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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Who paid for the new Levee around NOLA? A new seawall for NY Harbor will come from the same place.
Could you imagine relocating/rebuilding New York/ New Jersey infrastructure away from the coast? That certainly would be cost prohibitive!
I am sure there are plenty of vacancies further inland. Also there are plenty of people who can foot their own bill and build efficiently and safely so we do not repeat.
Very interesting discussion on size..
I'm in a hurry this am so will write more later as I digest the info..
Thanks again
Afternoon all..made it back..
I checked on the research by Rotunno and Emanuel (1987) Numerical simulation of tropical cyclones by an axisymmetric nonhydrostatic model and they were using mathematics to simulate the overall expansion.
Their conclusions were repetitive and so they were able to duplicate their findings.
I agree with them..I tried(in my own clumsy way) to follow along and soon it made sense that the math/time frame/RH/SST/and other factors (too much to include here) fell into place as too an expansion of the "mathematical storm" would..
Thanks again Dr. Masters for the blog info and Sandy's expansion explanation..
From the last blog:
My local forecast blog.
Have a great day everyone.
Why are you not pushing your local/state/federal govt to do something about changing from gas to something more environmentally friendly. Starting a local community interest group. You seem to know what your talking about. Instead of just talking about it here, why not kick it up a notch and get pushing. The more people that push for change, the harder it is for local/state/federal govt not to listen.
In early November 2012, a wintery nor'easter followed on the heels of Hurricane Sandy. When that second storm cleared out of the region, it left behind snow stretching from New Jersey to Massachusetts. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this natural-color view of the region on November 9, 2012.
I would say neither in my opinion, as we've seen intense systems like Sandy become massive as they head north and begin to loose tropical characteristics. Igor in 2010, to name an example. I would also say that Cuba and other landmasses Sandy interacted with may have contributed, as we've all seen systems become larger (Isaac) when they hit land and emerge off the coast.
Oh to some everything is evidence of AGW...I'm quite sure the fact that October was a cooler than normal month set them back for a bit LOL
a few weeks ago:
**As rising temperatures continue to shrink the extent of Arctic summer sea-ice, there has been much speculation as to why the ice cover on the opposite side of the planet has expanded slightly in recent years. Now British scientists have found the explanation–and it’s related to climate change.**
Link
"...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."
There you have it, in language so simple even a third-grader could understand it, no?
The more than 3.4 million tons of fossil fuel CO2 we humans pump into the environment each and every hour has consequences. At least part of Sandy's size, ferocity, or path may be one of those consequences. It's premature to state with certainty how much AGW influenced Sandy, but it's premature--and utterly illogical--to claim that it didn't affect it at all.
It seems people have already forgotten about the storm that broke up a lot of the arctic ice this summer.
Weather is not climate, now preach somewhere else.
Link
What we call "Climate" is the statistics of weather. Thus, Climate Change implies change in the weather.
NASA and British Antarctic Survey scientists have reported the first direct evidence that marked changes to Antarctic sea ice drift caused by changing winds are responsible for observed increases in Antarctic sea ice cover in the past two decades. The results help explain why, unlike the dramatic sea ice losses being reported in the Arctic, Antarctic sea ice cover has increased under the effects of climate change.
Research scientists Ron Kwok of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and Paul Holland of the Natural Environment Research Council's British Antarctic Survey, Cambridge, United Kingdom, used maps created by JPL from more than five million individual daily ice-motion measurements. The data, captured over a period of 19 years by four U.S. Defense Meteorological satellites, show, for the first time, long-term changes in sea ice drift around Antarctica.
"Until now, these changes in ice drift were only speculated upon, using computer models of Antarctic winds," said Holland, lead author of the study published this week in the journal Nature Geosciences. "This study of direct satellite observations shows the complexity of climate change. The total Antarctic sea ice cover is increasing slowly, but individual regions are actually experiencing much larger gains and losses that are almost offsetting each other overall.
"We now know that these regional changes are caused by changes in the winds, which, in turn, affect the ice cover through changes in both ice drift and air temperature," he continued. "The changes in ice drift also suggest large changes in the ocean surrounding Antarctica, which is very sensitive to the cold and salty water produced by sea ice growth."
Holland said sea ice around Antarctica is constantly being blown away from the continent by strong northward winds. "Since 1992, this ice drift has changed," he said. "In some areas, the export of ice away from Antarctica has doubled, while in others it has decreased significantly."
Sea ice plays a key role in Earth's environment, reflecting heat from the sun and providing a habitat for marine life. At both poles, sea ice cover is at its minimum during late summer. However, during the winter freeze in Antarctica, this ice cover expands to an area roughly twice the size of Europe. Ranging in thickness from less than three feet (a meter) to several meters, the ice insulates the warm ocean from the frigid atmosphere above.
This new research also helps explain why observed changes in the amount of sea ice cover are so different in the two polar regions. The Arctic has experienced dramatic ice losses in recent decades, while the overall ice extent in the Antarctic has increased slightly. However, this small Antarctic increase is actually the result of much larger regional increases and decreases, which are now shown to be caused by wind-driven changes. In places, increased northward winds have caused the sea ice cover to expand outwards from Antarctica. In contrast, the Arctic Ocean is surrounded by land, so changed winds cannot cause Arctic ice to expand in the same way.
"The Antarctic sea ice cover interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent," said Kwok.
Climate change has had contrasting impacts across Antarctica in recent decades. The Antarctic Peninsula has warmed as much as anywhere in the Southern Hemisphere, while East Antarctica has shown little change or even a small cooling around the coast. The new research improves understanding of present and future climate change. The authors note it is important to distinguish between the Antarctic Ice Sheet - glacial ice - which is losing volume, and Antarctic sea ice - frozen seawater - which is expanding.
The research was funded by NASA and the Natural Environment Research Council.
Link
In Louisiana after Huricane Isaac, there are those in Plaquemines and St John the Baptist Parishes who would argue with you about how bad Isaac was. Their homes too were totally underwater. Hundreds of thousands of acres of marsh grass in big slimy piles, filled with dead animals and living snakes. Chemical spills, Power out. But you get the picture. These people had not built near the shore and had never before been flooded. When one of these storms come along it's a news wonder for a few days and people are left to clean up for years. Let's don't forget the struggling citizens of Louisiana in our zeal to help those equally struggling citizens of the Northeast. God bless you all.
Check them out.
??? Not sure what you mean. Are you implying British scientists are forgetful?
________________________
Major Storm for Adak, AK (Adak is located very close to the big L)
click the pic for a bigger pic...
HIGH WIND WARNING FOR ADAK, ALASKA
.. HIGH WIND WARNING REMAINS IN EFFECT UNTIL MIDNIGHT AKST TONIGHT...
* WIND... SOUTHWEST WIND 50 TO 65 MPH WITH GUSTS TO 85 MPH.
* TIMING... THROUGH LATE THIS EVENING.
* IMPACTS... HIGH WINDS MAY MOVE LOOSE DEBRIS AND MAY DAMAGE PROPERTY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED OR OCCURRING. PEOPLE ARE URGED TO SECURE LOOSE OBJECTS THAT COULD BE BLOWN AROUND OR DAMAGED BY THE WIND.
http://www.osdpd.noaa.gov/data/sst/anomaly/2012/a nomw.10.22.2012.gif
Here's the same graphic after:
http://www.osdpd.noaa.gov/data/sst/anomaly/2012/a nomw.11.1.2012.gif
That warmer than normal water fed energy into the storm as it passed above. Notice too that the Gulf Stream remained very warm after Sandy's passage. The energy in the deep Gulf Stream may have added energy and moisture to the Nor'easter which passed over the area later.
I see the letters for today are G and W so I will make this brief..
HurricaneTrack.com
You have got to be kidding me? Another powerful storm possible for Northeast next week?
Actually, a reasonable hypothesis might go something like:
"Take any closed fluid system and heat unevenly and you will get more motion."
A reasonable default supposition would be that you would get more large-scale motion as well as more small and mid scale motion.
That may not, in the end be true, but it is a reasonable and testable default assumption to start with.
Anyone out there with some glitter and a flask of water, some motion detection equipment and some software that can crunch a whole bunch of curves?
Experiments in a variety of closed fluid systems and with a variety of closed fluids should reveal some general properties, one of which might be a tendency to larger-sized discrete 'fluid particles' with relatively greater energy input levels.
Link
sandy has nothing too do with climate change none of are hurricanes have that made land fall had its this the way the weather works
RT @weathernetwork: British Columbia announces new tsunami warning system: http://www.theweathernetwork.com/news/storm_watch_ stories3&stormfile=British_Columbia_rolls_out_new_ tsunami_alert_process_12_11_2012
Nor'easters on the way they start freaking out.Nor'easters are nothing new in this part of the country and people shouldn't pretend they are just because of Sandy.When we lost power up here after the derecho we were in sweltering heat and humidity and some people were without power for three weeks to a month so I can't really say I feel for those people that are in the cold.I see GW is the topic of the day.So I'm going to stay far far away.No point in blogging on a subject your not in to.Good day.
Global climate disruption messes with our water. As sea levels rise, we get more water in the places we don’t want it. But what about the water we do need? Scientists are finding that the impacts of climate change make freshwater inhospitable for fish and wildlife.
It starts with dirty energy — the fossil fuels that pollute the atmosphere. Dirty energy leads to dirty weather — more frequent and more extreme floods, storms and droughts. As storms become more intense and frequent, sewers overflow — washing sediment, pollutants and nutrients into our rivers and lakes. Rising sea levels can contaminate nearby freshwater with salt.
Now, scientists at Yale have found that hurricanes and other large rainfall events may alter the water quality of rivers and lakes by transporting large amounts of dissolved organic matter (carbon and nitrogen) downstream. In moderate amounts, dissolved organic matter provides important nutrients for the base of the food chain. But in excess, this organic matter can block pathogen-killing UV light, transport metal pollutants, and potentially lead to the formation of carcinogens.
In another recent study, scientists found that warming temperatures, thawing permafrost, and lower water tables are the underlying cause for increased concentrations of heavy metals in the Snake River watershed in Colorado. The metals, which can drain out of abandoned mines or through oxidation of sulfide minerals in rocks, are recognized as one of the biggest threats to water quality in the western United States. If the levels reach toxicity thresholds, the waters may become uninhabitable to fish and toxic to humans.
Toxic metals are bad news for our water. So that’s why we need to move away from dirty energy and stop the dirty weather in the first place. Be sure to tune in on November 14 for 24 Hours of Reality: The Dirty Weather Report and join with millions of others across the world to learn more about how climate change is connected to extreme weather and what we can do about it.
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