Journal #8 - Thoughts and Reflections

With a lack of consensus amongst the professionals, it’s tough to say with a definite answer as to who is right and who is wrong. However, after reviewing the e-mails I’ve received from these meteorologists, I’ve come to a few conclusions. First, the Saffir-Simpson scale, with regard to maximum wind speed, should not be abandoned. The scale is simple, works well at warning the public, and is too historically important to avoid. Any ideas of changing it would make the scale either too complex or unusable with regards to the nearly 150 years of prior data. However, there seems to be as well a bubbling for another idea or method of determining hurricane energy. While some meteorologists like ACE, it makes little sense to just ignore storm size with regards to the calculation of accumulated cyclone energy. The index that seems to be the leading candidate to replace ACE would be IKE, but the crucial problem with IKE is that it requires information on tropical systems that is only available for certain storms at certain times. It is unlikely that we will have enough information to implement IKE within the next twenty years, and even then we may not be able to use it to its fullest extent. Therefore, I am proposing a middle ground – somewhere between IKE and ACE, at least until IKE can be used fully. Wind radii should be used in calculating an accumulated energy index, in such a method. The area of wind from 35kts to 49kts, from 50kts to 64kts, and from 64kts to the max wind speed for each storm should be calculated, and then multiplied by the square of the average wind speed for each area (42kts, 57kts, and (maxkt + 64kts)/2) to get a basic general accumulated cyclone energy for each six hour period of a tropical system.

Journal #7 - And now, part two

With regards to ACE, meteorologists were more split than with regards to the Saffir-Simpson scale. The biggest split seemed to appear between operational meteorologists (those working for the NHC) and research meteorologists (those working at universities and the HRD). Among the operational meteorologists, Stewart sees no reason to change ACE as is. And Franklin believes ACE is pointless because it refuses to differentiate between “tropical cyclone activity and tropical cyclone activity that matters”, or, that ACE gives to much weight to long lasting storms than storms that have any actual affect on the populace. This opinion changes amongst the research meteorologists, however. Prof. Bourassa believes that IKE (Integrated Kinetic Energy) makes significantly more sense than ACE, and ignoring storm size makes no sense; however, he notes the lack of data available is a limitation on the usage of IKE. Prof. Emanuel thinks ACE is decent, however, he prefers to use a method of “power dissipation” – power dissipation is basically the same as ACE, except for in power dissipation, the max wind speed is cubed (as opposed to squared in ACE). Prof. Klotzbach said he would not make any changes to ACE and that he preferred it greatly to the power dissipation method (as, he said, the power dissipation method would have a tendency of magnifying small errors). Prof. Evans saw a need for an alternative index, although she was not sure exactly what kind of index was needed, and suggested I take a look at Mark Powell’s paper on IKE. Aberson, as well, forwarded me the paper on IKE by Powell.

Journal #6 - Will the consesus of forecasters please stand up?

So far, I've gotten 9 responses out of the 20 e-mails I've sent out - 2 of them referred me to other meteorologists who have, as of yet, not responded to me. But, in general, I received a very impressive response. Because of the two part question I’ve asked, I’m going to split my summarization of e-mails into two journal entries – one for ACE, and one for Saffir-Simpson. This entry will have to do with the Saffir-Simpson scale. In general, the response I received was that the meteorologists were against altering the Saffir-Simpson scale. Most of the meteorologists (Prof. Bourassa, Franklin, Prof. Klotzbach,
Prof. Evans, Stewart) all pointed out that the National Hurricane Center recently removed storm surge and pressure from the Saffir-Simpson scale, making the S-S scale simply about top wind speed. Prof. Bourassa stated that while he had a positive reaction towards the new S-S scale, he had not been able to investigate it fully and expressed doubts over the new solution with regards to storm surge. Prof. Emanuel said that he was not a supporter of the S-S scale in its current form, and would prefer to “would reform it by making the scale a strict function of the maximum wind speed over a threshold, raised to some power, allowing for two significant figures (e.g. cat 4.2) and leaving it open ended (e.g. cat 6.1)”. Franklin noted some attempts in recent years to redesign the hurricane scale, and that these attempts usually involved storm size; however, he notes that such scales would most likely only serve to confuse the public (his concern makes sense as a forecaster for the NHC). Prof. Klotzbach noted that the NHC had recently made changes to the S-S scale. Prof. Evans believes we should keep the S-S scale because we’ve been keeping records that way for over 100 years, and that the S-S scale acts as a sort of “comfort” for the public, however, she notes the need for an alternative index. Stewart believes that the S-S scale is fine as is. Aberson recommended I look at a measure entitled Integrated Kinetic Energy of a system as a possible method of using storm size.

Journal #5 - Where I Stand

So, where am I to go with my project? Well, so far, I seem to have gotten the impression from my e-mails (and from my personal thoughts beforehand) that ignoring storm size when trying to assess cyclone energy is a poor idea. However, the reason that storm size has been ignored in tropical cyclone energy calculations for so many years is not due to a lack of interest, but rather due to a lack of information. Usually, the only data available about hurricanes was the maximum wind speed. However, now that technologies are significantly more advanced, we are able to capture the wind radii of a tropical system to a somewhat accurate estimate. Because we are now collecting more data on hurricanes, it can be put to good use as a measure of overall cyclone intensity. The only thing holding us back is the old customs from a time when we had less data. What does this mean? I’m still on the same track I was before (so far). Nothing has changed my mind about the inclusion of storm size into Saffir-Simpson or ACE; everything has indicated that the inclusion of storm size would be beneficial in making the findings for Accumulated Cyclone Energy more accurate. The only remaining question is a how – what would be the best way to include storm size? Should only hurricane force wind radii be included? 50 knots? 34 knots? These are questions I will have to further investigate, and hopefully get some more answers on.

Journal #4 - E-mails!

So, I sent out my e-mails to various meteorologists in both academic and professional fields over the past week or so, and I’m beginning to get some replies back. Some of them are “sorry, can’t help you” with a subtle undertone of “I’m really much too busy to help you”, however, these e-mails usually included another name that the meteorologist suggested I contact (Professor Lindzen, from MIT, suggested I contact William Gray, from Colorado State University – I thanked him for his recommendation, even though I had already e-mailed Professor Gray). Another e-mail I received, from Mark Bourassa from Florida State University, gave me a quick overview of what I wanted to know, letting me know that his answers were short, but good. So far I’ve gotten a few of each e-mail, and these e-mails are going to help me in my quest to define my research for this second semester of my project. My goal is the once I collect more and more of these e-mails, I’ll have an idea of where I should go with my research project. I must say, however, it’s been incredibly reassuring to receive some e-mails, any e-mails at all. When I first sent them out, I was almost positive that I would get no response, or that the response I would get would minimal or unimportant. I have been pleasantly surprised that experts in the field of meteorology are willing to take a few minutes to respond to my question.