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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Buy reconstruction bonds!
The logical place to push is at the ballot box, but when it is political suicide for a candidate to offer a choice on the matter, work has to continue on educating the public as well as exposing corruption and hypocrisy.
I was amazed at a recent satellite picture showing how the land alongside the river below English Turn has disappeared. I grew up in Louisiana and know that all the maps used to show marsh across large areas that are now open water. People may have not built near the shore, but I think the shore has come to them.
Since the Hurricane became so large because it interacted with the trough and became a Nor'easter. All the reasons he gave had nothing to do with the climate and everything to do with the presence of other systems and the physics of the Earth's Rotation?
His views are becoming more and more radical all the time.
If you cant use a cold snap to disprove GW, then how can you use a Hurricane to prove it? It seems a little disjointed?
The Great Storm of October 29, 1693: Virginia to Long Island
A tremendous storm, possibly tropical in origin, changed the course of rivers and modified the coastline from the Delmarva Peninsula to Long Island. It is believed that Fire Island (just east of New York City) was bisected by the storm. The same apparently occurred to many coastal portions of the Delmarva Peninsula and region around Chesapeake Bay.
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This hit on the same calander day as Sandy and sounds much more severe.
It also hit a long, long time before the onset of the industrial revolution.
So IMO that makes the argument that Sandy was triggered or affected by global warming harder to make. When you have a precendent from outside the era of human-added CO2, hitting at exactly the same time of year in the same region, it shows that natural forces alone are capable of triggering such an event.
Interesting article. Sample quote:
"For a long time, climate change was treated by environmentalists as a great equaliser, the one issue that affected everyone, rich or poor. They failed to account for the myriad ways by which the super rich would protect themselves from the less savory effects of the economic model that made them so wealthy. In the past six years, we have seen in the US the emergence of private fire fighters, hired by insurance companies to offer a "concierge" service to their wealthier clients, as well as the short-lived "HelpJet" – a charter airline in Florida that offered five-star evacuation services from hurricane zones. Now, post-Sandy, upmarket real estate agents are predicting that back-up power generators will be the new status symbol with the penthouse and mansion set."
Also, amazing how people become oversensitive here the moment Climate Change is mentioned... As far as I'm concerned, I have nothing to argue about, because I know it's happening.
In any case, I think we can all agree that the weather (climate is weather over-time) will always change. Patterns we were so used to before, are rapidly changing, and will undoubtedly continue to change into the future. Even if--or more precisely, when--we cease all fossil fuel emissions, world weather patterns will continue to change naturally (and unnaturally) just as they always have. We will continuously adapt to those changes just as we are doing this very moment. Of course, now, we need to adapt at an alarming rate because the climate is changing at an unprecedentedly rapid rate but, the way I see it, it provides us with solid experience in infrastructure and so forth.
What I'm trying to say is we won't ever be able to escape nature's wrath, but only adapt to it.
This is from Dr. Master's blog " we should be concerned about the possibility that Hurricane Sandy's freak size and power were partially due to human-caused climate change." Note the words possibility and partially due to. No one is using Sandy to prove anything, but instead saying it is possible that Sandy was influenced by GW. That is a very important distinction, especially in science.
The first quest must be to show the public the deceptions of the denial industry. The truth is that the denial industry has been very efficient in spreading doubts and confusion among the masses. The denial industry does not do this through the use of sound, peer reviewed science but, rather, through disinformation and the creation of doubt among the masses. When you look at the denial industry's portrayal of the AGWT, in the U.S. assuredly, you see a political party's leadership that is bent towards helping the denial industry create doubts about the theory itself. This has not been done in the manner a true skeptic would approach a scientific theory, but as an ideological pursuit. Until the public becomes aware of the most likely consequences of AGW and the denial industry's false claims concerning the AGWT, then a small group of citizens standing on the steps of Congress will be ignored, at best, or attacked. Sadly, the first quest remains in the exposure of the denial industry for what it truly is. Until the public becomes more aware of the deceptions of the denial industry, then the public will not be willing to support the changes that need to be made. This is true no matter who delivers the message before our political leadership. ... Step 1 has been and still remains the exposure of the denial industry for what it truly is. Step 2, not matter what it is, cannot be successfully made until step 1 has been completed or at least made considerably less of an issue.The denial industry is keenly aware that they will ultimately lose the "war". Their only quest is to win all the battles they can before the "war" is lost to all.
Thanks! I am in a wait and see mode regarding Thanksgiving company... I am at the Jersey shore and "lurking" among you incredibly knowledgeable weathernistas. WUnderground is my #1 source, since 2007 :-)
Choices for Deficit Reduction - NOVEMBER 2012
Excerpt:
It is possible to keep tax revenues at their historical average percentage of GDP—but only by making substantial cuts, relative to current policies, in the large benefit programs that aid a broad group of people at some point in their lives.
Alternatively, it is possible to keep the policies for those large benefit programs unchanged—but only by raising taxes substantially, relative to current policies, for a broad segment of the population.
Floodgates like the Dutch have on the Schelde river should be placed on Arthur Kill, Verrazano Narrows, and the East River, sea walls on the lower parts of Staten Island and Long Island. Add some protection against beach erosion and many is done. Invest five to ten billion Dollar and after ten years of work most of New York City would be protected.
However the New Jersey shore and the West End of the Long Island Sound are issues from much larger magnitude.
Obviously, a perfect storm could occur, given the right setup, 300 years ago, or 1000 years ago, or 1 million years ago...
You don't need Global Warming to have a powerful storm.
Are humans responsible, in some part, for the storms we are experiencing today? One can easily correlate that the radically different composition of the atmosphere today has an obvious influence on storms.
Natural forces alone are capable of producing such storms, yes. But, the atmosphere is much different now. It is not far-fetched at all to think that every storm today is different than what would have occurred if humans hadn't poured CO2 into the atmosphere.
+1000
Did anyone notice that the President, and his opponent, did not mention climate change during the campaign? But as soon as the election results were in... Link
Political suicide, indeed.
Louisiana has also reached the 25,000 threshold, and Florida is not far behind.
Anyways, it must really suck living in the Northeast. First a historic hurricane/nor'easter combo, then a significant winter storm, and now yet another storm capable of producing gusty winds and very heavy rainfall.
This is the pattern for the winter, it appears. People hoping for snow in the Northeast...you'll probably get it.
It actually does no such thing. Comparing one event to another event does not really compare climate. I'm sure anyone can find numerous anecdotes of lung cancer in cultures that did not smoke, yet we still know that smoking causes cancer.
You might also wish to refresh yourself on the definition of climate, and how it contrasts from weather... hint: Dr. Masters' discussion of intensity and frequency of storms overall, but little discussion of individual storms.
Some people have just reached the point that they want to complain about Dr. Masters just to do it. And they already get their mind made up that they want to complain about climate science before they've even fully read Dr. Masters' post on it.
The petition site is not official (legally), and there are a couple interesting things to point out. First 70,000 people is still only .3% of Texas' population, and that 70,000 number also includes signatures not from Texas as it is an open online form. This is a very small amount of people over reacting. Secession of any state would ultimately destroy the state's economy as most of those states signing the petition receive more federal dollars than they pay in. This would force some states to raise or institute new income taxes. (Note: Texas receives $.94 for every dollar paid in)
I simply believe that those who can conserve should, and I am in a position where I can - but what of the soccer mom who has to shuttle kids around and go get the groceries? That is the greatest impediment to reducing carbon output - to change it will require massive structural shifts away from a suburbuan/exurban lifestyle that the strong majority of Americans favor. And IPCC bureaucrats flying halfway around the world to assemble questionable reports won't change that.
This begs the question- just what will this petition accomplish? The election results are not in dispute. President Obama will still be inaugurated in January. He has to sign off and agree to allow a state to secede, and I don't think that will happen. The president will make a formal response, but it won't be what they want to hear.
Maybe a continental congress would work, but as to how those opposing the election would choose to amend the Constitution, I can't guess.
Texas has the one of the only great economies left in the US. They're trying to ditch the Titanic in the last life raft left... Let them leave, see what happens, they're better off then these welfare states that beg for the federal government to give them money...
The states can't secede without a vote of some sort. The petition site is basically "Ask the government a question, we will respond if you get 25,000 signatures". Which is cool as far as allowing the people to ask questions, but means nothing as far as any action taken by the federal government. This is just a very small number of people being upset, which is their right. :)
5 to 10 billion? get a grip. That wont touch construction of just earthern structures...check the Corps website for work going on regarding Katrina
The economic numbers may ad up at the moment, but wait until international tariffs and trade deficits start adding up over time. On of the reasons the U.S. works well is because we are very diverse due to the specialization of states. I find it hard to believe one state, despite the size or relative well being of their economy, can do it on their own in the long run.
Still only 1.95. I will start to take this seriously if they hit 2.5 million (The 10% mark).
you are side stepping the point.....
In our history it took a war to confirm it, but there is no succession clause in the US Constitution.
Good post. What amazes me is that the PR industries that spread the anti-science nonsense employ well educated people to blog all day long distorting reality and their blogs will eventually hasten the demise of their kids and grand kids. Some people will do anything for a buck.
It's arguable since the 10th amendment allows states or the people to assume powers not directly delegated to the federal government (secession is not one of these powers). This discussion is all hypothetical, but I think the states could make a valid constitutional argument if they really wanted to.
They have done it before, of course they failed miserably, but they've come to better terms about how to steady the economy. Rick perry on the other hand just doesn't want to be caught in a bad spot, which is why he's denying he want secession.
Now, sorry for the interruption. You were saying?
Mitt Romney mentioned the rise of the oceans at the Republican National Convention.
The constitutional argument did not work in 1861.
It will become necessary by 2100 or so even with the average predicted sea level rise. By the time you factor in the average sea level rise PLUS the increased maximum intensity of hurricanes due to the hot water, you could expect average and maximum storm surges to increase by a total of 6 to 10 feet above today's average in the same region.
Plus 3 feet for mean sea level rise.
Plus another 3 to 7 feet or so because the storm is a half category to a category stronger.
Gives a total of perhaps 6 to 10 feet above average and maximum storms in today's conditions.
I doubt many/any people reading this will be alive in 2100, but that's irrelevant.
........
Is it just me or was he acting like a little boy?
"Obama promises this, LOL, I promise that :D."
And is it wrong to feel incredibly angry after watching this...
Politicians acting as if this were a huge game.
Eh, I think I just got a reality-check.
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