Another interesting news item... wonder who is right

[jabber]

http://www.palmbeachpost.com/localnews/ ... _0411.html

[Javlin]

http://news.bbc.co.uk/1/hi/sci/tech/56456.stm

Then I guess Gray and these guys are out there also.They say blame the sun for some of the global warming and its solar flare cycle.Maybe Jim can opt an opinion on the sloar flare cycle.Personally I like to opt for the cycle idea to tell me we might very well have another 100 yrs and the weatherman cannot tell me if it's going to rain next week on Tuesday Pleeasee.

[Dionne]

I don't like using the doom and gloom approach. The thought of dealing with another catastrophic hurricane in this region brings on an overwhelming fear of helplessness. The next few hurricane seasons will tell the tale. If the northern GOM gets slammed again this season it will signal an abrupt end in the recovery process. It will force us to rethink long term planning. There is no reason to live like this everyday. Did y'all know that there are still people making the decision everyday......and then just up and leaving. At one time I had this grand plan to live in our Hattiesburg home and work the coast recovery. Not anymore. I'm going to stay 160 miles inland and just wait and watch. In the event another monster storm comes this way.....we intend to evacuate even further inland.

[JPmia]

One thing is for sure, this debate will continue to rage on this year and probably for many years to come until someone can come up with reliable data to prove either way concretely. Each side has their theory, and each side believes they are ABSOLUTELY correct about it.

[benny]

It certainly is an interesting theory that Emanuel has come up with. I saw his talk a few months ago and it certainly is thought-provoking. He doesn't have a really good explanation for the inactive decades of the 70s/80s/early 90s and Gray's thermohaline circulation is a better idea IMHO. However his correlations of Atlantic SSTs and global surface temperature are worthy of study. If Gray is correct the extreme warmth of the north atlantic will be tempered by warming in the Arctic which releases fresh water into the north atlantic and slows the mixing of the area (one of the only deepwater formation regions in the world) by decreasing salinity. A similar thing happened in the late 60s. There were some articles that showed a decrease in the gulf stream current so i wonder if it hasn't already begun to some extent... ?

[Javlin]

I think a good Nino could snap the setup with the ridging and jet stream we have had and maybe we might see that by next fall.

[DoctorHurricane2003]

I think it is a combination of the two, IMO. After going over decades of storms and SSTs, it seems that this active period in the ATHC is much more active than the previous active phase, probably induced by Global Warming. I do believe there will be another cool phase, though.

[Javlin]

Yea Doc but the amount of data that we have on Global warming is miniscule in the life of the planet a blink of the eye.Does that discount GW no I do not think so but for me it is not a proven fact yet.Cycles can be traced some through soil analysis,tree rings and even these only give a glimpse.

[SouthFloridawx]

I think it is a combination of the two, IMO. After going over decades of storms and SSTs, it seems that this active period in the ATHC is much more active than the previous active phase, probably induced by Global Warming. I do believe there will be another cool phase, though.

Yeah why can't people combine ideas together and say yeah I think it is partly due to the fact that the SST's are above normal and also partly because of some type of warming in the climate.

[Aslkahuna]

The only problem with trying to bring a possible connection of the Solar cycle into this discussion is that it can't be posted in this section but only in the Global Weather Forum.

Steve

[DoctorHurricane2003]

Yea Doc but the amount of data that we have on Global warming is miniscule in the life of the planet a blink of the eye.Does that discount GW no I do not think so but for me it is not a proven fact yet.Cycles can be traced some through soil analysis,tree rings and even these only give a glimpse.

That makes no sense. I've seen the data, and the global temperatures are indeed rising. What happened 30 Million years ago or what will happen 30 Million years from now does not matter at all when we are talking about effects on hurricanes today. What matters is what is happening right now when we are looking at time on a yearly or decadal level.

Also, Global Warming is as much as a cycle as anything else, it is just on a much, much larger time scale

[Javlin]

Also, Global Warming is as much as a cycle as anything else, it is just on a much, much larger time scale............That might just be the point Doc.The point I argue is it actually mankind or is it the way the system just evolves.We have had ice ages and warm episodes they have come and gone and will continue.

As a result, "it's unlikely we'll ever see a quiet decade for the next 100 years in the Atlantic," said Emanuel, a professor of tropical meteorology and climate, and author of the respected 2005 hurricane text Divine Wind. "I don't think there's any evidence of anything you would call a cycle

While I would not argue that sst's and global temps have risen some but I would maybe argue that maybe the cycle has more credence and data for support than the 20-30yrs global warming research.The fact that the author states this could continue for another 100yrs seems a stretch.I have been under the belief that for the most part that the energy expended globally in Hurricanes remains constant,has an average.That when the ACE index increases in the ATL basin then you may and most likely will see a decrease in the PAC basin.Then furthermore would not a couple of good EL Nino seasons temper the ATL basin significantly for a period of time thus breaking what he is calling a 100 yr cycle.This activity has been growing since 95 with if memory serves me right a strong and a weak El Nino back to back?(96-97 or 97-98) with a gradual increase since in activity cumulating in the last 3-4yrs.Hey I am just a layman here to learn slammy away I might be way off base in my thinking.Kevin

[gatorcane]

As much as I want to say that 2005 was an anomaly with so many records that were broken including the most CAT 5 hurricanes in any given season, you wonder if we really are moving into uncharted climatology. Since 1995, the number of storms in the Atlantic basin has been averaging about 15 and then suddenly we jump to 27 and shatter a slew of records? To say that we are in an active cycle like the 1930s and 1940s cannot be fully justified since we only have hurricane records for the past 150 years. At the same time - we cannot say that we are seeing a climatological shift as well.

Here is what NOAA Hurricane Research Division says about this topic. Notice the last line that I have bolded.

Subject: G4) Are we getting stronger and more frequent hurricanes, typhoons, and tropical cyclones in the last several years?

Contributed by Chris Landsea

Globally, no. However, for the Atlantic basin we have seen an increase in the number of strong hurricanes since 1995. As can be seen in section E9, we have had a record 33 hurricanes in the four years of 1995 to 1999 (accurate records for the Atlantic are thought to begin around 1944). The extreme impacts from Hurricanes Marilyn (1995), Opal (1995), Fran (1996), Georges (1998) and Mitch (1998) in the United States and throughout the Caribbean attest to the high amounts of Atlantic hurricane activity lately.

As discussed in the previous section, it is highly unlikely that global warming has (or will) contribute to a drastic change in the number or intensity of hurricanes. We have not observed a long-term increase in the intensity or frequency of Atlantic hurricanes. Actually, 1991-1994 marked the four quietest years on record (back to the mid-1940s) with just less than 4 hurricanes per year. Instead of seeing a long-term trend up or down, we do see a quasi-cyclic multi-decade regime that alternates between active and quiet phases for major Atlantic hurricanes on the scale of 25-40 years each (Gray 1990; Landsea 1993; Landsea et al. 1996). The quiet decades of the 1970s to the early 1990s for major Atlantic hurricanes were likely due to changes in the Atlantic Ocean sea surface temperature structure with cooler than usual waters in the North Atlantic. The reverse situation of a warm North Atlantic was present during the active late-1920s through the 1960s (Gray et al. 1997). It is quite possible that the extreme activity since 1995 marks the start of another active period that may last a total of 25-40 years. More research is needed to better understand these hurricane "cycles".

For the region near Australia (105-160E, south of the equator), Nicholls (1992) identified a downward trend in the numbers of tropical cyclones, primarily from the mid-1980s onward. However, a portion of this trend is likely artificial as the forecasters in the region no longer classify weak systems as "cyclones" if the systems do not possess the traditional tropical cyclone inner-core structure, but have the band of maximum winds well-removed from the center (Nicholls et al. 1998). These changes in methodology around the mid-1980s have been prompted by improved access to and interpretation of digital satellite data, the installation of coastal and off-shore radar, and an increased understanding of the differentiation of tropical cyclones from other type of tropical weather systems. By considering only the moderate and intense tropical cyclones, this artificial bias in the cyclone record can be overcome. Even with the removal of this bias in the weak Australian tropical cyclones that the frequency of the remaining moderate and strong tropical cyclones has been reduced substantially over the years 1969/70-1995/96. Nicholls et al. (1998) attribute the decrease in moderate cyclones to the occurrence of more frequent El Nino occurrences during the 1980s and 1990s.

For the Northwest Pacific basin, Chan and Shi (1996) found that both the frequency of typhoons and the total number of tropical storms and typhoons have been increasing since about 1980. However, the increase was preceded by a nearly identical magnitude of decrease from about 1960 to 1980. It is unknown currently what has caused these decadal-scale changes in the Northwest Pacific typhoons.

For the remaining basins based upon data from the late 1960s onwards, the Northeast Pacific has experienced a significant upward trend in tropical cyclone frequency, the North Indian a significant downward trend, and no appreciable long-term variation was observed in the Southwest Indian and Southwest Pacific (east of 160E) for the total number of tropical storm strength cyclones (from Neumann 1993). However, whether these represent longer term (> 30 years) or shorter term (on the scale of ten years) variability is completely unknown because of the lack of a long, reliable record.

[stormtruth]

Global Warming is not always a cycle. Think Venus.

[Javlin]

Global Warming is not always a cycle. Think Venus.

missed that one

[sponger]

Seems a bit bold to state that the well documented hurricane cycle does not exist. This is typical of the gw debate in that anything that could be linked to global warming is hyped and any indicator that would point away is ignored.

Does anyone believe that if we where in a quiet period he would say global warming is a farce. I am sticking with Dr Gray as he is the hurricane specialist.

[x-y-no]

Global Warming is not always a cycle. Think Venus.

Well, yeah, but we're a very long way from a ruanaway greenhouse effect. The best theoretical estimates I've seen suggest that we'd need something like another 75 Watts/m2 of forcing at the very least (probaly a fair bit more) to get to the neighborhood of the threshold of a runaway. And I've not seen a realistic worst-case AGW scenario that takes us up more than 10 Watts/m2 or so.

[benny]

This is a really complicated problem regarding the alleged increase of TC intensity due to global warming. First of all.. the hurricane records are incomplete at best before the age of continuous geostationary satellite (1966 or so). I really wonder how many tropical storms or hurricanes were missed over the open ocean. In addition.. before recon.. unless you had an unfortunate ship.. you never had a true estimate of the intensity. Really all you will ever get from a ship is central pressure anyway. Any small scale variations that you will catch today you would have missed 40-50 years ago. The probability that we would have even been able to observe a Wilma-like intensity change was very low in the 40s-60s and near zero before that. Even Zeta or Epsilon.. the chances are so remote. Even in the age of dropsondes.. now we have all these flight level winds going back 30 years or so that had inconsistent use to estimate surface winds. It is hard to believe the the Georgia Tech group (who published a paper that basically states that global warming is causing stronger hurricanes) or Emanuel really believe in this data enough to use it for the type of purposes they are suggesting. ???

[x-y-no]

benny:

As I understand it, that's the essence of Chris Landsea's argument (and he's certainly worth listening to given his deep involvement in the analysis of this old data). But it's not like Emmanuel et. al. have ignored the issue. It's more a matter of how much confidence one can put in the efforts to compensate for error and uncertainty.

My reading of the evidence so far is that there's fair support for the idea that AGW is resulting in a somewhat higher proportion of intense storms, but not much evidence that it's leading to greater frequency of storms.

[MGC]

"But Emanuel argues that the 1970's-80's lull arose from a temporary cooling in the Northern Hemisphere caused, amoung other things, by industrial pollution clouding the atmosphere."

Maybee Emanuel has found the solution for GW. Pollute the atmoshere! This is a foolish theory......MGC