This YouTube Channel Achieves Fractal Wrongness in Data Misuse

This one. The channel of “GOOD Magazine”. I take it it’s one of those ironically named things, like how Fox News’ Slogan is “Fair & Balanced”, because the bad data is strong with this one.

Let’s take a look at one of their YouTube videos titled “Top 10 Most Powerful Hurricanes Ever“.

Let’s start at 0 seconds in. Do you see a problem?

I see a problem. The title of the video is “Top 10 Most Powerful Hurricanes Ever”. What does that mean? What is their metric for “Most Powerful”? Hmmm, maybe we’ll find out after watching this video for a while. Let’s see…

Okay, 15 seconds in, the text on screen tells us that they’re clarifying that “most powerful hurricanes” means “biggest hurricanes”.

…really? Because I think for most people “biggest” defaults to meaning “biggest by area”, and I’m not quite convinced at all how big a hurricane is tells anything about their power. (Watching the video a bit, one can see that in fact this is not the case and the video uses “biggest” in a more metaphorical sense.)

All right, let’s roll their top 10 through.

Done watching it? How many things bothered you? If your answer is zero, you should go and rewatch it again, until you find something fishy. No really, there are things in this top 10 that are fishy that do not require knowledge about hurricanes to detect.

Let’s start with realizing what their metric of hurricane power is: it’s the smallness of the central pressure. But even they decide to put this metric second in their data display, so certainly it should also be nonobvious to them that this is a nontrivial clarification to make?

But second of all, how reliable is their data on central pressure (which, incidentally, appears like it should have been labeled minimal central pressure—the central pressure of a hurricane changes over time)? Notice that they report one hurricane (the “Labor Day” Hurricane) from Gregorian calendar 1935, long before the other hurricanes mentioned. What was the quality of meteorological instruments back then?

It turns out the “Labor Day” Hurricane occurs significantly before accurate hurricane data became available, and “892 mb” is merely the hurricane’s pressure at landfall. As hurricanes tend to weaken around landfall, the storm was likely more powerful (and its central pressure a lower reading) at some point prior at sea. (Alternatively, since they didn’t explicitly say “minimal” on the data label, one could suggest that maybe they are reporting landfall central pressure rather than minimal central pressure, but in that case the landfall central pressures of other hurricanes are incorrect, so this is a theory of more discrepancy.) This fact was ignored simply because data was unavailable because of the state of meteorological technology eighty years ago, and the data point that was the strongest data available was presented as the strongest data. Other hurricanes from way-back-then were strong enough to potentially be close contenders for this list, but their data is unavailable, so their possibility is silently discarded.

They also present wind speeds. Like how they left out the “minimal” before “central pressure”, they also left out the “maximal” before “wind speed”. But also notice that all the wind speeds presented are divisible by 5 except for Katrina’s. Did it just happen that among the top 10 only Katrina’s maximum wind speed was not divisible by 5?

It turns out that hurricane wind speeds are typically reported to the nearest 5 mph in the US. I have no idea where they got their 174 figure for Katrina from, but it’s probably not from the same source as their figures for the other hurricanes on the list.

Speaking about mph and the US, isn’t it odd that all the strongest hurricanes decided to pick on North America? Do hurricanes have a thing against imperial units? (If this helps the US get off the imperial system, I don’t think I actually mind that much.)

It turns out they get away with a technicality here, because “hurricane” is a term that’s local to North America. There are more powerful cyclonic storms than the ones presented in the Western Pacific, but there they are not called “hurricanes”; they’re called “typhoons”. Still, this is a technicality against intuitive interpretation, and storms of the same meteorological nature that just happened to be called different names should not be discounted in the creation of such a list.

Okay, so circles appear on a map above this presented quantitative data. It looks like they mean to present the path of travel that each of the hurricanes took. But first of all, the paths are wrong. They do generally have the shape that the actual paths of the hurricanes had, but the paths are quite shifted from the actual paths the respective hurricanes took.

But also, one would suppose that the circles are equidistant in time. (They’re certainly not equidistant in space—note Gilbert’s path versus the paths of the others, for instance.) That is, one would think the amount of real-life time it took for the hurricane to move from one plotted location to the next location is the same as the amount of real-life time between the hurricane being at that second location and being at the one after that. But three days pass between the second and third circles shown for Hurricane Wilma whereas only six hours separate consecutive circles at the end of the path presented for Wilma (that is, if we assume that the presented path is just a position-shift from the correct path, and not something crazier).

Continue reading “This YouTube Channel Achieves Fractal Wrongness in Data Misuse”

Intensity Distribution: Atlantic and Eastern Pacific Hurricane Seasons, 1990-2012

The number in a row and a column for each basin is the number of storms that achieved a minimum millibar pressure less than the pressure listed for the row in the year for the column. The two most intense storms of each season with their minimum millibar pressure are listed below the columns for each year.

Some notable storms that did not make the top two for their season: Atlantic: 1995—Luis (935), 1999—Lenny (933), 2005—Dennis (930), 2005—Emily (929), 2005—Katrina (902); Eastern Pacific: 1993—Fernanda (934), 1994—Emilia (926), 1994—John (929), 2002—Hernan (921, actually tied for 2nd).

Note the utter dominance of the 2005 season in the Atlantic basin.

intensitydistribution

Post-2000 Major Hurricane Formation Distribution

Plotted in the following map (background from Google Satellite) are the formation locations of all category 3+ hurricanes since 2000 exclusive that dealt sufficient damage to have their name retired. Typically through history, the strongest of hurricanes in the Atlantic form around the western coast of Africa (and are called Cape Verde Type Hurricanes); as they move west, they can gradually build a significant amount of strength in warm ocean water before reaching land. Recently, with significantly increased warmth of ocean water in general, more and more strong hurricanes have been forming further west—hurricanes for which there is less time to prepare for.

Global Warming is *Not* Causing More Hurricanes

There is no doubt that global warming is happening. Denying that global warming is occurring is simply a refusal to accept statistics. It’s really more of an issue of whether humans are causing global warming. That’s the more acceptable question.

In any case, many sources say that global warming is responsible for the recent surge of hurricanes. There are suddenly more hurricanes, what could it be, hmmm warm water is needed for hurricanes, what warms, oh yes it’s global warming, etc. Okay, valid point so far. It makes logical sense that when the Earth warms, the water part warms as well; after all, the majority of the surface of the Earth is water. That makes sense.

But there is actually a major problem with this theory.

There aren’t more hurricanes.

If p then q, p, therefore q. We have p; global warming is indeed happening; we also, however, have not q. Over the past few decades, the number of hurricanes has actually stayed more or less consistent.

It’s frequently been said that we’ve been having more hurricanes, but that’s actually not true. Such claims are supported by graphs like these, where there is an upward trend occurring, but the problem with this is that global warming is a global issue, and those are statistics for the Atlantic Basin.

I decided to make a graph showing Accumulated Cyclone Energy statistics for both the Atlantic Basin and the Eastern Pacific Basin.

The total amount of tropical cyclone activity around North America has not really changed much over the long run, with only short-term fluctuations. Unfortunately, I could only find Accumulated Cyclone Energy statistics for these two basins. Now, I could just leave this issue with a semantics argument that tropical cyclones are only called hurricanes around North America, but looking elsewhere in the world, the Western Pacific Basin, the most active season in the timespan of the above graph is 1997, two other highly active seasons are 1979 and 2002, and both of these are dips in activity around North America. (There is one thing to note, though: 1977 was also a year of particularly low activity in the Western Pacific. Something interesting was happening that year.) The Western Pacific Basin also is currently in lesser activity mode, so cyclone activity is definitely not really increasing recently.

So why does it sound like there are more hurricanes? Part of it could be blamed on media craze, especially post-Katrina, but really it is the fact that due to wind patterns, hurricanes tend to travel west. In the middle of the pacific, there is a sort of a trough that is unfriendly to hurricanes  and thus make it so that many hurricanes in the Eastern Pacific never hit any sort of land, and no matter how strong Eastern Pacific hurricanes get, if they don’t hit land, they don’t cause much damage, and it is not very newsworthy. On the other hand, Atlantic hurricanes do have land to hit in the west, and thus have a high potential for damage. And thus, in North America, the amount that we hear about hurricanes is roughly proportional to Atlantic hurricane activity, and thus it seems that there are more hurricanes recently, when in reality, it is not a new era of hurricanes, it is a new shift of hurricanes.

Pacific/Atlantic Hurricane Patterns

As some of you know, I’ve for quite a while been very fascinated by hurricanes, although most of the time I spent mystifying myself by them was before I made this blog. Because this is, after all, my blog, I guess I should add a touch of hurricane research here as well.

So I wanted to make a few charts comparing Accumulated Cyclone Energy (ACE), a property of hurricanes that is ideally the integral of its strength over its lifetime. Of course, hurricane strength can’t quite reasonably be sampled all the time real time, and in fact the National Hurricane Center samples it once every six hours. I remember a few years ago charts showing the ACE of hurricanes were on Wikipedia hurricane season pages, but for some reason someone deleted them. Darn. Because I don’t want to find a database and recalculate all the ACEs of the hurricanes by hand, I decided instead to invent a new unit which would mean approximately the same thing as ACE; this is done by giving each hurricane a score equal to n points for each six-hour interval it is a Category n hurricane. Like ACE, a hurricane will thus have a higher ACE with a higher general strength, measured by wind speed, as well as a higher ACE with lasting longer.

I decided to call this unit describing hurricanes the “hurrscore,” since, well, this unit is pretty hurr. In any case, note that the assignment of the scores do not flow linearly with wind speed, as remember that Category 1 does not start until 74 miles per hour winds. Thus, this system assigns higher scores in comparison to ACE to hurricanes that generally achieve a higher maximum wind speed than to hurricanes that display high endurance.

In the following chart, I list the hurrscores of all hurricanes in the Atlantic Basin since 1979, as well as for a few major ones before (in which I think I included every cat-5 since 1953 with the exception on 1977’s Anita).

In the following chart, the light grey highlight is for hurricanes that achieved at least category 3 status (and thus would be meteorologically dubbed a “major hurricane”) at some point in their lifetime, and the grey highlight is for hurricanes that achieved category 5 status at some point in their lifetime. The single asterisk designates a hurricane name that is retired that year.

Here is the same for the Eastern Pacific Basin.

(For those of you wondering what retiring hurricane names means, each year hurricanes are named from a list of names with the first storm named a name starting with A, the second named a name starting with B, and so on. Since 1979, convention is to recycle hurricane name lists every six years, with the exception of hurricanes that caused devastating damage, which are removed from the name list (“retired”) and replaced with new names (although sometimes for some reason they start using it in another basin…hmmph). Three things: note that storms are named when they become a storm, i.e. reach 40 mph winds; not all named storms make it to hurricane status. Also, the name list contains no entries for QUXYZ in the Atlantic Basin and QU in the Eastern Pacific Basin. Furthermore, wonder what happens when they run out of alphabets? The answer is actually in the chart (it’s only happened one year). Double asterisks represent hurricane names retired due to political complaints or pronunciation complaints. Take a look at the Eastern Pacific basin and despair at how this causes more hurricane name retirings there than for the original reason.)

Looking at the ACE totals given on Wikipedia, my hurrscores comes pretty close, although somehow the top seasons in both basins are different: by ACE, 2005 and 1992, respectively, are the strongest seasons in the Atlantic and Eastern Pacific, respectively, a result I would agree with.

By hurrscore, the eight strongest seasons in the Atlantic Basin are, in order, 2004, 2005, 1995, 1998, 1999, 1996, 2003, and 2010, with the eight weakest seasons being 1983, 1987, 1994, 1982, 1991, 1993, 1986, and 1997. By hurrscore, the eight strongest seasons in the Eastern Pacific Basin are, in order, 1990, 1992, 1993, 1984, 1994, 1991, 1984, and 1997, with the eight weakest seasons being 2003, 2007, 2010, 1981, 1979, 1996, and 2004.

Here is a line chart and a scatterplot:

El Niño years tend to see more Pacific hurricane activity and less Atlantic hurricane activity than usual. Many meteorologists note cycles in the history of the Atlantic Hurricane Basin, with periodic decades of increased hurricane activity, like 1880-1900 and 1950-1970, as well as the current 1995-?. Although Eastern Pacific hurricane records go back barely past what I’ve included, it seems like not only do Pacific and Atlantic hurricane activity receive coupled action from El Niño cycles, but that their activity seems coupled in the larger cycles as well: with the current onslaught of Atlantic hurricanes, Eastern Pacific hurricanes seem to clearly be ebbing in quantity.