Monday News and Links

  • With the Olympics wrapping up in London last night, here’s a very cool interactive map that illustrates the medals breakdown by country.
  • By far my favorite Olympic news item of the last two weeks was the Australian newspaper that rebranded North and South Korea the “Naughty” and “Nice” Koreas, respectively.
  • The ever increasing availability of global air travel prompted researchers at MIT to study the role of U.S. airports in the spread of infectious and potentially epidemic diseases.  They rank 40 of America’s largest airports in their susceptibility at spreading an infectious disease based on factors such as traffic, connectivity, geography, and even average wait time.  You can watch a short video they produced here, and you can read more about the study, including the ranking, here.
  • In a decidedly more light-hearted use of GIS, a data scientist at Twitter used the social media platform to determine which areas of the country refer to soft drinks as “pop” and which refer to them as “soda.”  Although a glib and somewhat superfluous finding, the study is a really great example of the way social media can be used as raw data in geographic inquiry.

Geographic Phenomenon: Contrails

You are probably familiar with contrails — the thin, vaporous streaks of what looks like engine exhaust left in an airplane’s wake.  What you might not realize, however, is that these vapor trails are not in fact engine exhaust, but artificially-induced clouds resulting from temperature and pressure disturbances airplanes create as they travel through the atmosphere.

“Jet Trails, 2007” from artist Chris Jordan

Contrails generally arise in one of two ways, depending on atmospheric conditions.

  1. First, and most frequently, hot water vapor released as a by-product of jet fuel combustion comes into contact with cold air at high altitudes causing the water vapor to condense into visible, cloud-like contrails.
  2. Less frequently, pressure differences created by the wingtips of aircrafts traveling through extremely humid, water-saturated air can be great enough to induce water condensation and contrail formation.  These pressure differences at the wingtips are called wingtip vortices, and their contrails look like this.

Again, depending on atmospheric conditions, contrails can either last a long time or dissipate quickly.  In humid air, which allows contrails to hang around well after their creation, the initial water condensation can sometimes induce further water condensation, and even full cloud formation.

Contrail patterns over Florida, Georgia, Alabama, and South Carolina (Photo credit: Courtesy NASA Langley Research Center)

Scientists believe that increased air travel, resulting in increased contrail formation, is having a significant effect on global climate patterns.  The high cirrus clouds that persistent contrails often resemble are known to trap the sun’s radiative energy, which has a net warming effect on atmospheric temperature.  Whether this contributes to global warming is, like all things climate change related, up for debate.  Interestingly, nearly all of the data linking contrails to global climate were collected in the three days following the September 11th attacks during which all commercial air travel was suspended over the United States, an unprecedented event in aviation history.

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