Friday, April 18, 2014

Climate Change Impacts and Mitigation

Some interesting things about climate change in Central America is about tropical convection.  A warm season precipitation has been dominate in Central and South America.  Over the past few decades the Amazon rain forest has had more rain than usual.  Displacement of the  South Atlantic Convergence Zone has given this region a positive precipitation trend.  It shows how some changes can actually help other areas of the world.  Information from: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch11s11-6-1.html

Rising temperatures is a big issue in Central America.  The temperature is going to rise which will cause plants to die out from lack of water.  Temperature will also cause certain crops to fail and livestock productivity to decline.  Warmer sea water temperatures will harm to coral living in this area.  Sea levels are projected to rise causing more flooding.  Warmer temperatures will also effect precipitation and how much water is readily available for our use.  Information from http://www.ipcc.ch/publications_and_data/ar4/wg2/en/spmsspm-c-11-latin-america.html

There are many different ways climate change effects Central America.  There has been changes in precipitation along with higher temperatures.  There is more severe weather and some of the severe weather is not usual for this area.   There is also a risk that species that will go extinct from higher temperatures.  There is also a concern  for the amount of water readily available in the future.  Information from http://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch13s13-es.html

 I think the most interesting threat is severe weather in recent years.  This is because when severe weather hits it usually affects everyone and there is nothing you can do to stop it.  Flooding can destroy homes and lives and will cost a lot of money for rebuilding.  On the other hand droughts will cause a lack of food and water for the people.  Central America has also seen an increase in hurricanes and even some tornadoes which is no usual for this area of the world.  The increase of severe weather will always have a negative impact on the population it affects and there isn't much anyone can do to stop it.


This is the rain totals for El Salvador in a 10 day period in 2011 due to warming waters. Picture from: climate


picture from here: el salvador


Thursday, April 10, 2014

Severe Weather in El Salvador

Tornadoes go through different stages of development.  First the vortex tube, a rotating body of air at the ground, forms from vertical wind shear.  Vertical wind shear is change in wind with height.  Next the horizontal rotating air is lifted off the ground by the updraft of a thunderstorm.  Once the horizontal rotating air is lifted vertically it is considered to be a mesocyclone.  Finally the mesocyclone is fully developed in the updraft of a thunderstorm and then a tornado will form.

In the United States tornadoes typically flow from southwest to northeast.  This is because thunderstorms more in this direction due to air flow and tornadoes flow the path of thunderstorms.  Tornadoes have occurred in El Salvador but are very rare.  The United States records an average of over 1000 tornadoes per year (noaa.gov).  El Salvador, however, averages zero tornadoes each year (ustornadoes.com).


photo from island.net
Above is a picture of tornado occurrences globally.  El Salvador is in the region where there is no orange.  This is because most tornadoes occur in latitudes 30-60 N and S.  Obviously there is always exceptions but El Salvador doesn't usually have the weather conditions needed for tornadoes to occur.

noaa.gov
Above is the annual tornado count since 1950.  The statistics have gone up and seem to keep increasing most years.  This might not actually be the case because a lot has changed since 1950.  First, we have better technology to predict and track storms.  We are much more accurate in predictions and forecasting severe weather more accurately.  Secondly, the United States has developed more and more over the years and what could have been farm land a few years ago can now be homes.  It is very possible that tornadoes occurred but were not reported and recorded.


Hurricanes are another form of severe weather.  They need three basic things in order to form.  First, a warm ocean temperature because the storm needs to evaporate a lot of warm water to form.  Second, the water needs to be warm deep in the ocean.  This is because when the wind is moving the water the layers deeper down are still warm enough to produce the storm.  Third, the coriolis force is needed to create the spinning.  

Hurricanes are called different things in different places.  The storm is called a hurricane in the Atlantic and East Pacific.  The storm is called cyclones in the Indian Ocean near Australia.  The other name they have is typhoon and they use this term off the coast of China and and Indonesia.

learnnc.org
In the United States hurricanes travel from east to west.  Once they hit land they travel north.  When hurricanes are over water they are directed east to west by trade winds and once they move into higher latitudes they are moved by the westerly winds.

Hurricanes do occur in El Salvador.  On average there are 6.1 hurricanes in the United States but only an average of 1.74 hurricanes make landfall each year (noaa.org).   There has only been 15 hurricanes recorded in El Salvador.  That is less than 1 hurricane per year.