Monday Mar. 10, 2014

We'll be talking about Micronesia near the end of today's class and Spring Break is looming on the horizon.  So some music with a tropical theme seemed appropriate: Israel Kamakawiwo'ole "Over the Rainbow/What a Wonderful World" and
"Ka Huila Wai". 

An Optional Assignment was collected today.  You should definitely review the answers that are now online before this week's quiz.

The Experiment #2 reports have been graded.  Normally you would have two weeks to turn in a revised report but that would mean a Mon., Mar. 24 due date (the Monday after Spring Break) so I'll give you until Fri., Mar. 28.  Please return the original report with your revised report.  And note you don't have to revise your report if you're happy with the present grade.

And there was an In-Class Optional Assignment today.  If you would like to download the assignment and turn it in before the quiz on Wednesday you can earn at least partial credit.

A little bit of a detour in class today


How would you describe Tucson's climate?  Hot and dry?  You're basically conveying information about temperature and precipitation.  Here we'll just concern ourselves with temperature.  It does get pretty hot in Tucson in the summer.  But it doesn't stay hot all year.  With just two numbers, (i) the annual mean or annual average temperature and (ii) the annual range of temperature you can give someone a pretty complete idea of the temperature in Tucson and how it changes during the year.  More detailed statistics for Tucson are available at this Tucson climate data link.

There are three or four main factors that determine a region's annual mean and annual temperature range.


Latitude affects both the annual mean and the annual range of temperature.  The polar regions have colder annual average temperatures than any other location on earth.  As we'll see, some of the other controls of temperature work together with high latitude to make Antarctica and the South Pole colder than the North Pole.  The hottest regions on earth are found near 30 latitude, not at the Equator (you'll find some discussion of this on pps. 79 and 80 in the photocopied ClassNotes which was part of the Causes of the Seasons 1S1P topic but wasn't discussed in class)

The annual range of temperature increases with increasing latitude.  There is little or no seasonal change at the Equator.

A region surrounded by land will have a much larger annual range of temperature than a region surrounded by or near a large body of water.  Oceans are slow to warm during the summer and slow to cool during the winter.  This is partly because water has a higher specific heat than soil.  Some other factors come into play.  The figure below tries to explain why soil and water warm at different rates during the summer

Water has a higher specific heat, it takes more energy to warm a gram of water than to warm a gram of soil.  Additionally, some of the incoming energy is used to evaporate rather than warm water.  Incoming sunlight penetrates into a body of water and is used to warm a larger mass of water.  These three factors mean that water will warm more slowly and won't get as hot during the summer as land.  If you've ever been to the beach in the summer you probably remember  that the sand on the beach gets much hotter during the day than the ocean water.

The table below summarizes the three controls of temperature that we have covered so far.  One of them affects both the annual mean and annual range, one affects just the mean, and the other just the annual range.

One final factor:

Cities on the west coast and east coast of the US can have very different climates even if they are at the same latitude and altitude.  A cold southward flowing ocean current is found along the West Coast.  The warm Gulf Stream current flows northward along the East Coast.  Winds at middle latitudes generally blow from west to east.  The city on the West Coast will feel the full moderating effect of the ocean.  The city on the East Coast will be affected by the Atlantic Ocean but also by winds blowing across the interior of the US.

A graphical summary.  You find cold locations over land at high latitudes (Northern Canada, Siberia).  Antarctica is the coldest region because it is found at high latitude, is a land mass, and much of Antarctica is high altitude.  The hottest regions on earth are found in the middle of land masses near 30 latitude.  Death Valley is the hottest location in the US (and one of the hottest locations on earth).  Death Valley is found near 30 degrees latitude, is in the middle of a land mass, and some parts of Death Valley are below sea level altitude.

What kind of climate would you expect to find at Point X, on the map above, near the Equator in the middle of the Pacific Ocean? 

We'll answer that question but first you must hear about an awesome field experiment that I took part in several years ago.  What is the tie in with this class?  A good part of the experiment was conducted at a relatively small island near the equator in the middle of the Pacific Ocean.  Now that we have just learned about some of the factors that control/determine a region's climate you should understand that there is very little change from summer to winter in regions like this.  I think you'll be surprised how little change there sometimes can be.


The photograph above appeared on the cover of the April 1994 issue of the Bulletin of the American Meteorological Society.  If you look closely you might recognize one of the two bald men in the photo.  This photo was taken on Kapingamarangi Atoll (shown on the map below, see pps 81 & 82 in the photocopied ClassNotes), shortly before part of the research team was to board ship and leave Kapingamarangi.  The remaining group members were going to remain behind and operate all of the research equipment. 

What we were doing on Kapingamarangi?  We were a small part of a much larger field experiment.  Our job was to install the tall white lightning detector at the left edge of the photograph.  We would later travel to Rabaul (on New Britain island) and Kavieng (New Ireland island) in Papua New Guinea and install two more detectors.  Papua New Guinea would turn out to be a very different place.  Until recently some of the highland tribes there practiced cannibalism and shrunk heads.   You can also get some very nasty strains of malaria in Papua New Guinea.





To get to Kapingamarangi you first need to fly to Pohnpei (an island in the Federated States of Micronesia).  The route is shown above.  Then you take a cargo ship for about a 4 day sail to Kapingamarangi.  We had intended to fly to Pohnpei, set sail for Kapinga the next day, and then spend about a month on Kapingamarangi.  The ship however was delayed 3 weeks.  That gave us plenty of time to visit the island of Pohnpei but ultimately meant we could only spend a few days on Kapingamarangi.  Here's a picture of the airport at Pohnpei.  Note the runway runs from one edge of a small island to the opposite edge.



Pohnpei is a fairly large island and, together with some of the other Micronesian islands, is a popular, world-class, snorkeling and scuba diving destination.   Here's a picture of Kolonia (the airport is at the left end of the causeway in the photo), the largest town on Pohnpei.  Kolonia has a weather station that is operated by the US National Atmospheric and Oceanic Administration (NOAA). 

Pohnpei is located at low latitude in the middle of the Pacific Ocean.  Both of those factors will reduce the annual range of temperature.  How large do you think the annual range is?


The following precipitation data show that Pohnpei is also one of the rainiest locations on earth

Close to 400 inches of rain may fall in the interior of Pohnpei.  The rainiest location on earth is in Hawaii with about 460 inches of rain per year.

Pigs are also an important part of daily life on Pohnpei, Kapingamarangi, and the other islands in Micronesia.

After we had finished our work in Micronesia and had traveled to Papua New Guinea, I began collecting carved wooden pigs from some of the local carvers.



The Micro Glory (shown below) sails back and forth between Pohnpei and Kapingamarangi about once a month.  The ship carries supplies to the people on Kapingamarangi and some other small islands.  They pay for the supplies with pigs (the pigs are sold on Pohnpei).  We shared deck space on the Micro Glory on the trip back to Pohnpei with 20 to 30 pigs (they were hoisted aboard in nets)


Most of the lower deck in the photo above (under the hoists) was occupied by pigs on the return trip.  One of the pigs died on the return trip - that was a very serious matter.

We also had a chance to sample some of the local beverages.


Drinking sakau (as it is called on Pohnpei) turns your mouth and throat numb.  It is supposed to relax you, make you sleep more fully, and doesn't seem to have any after effects.  Until fairly recently you could buy kava in pill form at local supermarkets.  However, because of reports that it can cause serious liver problems, that is no longer the case.  There are no reports of liver problems when drinking kava that has been prepared in the traditional way.  Here is a link to a Wikipedia article on kava.

We never tried betelnut.  Areca nuts are wrapped in betel leaves and chewed together with lime (lime is pretty caustic, that is one of the reasons I didn't try betelnut).  The resulting mixture is a mild stimulant (some people add tobacco to the mix).  The most interesting aspect, however, is that chewing betelnut colors your mouth and teeth bright red.  You don't swallow betelnut, you spit it out.  You see the bright red stains on sidewalks and the ground wherever you go.  Most hotels will also have a large sign near the entrance reminding guests not to chew betelnut inside the hotel.  You can read more about betelnut here.

During the spring semester I sometimes suggest you might consider a trip to Pohnpei for Spring Break.  The last time I checked a roundtrip flight from Pheonix to Pohnpei (by way of Honolulu, Guam, and Houston on the return flight) wasrunning about $3400.