Northern Indian Ocean Hurricanes

I’m looking at some of the details of the Webster, Curry et al 2005 claim that the proportion of intense hurricanes has increased. While I was doing so, I noticed an interesting issue in the Northern Indian Ocean tropical storm counts. Here is an excerpt from Webster et al 2005 Figure showing the count of cyclonic storms per year. The brown curve is the North Indian Ocean.

Webster et al 2005 Figure 3. Number of Cyclonic Storms/Year. Brown is North Indian Ocean.

I’ve collated storm track data and here is what I obtained when I tried to replicate the count for the Indian Ocean. Note that the period covered in the graphs are different. The solid line is the count according to the archive of storm tracks. However in this area, most storms do not have any wind speed estimates. For example, the 1970 Bhola Cyclone killed over 300,000 people in Bangladesh, but has not wind estimates in the archive is not counted as a storm in the Webster et al graph. The red dashed line shows the number of storms with wind speeds exceeding 18 msec-1 (and this is virtually identical to the number of storms with any data). If you look closely, the corresponding counts in Webster et al differ in detail for unknown reasons.

North Indian Ocean – Number of Tropical Storms. Collated from information at

A couple of questions obviously arise – which may or may not be easy to resolve. There’s a sharp decrease in the number of tropical storms whose storm tracks are archived in 1976 – with seemingly different average levels before and after 1976. Is this due to a measurement artefact or to some climatic change? I have no idea. There is no discussion of the issue by Webster et al. It’s too bad that climate scientists reporting on hurricane counts in Nature and Science are not obligated to provide such accounting details.

Webster et al observed of the Pacific data:

The need for reprocessing the western North Pacific tropical cyclone data set is very clear.

This would also seem to be true of the North Indian Ocean data.

It’s also worth noting that North Indian Ocean SSTs were supposedly rising particularly quickly according to Hansen’s PNAS article, discussed here recently, but the number of tropical storms in the North Indian Ocean has not increased according to any metric.


  1. Pat Frank
    Posted Oct 21, 2006 at 7:02 PM | Permalink

    1976 is also when the PDO under went its sharp phase change into a warm bidecadal cycle. What happened to tropical cyclones there? I don’t have time to look just now, but maybe the stroms of the north Indian Ocean is tracking the same phases as the Pacific

  2. TCO
    Posted Oct 21, 2006 at 10:18 PM | Permalink

    Steve, this issue is very hard to understand without better figure captions and step by step explanation of the graphics. I know you think you are giving it, but it’s not good enough. We can’t read minds. This is not a new kvetch.

  3. Steve McIntyre
    Posted Oct 21, 2006 at 10:29 PM | Permalink

    Webster,Curry et al count 0 tropical storms in 1970-71, while the track data shows about 15 tropical storms – it has information on storm tracks but not estimated wind speeds. So when you compare totals from the 1970s and early 2000s, this needs to be reconciled. You can’t just use 0 tropical storms from the N Indian Ocean as Webster, Curry illustrate in their Figure.

    I think that the seeming decline in N Indian tropical storms while SST is supposedly increasing speaks for itself. Why is this not being discussed by the hurricane authors? Maybe there’s some kind og nonhomogeneity but what is it?

  4. TCO
    Posted Oct 21, 2006 at 10:42 PM | Permalink

    Thanks, Steve. Is it possible (from recent data) to have a year or two with no hurricanes? I guess there is some chance that the tracks could be sub-hurricane speed, no? How likely/unlikely is this?

  5. Steve McIntyre
    Posted Oct 21, 2006 at 10:59 PM | Permalink

    #read the frigging post. The 1970 Bangladesh cyclone killed over 300,000 people. That didn’t happen at sub-hurricane speed.

  6. David Smith
    Posted Oct 21, 2006 at 11:01 PM | Permalink

    I looked at the Unisys database for category 4 and 5 hurricanes (“severe hurricanes”) in the northern Indian Ocean region. Severe hurricanes are the ones used in Webster et al’s key graph (Figure 4).

    I counted seven storms, 1990-2003, listed as severe (4 or 5) in the database. That matches the tally shown by Webster.

    The head-scratcher, though, is that the listed peak windspeeds for five of the seven storms do not match the Saffir-Simpson definition of cat 4 and 5.

    Here are the numbers. To be considered as a cat 4, a storm must have peak winds of 135mph or higher. Here are the peak winds for the seven storms used by Webster:
    125 mph
    As can be seen, only two of the seven Indian Ocean storms meet the Saffir-Simpson cat 4 definition. Yet Webster reports seven such severe storms.

    Perhaps the listed peak windspeed is in error. Or, perhaps 2004, which is missing from my data but included in Webster, had 5 severe hurricanes.

    More likely, perhaps the definition of cat 4 and 5 are different in that part of the world. I believe that the Australians use a different scale for hurricanes than the Saffir-Simpson scale, yet all use the names cat 4, cat 5, etc. Confusing.

    It does make me wonder if Webster inadvertently used a mix of defintions for cat 4 and 5, and their Figure 4 is apples and oranges. Since the Australians do the storm tracking near their coast, there may be a similar problem in the Southern Ocean.

    Maybe Judith can clear this up for us.

    Also on Indian Ocean storms, I looked at an old (1964) book on hurricanes, which shows a historical frequency of 7 or 8 tropical storm/hurricanes per year in the northern Indian Ocean region.

  7. David Smith
    Posted Oct 21, 2006 at 11:11 PM | Permalink

    This is a bit outside the thrust of Climate Audit, but I’ll mention it anyway. The thing that bothers me the most about all of the talk about increases in severe hurricanes is that I have not seen a clear discussion of the physical model wherein a 0.5C increase in SST leads to a large increase in severe hurricanes.

    The only model I’ve seen are Emanuel’s potential intensity equations, which I agree with and which, if taken on face value, lead to only small increase in windspeed. Where is the physical explanation of how a 0.5C increase in SST leads to doubling of PDI or large increases in cat 4 and 5 storms? Whatever that model is, it needs to explain other findings like no increase in seasonal peak winds, no increase in hurricane count, no increase in tropical storm count, etc.

  8. Steve McIntyre
    Posted Oct 21, 2006 at 11:22 PM | Permalink

    I’m very suspicious about the supposed change in distribution which I’m planning to post on. Hurricanes are an extreme event and you’re already in tails of distributions. In any sort of plausible distribution e.g. negative exponential with wind speed or something like that, it’s hard to cause changes in proportions between the intervals. In fact, a change in distribution of the type supposedly observed by Webster Curry et al in – which commences in the W Pac in 1987 – is much more plausible as a change in methodology, which we already know occurred in the exact year that the distributions seem to change. I’ll post up some graphics tomorrow or the next day.

  9. TCO
    Posted Oct 22, 2006 at 12:26 AM | Permalink

    Here is the wiki entry on the Bhola cyclone. At a (speculated, not measured) wind speed of 120 mph, it would easily by a hurricane. It would not be cat 4 level though. Within the context of the post, it is not clear if Webster (and you) are concerned with tropical storms, hurricanes, cat 4 and above…or what.

  10. Eduardo Zorita
    Posted Oct 22, 2006 at 5:41 AM | Permalink


    Those living in Hamburg, Germany, will have the chance to learn something on this topic next Wednesday. L. Bengtsson is former director at the Max-Planck- Institute of Meteorology

    The abstract of a recent paper by him and others in Journal of Climate reads:

    Storm Tracks and Climate Change

    Lennart Bengtsson and Kevin I. Hodges
    Environmental System Science Centre, University of Reading, Reading, United Kingdom

    Erich Roeckner
    Max Planck Institute for Meteorology, Hamburg, Germany


    Extratropical and tropical transient storm tracks are investigated from the perspective of feature tracking in the ECHAM5 coupled climate model for the current and a future climate scenario. The atmosphere-only part of the model, forced by observed boundary conditions, produces results that agree well with analyses from the 40-yr ECMWF Re-Analysis (ERA-40), including the distribution of storms as a function of maximum intensity. This provides the authors with confidence in the use of the model for the climate change experiments. The statistical distribution of storm intensities is virtually preserved under climate change using the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario until the end of this century. There are no indications in this study of more intense storms in the future climate, either in the Tropics or extratropics, but rather a minor reduction in the number of weaker storms. However, significant changes occur on a regional basis in the location and intensity of storm tracks. There is a clear poleward shift in the Southern Hemisphere with consequences of reduced precipitation for several areas, including southern Australia. Changes in the Northern Hemisphere are less distinct, but there are also indications of a poleward shift, a weakening of the Mediterranean storm track, and a strengthening of the storm track north of the British Isles. The tropical storm tracks undergo considerable changes including a weakening in the Atlantic sector and a strengthening and equatorward shift in the eastern Pacific. It is suggested that some of the changes, in particular the tropical ones, are due to an SST warming maximum in the eastern Pacific. The shift in the extratropical storm tracks is shown to be associated with changes in the zonal SST gradient in particular for the Southern Hemisphere.

  11. David Smith
    Posted Oct 22, 2006 at 7:10 AM | Permalink

    A note on the Bhola cyclone: the winds mentioned are a low-end estimate and are likely based on landfall observations. “At landfall” is important, because the majority of strong storms weaken somewhat as they approach land.

    Three former category 5 storms (Ivan, Katrina and Rita) hit the US in 2004 and 2005. By the time they touched land, their reported winds were category 3, at most.

    However, their associated storm surge remained at severe levels, because of the size of the wind field and that fact that it takes time for water to unpile. So, I wonder if a similar thing happened in Bangladesh, where a severe storm still had the storm surge of a category 4/5 storm even though the winds had dropped to lower levels.

  12. Steve McIntyre
    Posted Oct 22, 2006 at 7:16 AM | Permalink

    #9. Cat 4 hurricanes start at 110 knots; hurricanes at 65 knots. So the ballpark Bhola estimate (120 mph – conversion 1.15 to knots) is at the cusp of Cat 4. The Northern Indian OCean may not “matter” for the claim of increasing proportion of Cat4/5 but they’ve also provided an illustration purporting to show a count of cyclonic storms which appears to have a significant error/inhomogeneity.

  13. Steve McIntyre
    Posted Oct 22, 2006 at 7:37 AM | Permalink

    #6. where did you get the number of 135 mph for Cat 4? Webster et al use following:

    Hurricanes in categories 1 to 5, according to the Saffir-Simpson scale (23), are defined as storms with wind speeds of 33 to 43 m s-1, 43 to 50 m s-1, 50 to 56 m s-1, 56 to 67 m s-1, and above 67 m s-1, respectively.

    Conversion to knots by dividing by 0.513. Thus 110 knots for Cat 4 hurricane. I’m pretty sure that Unisys reports in knots rather than mph.

  14. David Smith
    Posted Oct 22, 2006 at 7:46 AM | Permalink

    RE #13 Aha! You are correct, the windspeeds shown are in knots, not MPH. I assumed, and that is deadly. My mistake. That’s another watch-out I need to remember, when flipping from one Unisys database to another.

  15. David Smith
    Posted Oct 22, 2006 at 8:01 AM | Permalink

    In looking at the databases, all the Unisys databases on the Unisys site are in knots. Jeff Masters’ site converts those to mph, I assume for convenience for us backwards Yankees.

  16. Jeff Weffer
    Posted Oct 22, 2006 at 8:14 AM | Permalink

    Every time someone looks into these hurricane studies, we find there is a “problem” with the data and the authors were playing fast and loose with that problem data.

    Every time someone looks into the base data, we are left scratching our heads asking the question, “how did they come up with those conclusions and those graphs?” The base data shows the opposite to be true or some other conclusion should have been reached.

    We are now in a world where everyone believes the number of tropical storms is increasing and the number of severe hurricanes is increasing. As usual, the climate change community is perfectly happy to continue pushing that myth and, as usual, the climate research community is perfectly happy to keep playing fast and loose to perpetuate the myth.

  17. Posted Oct 22, 2006 at 9:05 AM | Permalink

    Dear Steve,

    very interesting. The first question is terminological: shouldn’t the word “hurricane” be used for the Atlantic ocean only? Note that the (large) cyclones are “typhoons” in the Pacific ocean, and having no special name for the Indian ocean indicates that it could be the most poorly understood basin.

    Did you get your bizarre plumetting step function graph purely from the UNISYS data by a uniform rule which storms you count and which you don’t?

    If the huge decrease is confirmed, I guess that the official explanation will be that a nasty (Republican) Gerald Ford was replaced by a nice (Democrat) Jimmy Carter in the 1976 elections. 😉

    Best wishes

  18. HFL
    Posted Oct 22, 2006 at 9:13 AM | Permalink

    Wind and damage characteristics of the five Saffir-Simpson Hurricane Scale categories are provided by the National Hurricane Center at

  19. TCO
    Posted Oct 22, 2006 at 11:16 AM | Permalink

    So is it cat 4/5 that you are checking on, Steve? Or number of hurricanes overall? Really ought to be more precicely explicit.

    If cat 4/5: Sure the 120mph may have been a low estimate. May not. But the only story I’ve found uses that number. Until you find a story showing a higher number, it is reasonable not to count it as cat 4. And it is possible for plenty of people to die from a cat 3. So death count does not make it a cat 4.

  20. Steve McIntyre
    Posted Oct 22, 2006 at 11:50 AM | Permalink

    I’m not checking on cat 4/5 specifically; I’m looking at the data and following my nose.

  21. Roger Pielke, Jr.
    Posted Oct 22, 2006 at 11:52 AM | Permalink

    Background reports here might be of interest, particularly Knutson’s:

    A bit of background is provided here in a post on a somewhat different topic:

  22. Steve McIntyre
    Posted Oct 22, 2006 at 11:57 AM | Permalink

    IF anyone wants to spot check the number of storms, here are two different sites which seem to have the same dataL:
    with Curry’s version at:

    You can manually count the number of 1970 storms in any of the data sets. I’ve done it with a little ad-hoc program but verified it manually.

  23. TCO
    Posted Oct 22, 2006 at 12:06 PM | Permalink

    I looked at the paper itself. It refers to “hurricanes”, not cat 4/5. So certainly missing Bhola seems to be a mistake in the graph.

    P.s. (Ignore if you have seen this) There is a reply by Curry, Webster et al to the Gray comment on the GATECH website.

  24. Steve McIntyre
    Posted Oct 22, 2006 at 12:16 PM | Permalink

    Gray comment is also at GA Tech website:

  25. bender
    Posted Oct 22, 2006 at 12:22 PM | Permalink

    Re #23
    Their point #6 in that reply to Gray is a good one:

    The logical fallacy of “statistical special pleading” occurs when the interpretation of the relevant statistic is “massaged” by looking for ways to reclassify or requantify data from one portion of results, but not applying the same scrutiny to other categories.

    Hmmm … sounds familiar. Thank her, TCO, for putting a name to that kind of error.

    At least Gray doesn’t use questionable statistical methods (relying on binning & pinning effects) to come to his conclusions. If he did, he would be accused of intentionally distorting the record. But, of course, we’re not allowed to to say that about the other side. If we do, the AAGW orthodoxy marginalizes us as guilty by association with the “stooges”.

    Team AAGW, of course, has no stooges.

  26. bender
    Posted Oct 22, 2006 at 12:29 PM | Permalink

    I think TCx is being tendentious and should publish more since it’s so sure of its facts on AAGW.

  27. TCO
    Posted Oct 22, 2006 at 12:31 PM | Permalink

    Endnote 5 of their reply addresses problems with the Indian Ocean record (although they have not corrected their paper itself). I can not see where the endnote reference is within the reply itself, which is annoying.

  28. TCO
    Posted Oct 22, 2006 at 12:33 PM | Permalink

    Huh? WHat is TCx? AAGW? And what makes it seem tendentious to you?

  29. David Smith
    Posted Oct 22, 2006 at 12:38 PM | Permalink

    Here is a Wikipedia page on the different storm classifications used by the various agencies around the world.

    Of interest is that the US uses a one-minute wind speed whereas most other agencies use a ten-minute average wind speed. China uses a two-minute average. Australia uses the speed of wind gusts. These differences can be significant, but I presume that the Joint Typhoon Center irons out the differences.

  30. bender
    Posted Oct 22, 2006 at 1:12 PM | Permalink

    Re #28

    AAGW = Alarmist Anthropogenic Global Warming

    Since we all (more-or-less) recognize that A in AGW in non-zero, I think it is important to distinguish alarmists (A very much gt 0) from those who argue on the basis of science alone (A gt 0). Demarcating between AAGwers and mere AGWers will make it easier to identify the stooges on the other side of the debate.

    One way to recognize AAGW stooges is by twisted statistical analyses that consistently bias the evidence in favor of the AGW hypothesis. e.g. If there are 2^n arbitrary “flavor” choices to be made in any analysis, and all n choices favor their hypothesis, then you’re on pretty safe statistical ground lumping them in amongst the AAGW stooges. If n/2 go one way, and n/2 the other, then you can’t be sure. This is a nice parametric method for measuring “tendentiousness”.

    Just trying to level the playing field here. I mean, if we think we can distinguish between AGW skeptics and their “stooges”, then why not between AGWers and their AAGW “stooges”?

  31. bender
    Posted Oct 22, 2006 at 1:15 PM | Permalink

    TCx is a hypothetical collection of “stooges” working for an AAGW “FUDtank”, where x=an element from the set of all AAGW stooges.

  32. Steve McIntyre
    Posted Oct 22, 2006 at 1:22 PM | Permalink

    #27. Footnote 5 mentions the issue but does not “address” it. You need to cross-check the Reply against Gray’s actual Comment – parsing what Gray actually said versus how it was characterized. This is long post all by itself.

  33. Bob K
    Posted Oct 22, 2006 at 2:11 PM | Permalink


    I wrote up a parser in VB6. Figured I’d do it for drill and make myself somewhat useful around here.:-) I’ve been mostly lurking since you started this site. I’ve noticed a couple incorrectly formated storms in tracks.bsh and one probable typo in My parser errored out on this one due to the last date not being consecutive. You may want to check them out.
    I’ll get to them all over the next couple days and let you know if I find any more problems.

    They sure seem to have a lot of pertinent missing values in these files.

    Questionable last date from

    19505 10/30/1990 M= 6 3 SNBR= 541 NOT NAMED XING=0 SSS=9
    19510 10/30* 0 0 0 0* 0 0 0 0* 0 0 0 0*0752677 20 0*
    19515 10/31*0832687 25 0*0962695 25 0*1102703 25 0*1252711 25 0*
    19520 11/01*1412719 25 0*1502725 25 0*1572731 25 0*1612736 30 0*
    19525 11/02*1642743 30 0*1662749 30 0*1682754 30 0*1712757 30 0*
    19530 11/03*1752760 30 0*1792761 30 0*1852758 25 0*1902753 20 0*
    19535 11/14*1952748 20 0* 0 0 0 0* 0 0 0 0* 0 0 0 0*
    19540 TD

    Appears mis-formated in their database from tracks.bsh

    61600 02/25/1990 M=10 17 SNBR=1317 NOT NAMED XING=0 SSS=9
    61605 02/25*1082348 15 0*61610 02/25*1192364 15 0*1102352 15 0*1132356 15 0*1162360 15 0*
    1222368 15 0*1252372 15 0*1282376 20 0*
    61615 02/27*1322380 20 0*1362383 20 0*1682397 20 0*1682397 20 0*
    61620 02/28*1682398 25 0*1692399 25 0*1692400 30 0*1712403 30 0*
    61625 03/01*1712403 30 0*1762411 30 0*1802422 30 0*1802437 30 0*
    61630 03/02*1772451 30 0*1762462 35 0*1782468 35 0*1822472 40 0*
    61635 03/03*1872475 45 0*1932479 50 0*1992484 55 0*2062489 60 0*
    61640 03/04*2122494 65 0*2192498 65 0*2282504 70 0*2392510 70 0*
    61645 03/05*2532513 65 0*2712512 55 0*2962501 45 0*3212477 40 0*
    61650 03/06*3422443 40 0* 0 0 0 0* 0 0 0 0* 0 0 0 0*
    61655 CY

    76180 12/21/1998 M= 4 8 SNBR=1575 NOT NAMED XING=0 SSS=9
    76185 12/21*2041501 25 0*2071506 25 0*2121513 30 0*
    76190 12/22*2211518 35 0*2331516 35 0*2461510 35 0*2581501 40 0*
    76195 12/23*2771483 45 0*2991467 45 0*3331435 50 0*3681397 35 0*
    76200 12/24*3991340 30 0* 0 0 0 0* 0 0 0 0* 0 0 0 0*
    76205 TS

  34. welikerocks
    Posted Oct 22, 2006 at 3:12 PM | Permalink

    Bender, This is from Mr. We Like Rocks. As a Geologist, and lurker on this and other sites, as well as doing my own research into the subject matter, I still haven’t seen one single paper that yet leads me to believe that Late Holocene warming trends are nothing other than natural. This includes the last 150 years or so, plus or minus a few.

    Does that make me some kind of radicle denialist, sort of like your AAGW label? Just wondering.

  35. KevinUK
    Posted Oct 22, 2006 at 4:27 PM | Permalink

    #33, Bob

    Don’t you just love how how well verified (and of course subsequently validated) all this data is that is used to prove the existence of man-made global warming? As Steve and Ross have pointed out we are expected to believe that climatologist are ‘real’ scientist who pay a great deal of attention to the data (which of course on most occasions we aren’t allowed to see and independently check) and subsequently show that their predictions of past climate change agree with this verified (and subsequently validated data because the climate model reproduce past climate change provided of course they have lots of degrees of freedom so that they can tweak the parameters so it does) data and so are in a position to claim that their future predictions o f climat echange of the next 100 year save validity. NOT! NOT! NOT!


  36. Cliff Huston
    Posted Oct 22, 2006 at 4:42 PM | Permalink

    That, of course, would be AGWRD. 😉

  37. bender
    Posted Oct 22, 2006 at 4:50 PM | Permalink

    Re #34
    I can’t judge if you’re a “radical denialist” because I haven’t seen all your counter-arguments. If you’ve read the whole literature and can’t find any points of agreement with, say, RC, then I’d certainly be interested in seeing your refutations published. Until then I’ll just have to reserve judgement.

    P.S. If I were to call you a “denialist”, or even a “radical denialist”, I doubt it would perturb you much.

    P.P.S Don’t deny the existence of radicles. I’ve seen them with my own eyes.

  38. KevinUK
    Posted Oct 22, 2006 at 5:07 PM | Permalink

    #36 and #37

    Hey guys lay off rocks and Mr rocks. Come on we all suffer from typos. Some of us (believe it or not) aren’t obsessed with proof reading what we type before we actually click that submit button. It would be nice if we had a second chance to to correct what we have posted but come on this is a s**t piece of blog software that doesn’t allow us to correct what we have posted. Oh and by the way this is a POST on a blog and not a comment on a post on a blog.


  39. bender
    Posted Oct 22, 2006 at 5:34 PM | Permalink

    Re #38
    1. Ref. to “radicle” was a joke. It wasn’t just any typo (of which I make plenty myself); it was a funny one.
    2. I don’t see where I’ve insulted the Rocks.
    3. I don’t see where #36 insults the Rocks either. I think he was poking fun at my running rampant with abbreviations, as in AAGW.
    4. Mr Rocks, being widely read, is perfectly capable of defending himself.
    5. For the record, I like rocks too.

    Further, on denialism: it is a far worse crime for a specialist to twist data to force an outcome than it is for an outsider to reject the specialist literature as mystical, uninterpretible, unintelligible, etc. I don’t see the point in having a “radical” category of denialist, as all denialists (and, according to the consensus-makers, there aren’t that many) are already on the fringe. Whereas there are so many AGWers within the consensus that I find it useful to demarcate between the AGWers, the AAGWers, and the AAGWer stooges.

  40. Ken Fritsch
    Posted Oct 22, 2006 at 5:48 PM | Permalink

    Re #23

    In your link, TCO, WHCC spend time taking Gray to task but do not attempt to explain their own evidence presented in Table 1 with binned category 3,4 and 5 hurricane values for numbers and days at those categories for the time periods 1975-84, 1985-94 and 1995-04:

    Table 1 shows steep increases in values from the first period (1975-84) to the second and then essentially level for the last two periods. Do they follow the SST trends? No (my answer not theirs). In light of not following SST, are there other possible explanations for this increase and its leveling off. Not that WHCC can see.

    Steve M, audit on.

  41. welikerocks
    Posted Oct 22, 2006 at 6:01 PM | Permalink

    Thanks KevinUK but I already got on Mr.We Like Rocks’ case about spelling that wrong. LOL
    Hey having bender come down on you is sometimes a good thing.

    Bender, husband will comment further after dinner here (he’s cooking yay) or later, or at some point. Maybe in the Road Map then? mrs.welikerocks

  42. Loki on the run
    Posted Oct 22, 2006 at 7:33 PM | Permalink

    Millennial-Scale Linkages Between High- and Low-Latitude Climate During the Holocene Warm Period has pretty graphs showing higher temps during the MWP in a number of places …

    Seems relevant to something or other.

  43. Bob K
    Posted Oct 22, 2006 at 7:58 PM | Permalink

    You can scratch my post with the storm data errors in it. I went back and downloaded the file again. Must have dropped a byte or two in my previous download. The only error that remained was the typo in one of the observation dates. I still flagged that as an error due to the last reading being 11 days after the storm disintegrated. I made a command decision and changed the date to fit.:-)

    Actually, I now have all the basins done and there are no more hiccups to be found. I only collated the ones that actually had a windspeed reading. 1000’s of the older records didn’t have the windspeed.

  44. David Smith
    Posted Oct 22, 2006 at 9:58 PM | Permalink

    Worth a glance is this 2002 report on some of the problems in the Pacific and Indian Ocean storm archives. Missing storms, double-counted storms, all sorts of woes. Even in the rather well-monitored Western Pacific the authors say they “suspect that TIROS (first weather satellite) imagery made available in 1960 allowed a higher detection rate of tropical cyclones (in the Western Pacific)”.

    Speaking of historical data, the Unisys database shows a total of 429 tropical cyclones (depression strength and higher) in the Southern Hemisphere from 1975-1989. Of those, 112 cyclones (26%) had no intensity data given at all. (I spot-checked 15 Unisys storms against the JTWC database and confirmed that the JTWC also had no intensity data reported on those storms, so I assume that Unisys is correct about all of these storms.)

    We don’t know if the unestimated Southern Hemisphere storms were tropical storms or category 5 hurricanes or in between. We just don’t know. So, I’m perplexed as to how Webster can compare 1975-1989 storm data with 1990-2004 in a meaningful way, when 26% of the cyclones in 1975-1989 have no intensity data given at all.

    It may be explained in the footnotes, but I have missed it.

  45. Steve McIntyre
    Posted Oct 22, 2006 at 10:02 PM | Permalink

    #44. I noticed the same problem with SH data and wondered if the N Indian Ocean was replicated. The SH data set used by Webster and Curry – see comment at differs from the version at unisys; it is attributed to C Neumann – it has many more wind speed measurements.

  46. David Smith
    Posted Oct 22, 2006 at 10:38 PM | Permalink

    C Neumann is with the NCDC in the US and, per various articles on the internet, he’s done various reanalyses of tropical cyclones.

    The only reference to his reanalysis of the Southern Hemisphere storms is a statement from the Australian meteorology agency that there is considerable disagreement between Neumann and the JTWC on Southern cyclones prior to the early 1980s.

    In looking for info, I stumbled across this link to a 1998 paper by all sorts of familiar people. Names like Emanuel, Gray, Holland, Landsea and Webster all on one document as co-authors. I assume that, at the time, they held opinions consistent with the content of the paper. Times have changed, I guess.

  47. David Smith
    Posted Oct 23, 2006 at 6:43 AM | Permalink

    I see a note here that 10-minute average windspeeds are about 13% lower than 1-minute windspeeds. Atlantic windspeeds are one-minute averages while some parts of the Pacific are 10-minute averages and some are one-minute averages. I hope that the TCWC converted all the Pacific historical data to 10-minute averages.

  48. David Smith
    Posted Oct 23, 2006 at 8:11 AM | Permalink

    I’ve searched without success for an explanation of the methodology Neumann used to estimate Southern Hemisphere windspeeds for the 1970s storms.

    I did see a note that the JTWC uses one-minute windspeed averages, consistent with the Atlantic windspeeds.

    Also, here is the Australian report that notes considerable disagreement between Neumann and JWTC in historical dat prior to 1992.

    Below, by 5-year buckets, are the percent of Southern Hemisphere tropical cyclones which were of hurricane intensity. This is JTWC data:

    1975-1979: 22%
    1980-1984: 43
    1985-1989: 48
    1990-1994: 46
    1995-1999: 50
    2000-2003 prorated: 53

    Globally, the figure is 55-65% and that figure has remained more-or-less constant over the last 35 years, per Webster.

    To me, this suggests that Southern Hemisphere storm intensities were underestimated into the early 1980s. If someone has offered an alternate, physical explanation for the low hurricane percentages in the early years, I have not seen it.

  49. Pat Frank
    Posted Oct 23, 2006 at 9:09 AM | Permalink

    #31 — Re: “x=an element from the set of all AAGW stooges.” We’re getting positively Russellian here. Let’s see, if ‘x’ is an element from the set of all AAGW stooges, then is the set of AAGW stooges also an AAGW stooge? If not, does the mathematics of alarmist climate warming survive? Time for you to write ‘Tractatus Mathematicus Climatologicus,’ Bender. Only you can do it. It’ll revolutionize the field. 🙂

  50. Steve Sadlov
    Posted Oct 23, 2006 at 9:36 AM | Permalink

    RE: #3 – Due to the immensity of the Eurasian land mass, along with the peculiarity of having a “wall” to low level moisture in the form of the Himalayan and other significant East West trending ranges, the mechanisms of the Monsoon are unlike any other Monsoon elsewhere. To what extent does the Monsoon interact with tropical cyclones? That may be a factor. Also, early onset of the “reverse Monsoon” (in point of fact, just the assertion of the Trades) during the tail end of the Northern Hemisphere tropical cyclone season, brings very dry northeasterly winds from Thailand clear across to Africa – they are dry both due to being winds off of some very dry country as well as due to the downslope compression from the mountains.

  51. Steve Sadlov
    Posted Oct 23, 2006 at 9:39 AM | Permalink

    RE: #10 – a weakening of the Mediterranean storm track

    I think that is a fairly outrageous claim. If anything, the “normal” summer drought has lessened especially over the past 5 years.

  52. fFreddy
    Posted Oct 23, 2006 at 9:46 AM | Permalink

    Re #49, Pat Frank

    is the set of AAGW stooges also an AAGW stooge?

    Yes. Excess group-think dissolves all individuality, leaving a single, soggy homogeneous mass.

  53. Ken Fritsch
    Posted Oct 23, 2006 at 10:14 AM | Permalink

    Re: #48

    To me, this suggests that Southern Hemisphere storm intensities were underestimated into the early 1980s. If someone has offered an alternate, physical explanation for the low hurricane percentages in the early years, I have not seen it.

    I would like a go at an explanation from a viewpoint newly acquired in my attempts to shake off the effects of spending time in the clutches of the anti-AGW stoogedom.

    We need to first look at the period of storms that fails to follow the “proven” or at least consensusly agreed upon relationship between SST and tropical cyclone intensities. Can we explain the observation with some of the non-SST related cyles that we know are in the data and can be superimposed onto the the known TC trend with SST? If the answer is no, then I would strongly guess that on reanalysis of the SST data in that region we will find that that SSTs were relatively low for the period 1975-1979 and then went up dramatically in the following 1980-1984 period followed by a lesser increase into the period 1985-2006 with a flat line SST over the past 15 to 20 years.

    Alternatively, we can reanalyze the reanalyzed TC data and find the known TC versus SST relationship.

  54. David Smith
    Posted Oct 23, 2006 at 3:26 PM | Permalink

    Re #53 Ken, I am always glad to help a friend in his recovery.

    Below are some numbers. Pardon me giving you a string of numbers, but I lack the skill to submit a chart to CA. Just plug them into Excel, see what they look like and whether they correlate.

    The first string is the percent of Southern Hemisphere cyclones which reach hurricane intensity, from 1955 to 2002 inclusive. This is from the Unisys database, which should match the JTWC database:


    This second string is the SST for the region (5S to 15S; 50E to 180E), 1955 thru 2002. The numbers are given in degrees C above 28C (so that I don’t have to type a bunch of 28s):

    -0.03, .092, .283, .615, .512, .419, .283, .28, .267, .416, .826, .071, .01, -0.02, .423, .573, .029, 0, .624, -0.036, .115, -.166, .318, .353, .365, .55, .324, .402, .808, .51, .408, .438, .513, .726, .443, .592, .604, .533, .26, .448, .604, .657, .548, .941, .642, .56, .694, .906

    If you spot a correlation, please post. If they don’t correlate, please double-smooth.

    Seriously, there may be something interesting in the 1970s, but I’ll wait until you’ve had a chance to look at the plots before commenting on that.

  55. Steve McIntyre
    Posted Oct 23, 2006 at 4:28 PM | Permalink

    There are some annoying errors in the BEst TRacks data set – one wonders how these get into the data. For example:
    [1] “Date: 09 MAR-14 JAN 2005”
    [2] “Cyclone WILLY”
    [4] ” 1 -13.70 118.10 03/09/18Z 35 – TROPICAL STORM”
    [5] ” 1A -13.70 118.10 03/09/18Z 35 – TROPICAL STORM”
    [6] ” 2 -14.40 115.70 03/10/06Z 55 – TROPICAL STORM”
    [7] ” 3 -15.40 114.50 03/10/18Z 65 – CYCLONE-1″
    [8] ” 4 -16.50 112.60 03/11/06Z 90 – CYCLONE-2″
    [9] ” 5 -17.40 112.10 03/11/12Z 90 – CYCLONE-2″
    [10] ” 6 -17.80 111.70 03/11/18Z 90 – CYCLONE-2″
    [11] ” 7 -18.60 111.20 03/12/00Z 90 – CYCLONE-2″
    [12] ” 8 -19.80 110.20 03/12/06Z 80 – CYCLONE-1″
    [13] ” 9 -20.40 109.80 03/12/12Z 75 – CYCLONE-1″
    [14] ” 10 -21.10 109.00 03/13/00Z 75 – CYCLONE-1″
    [15] ” 11 -21.50 108.00 01/13/12Z 55 – TROPICAL STORM”
    [16] ” 12 -21.70 107.50 01/14/00Z 35 – TROPICAL STORM”

    The dates in the last couple of lines are screwed up. Why would this get into the data set? Why wouldn’t this turn up in the q.c. reading by Webster or that crowd? I only notice this because it crashes my collation program.

    There’s another one like this in

    where there is some kind of weird glitch in the lines.,

    [1] “61600 02/25/1990 M=10 17 SNBR=1317 NOT NAMED XING=0 SSS=9”
    [2] “61605 02/25*1082348 15 0*61610 02/25*1192364 15 0*1102352 15 0*1132356 15 0*1162360 15 0*”
    [3] “1222368 15 0*1252372 15 0*1282376 20 0*”
    [4] “61615 02/27*1322380 20 0*1362383 20 0*1682397 20 0*1682397 20 0*”

    It’s very annoying when you’re trying to make data sets.

  56. Steve McIntyre
    Posted Oct 23, 2006 at 4:42 PM | Permalink

    Here’s another annoying one:
    Cyclone Monica in April 2006 is listed in both the South PAcific and South Indian Ocean hurricanes

    How do they generate these irritating errors? It’s not like I’m trying to pick at these things.

  57. Ken Fritsch
    Posted Oct 23, 2006 at 8:21 PM | Permalink

    Re: #54

    David, in order to put my recovery to the test I did as you instructed.

    I looked at the plot for cyclones vs year and immediately felt twinges of stoogedom and I am certain you know what I mean. That very low level of cyclones from 1955 through 1970, the transition from 1970 to 1980 and the nearly level output from 1980 through 2002 may have tempted me in my previous state of confusion, but now I labored through it.

    Next without thinking I plotted the 1955 through 2002 cyclones vs SST anomoly and calculated an R^2 = 0.28 and p = 0.00008.

    After thinking more clearly with my newly gained analytical skills and insights I remembered that I should start with 1970 as that is the time period of satellite observations and more accurate measurements. Cyclones vs SST for that period yielded R^2 = 0.43 and p = 0.00002.

    What followed was a horrible case of recidivism on my road to recovery whereby I could not resist the urge to look at the period from 1980 to 2002 for cyclones vs SST and found R^2 = 0.04 and p =0.000003. I did it and felt terrible until I remembered how we now handle that situation. My sin is called “statistical special pleading” and falls under one of the many named cases of logical fallacies — that are used primarily in stoogedom.

    In conclusion, look no further and accept the results from the 1970 to 2002 period as adding to the growing evidence for the consensus.

  58. David Smith
    Posted Oct 23, 2006 at 8:43 PM | Permalink

    Well done, my friend. You are hereby designated as CURED (CUeilleur Rouge CErise De luxe) and may now submit to Nature or Science.

    Next, thou must develop a condescending and arrogant tone. I fear that this may be thou’s toughest challenge.

  59. Ken Fritsch
    Posted Oct 23, 2006 at 8:44 PM | Permalink

    Re: #56

    Monica is tracked in the South Pacific Ocean for a week going from a TS to a cyclone 5 category then at lat -11.70 and lon 134.50 @ 04/24 at 06 hours Monica is counted in both the SPO and the South Indian Ocean as a category 5 cyclone and then goes to a TS the next time period in the SIO.

    According to my world map that 134.50 longitude must be on the line of demarcation between the Indian and Pacific Oceans. Does that mean that total storms worldwide that cross borders would get double counted or is there a separate world count of all storms?

  60. Steve McIntyre
    Posted Oct 23, 2006 at 9:11 PM | Permalink

    #59. The SIO and SP seem to re-combined in the Best Tracks data – so this is just annoying when one is trying to update. BTW I’m wondering how Webster, Curry actually updated the interim data in their hurricane-day counts. The best tracks data is done on 6-hour increments, while the interim data can be irregular. WHCC do not provide any description of their regularization method.

  61. Gerald Machnee
    Posted Oct 23, 2006 at 9:25 PM | Permalink

    You guys are finding errors? Must be “amateurs”.

  62. Steve McIntyre
    Posted Oct 23, 2006 at 10:58 PM | Permalink

    Another annoying error. This track contains two storms in it, which screws up the collation.

    I have trouble thinking up ways in which these files can be screwed up like this. ONe can work around it, but it’s annoying and a total waste of time.

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