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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Meaning what? Why does it matter?
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.
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.
Let's just say they won't and he has been hit by some bad hurricanes.
Louisiana.
I see a rodent...
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.
look at this stunning pic from Australia total eclipse...NASA
i might use it as my desktop picture
Large with a large blocking high to the north..
I think those clouds.. look like clouds.
Thanks for sharing this. I found a large version of the photo here:
Link
I see the gerbil.
Bruce’s ingenious design of covering our glass-fronted Bay-front house with upturned decks is still working. Here’s how I covered up for Hurricane Sandy. Hope I don’t need to use it often.
–Nancy Bauer, Deale
Editor’s note: Nancy’s deceased husband Bruce Bauer wrote about his ingenious design in Bay Weekly back in the last century.
I'll repost this. Note that the US is the third most populous nation.
The San Andreas Fault is a strike-slip fault. The Asian zone of the Pacific ring of fire is a subduction area, which means 1 plate is riding over another and it pushes that one down. The mega quake off Japan in March 2011 was a result of the top plate flexing/bouncing back after being pulled down by the sub-ducting plate called a mega-thrust quake. Similar to the 2004 Sumatra-Andaman earthquake which was also a mega-thrust quake. The difference is the 2004 Sumatra-Andaman earthquake ruptured a long a 1000km-1300km length of the fault. The 2011 Tohoku earthquake ruptured along about 500km's of the fault. There is still another 1500km's of the Tohoku fault to rupture both north and south of the 2011 Tohoku earthquake rupture zone. There is another dangerous area that has not gone off for a long time and is actually gone over the expected time, that's the Cascadia subduction zone, which is off the west-coast of the Pacific Northwest from northern California to Vancouver Island, British Columbia. On the east coast there is the Atlantic ridge that runs from north to south and can be clearly seen on google earth, the plates there are spreading apart.
Thr decking must be hinged at the bottom so it can be lifted up next to the house .. good idea ...
Also note many countries are white. Take in Asia and Africa for example.
South America too.
Tropical Cyclone Advisory #1
PERTURBATION TROPICALE 02-20122013
10:00 AM RET November 15 2012
========================================
At 6:00 AM UTC, Tropical Disturbance 02 (1004 hPa) located at 9.6S 71.3E has 10 minute sustained winds of 25 knots with gusts of 40 knots. The disturbance is reported as moving west southwest at 6 knots.
Dvorak Intensity: T1.5/1.5/D 0.5/6 HRS
Forecast and Intensity
=======================
24 HRS: 9.9S 68.7E - 30 knots (Depression Tropicale)
48 HRS: 10.0S 66.1E - 25 knots (Perturbation Tropicale)
72 HRS: 9.7S 62.7E - 24 knots (Perturbation Tropicale)
Additional Information
=========================
Vertical wind shear has decreased since yesterday over the disturbed weather area monitored since a few days ago. System has organized and deep convective activity keeps on persisting near the center since 1600 PM UTC. It presents now a curved band pattern (refer to 2243 PM UTC, F17 0116 AM UTC, WINDSAT 0123 AM UTC, and F18 0329 AM UTC).
OSCAT 1856 PM UTC and partial covered ASCAT 0512 AM UTC swath confirms that near gale force winds 30 knots exists in the southern semi-circle.
A weak to moderate wind shear window is expected to keep on persisting up to 1200 PM UTC before east northeasterly upper level winds strengthen back. Despite the indirect equatorward low level inflow and an only sustained poleward one, system is expected to deepen into a tropical depression stage within the next night (a more rapid intensification is however not excluded)
Current intensity of the system does not justify issuance of regular advisory
Last eve I posted a comment that was uncalled for.
It was a cheap-shot, knee-jerk reaction to one of his posts that I didn't agree with. I regret it, and I am sorry.
I read your blog, Kori. You do a good job with it and you bring alot of positives to this place.
Sincerely
Doug
FIRE WEATHER WARNING
for the Channel Country, Maranoa and Warrego and parts of the North West,
Central West and Darling Downs and Granite Belt districts.
Issued at 6:55pm EST on Thursday the 15th of November 2012
for Friday.
A trough extending across northern South Australia and northern New South Wales is moving slowly in an eastwards direction. The trough is expected to continue moving eastwards on Friday and enter southwest Queensland during the day. Hot, dry and gusty winds associated with the trough are expected to cause the following conditions on Friday:
Extreme Fire Danger in southern parts of the Channel Country and southwest parts of the Maranoa and Warrego districts, particularly during the morning and early afternoon. Temperatures up to 41 degrees, relative humidity to less than 10% and winds between 40 to 45 km/hr are expected. Locations which may be affected include Thargomindah and Cunnamulla.
Severe Fire Danger in remaining parts of the Channel Country, Maranoa and Warrego, southern parts of the Northwest, southwest parts of the Central West and southwest parts of the Darling Downs and Granite Belt districts.
Temperatures up to 43 degrees(109F), relative humidity down to 10% and winds to 35km/hr(22mph) are expected.
The next warning will be issued at 11pm AEST.
awesome dy today for me here
i don't have a conclusion was just making a simple statement.....just like we are 16 trillion in debt is a simple statement.....
________________________________
California storm
click it for bigger size
Hey wunderkid..
make sure you have it placed in the correct location is it near a fan, vent, steam???? to be really safe you should have them ran in seris with electricty with a battery backup....remember smoke detectors save lifes....
12-12-12: The Concert for Sandy Relief will also feature performances by Bruce Springsteen and the E Street Band, Roger Waters, Jon Bon Jovi, Billy Joel & more
Storm damage boosts requests for benefits by 78,000 to 439,000
Viewing: 901 - 951
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