Tisdale on debunking AGW intensification claims about Irene

Previously on WUWT we saw this:

Now Bob Tisdale does a numeric analysis along the track, finding some interesting results. Bill McKibben’s wacky claim seen here Climate activist McKibben bizarrely blames Hurricane Irene on global warming is now dead and buried.

Sea Surface Temperature Anomalies Along The Track Of Hurricane Irene

by Bob Tisdale

There’s been speculation that Anthropogenic Global Warming had an impact on the Sea Surface Temperatures that fueled Hurricane Irene. Let’s put that to rest.

I downloaded the Sea Surface Temperature anomalies for the 5-degree (longitude and latitude) grids, Figure 1, that captured the track of Hurricane Irene, and created a weighted average of the Sea Surface Temperature anomalies for those grids. The weighting accounted for latitude and percentage of ocean surface per grid, since portions of some of the grids were covered by land mass.

Figure 1

The Unisys Hurricane Irene Tracking map is available here:

http://weather.unisys.com/hurricane/atlantic/2011/IRENE/track.gif

SATELLITE-ERA SEA SURFACE TEMPERATURE ANOMALIES

Figure 2 is a time-series graph of the weekly satellite-based Reynolds OI.v2 Sea Surface Temperature anomalies for the track of Hurricane Irene. (The more recent weekly data for that dataset starts the week centered on January 3, 1990.) Also highlighted in red is the SST anomaly (+0.714 deg C) for the week centered on August 24, 2011. The most recent Sea Surface Temperature anomalies were elevated but nowhere near record levels. The linear trend of +0.045 deg C per decade for the hurricane track is also not exceptional. It’s about 56% of the linear trend for Global Sea Surface Temperature anomalies (+0.08 deg C per decade) for the same period.

Figure 2

Figure 3 provides a longer-term graph of the Sea Surface Temperature anomalies for the track of Hurricane Irene, using monthly Reynolds OI.v2 SST data. Again, Sea Surface Temperature anomalies were elevated but not unusually high in August 2011. Note also how the trend for the data is relatively flat at +0.016 deg C per decade. It is about 18% of the trend for global SST anomalies, which are approximately +0.09 deg C per decade.

Figure 3

A LOOK AT A LONGER-TERM DATASET IS REVEALING

The Hadley Centre’s HADISST Sea Surface Temperature dataset starts in 1870. Unfortunately, there is a lag in its update, so the HADISST data currently ends in June 2011. Luckily, another two months of data would not change the following results appreciably.

Figure 4 illustrates the Sea Surface Temperature anomalies and linear trend for the track of Hurricane Irene from January 1950 to June 2011. The trend is negative, meaning the Sea Surface Temperatures for the track of Hurricane Irene have cooled over that period. Since it’s a noisy dataset, I’ve also included the curve of the data smoothed with a 13-month running-average filter.

Figure 4

Figure 5 illustrates the Sea Surface Temperature anomalies for the Hurricane Irene track since the start of the dataset in 1870. Note how the Sea Surface Temperatures rose during the early 20thCentury warming period, but then cooled since 1950.

Figure 5

This becomes clearer if we smoothed the data with a 121-month running-average filter, Figure 6.

Figure 6

THE SST ANOMALIES OF A PORTION OF IRENE’S TRACK HAVE COOLED SIGNIFICANTLY SINCE 1950

Figure 7 presents a map of the change in the Sea Surface Temperature anomalies of the Western North Atlantic from 1950 to 2010 based on local linear trends. The map was cropped from a global map created at the GISS Surface Temperature Analysis Global Map Making Webpage.I’ve highlighted the portion of Irene’s track used in this post where Sea Surface Temperature anomalies have cooled since 1950.

Figure 7

The Sea Surface Temperature anomalies from 1870 for that portion of Irene’s track (25N-35N, 80W-75W) are shown in Figure 8. The green curve shows the data smoothed with a 13-month filter. Also illustrated in red are the Sea Surface temperature anomalies since January 1950, along with the linear trend (- 0.06 deg C per decade). Based on the linear trend, Sea Surface Temperature anomalies for that portion of Irene’s track dropped approximately 0.37 deg C since 1950.

Figure 8

THE NORTHERN AND SOUTHERN PORTIONS OF IRENE’S TRACK

I had originally planned to end the post at that point, but someone was bound to ask for time-series graphs of the Northern and Southern portions of the track of Hurricane Irene. Figure 9 illustrates the grids included for those subsets.

Figure 9

As illustrated in Figure 10, the Sea Surface Temperature anomalies of the Northern Portion peaked in 1949, similar to the overall dataset, but dropped significantly until the late 1960s, when they rose again. On the other hand, the Sea Surface Temperature anomalies of the Southern Portion did not peak until 1960 and made a minor dip and rebound since then. In both cases, Sea Surface Temperature anomalies were warmer during the 1950s and 1960s than they are today.

Figure 10

A NOTE ABOUT THE RISE IN GLOBAL SEA SURFACE TEMPERATURES

Earlier I noted that Global Sea Surface Temperature anomalies have a linear trend of 0.09 deg C per decade during the satellite era; that is, since November 1981. Some readers new to discussions of Sea Surface Temperature during that period are bound to assume the rise in Sea Surface Temperature has an anthropogenic cause. I have illustrated and discussed in numerous posts over the past few years how and why most if not all of the rise in Sea Surface Temperature anomalies result from the a combination of two natural processes: the El Niño-Southern Oscillation or ENSO and the Atlantic Multidecadal Oscillation or AMO. My most recent posts that discussed this at an introductory level were ENSO Indices Do Not Represent The Process Of ENSO Or Its Impact On Global Temperature and Supplement To “ENSO Indices Do Not Represent The Process Of ENSO Or Its Impact On Global Temperature”.

SOURCES

The Reynolds OI.v2 SST anomaly data is available through the NOAA NOMADS webpage:

http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_sst.sh?lite=

The HADISST SST anomaly data is available through the KNMI Climate Explorer:

http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere

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25 Responses to Tisdale on debunking AGW intensification claims about Irene

  1. JamesD says:

    Bob is one intense, obsessed dude. Which is why we love him. Nice job and thanks for the work you put in.

  2. pat says:

    [SNIP - you are welcome to resubmit your comment, but lose the insult ~mod]

  3. pat says:

    Well that was actually meant as sarcasm. But I accept my punishment.

  4. Tim Curtin says:

    Very good indeed!

    Please work it up as a publishable paper.

    Best

    Tim

  5. David Walton says:

    Thank you Mr. Tisdale.

  6. Dusty says:

    From McKibben’s story:
    “Sea surface temperatures 1° to 3°F warmer than average extend along the East Coast from North Carolina to New York. Waters of at least 26°C extend all the way to southern New Jersey, which will make it easier for Irene to maintain its strength much farther to the north than a hurricane usually can,” says Masters.
    ——-
    So, does this mean that Masters assertion that SST’s were 1-3d F warmer than average is incorrect, or, at the very least, exaggerated?

  7. omnologos says:

    But why… where things have warmed it’s because of AGW. Where they have cooled, they have either cooled because of local effects of AGW or they would’ve cooled much more were it not for AGW.

    Did I win any prize for providing the right answer?

  8. bushbunny says:

    While the rest of the world is waking up about the AGW scam. Here down-under they are still attempting to push this carbon tax even when 85% of the population from all sides of the political fence are against it. I’ve written to various politicians and pointed out the recent CERN report, only one Barnaby Joyce has put it on his blog.

    By the way Bob, great analysis, when I lived in Bermuda the sea in warmer months was balmy, like swimming in a tropical aquarium. Not being a great swimmer and used to English and Australian
    sea temperatures it was lov-i-ly. No shock to the system when you entered the water. Spoiled me for even Australian bathing. (Other than in a bath and swimming pool LOL)

  9. Kasuha says:

    Could we have a “before Irene” and “after Irene” versions of figure 1?

  10. Richard S Courtney says:

    [sarc on] But the scientists say weather is getting worse because we are destroying the planet with global warming so your data must be wrong. [sarc off]

    Richard

  11. Bob Tisdale says:

    Dusty says: “So, does this mean that Masters assertion that SST’s were 1-3d F warmer than average is incorrect, or, at the very least, exaggerated?”

    Masters’s post is here:
    http://www.wunderground.com/blog/JeffMasters/article.html?entrynum=1896
    Masters provides an SST map in that post, but no SST anomaly map. Here’s a map that shows SST anomalies for the week centered on August 24, 2011. At the north end of Chesapeake Bay, SST anomalies were + 3 deg C, not + 3 deg F. (That’s a map of Reynolds OI.v2 satellite-based data, and they use 1971 to 2000 as the base years for anomalies.) Note, however, that the majority of the track of Hurricane Irene is well below those values.
    http://i54.tinypic.com/xduonb.jpg

    Masters also includes the following statement in that paragraph:
    “During the month of July, ocean temperature off the mid-Atlantic coast (35°N – 40°N, 75°W – 70°W) averaged 2.6°F (1.45°C) above average, the second highest July ocean temperatures since record keeping began over a century ago (the record was 3.8°F above average, set in 2010.)”

    For his SST anomalies, Masters uses HADSST2 data (and they use 1961-1990 as base years). The July SST anomaly for that dataset and for that grid was 1.45 deg C, so he’s correct with that.
    –BUT–
    The rest of his description is not entirely factual. Here’s a graph of the HADSST2 July SST anomalies from 1850 to 2011. This year’s reading was not the second highest. Looks to me like it came in in sixth place, not second.
    http://i53.tinypic.com/28w10kk.jpg

    And why is he discussing July SST anomalies for that grid? The hurricane came through there in late August.

  12. Bob Tisdale says:

    Kasuha says: “Could we have a ‘before Irene’ and ‘after Irene’ versions of figure 1?”

    Figure 1 is the tracking map. Are you referring to the map Anthony included in his introduction? If so, here’s a link to the archive. Anthony used the Western Hemisphere map:
    http://www.osdpd.noaa.gov/ml/ocean/sst/anomaly.html

    Here’s the “before”
    http://www.osdpd.noaa.gov/data/sst/anomaly/2011/anomw.8.25.2011.gif

    And here’s the “after”:
    http://www.osdpd.noaa.gov/data/sst/anomaly/2011/anomw.8.29.2011.gif

  13. Les Johnson says:

    Bob: Good work. May I suggest that you also do this for the poster child of global warming storms; Hurricane Katrina?

  14. P. Solar says:

    This analysis is interesting but I’m not sure it disproves the claim that Irene was related to global warming (a proposition that I find ludicrous BTW).

    The area you studied is not where hurricanes develop, it’s the fall-out zone. What you probably do show is why it did not maintain it’s force and why apocalyptic forecasts were unfounded.

    The fact that this strip has seen less warming that the global average over the last 50 years may well largely be due to the cooling effect of the annual passage of hurricanes and tropical storms.

    It is also probably why “Irene” was never a hurricane over land

  15. John Marshall says:

    I don’t think that sea surface temperatures for 1870 would be very either accurate or representative of true temperatures world wide. I used to record SST’s for the UK Met. Office in the 1970’s from a helicopter. A thermometer suspended in the sea below the aircraft for 5 mins then hoisted into the aircraft to read it. What reading change between water and aircraft I have no idea.

    The ARGO system is probably the most accurate and some even argue with that data.

  16. David A says:

    Re P. Solar says:
    September 4, 2011 at 2:33 am

    This analysis is interesting but I’m not sure it disproves the claim that Irene was related to global warming (a proposition that I find ludicrous BTW).

    The area you studied is not where hurricanes develop, it’s the fall-out zone. What you probably do show is why it did not maintain it’s force and why apocalyptic forecasts were unfounded.

    The fact that this strip has seen less warming that the global average over the last 50 years may well largely be due to the cooling effect of the annual passage of hurricanes and tropical storms.”

    Dear P. Solar, the first five grids cover both the long and lat where tropical systems usually intensify and for certain all the grids used cover the area where CAGW enthusiasts claim Irene demonstrates an anthropogenic signal. As to the “CAGW causes such events” claim, the ace chart of hurricane intensity does not indicate any such trend.

  17. Bill Illis says:

    This is really good Bob.

    It is the most appropriate analysis on the topic I have seen. Someone mentioned this could be published (and there have been a few similar papers – just not as to the point). I think you and Ryan Maue should get together and look at the all the typical hurricane tracks. It would have a big impact (if it gets through peer review of course).

  18. Wade says:

    And what do we have now? The tropical cyclone named Katia has trouble with being a hurricane. A few days ago, NOAA predicted this would be a major hurricane, which cat-3 or higher (link: http://www.nhc.noaa.gov/archive/2011/graphics/al12/loop_5W.shtml ). It certainly made sense, it was over the prime development zone. And yet the one thing NOAA does not, or perhaps cannot, take into account is how much deep heat is in the ocean. Look at the ocean temperature at where Katia was. ( http://www.osdpd.noaa.gov/data/sst/anomaly/2011/anomw.9.1.2011.gif ) There is a lot of blue in its wake. This means there is no DEEP ocean heat, and by extension no “missing” heat. Once you get past the surface temperatures, there is no heat left for storms to draw upon, heat they need. No fuel means less intense tropical cyclones.

    This is very bad news! The ocean is running out of heat to warm our climate. The end is nigh for global warming proponents.

    And, once again, Irene WAS A HURRICANE AT LANDFALL! I lived through enough storms to know the difference between a hurricane and tropical storm. Tropical storms don’t do the damage that Irene did.

  19. Kasuha says:

    Bob Tisdale says:
    September 4, 2011 at 2:03 am
    Here’s the “before” … And here’s the “after”

    Thank you, that’s really impressive change. I wonder why it didn’t it leave similar footprint when it was still going westward when it was still strong and picking up force. Maybe the release of the energy and subsequent rainfall etc was the cause of the temperature change?

  20. Roger Knights says:

    Wade says:

    Irene WAS A HURRICANE AT LANDFALL! I lived through enough storms to know the difference between a hurricane and tropical storm. Tropical storms don’t do the damage that Irene did.

    Even if it was one at landfall, it was only a borderline Category 1 storm, barely above a TS. And Irene did its worst damage in northern New England, well after it had been downgraded to a TS. Irene’s worst damage was from rainfall (on saturated ground) and subsequent flooding and tree-fall (from loosened trees). Wind damage was a minor component.

  21. Dusty says:

    Bob Tisdale says:
    September 4, 2011 at 1:52 am
    —-
    Thanks for that, Bob. Until reading your response, Masters’ switch from F to C did not click for me or I wouldn’t have made such an implication of its accuracy, though it was great to see the details you provided on it.. And I was also interested, moreso, in the average he was using, so thanks for anticipating it and the extended exploration of that, too.

    I’m interested in comparing Irene to hurricanes with a similar tracks, eg, Fran, Floyd, Bob, Gloria, NE(1938), NE US (1944), Carol, as it doesn’t appear, on its face, that temperature anomaly has much to do with intensity (and, as such, surge, too), though it might wrt to rainfall. I have to think about this some more.

  22. Robw says:

    “Very good indeed!

    Please work it up as a publishable paper.

    Best

    Tim”

    Now Tim are you looking to get another Editor fired(oops to resign) for demonstrating observation data do not match models? We all know data is background noise to real models [sarc off]

  23. timetochooseagain says:

    omnologos-Nice! A “Keynesian Theory of Climate” to fit well with “Keynesian Theory of Aging

  24. higley7 says:

    The up and down of coastal water temperatures has been know for a long time in Maine. Many moons ago, I did research on the 3 Homaridae species (lobsters), one being Homarus vulgaris, our Maine lobster. I found lobster fishing references and even verbal info from lobstermen that the waters were really good for lobsters about every 35-37 years. You could watch the number of lobster pots in the harbor and assess the fishing effort involved to catch enough “bugs.” Fewer pots meant life was good.

    So, what goes on here is that the common lobster has adapted to the most common water temperatures which is the range passed through twice, once going up and once going down.. Too warm and too cold are both not the best. This means a total time from warm peak to warm peak of about 70-75 years, which is pretty much what we see in the water temperature records shown here, particularly in Figure 6.

    Nothing unusual happening here. Ayuh.

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