Modiki El Niños and Atlantic hurricane activity
It's an El Niño year, which typically means that Atlantic hurricane activity will be reduced. But not all El Niño events are created equal when it comes to their impact on Atlantic hurricane activity. Over the past 150 years, hurricane damage has averaged $800 million/year in El Niño years and double that during La Niña years. The abnormal warming of the equatorial Eastern Pacific ocean waters in most El Niño events creates an atmospheric circulation pattern that brings strong upper-level winds over the Atlantic, creating high wind shear conditions unfavorable for hurricanes. Yet some El Niño years, like 2004, don't fit this pattern. Residents of Florida and the Gulf Coast will not soon forget the four major hurricanes that pounded them in 2004--Ivan, Frances, Jeanne, and Charley. Overall, the 15 named storms, 9 hurricanes, and 6 intense hurricanes of the hyperactive hurricane season of 2004 killed over 3000 people--mostly in Haiti, thanks to Hurricane Jeanne--and did $40 billion in damage.
A new paper published in Science last Friday attempts to explain why some El Niño years see high Atlantic hurricane activity. "Impact of Shifting Patterns of Pacific Ocean Warming on North Atlantic Tropical Cyclones", by Georgia Tech researchers Hye-Mi Kim, Peter Webster, and Judith Curry, theorizes that Atlantic hurricane activity is sensitive to exactly where in the Pacific Ocean El Niño warming occurs. If the warming occurs primarily in the Eastern Pacific, near the coast of South America, the resulting atmospheric circulation pattern creates very high wind shear over the tropical Atlantic, resulting in fewer hurricanes. This pattern, called the Eastern Pacific Warming (EPW) pattern, occurred most recently during the El Niño years of 1997, 1987, and 1982 (Figure 1). In contrast, more warming occurred in the Central Pacific during the El Niño years of 2004, 2002, 1994, and 1991. The scientists showed that these Central Pacific Warming (CPW) years had lower wind shear over the Atlantic, and thus featured higher hurricane activity than is typical for an El Niño year. One of the paper's authors, Professor Peter J. Webster, said the variant Central Pacific Warming (CPW) El Niño pattern was discovered in the 1980s by Japanese and Korean researchers, who dubbed it modiki El Niño. Modiki is the Japanese word for "similar, but different".
Figure 1. Difference of Sea Surface Temperature (SST) from average during the peak of hurricane season, August-September-October, for seven years that had El Niño events (except for 2009, when the SST anomaly for July 1 - 3 is plotted). On the left side are years when the El Niño warming primarily occurred in the Eastern Pacific (EPW years). On the right are years when the warming primarily occurred in the Central Pacific (CPW years). Shown on the top of each plot is the number of named storms (NS), hurricanes (H), and intense hurricanes (IH) that occurred in the Atlantic each year. Atlantic hurricane activity tends to be more prevalent in CPW years than EPW years. An average hurricane season has 10 named storms, 6 hurricanes, and 2 intense hurricanes. Image credit: NOAA/ESRL.
What, then, can we expect the current developing El Niño event to do to 2009 hurricane activity? Kim et al. note that in recent decades, the incidence of modiki CPW El Niño years has been increasing, relative to EPW years. However, the preliminary pattern of SST anomalies in the Pacific observed so far in July (lower left image in Figure 1) shows an EPW pattern--more warming in the Eastern Pacific than the Central Pacific. If Kim et al.'s theory holds true, this EPW pattern should lead to an Atlantic hurricane season with activity lower than the average 10 named storms, 6 hurricanes, and 2 intense hurricanes. There is still a possibility that the observed warming pattern could shift to the Central Pacific during the peak portion of hurricane season, however. We are still in the early stages of this El Niño, and it is unclear how it will evolve.
Jeff Masters
Reader Comments
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Terrible.
Good...great news.
So my belated prediction of 10-4-2 may be too high.
I would be surprised if we hit those numbers... the interesting part..if I am reading what Weather456 is saying... its not a good omen for next year.
Blog Update
WU Climate Change Webpage
thunderstorms, nothing more, nothing less
These Modiki El Niño's are also the weaker of the two and the current sub-surface anomalies and thermocline suggests that this won't be a mind blowing El Niño event. It's also noteworthy that AAM has been dipping over the last 2 weeks, likely slowing down our progression towards El Niño over the next couple of weeks.
El Niño is really interesting study, especially the way it correlates to Atlantic hurricane activity. As this new study shows, the spatial pattern of SST anomalies associated with ENSO events has an additional moderating factor on Atlantic tropical cyclone activity.
Digging a bit further, I bet there's a nice correlation between TanomMDR-TanomNINO3+Nino(1+2)/TanomNINO4.
72 on ignore now.
July 9 2005
July 7 2009
As of 5 days ago (should be updated later today)
Link
I call it the Troll List.
Are you talking to yourself? With 72 on your ignore list I doubt you see too many of us!
I can predict this though,
Tropical cyclone development is not expected in the next 24 hours. Nothing really out there of note, and it might stay that way for a few weeks.
He needs to go mow his yard...wash his car...a wound up person.
Interesting blog Dr. Master's. It's not just that there is an El Nino, it's where it's at in the Pacific ocean.
Shear rules!
These go back a few years. I've just never deleted one's from at least 2 years ago.
A google earth file, I had.
The code in the file says 20090707
The website itself is giving problems.
Charley and Frances, nice drought busters
More ice coverage than in early July during the record melt of 2007, but less coverage than in early July of 2005 (which had held the melt record prior to 2007)
from the NationalSnow&IceDataCenter's monthly Arctic sea ice news brief.
Surprisingly, progression is low in the EPAC and WPAC since we should be up to 4 named storms in the EPAC and even more in the WPAC.
Only the Atlantic seems near the long-term average.
The N Indian Ocean normally sees 4-6 named storms a year, they already have 2 and they have another peak in October/November this year.
Looks like the wave at about 20W is still together. Also, looks live some waves lined up on the African continent.
Definately interesting for the time being. I'll be keeping an eye on oit throughout the day.
Google Earth file
Link
Oss~ You may be right. I do remember '83 & '98 being dry years with really large fires. It's hard to forget years when you get a sprinkler system together for your roof.. Maybe it's more a cause of rediculous big fires than more fires. '85 which is another dry fire year behind '98. Seems like it was worse in '83 but that was probibly a stubborn swamp fire (I was pretty young). Looking at that FL site which did look at drought & fire, then compared to the enso history page the corrilation looks like the La Nina following the EPW years are the worst FL fire years..
Thanks Dr. M for the update.
This is how we felt in the Northeast for the entire month of June. :)
Have fun. We finally have sunny days up here.
you must be north of me.....we haven't got all that much. but north of me has been getting hammered all week.
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