Why We Don’t Need the Anthropocene

I was recently asked to reply to the following discussion prompt:  “Discuss the merits of a ‘new’ geological epoch, the Anthropocene. What value does it provide and how can archaeologists contribute towards its definition?”

Here is my reply:

Earlier this year, the Subcommission on Quaternary Stratigraphy (part of the International Commission on Stratigraphy, which in turn is part of the International Union of Geological Sciences) announced the ratification of the division of our current Epoch (the Holocene) into the following three Ages:

Greenlandian – 11,700 to 8,236 years before 2000 CE (b2k)

Northgrippian – 8,236 to 4,250 years b2k

Meghalayan – 4250 years b2k to the present


The start of the Meghalayan is marked by a so-called “Golden Spike,” or, more specifically, a Global Boundary Stratotype Section and Point (GSSP).  As can be seen on the International Chronostratigraphic Chart above, GSSPs are used to define most Eon, Era, Period, Epoch, and Age boundaries.  The specific GSSP associated with the beginning of the Meghalayan is the onset of a two-century global drought event which, for those familiar with Ancient Egypt, roughly coincides with the First Intermediate Period.

This dramatic change in global climate left evidence on all seven continents simultaneously; the geological requirement for a Golden Spike.  What is most interesting about the Meghalayan GSSP is that it is the first one to be associated with a “global cultural event…sparked by a global climatic event.”  Not only did Egypt experience a Dark Age between the Old and Middle Kingdoms – Mesopotamia saw the fall of Akkad and the Indus Valley Civilization went into decline.

Outside of the work done to subdivide the Holocene, the Working Group on the ‘Anthropocene’ was convened under the auspices of the Subcommission on Quaternary Stratigraphy in 2009.  The name ‘Anthropocene’ was popularized in 2000 by Nobel Laureate chemist Paul Crutzen to highlight man’s impact on the Earth.  Unlike the Holocene (and Meghalayan), defining the ‘Anthropocene’ as a geological epoch is a matter of “political relevance” and has no scientific merit.

A geologically-defined stratigraphic boundary must be globally discernible.  A well-known example of this is the K-Pg Boundary associated with the end of the Cretaceous.  With respect to human impacts on the planet, different proposed markers (such as anthropogenic extinctions, mining, agriculture, irrigation, and industrial pollutants) entered the record at different times throughout the world.  When the search for an ‘Anthropocene’ Golden Spike is narrowed to global phenomena (such as radioactive signatures from mid-twentieth-century nuclear testing), the term becomes decoupled from the very thing it was intended to define, since the vast majority of humanity had no part in creating such a layer.

Human impacts on the landscape…and on the environment, didn’t start at the same time everywhere on Earth.  If you live in China, these things began 5,000 or more years ago.  If you live in North America, they seem to have begun roughly in the 1700s…To draw a single line – which is what geologists have to do – that is the same age everywhere on the Earth’s surface, we have to have [a global] event.  Either a change in the biology…or some change in the physical environment such as the geochemistry.” – Paul Gibbard, Secretary General, International Commission on Stratigraphy

Although there is no merit to a geological definition of the ‘Anthropocene,’ it is still a valuable anthropological (and especially archaeological) term.  Just as the Three Age System can be applied in certain situations to locally parse prehistory, so too could a localized ‘Anthropocene’ be used to discuss a tipping point after which man’s impact on the environment resulted in observable changes in the behavior of that particular group.  The resulting feedback loops could then be compared between sites to find patterns, and those patterns could be investigated to uncover commonalities that resulted in both successful and unsuccessful strategies.

Hitler’s “Struggle”: The Antithesis of Social Darwinism


Evolutionism, or unilinear cultural evolution, is the notion that human development progresses from “savagery” to “civilization” gradually over millennia. The main proponents of evolutionism were Edward Tylor and Lewis Henry Morgan. (Fagan 2012: 19-20) The term “social Darwinism” was popularized in the 1940’s by Richard Hofstadter to describe the mechanism by which the development described in evolutionism occurs:

Richard Hofstadter seems to be the principal source of the widespread modern belief that both [Herbert Spencer and William Graham Sumner] were “social Darwinists.” But were they? What precisely is this “complex of late-nineteenth-century ideas,” as Eric Foner puts it, that the phrase “social Darwinism” is supposed to stand for? Perhaps the most frustrating thing about doing a little general reading in this field is discovering how difficult it is to find any sort of definition of that phrase — “social Darwinism” — especially if one is hoping to find a succinct and quotable definition of it. Entire books are written on the subject without ever carefully and clearly delimiting exactly what that subject is. In essence, however, “social Darwinism” seems to be the notion that success in the market proves an individual’s fitness to survive in the struggle for existence, so that both legislation and private charity meant to assist those who fail in the market are inadvisable, since our species will grow stronger if these “unfit” individuals are allowed to die off. [Riggenbach April 22, 2011]

Harris and Johnson identify Herbert Spencer as “[t]he most influential social Darwinist” and define the social Darwinism movement as being “based on the belief that cultural and biological processes depended on the free play of competitive forces in the struggle of individual against individual, nation against nation, and race against race.” (Harris and Johnson 2007: 24) Greene sees social Darwinism as “laissez-faire political economy rendered ‘scientific’ by association with Darwin’s theory of natural selection” (Greene 1981: 3) and goes on to point out that Harris viewed even Darwin himself as a social Darwinist, “accusing him of ‘biological Spencerism,’ or racial determinism.” (Greene 1981: 95)

Richard Hofstadter describes William Graham Sumner as “the most vigorous and influential social Darwinist in America” without offering his own definition of social Darwinism. (Hofstadter 1959: 51) He does, however, quote Sumner as saying “Let it be understood that we cannot go outside of this alternative: liberty, inequality, survival of the fittest; not-liberty, equality, survival of the unfittest. The former carries society forward and favors all its best members; the latter carries society downwards and favors all its worst members.”


Herbert Spencer and William Graham Sumner advocated ideas related to self-sufficiency and “survival of the fittest,” with Spencer going “so far as to advocate the end of all attempts to provide charity and relief for the unemployed and impoverished classes.” (Harris and Johnson 2007: 24) Hitler, on the other hand, supported the exact opposite:

The German worker will not be raised to the framework of the German national community via feeble scenes of fraternization, but by a conscious raising of his social and cultural situation until the most serious differences may be viewed as bridged. A movement which sets this development as its goal will have to take its supporters primarily from this camp. It may fall back on the intelligentsia only in so far as the latter has completely understood the goal to be achieved. This process of transformation and equalization will not be completed in ten or twenty years; experience shows that it comprises many generations. [Hitler: 245]

In fact, Hitler seems to admit that natural selection actually favors the Jewish people:

When over long periods of human history I scrutinized the activity of the Jewish people, suddenly there rose up in me the fearful question whether inscrutable Destiny, perhaps, or reasons unknown to us poor mortals, did not with eternal and immutable resolve, desire the final victory of this little nation. [Hitler: 50]

This is a theme which he reiterates throughout Mein Kampf:

In gaining political power the Jew casts off the few cloaks that he still wears. The democratic people’s Jew becomes the blood-Jew and tyrant over peoples. In a few years he tries to exterminate the national intelligentsia and by robbing the peoples of their natural intellectual leadership makes them ripe for the slave’s lot of permanent subjugation. [Hitler: 236]


Although Hitler’s views on and treatment of the Jewish people are often attributed to social Darwinism, a careful reading of Mein Kampf demonstrates this is not true. Hitler emphasizes again and again that the German race, and especially the German worker, has been subjugated by the Jews. From a Spencerian perspective, this would indicate that the Jewish people were more fit than the Germans, rather than less. Instead of looking at the rise of the Jews to prominence (especially through capitalism) as an indication of their fitness, however, Hitler views them as a threat to the German race. His call for the ‘conscious raising of [the German worker’s] social and cultural situation” is in direct opposition to the beliefs espoused by Spencer and Sumner, as quoted above. Hitler’s views, as expressed in Mein Kampf, are therefore the antithesis of the ideas put forth by these so-called social Darwinists:  to quote Sumner, Hitler seems to favor “not-liberty, equality, survival of the unfittest” which “carries society downwards and favors all its worst members.”


Fagan, Brian M. 2012 Archaeology: A Brief Introduction. 11th ed. Boston: Pearson Education

Greene, John C. 1981 Science, Ideology, and World View. 1st ed. Berkeley: University of California Press

Harris, Marvin and Orna Johnson. 2007 Cultural Anthropology. 7th ed. Boston: Pearson Education

Hitler, Adolf. Mein Kampf. Noontide. Web. Accessed January 18, 2018. http://www.angelfire.com/folk/bigbaldbob88/MeinKampf.pdf.

Hofstadter, Richard. 1959 Social Darwinism in American Thought. 3rd revised ed. New York: George Braziller, Inc.

Riggenbach, Jeff. Ludwig von Mises Institute, “The Real William Graham Sumner.” Last modified April 22, 2011. Accessed January 18, 2018. http://mises.org/daily/5206/The-Real-William-Graham-Sumner.

How to Talk to a Climate Change Zealot

If you don’t have time to read a 2000 word blog post, here are the basics of talking to a Climate Change Zealot (don’t continue the conversation if the CCZ can’t complete a step):

  1. Agree that the climate changes
  2. Ask for one specific policy proposal
  3. Ask how much that specific policy proposal will cost
  4. Ask how much doing nothing will cost
  5. Ask for peer-reviewed journal articles supporting the hypothesis that this specific policy proposal will have the desired outcome
  6. Contact me if you meet a CCZ who completes step 5!

But really, it’s a good post…

Who Are You and What is a Climate Change Zealot?

Great questions.  Hi, I’m Debbie, and I am not (nor have I ever been) a climatologist.  I was also not paid to write this blog post, so put that conspiracy theory back in your pocket as well.  I recently retired from the US Navy, having served for just over 20 years as an instructor at Naval Nuclear Power Training Command (1996 – 1999), a weather forecaster and ship router (2002 – 2003), a hydrographer (2003 – 2006), Navy’s Geospatial Information & Services Officer (2006 – 2009, and yes, this is where I admit that the first ever convention I attended at the San Diego Convention Center was not, in fact, Comic-Con, but was actually the ESRI User Conference), and finally as an assistant program manager (2009 – 2015, both at the Pentagon and finally in San Diego).  For my full résumé, including details on my three MS degrees (Mathematics, Meteorology and Physical Oceanography, and Hydrographic Science), please refer to my LinkedIn profile.

Climate Change Zealots, like art and pornography, are hard to define, but we tend to know them when we see them.  For the purpose of this blog post, I am referring to people who can be characterized by five basic behaviors:

  1. They do not differentiate between climate change (i.e. Earth’s climate has always been and will always be changing, regardless of human activity) and Climate Change (i.e. the amount that humans are adding – which may or may not be negligible – on top of the lower case climate change that was already happening).
  2. Anything bad that happens, from a hurricane to a plane crash to a bad date, can and will be tied to Climate Change.  Here is just one example:  Why Climate Change and Terrorism are Connected
  3. Nothing in the world is more important than Climate Change!  Here’s a great example from Twitter:
  4. Environmentalism is their religion and not believing in Climate Change is a heresy. Since they don’t differentiate between climate change and Climate Change (see number 1 above), your heresy of daring to question Climate Change will be ridiculed in a manner that would make both Torquemada and Alinsky proud.
  5. Last and most important, WE MUST DO SOMETHING ABOUT IT!  By “we,” they mean government, and by “do something about it,” they mean spend money on it.  So properly translated from Climate Change Zealot into English, GOVERNMENT MUST SPEND MONEY ON IT!

But I’m Not A Scientist!

OK, so now  you know who you’re dealing with, but you’re worried that since you’re not a scientist you won’t know how to talk to a Climate Change Zealot.  Trust me when I tell you:  this should be the absolute least of your worries.  Not being a scientist has certainly never stopped a Climate Change Zealot from having an opinion, and it shouldn’t stop you.  All you need to know about science are the basics, and the most basic of basics is the scientific method, which I’ll review for you here.

The Scientific Method

The University of California Riverside has a nice little slide show about the scientific method.  The Science Buddies website presents the scientific method as a flowchart.  Regardless of how you visualize it, the scientific method boils down to four very basic steps:

  1. formulate a hypothesis
  2. design an experiment to test the hypothesis that isolates only the thing you are testing
  3. analyze data from the experiments (usually with statistical tests)
  4. determine whether your data support your hypothesis or not

To illustrate how the scientific method works, I will use my son’s fifth grade science fair project as an example.  He had heard that batteries kept in the refrigerator and then used at a later date lasted longer than batteries kept at room temperature, so he formulated the following hypothesis:  “AA batteries kept in the refrigerator will power a small motor longer than AA batteries kept in the kitchen drawer.”  He then used a model train motor to push the = button (having first entered 1 + 1) on a calculator until the battery powering the motor ran out.  By looking at the number after the motor stopped running, he could tell how long the battery had lasted.  He repeated the test 20 times, ten with batteries that had been kept in the refrigerator for a month, and 10 with batteries that had been kept in the kitchen drawer for a month (yes, I know, ideally they would have been kept in those locations for a year or two, but kids only get a couple of months for their science fair projects).  After analyzing the data, he found that they did not support his hypothesis.  That doesn’t mean putting batteries in the refrigerator isn’t a good idea, there just wasn’t a statistically significant difference between how long the refrigerator batteries lasted and how long the kitchen drawer batteries lasted.  As a consumer of batteries, you probably wouldn’t put them in the refrigerator without additional information.

OK, now you’re as smart as a fifth grader, and probably smarter than a Climate Change Zealot.  Let’s start the conversation.

Agree That the Climate Changes

Remember, Environmentalism is the religion of the Climate Change Zealot and you won’t even be able to have a discussion if you are found guilty of the heresy of being a Climate Change Denier.  One of my favorite mantras when dealing with CCZs is “the climate changes, the climate has always changed, the climate will always change.”  Sometimes they make it easy for you and ask “Why don’t you believe in climate change?” The answer is simple: “I do believe in climate change.”  Here are some great examples.

Drought is not a modern phenomenon.  Human and animal populations have been moving to find water since there were humans and animals.  A great example of the impact of (lower case) climate change on humans is how drought contributed to the collapse of Mayan society over 1000 years ago, well before Climate Change can be blamed (unless time travel is equally to blame).  This article is from the Washington Post, lest you be accused of citing a right-leaning source:

More evidence Mayan civilization collapsed because of drought

Rising sea levels are also nothing new.  Once upon a time, you could walk from London to Brussels.  Ask your friendly neighborhood Climate Change Zealot if he or she has heard of Doggerland.  If not, invite them to read this informative primer from National Geographic:

Doggerland – The Europe That Was (The British Isles were once neither British nor isles)

The human race survived the rising sea levels following the Last Glacial Maximum, we survived the droughts of 1000 years ago, and we will survive whatever changes the future holds.

The climate changes.

The climate has always changed.

The climate will always change.

Ask the Climate Change Zealot What, Specifically, They Want to Do

Now that you have both agreed that the climate changes, don’t let the Climate Change Zealot argle bargle at you ad infinitum with nonsense.  Ask for specifics.  Be blunt.  Tell the CCZ that you really want to agree on something, so ask what one specific thing they want to do differently.  At this point, most CCZs will throw a link at you, and it will probably be to a 100 plus page Climate Change study from at least five or ten years ago.  Thank them for the reference and ask what page you should look at for the specific policy proposal they are recommending.  Just one specific policy proposal.  If they can’t offer a single specific policy proposal, continue the conversation later when they can be more specific.

Ask the Climate Change Zealot How Much It Will Cost

Wow, if you’ve gotten this far you have found a truly special Climate Change Zealot.  Remember, and this is very important, don’t argue the merits of the specific policy proposal.  Just ask how much it will cost.  If they say it doesn’t matter, tell them that you are very interested in being won over to their cause, but as a fiscally responsible working adult and taxpayer, you are interested in the cost.  If they do manage to come up with a number, find out if that is the total cost or an annual cost.  Most government budget proposals aren’t straightforward, and they have hidden sustainment tails that aren’t always obvious.  For example it may only cost $100 million to set up a program, but that doesn’t include the sustainment costs of keeping the program going for the next 5 or 10 or 50 years.

Ask the Climate Change Zealot How Much It Will Cost to Do Nothing

A great example here is rising sea level.  I live literally (and I mean literally literally) a stone’s throw from the ocean.  I do not say this idly as someone speaking from Lebanon, Kansas (the geographical center of the contiguous United States, for those of you not in the know).  Humans know how to deal with rising sea levels.  We simply move away from the ocean.  Yes it costs money and causes heartache, but at some point reasonable people have to consider whether it makes more sense to try to stop the whole f***ing ocean or to just move a mile or two away.  Just a thought.  But seriously, you really should ask the CCZ for the business case analysis of DOING SOMETHING versus doing nothing.  In the unlikely event that the analysis has even been done, it may turn out that it is more cost effective to react to climate change than to try to change the climate.

And Speaking of Trying to Change the Climate…

Well hopefully you won’t get this far (most people don’t), but if you do, this is where that little lesson on the scientific method will be helpful.  Let’s assume for the moment that your CCZ has a specific policy proposal in mind, knows the price tag, knows how much it will cost to do nothing, and the quoted price tag is significantly less than the cost of doing nothing.  Now you must ask the Climate Change Zealot about the science behind his pet policy.  Ask for specifics on how he knows it will work.  Ask for peer-reviewed journal articles supporting the hypothesis that this policy will have the desired impact on the climate.  The CCZ will almost certainly not be able to provide these, but in the rare case that he does, please do get in touch.  I would be very curious to both read such an article and meet the one Climate Change Zealot who actually understands the scientific method.

In Summary

It is entirely possible that there are one or two policies out there that make both scientific and fiscal sense.  The best way to effectively combat the Climate Change Zealot is to think of yourself as Indiana Jones and to think of a scientifically feasible and fiscally responsible environmental policy as the Holy Grail.  Be genuinely curious when you engage with a CCZ.  If you ask this series of questions with the honest intent of finding this proverbial Holy Grail, you will have a much more meaningful exchange with the Climate Change Zealot, you will (hopefully) not be branded a heretic, and through your patient questioning you may just win over a rare convert.

You Can’t Fight City Hall (At Least Not Without a Time Machine)

Earlier this year (May 9, 2015, a Saturday, to be exact), I got one of those late night phone calls that all parents dread.  Fortunately it turned out to be not all that bad.  My 18-year-old son and my 12-year-old Mini Cooper were stranded on the side of a dark and lonely highway, where the fully fueled car refused to start.

After reminding my son that the safest place to wait was in the car, I called a tow truck.  I asked my son to have the tow truck driver bring the car to a mechanic we had used in the past, and started walking from my house.  I arrived at the corner of Market & 17th at about the same time as they did, and we realized there was a spot right next to the shop.

Unfortunately, that entire side of the street was marked as No Parking, ostensibly for street sweeping, during the wee hours of Monday, Wednesday and Friday mornings.  I asked the tow truck driver if he could get the car into my parking garage, but he said it was not possible due to the overhead clearance.  We finally decided that the best choice at that moment (nearing 1 am Sunday morning) was to unload the car and park it in the space next to the shop.

As soon as I got home, I called and emailed the shop, hoping that someone might check on Sunday when they were closed, but got no reply.  I also did some research online and found that the City of San Diego did not actually sweep the streets during the posted times, even though they were still issuing tickets.  I checked on the car throughout the day, looking for a space within a block or two where I might push the car, but had no luck.  I went back as late as midnight, but finally had to get some sleep.

I went back as soon as the shop opened Monday morning, and sure enough I had a $52.50 ticket for parking during street sweeping hours.  I later found out that the Mini Cooper had suffered a broken timing belt and would need to have the engine replaced (to the tune of approximately $5000), so I ended up selling it for parts and buying a new car.

Heaped on top of everything else that had happened, that parking ticket was really bothering me, so I looked up the parking citation appeal procedure.  One of the questions they ask is “Were there mitigating circumstances that prevented the driver from complying with the relevant parking regulation and, if so, did the driver take reasonable and timely steps to cure the violation?”  I felt that everything I had been through would certainly qualify as mitigating circumstances and I had most definitely taken “reasonable and timely steps” to get my car off the street as soon as I could.

Of course, as I’m sure you guessed, my initial appeal was denied.  That’s when I requested a hearing.  My hearing date was set for tomorrow, September 30, 2015.  Last week, I received this notice in the mail.  It is dated 9/10/2015:


Apparently the evidence I would have presented tomorrow would not have been good enough.  Obviously at this point I’m not even going to bother to show up.  At least I don’t think I am.  I mean, you know, who knows?  Years from now I might come back in my time machine.  Then again, if I had a time machine I never would have gotten the ticket in the first place.

Hector: Thunderstorms over the Tiwi Islands in the Maritime Continent


Hector from Gunn Point, Northern Territory

Three articles involving the thunderstorm phenomenon known as Hector were investigated. These storms take place over the Tiwi Islands, which are located approximately 80 km north of Darwin, Australia, during monsoon transition periods (November to December and February to March). Since the islands (Bathurst to the west and Melville to the east) are only separated by a narrow channel (Apsley Strait), they are treated as a single island in all three studies (see Figure 1, Beringer, et al.) and the total dimensions are approximately 150 km east to west and 60 km north to south.

Figure 1

Two of the articles attempted to describe and classify the thunderstorms themselves. Beringer, et al. used satellite imagery and soundings from the Darwin airport while Crook used linear and nonlinear models. The third article used data from the Maritime Continent Thunderstorm Experiment (MCTEX) to describe the diurnal cycle of the boundary layer.

All three articles recognized the existence of two wind regimes and also noted various modes of development or non-development. Only Beringer, et al. related the importance of Hector to the global climate: “[T]he Tiwi Islands heat the atmosphere from below…result[ing] in convective towers that penetrate upward carrying latent heat into the upper troposphere…resulting in the transport of heat and moisture that provides a meridional energy balance” by driving the Hadley and Walker circulations which are “vital to global atmospheric circulation.” (Beringer, et al., p. 1022) The other two studies focus very narrowly on the Tiwi Islands, never mentioning global implications.


All three studies took advantage of data from MCTEX, which was conducted in November and December of 1995, and an earlier experiment, the Island Thunderstorm Experiment (ITEX), that was conducted in 1988 and 1989. Schafer, et al. made extensive use of the MCTEX data to describe the boundary layer while Crook and Beringer, et al. relied on the same data for initialization and validation. All three studies compared and contrasted their results with ITEX data.

Beringer, et al. used infrared images from the Japanese Geostationary Meteorological Satellite between 0700 and 1800 local time (all times will be reported in local time which is UTC + 9.5 hours). They also took advantage of the 0730 radiosonde soundings at the Darwin airport. From these two sources they determined convective available potential energy (CAPE), precipitable water (PW), wind shear at the 600 hPa level, surface and 700 hPa wind speeds, convective inhibition (CIN) and the bulk Richardson number (BRICH). These values were used to sort 55 unambiguous event days (which were also not complicated by widespread oceanic convection) into four modes: Hector, suppressed Hector, no Hector, and late developing Hector.

While Beringer, et al. relied on soundings from the Darwin airport, Schafer, et al. took advantage of a comparatively dense network of sensors on Bathurst and Melville Islands. This network consisted of 15 automatic weather stations, three boundary layer wind profilers (levels of  every 100 m up to 2000 m and every 300 m up to 20 km), radiosonde launches every two hours at one location, a Doppler weather radar, a remotely controlled aircraft (aerosonde) and two all sky cameras. These observations were used to determine horizontal winds, mean virtual potential temperature, boundary layer depth, air temperature, and convergence. Horizontal and vertical variations of these descriptors were used to characterize the development of the boundary layer.

Rather than collecting or interpreting data, Crook used a linear and a nonlinear model to approximate the environment. The microphysics, topography and island shape were held constant in both models. Five parameters (surface wind speed, surface wind direction, surface flux of moisture, surface flux of heat and low-level moisture) were varied and each case was compared to a control experiment. Typical values for the control experiment (as well as a typical wind profile) were derived from MCTEX data.

Wind Regimes

All three studies recognized the existence of two dominant wind regimes. The east to northeasterly regime resulted in development on the western side while the west to southwesterly regime resulted in development on the eastern side. Beringer, et al. found a majority of the 55 cases they studied were in the easterly group while Schafer, et al. had eight cases in the easterly group and nine cases in the westerly group. Crook used only the westerly regime in his studies and demonstrated that convection was favored when winds were parallel to the major axis of the island. Only Beringer, et al. argued that storms in easterly flow had a larger areal extent (consistent with an earlier study: Down Under Doppler and Electricity Experiment) while storms in westerly flow had greater vertical development (as evidenced by -700 C cloud top temperatures instead of -600 C). This was explained by enhanced convection in the westerly regime due to advection of moist oceanic air over land.


Crook offers a good discussion of the historical understanding of Hector. Prior to MCTEX, it was hypothesized that sea breeze convergence over the island was the main trigger for convection. MCTEX demonstrated that sea breezes seldom collided. This led to a new explanation with two modes of development. The most common (80% of Hector events) is due to the collision of one of the sea breeze fronts with an evaporatively produced cold pool and is termed “type B”. This is similar to the “Hector” mode described by Beringer, et al., but also seems to lump the mode Beringer, et al. terms “suppressed Hector” into the same group. 36 out of 42 storm events studied by Beringer, et al. were either determined to be in the Hector mode or the suppressed Hector mode. This gives a frequency of 70%, very similar to the 80% mentioned by Crook.

The other 20% of events were “type A” according to Crook (who takes his categorization from a 2000 paper by Carbone, et al.). Type A Hectors owe their convergence to the collision of the two sea breeze fronts. This is analogous to the “late developing Hector” mode described by Beringer, et al. 14 of 46 or 30% of developments were determined to be late developing. Although Schafer, et al. were studying boundary layer development rather than the development of the actual Hector events, they also described a difference between early (type B after Crook and Hector/suppressed Hector after Beringer, et al.) and late (type A after Crook and late developing Hector after Beringer, et al.) developing events. They noted specifically that storms occurring after 1330 had a better developed boundary layer (~2 km deep) while storms occurring prior to 1330 had a shallower boundary layer (~1.5 km).

Based on Crook’s nonlinear moist model runs, he determines that low-level moisture (represented in his Figure 2 – originally Crook’s Figure 15 – by CAPE) is the primary factor in determining which mode will occur. From this figure, it can be seen that large CAPE results in type B development while small to moderate CAPE results in type A development. Beringer, et al. did not rely on a single parameter but rather the combination of low-level moisture (CAPE), CIN and shear (whereas Crook used a constant shear based on MCTEX data and does not consider CIN). They conclude (as is summarized in Table I) that large CAPE combined with large shear and large CIN lead to type A or late developing Hector. This contradicts Crook’s conclusion.

Figure 2. Total condensate against time for simulations with upstream CAPEs of 1000, 1500, and 3000 J/kg. All measures are normalized by the maximum value from the control experiment.

Figure 2. Total condensate against time for simulations with upstream CAPEs of 1000, 1500, and 3000 J/kg. All measures are normalized by the maximum value from the control experiment.

What is conspicuous about Table I, however, are the large standard deviations, especially for CAPE. Schaefer, et al. found that variability in boundary layer characteristics was minimized when sea breezes are most active, between 1000 and 1400. This helps to explain the large variability in Table I since 0730 soundings were used.

Table 1

Unique Findings of Each Study

Up to now, the overlapping areas of each study have been examined for similarities and differences. This analysis could only be carried so far since each study had its own unique objective. Exciting findings from each paper that do not necessarily overlap with the other two will now be discussed.

    • Evolution of maritime continent thunderstorms under varying meteorological conditions over the Tiwi Islands (Beringer, et al.)

      This study was the only one concerned with conditions leading to the most rare situation, the non-Hector. Beringer, et al. first discuss the suppressed Hector development mode, which is most likely due to suppression by pre-existing convection from a squall line moving through the area consuming CAPE. Although the non-Hector mode is also characterized by low CAPE, the presence of large shear (as opposed to small shear in the suppressed Hector development mode) indicates a different mechanism is responsible for this mode than for the suppressed Hector mode. Two proposed explanations were (1) mid-level subsidence combined with advection of dry continental air over the islands and (2) existence of residual cloudiness from previous deep convective activity over the ocean.

    • Understanding Hector: The dynamics of island thunderstorms (Crook)

      Upon recognizing that a majority of Hector events are not due to convergence of the two sea breezes, Crook proposes that perhaps a peninsula will produce the same results as an island. For the linear case, rainwater decreases by a factor of approximately two when a peninsula is used. For the nonlinear case, very little convection occurs over the peninsula (which has the northern Tiwi Islands coastline). From this he concludes that although sea breeze convergence is not the primary mechanism, interaction between the sea breezes and cold pools is enhanced by the proximity of the two coastlines and thus that an isolated heat source is a necessary condition for the Hector convective system.

    • Boundary layer development over a tropical island during the Maritime Continent Thunderstorm Experiment (Schafer, et al.)

      As mentioned previously, the first two papers are similar in that they strive to classify the Hector thunderstorm event. This paper practically ignores the thunderstorm events while it focuses on the development of the boundary layer throughout the diurnal cycle. Because of this, it was the only study to investigate the overnight environment and to describe what happens to reset it such that development can occur again the next day.  After sunset, a surface-based temperature inversion forms. A remnant mixed layer persists over the surface inversion until it is replaced by advection of an oceanic mixed layer over the island. Without this oceanic mixed layer, convection for the following day would be suppressed.


The three articles discussed took very different approaches to the same phenomenon. Beringer, et al. used available data (satellite images and airport soundings) to study the different wind regimes and development modes of Hector thunderstorms over the Tiwi Islands. From the reader’s standpoint, this was the best paper by far since it emphasized the importance of understanding Hector to making more accurate global predictions.

Crook approached the problem dynamically by applying linear and nonlinear models. In this manner, he was able to limit variability to one parameter at a time in order to investigate its effect on convection. Although conclusions about the different modes of Hector did not agree exactly with Beringer, et al., the importance of low-level moisture content was demonstrated. One of the main shortcomings of this study was the failure to investigate the easterly wind regime.

The most expensive of the three studies was certainly Schafer, et al. since it relied almost solely on data collected in situ with multiple sensors (rather than taking advantage of previously collected data sets). This paper was also the most difficult to compare and contrast with the other two since it focused on boundary layer development rather than the thunderstorms themselves. An important conclusion was the resetting of the mixed layer by oceanic air.


Beringer, J., N. J. Tapper, and T. D. Keenan, 2001: Evolution of maritime continent thunderstorms under varying meteorological conditions over the Tiwi Islands. Int. J. Climatol., 21, 1021-1036.

Crook, N. A., 2001: Understanding Hector: The dynamics of island thunderstorms. Mon. Wea. Rev., 129, 1550-1563.

Schafer, R., P. T. May, T. D. Keenan, K. McGuffie, W. L. Ecklund, P. E. Johnston, and K. S. Gage, 2001: Boundary layer development over a tropical island during the Maritime Continent Thunderstorm Experiment. J. Atmos. Sci., 58, 2163-2179.