care about tomorrow. Opinions just vary about the best way to make tomorrow better.
Oh, and check out these webcam shots of the mountain wave cloud set up over the Continental Divide today:
Nice shots for sure...hummmmm...continental divide huh?
Ha! There aren't actually any what ifs in my post, but whatever.
You just want facts you like better. Human tendency. Understandable and yet rather problematic, when it comes to ignoring the facts you'd rather not see until they smack you in the face.
I can only wish that the folks refusing to see the rather unfortunate facts here were the only ones going to get the face-smacking on the other end.
Not much point in "debate." It's not really a matter of conflicting opinions, at least at this level. What any of us "think" makes about zero difference to the laws of physics here.
140,
Soooooo you are saying the oceans have never been higher?
The global temperature has never been higher?
The ice never melted before, let alone the new high Antarctic Ice extent record set this year that does not get discussed on this site.
Even though the global temperature has not gone up in 16 years as documented recently that does not count?
And CO2 has a linear relationship to temperature and all feedbacks and forcings are positive to temperature rise?
I don't have time to address your other undocumented generalizations.
Your reference to weather extremes are addressed here.
Where are the trending extreme weather events?
I wish him luck. He's going to need it.
__________________________
Adak major storm...tropical storm force with hurricane gusts reported
That was yesterday's 6.4 quake south of AK/CAN border
as always click on the pic for a better quality
How about the Texas State Library? Perhaps they might be trustworthy...information here: Texas Annexation
Summary quote: "In fact, Texas received no special terms in its admission to the Union. Once Texas had agreed to join the Union, she never had the legal option of leaving, either before or after the Civil War."
And on the multiple state question, the answer is here: Can Texas divide itself into multiple states?
Summary quote: "Although in theory Texas could still be divided into multiple states, any possibility of carving additional states from Texas ended when the Civil War settled the question of slavery once and for all."
Also from Article IV Section 3 US Constitution.
New states may be admitted by the Congress into this union; but no new states shall be formed or erected within the jurisdiction of any other state; nor any state be formed by the junction of two or more states, or parts of states, without the consent of the legislatures of the states concerned as well as of the Congress.
Sorry for the off topic post, but as a Texan, I hope to put this part of the discussion to rest.
Pretty pics. When I was a kid, and I saw stuff "caught" on the peaks like that from the valley I lived in -- usually coastal fog, where I was at the time, but similar visual effect -- I used to make believe it was a gigantic tsunami-type wave about to smash into my town and wash us all away.
Yeah, I was a weird kid. But you can even make the tops of the mountains into sea foam, if you have a kid imagination.
you were not saying either way about some 1690 storm like i said bring up facts not something that can go either way..... and i agree with the law of physics but you can't prove why things are changing...
Or do we need to say, never, when it mattered.
who is the nobel prize winning world leader??? and did this leader lead with facts or bs???
Nothing weird about that. When I was growing up in Ohio I would frequently pretend that the massive storm clouds on the horizon were mountains. When I grew up I moved to Colorado because all my pretending was starting to weird people out.
I guess the cloud that's right ON the mountains (in my post #157) is considered a "cap cloud", while the cloud floating up above the divide would probably be considered a "rotor cloud." I believe they're all considered different types of "mountain wave" clouds, but someone please correct me if I'm wrong.
We had some great lenticular clouds last night, but they haven't reformed yet this morning.
Excerpt:
LOOKING AHEAD TO THE WEEKEND...GLOBAL MODELS ARE IN CLOSE AGREEMENT SHOWING AN NEGATIVELY TILTED MID TO UPPER TROUGH PUSHING INTO THE SE UNITED STATES BY FRI. THE ECMWF IS TRENDING IN BETTER AGREEMENT WITH THE UKMET INDICATING A CUT OFF LOW FORMING OVER GEORGIA BY SAT...WITH THE GFS REMAINING SOMEWHAT WEAKER. THE UKMET FORMS A SURFACE LOW OFF NE FLORIDA FRI INTO SAT. FORECAST FOLLOWS MORE CONSERVATIVE GFS SOLUTION FOR NOW BUT GIVEN THE SLIGHT NEGATIVE TILT TO THE SUPPORTING UPPER TROUGH THIS MAY BE ADJUSTED IN TIME. AT ANY RATE...ALL SOLUTIONS SHOW ONLY MODERATE WINDS FRI AND SAT.
This was done by the Army Corps of Engineers and to date, they have no input in New York. A New York seawall will likely still need federal dollars but don't see where that is coming from in this economic climate.
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First contact on one of the streams
just some friendly advice you should hitt the f5 key every now an then on your talking points.....
My point was that there's no fact based way to compare the same storm in different conditions, since we only have one reality (so far as we experience, anyway -- I'll skip the foray into weird quantum physics things.)
Here's some things we _do_ know:
CO2 (and methane and so on) holds heat differently than other constituents of the atmosphere.
We are adding CO2 to the atmosphere, increasing its proportion.
This will change the way the atmosphere holds heat energy.
That heat energy will be unevenly distributed -- both because the earth is a round spinny thing, and because it is tilted and therefore still has seasonal variation.
Uneven heat changes will change local pressure systems. You cannot change temp gradients without changing pressure gradients. If it's hotter in the arctic, the pressure systems across the entire northern hemisphere "feel" that.
Local pressure systems interact with other pressure systems, and will move in different ways. Circulations will change. The details, that's complicated. They can't not change, though. That's fundamental fluid dynamics.
A hotter atmosphere will also have more ability to hold gaseous water.
The ocean is a great heat sink for the earth, and it is warming considerably (and also unevenly.) This can effect ocean currents, and it has a huge effect on weather systems as a whole -- as anybody on this blog should be plenty aware, given the focus on SST.
I could go on. There is nothing here that's especially debatable. These are facts, all based fundamentally in physical law.
and CLEAR!..
"I think I got a pulse for the blog doctor..weak but its there.."
12z CMC
12z Euro
huh?
That looks wayyyy too extratropical in my opinion.
tropical or not, the Northeast doesn't need it..
No, but the war argument certainly did.
Warming has _not_ been flat. I have no idea where you would even get that from.
Not flat.
Nope. Not flat.
From the last link: "There are slight differences in global records between groups at NCDC, NASA, and the University of East Anglia. Each group calculates global temperature year by year, using slightly different techniques. However, analyses from all three groups point to the decade between 2000 and 2009 as the hottest since modern records began more than a century ago."
Complete and utter nonsense. According to the NASA GISS data, globally, 2010 is the warmest year on record, at 0.64 degrees C above the average for 1951-80.
These are the decadal average temperature anomalies with reference to 1951-80:
1981-90 0.20C
1991-00 0.32C
2001-10 0.55C
You need to stop reading the antiscience on denier websites.
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Flat eh?
oh, you mean since the last highest outlying freak temp ever in recorded history?... because as we all know, time began during the peak of the 1998 El Nino..
you could not be more incorrect about this so called "flat" temperature of the last 15yrs. my source? every statistic released regarding satellite observed temperatures accumulated throughout the satellite era.
and queue Watt's misrepresentation of UAH graphs starting in 1998, not dated beyond 2009...
was there a large earthquake a few yrs back that changed the tilt & axis of the earth???
And once again we see that local atmospheric water vapor levels are positively correlated with the awesomeness the astronomical event at a given area.
In other words: it's always #$%*ing cloudy when there's an eclipse or a meteor shower (at least in Colorado... whose normal blue skies always cloud up when a major astronomical event begins...)
And with that, he is part of the problem. The uncompromising position he stands for will cause the other side to dig in their heels as well and will ensure nothing gets done ... like they do in Washington ... but at least they can blame it on the other side.
Heh. "Mixon's Law."
Happens here, too. "OOOoo, there's going to be an awesome meteor shower! Oh, crap, it's going to rain that night."
should we only use modern records?
When you guys calm down can somebody send me a quick message? I want to post some weather images.
That graph is a pure fabrication, and shows just how desperate the denier camp has become.
Are you seriously calling "selective editing" and then showing data over a 15 year period to try and use a three year sample to prove that the earth is not warming anymore? Because that's what it looks like.
can you put data on a graph?
Try this one .... Link
Several links available ... heard another was clearing up
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