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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That's a question.
so life could reform again??? good point...
As I said, I haven't worked around snow geese, only seen them on occasion. Does this help? Link
"big burning ball of gas" is that gas your talking about fossil fuels??? does shell, exxon etc own that burning ball of gas??? so in your words the bible is a hoax??
thanks for sharing the link...
Parts of it are, yes. But how does that relate to global warming?
You know, there are many rocks out there!
You, out of all people, should know that life has been driven to near extinction once on this planet before...
...But hey, we survived!
Go team life!
The day someone claims legitimate ownership of the sun... Is probably the day we'd be in trouble...
I wouldn't say it can't happen though ;).
i know like noah and the ark....
Asking if the Bible is a hoax is a poorly worded and charged question. I think the Bible was a good book teaching moral lessons and rules for a time period when there was a lack of uniform rule and morals. There is also many parts of the Bible no longer followed such as rules on marriage, slavery, etc, which have evolved over time as civilizations morals have evolved.
I don't believe it to be the word of God anymore than I believe any religious text is the word of God. It was written by men, for men, with no way to prove whether it is divine or not. I believe in science and testable hypothesis with tangible results.
So you believe in the Bible, but not creation? Or do you believe in another creation? Can I choose what to be next time?
By Chris Wickham
LONDON | Tue Nov 13, 2012
(Reuters) - Excerpt: An international team of astronomers has produced the first map of the universe as it was 11 billion years ago, filling a gap between the Big Bang and the rapid expansion that followed. The study, published in the journal Astronomy & Astrophysics, shows the universe went through a phase roughly three billion years after the Big Bang when expansion actually started to slow, before the force of so-called 'dark energy' kicked in and sent galaxies accelerating away from each other. The map, the work of 63 scientists from nine countries, was compiled using a novel technique for studying the intense light from 50,000 distant quasars as it passes through clouds of hydrogen in space on its way to Earth.
Complete story here.
I have a feeling this topic is in no way, shape, or form related to global warming so I'm just going to drop it now. If you'd like to answer how it relates without a barrage of questions, be my guest...
For the record, most christians in more liberal nations have accepted that they keep losing to science (especially with evolution) and have started to accept gradual decline. Even hard core religious people here don't force creationism on anyone since they know it's been constantly disproved for nearly 2 centuries.
That's all I will say about this.
You are missing the point, it is still a charged question. What is it you are trying to prove or get at?
so let's censor certain books about the world??? i am not like that i say let's look at all books...
And... wait, has this blog become one big version of the question game?
I think in the next 24hrs we should see a circle. Subtropical develop of this system is possible near Bermuda.
Anyone have links for the model runs for the predicted Nor'easter? That is actually what I came in here for.
Evidence. It's not about books. It's about testable, tangible evidence. Read all the books you want, take and learn what you want from those books, that's great. But you cannot use "all books" as real proof of anything, you can only use work that can be tested, retested, and proven to be. You cannot use unverifiable books as evidence.
the main topic of the day was climate change by DR Jeff Masters.....i am just using a book i go by......but please list the books we have to go by and the books that are tabboo
You woke me up darn it :-)
Lol, people say we came from monkeys...
But that's because their thinking is short...
...They can't see the bigger picture.
...You see we aren't here because some man saved some good people and animals from a flood because they were on a boat...
...We are here because a few bacteria were given the fortune to survive in very harsh conditions...
...Even if the human race is driven to extinction because of what ever reason...
...Most likely the ones worthy of survival aren't those who can come up with technology to settle other planets...
...But the so called "scum" that can hitch a ride!
...But that doesn't mean we are helpless. I mean, we do have people living in the desert and tundra right? We can survive global warming. Doesn't mean that it's going to be politically easy... Or easy in anyway, shape or form.
...But if you think the end of times for the human race is from global warming, think again.
Following six more confirmed deaths, not in the United States this time, but in Haiti, the overall fatality count for the superstorm is up to 199. 121 of these deaths occurred in the United States, 11 occurred in Cuba, and 2 each occurred in the Bahamas, Canada, and the Dominican Republic. 1 person was killed in Jamaica.
There is currently 1 person missing in the United States, with a more significant count of 21 in Haiti. Hopefully they all turn out fine...we don't need the death toll rising any further.
As it stands right now, Hurricane Sandy is the 2nd costliest hurricane in United States history, eclipsed only by Hurricane Katrina, and the 25th deadliest hurricane in United States history. With an estimated damage total of at least $52 billion, Sandy has brought the total season damage total up to at least $55 billion, making it the most costly since 2005.
taz we are all being respectful with our different views we are using our freedom of speech and are being respectful on both sides of the discussion
Guess I should study or something...
The only model that goes out far enough for the full scope of the nor'easter is the GFS.
18z GFS 500mb heights/PMSL Atlantic Tropical
you are correct i don't thing humans can determine how the earth will destroy i do think humans can cause climate to make us suffer undo stress but not the final outcome....
Freedom of speech and following blog rules are two entirely different things.
You can say all you want. And WunderBlog Admin can smack you with the banhammer and tell you to be quiet for 24 hours. Freedom of speech would not apply in this case, please take your straw man 2 doors down the hall on the right, to the Theology discussion board.
I appreciate everyone is being respectful (for once), but really... this isn't the proper venue for such a heady discussion.
sorry ya fell asleep.....
Nah, religion is just a small part of this, the real talk is about whether or not, in light of "climate change" someone will carry on the throne of life it self. People reference religion in whether the world ends when humans die out, but those people need to be humbled by the fact that there are many more fit beings more worthy to keep on living. The world will not end when humans will die, nor did it begin when the first humans were born.
"Political comments are allowed, as long as they're in reference to science, science policy, or the blog topic. "
i am glad ya see the big picture....i plused ya on that comment...
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