Few Degrees

Global average temperatures are expected to increase by about two to thirteen degrees Fahrenheit by the end of the century. That small change in global average temperature can lead to really large changes in the environment. Only a few degrees have made the difference between ice ages, temperate periods, and a hothouse Earth with green poles. During the last ice age, global average temperatures were only seven to thirteen degrees Fahrenheit colder. About 125,000 years ago, average temperatures were only a degree or so warmer than today, but sea levels eventually rose as much as 20 feet higher.

Small changes in the global average temperature also mean heat waves get hotter and droughts get drier. This happens when small changes in the way air and water circulate around the globe take place. For instance, during the wetter and cooler climate of the last ice age, the Great Basin of California was filled by a great lake ringed with pine forests. When the climate became warmer and drier at the ice age's end, the lake dropped 500 feet and lost 90% of its surface area. The pine forests became sagebrush desert. Such changes in precipitation could be just as important as temperature increases for many parts of the Earth.

Some places and some years are going to be warmer or cooler than average. However, summers will get hotter, not only because of higher temperatures but also because humidity will increase. In addition, models predict that in many places, an extreme heat event that we only see once every twenty years today will happen once every three years by the middle of this century. Winters will also be warmer in many places, reducing heating bills. The number of days with frosts is likely to decrease. This means more snow may fall as freezing rain, making ice more of a problem for humans.

http://www.meted.ucar.edu/broadcastmet/climate/print.htm#page_2.0.0

Evidence of Climate Change

Snow and ice reflect the sunrays back to the atmosphere. Without snow and ice, more water can evaporate into the atmosphere where it acts as a greenhouse gas. The ground will then absorb more heat. Snow and ice are melting at rates unseen for thousands of years, and this has profound climate consequences.

Spring snow cover has decreased since 1922 at an average rate of about two percent per decade in the Northern Hemisphere, including a steep five percent drop during the 1980s. River and lake ice don't last as long as they used to either. As permafrost melts in the vast northern tundra, trees locals colorfully call drunken trees are falling over and buildings are crumbling as the ground disintegrates beneath them.

Glaciers have been shrinking across the globe with a few exceptions. In Glacier National Park, for example, there were 150 glaciers in 1850. Today, there are 26. In Switzerland, the Tortin Glacier, which supported a local ski area, shrank so much that the Swiss put a city-block sized insulating sheet over the glacier's edge to slow its retreat. Sea ice is becoming smaller and smaller too especially in the Northern Hemisphere. Satellites have seen average Arctic sea ice shrink by 2.7 percent per decade from 1978 to 2006, with faster melting in summer. In summer 2007, the Northwest Passage north of Canada became navigable for the first time as the polar cap melted to its lowest level on record. 30 years faster than IPCC scientists had predicted. 2008's melt was second only to 2007. 

http://www.meted.ucar.edu/broadcastmet/climate/print.htm#page_2.0.0

Sandstorms

A sandstorm is a very strong windstorm that carries clouds of sand or dust, especially in the desert, and greatly reduces visibility. Sandstorms are also known as dust storms. This wind is usually caused by convections currents, which are created by intense heating of the ground, and is usually strong enough to move entire sand dunes. Air is unstable when heated and the instability in the air will cause the mixture of higher winds in the troposphere with winds in the lower atmosphere, producing strong surface winds. Sandstorms can interfere with travel and sometimes black out entire roads. They can be seen as solid walls of sand that are up to 5,000 high. Sandstorms usually arrive without warning and advance in the form of big wall of dust and debris.

In the United States, sandstorms are very rare due to the lack of large deserts, the development of proper agricultural techniques, and common cloud cover, which will block out some of the sun’s heat. Over grazing and excessive use of water resources can also cause sandstorms. Most sandstorms occur in spring and during the daytime. The last recorded devastating sandstorm in American history was the Dust Bowl which caused a depression.

A way to protect ourselves from sandstorms is to wear goggles and suits. People can also install special air filters in their cars to prevent sand from getting into the engine. Sandstorms do not only have the potential to damage possessive items we own but does also has the potential to harm humans. Sand particles will clog air passages and cause the person who breathes them in to choke. Dust particles may cause an allergic reaction. Sand and dust have also been known to be capable of carrying infectious diseases.



http://library.thinkquest.org/03oct/01027/sandstorm.html

Rainbows

A rainbow is a circular arc of concentric colored bands, caused by a combination of refraction and reflection of sunlight by raindrops. (Refraction is the bending of light as it passes from one transparent medium into another transparent medium.) Sunlight striking a shaft of falling raindrops is refracted twice and internally reflected by each drop of rain. A solar ray is refracted as it enters a raindrop. Then, the ray is reflected by the inside back of the drop before being refracted again as it exits the drop. Each person sees his or her own rainbow.

Because of reflection, a rainbow appears to an observer who has his or her back to the Sun and is facing a distant rain shower. A rainbow never forms when the sky is completely cloud covered. The Sun must be shining. For the reason of geometric considerations, the Sun can be no higher than 42 degrees above the local horizon in order for someone on the ground to see a rainbow. If the solar altitude is greater than 42 degrees, then the returning solar rays are not directed towards Earth’s surface. A rainbow is more likely during a morning or evening shower than a shower at noon. At middle latitudes, weather systems usually progress from west to east so that appearance of a rainbow to the east in the early evening usually signals improving weather. Rain showers are moving away toward the east and clearing skies are approaching from the west, where the Sun is setting. A morning rainbow to the west signals approaching rain.

When raindrop refraction disperses sunlight into its component colors, it forms the concentric bands of color of a primary rainbow. From outer to innermost band, the colors are red, orange, yellow, green, blue, and violet. In some occasions, a secondary rainbow appears about 8 degrees above the primary rainbow. Double reflection within raindrops produces the secondary rainbow with the order of colors reversed.

http://www.photocentric.net/rainbow_physics.htm



Features of a Hurricane

A hurricane is more than a point on weather map, and its path is more than a line. A hurricane has several futures. The main features of a hurricane are the rainbands on its outer edges, the eye, and the eye wall. Air spirals in toward the center in a counter clockwise direction and out the top in a clockwise pattern. In the center of the storm, airs sinks and forms a cloud free eye.

The hurricane’s center is known as the eye. It is relatively calm and has a clear area usually 20-40 miles across but sometimes as small as 5 miles or as large as 60 miles. When in the midst of a hurricane strong winds and rain can suddenly stop and the sky clears when the eye comes over a region. Then as soon as the eye moves out of that region rain and wind begins again but from the opposite direction.

The dense wall of thunderstorms surrounding the eye is the eyewall. The circle of thunderstorms around the calm eye has the strongest winds within the storm. Changes in the structure of the eye and eyewall can cause changes in the wind speed which is an indicator of the storm’s intensity. The eye can grow or shrink in size and could double or concentric eyewalls can also form. Concentric walls usually occur in major hurricanes. Concentric walls tend to weaken the storm but they strengthen again when a single eyewall is in place.

A hurricane’s outer rainbands can extend a few hundred miles from the center. These dense bands of thunderstorms range in width from a few miles to tens of miles. Typical hurricanes are about three hundred miles wide. A hurricane rainband is the location where a tornado usually occurs at.

http://www.meted.ucar.edu/hurrican/chp/print_2.htm



What Is a Hurricane?

A hurricane is an intense, rotating oceanic weather system that possesses maximum sustained winds exceeding 74 mph. In North America, we call this storm a hurricane. In other parts of the world, a hurricane is known by other names. In the Western North Pacific they are known as a typhoon and in the Indian Ocean and the Western South Pacific as a tropical cyclone. It forms over tropical oceanic regions. Hurricanes are generally smaller storms in mid-latitudes, typically about 500 km in diameter. In the Northern Hemisphere, the air spins inward and in a counterclockwise direction. Hurricanes depend on six conditions to form.

1.       A pre-existing disturbance providing some initial spin and flow into the system.

2.       Warm ocean temperatures (at least 80 degrees Fahrenheit) to a depth of about 150 ft.

3.       Relatively light winds that do not change much in direction and speed up through the atmosphere.

4.       A location at least 300 miles from the equator. Tropical cyclones require some of the spin provided by the Coriolis Effect.

5.       An atmosphere that cools enough with height to allow thunderstorms to develop.

6.       An atmosphere that is moist enough to fuel the thunderstorm.

Tropical cyclones are classified into four types, based on their wind speeds. These are the terms commonly used by forecasters:

·         Tropical Depression: Maximum sustained winds of 38 mph or 33 knots

·         Tropical Storm: Maximum sustained winds of 39-73 mph (34-63 kt)

·         Hurricane: Maximum sustained winds of 74 mph (64 kt) higher

·         Major Hurricane: Maximum sustained winds of 111 mph (96 kt) or higher

Hurricanes are categorized according to the strength of their winds using the Saffir-Simpson Hurricane Wind Scale.  A Category 1 storm has the lowest winds speeds, while a Category 5 hurricane has the strongest.

·         Category 1: Winds of 74-95 mph; Very dangerous winds will produce some damage

·         Category 2: Winds of 96-110 mph; Extremely dangerous winds will cause extensive damage

·         Category 3: Winds of 111-130 mph; Devastating damage will occur

·         Category 4: Winds of 131-155 mph; Catastrophic damage will occur

·         Category 5: Winds of 155+ mph; Catastrophic damage will occur

http://www.comet.ucar.edu/nsflab/web/hurricane/312.htm

Hurricane Rita

On September 18, 2005, less than a month later after Katrina had devastated the central Gulf Region, Hurricane Rita formed from a tropical depression that had formed the same day near the Turks and Caicos Islands. The storm increased intensity over the next two days, becoming category 1 on the 20^th. Later that afternoon, Rita grew to a category 2 as it passed near the Florida Keys and South Florida. It caused sustained tropical storm force winds on Key West with gusts of up to 76 mph.

Rapidly intensifying, Hurricane Rita tracked westward into the Gulf of Mexico. By the afternoon of the 21^st, Rita reached category 5 strength on the Saffir-Simpson scale, with winds of 165 mph. It became the second hurricane of the season to reach category 5 and first time in record that two hurricanes reached category 5 strength in the Gulf of Mexico in the same season.

Rita continued to intensify and reached wind speeds of 175 mph and the minimum central pressure of the storm reached to 897 mb. It became the third lowest on record for the Atlantic Basin, after Hurricane Gilbert (888 mb) and 1935 Labor Day Hurricane (892 mb).

During the afternoon of the 22^nd, Rita started to weaken due to an eye wall replacement cycle and perhaps some influence of slightly cooler sea surface temperatures. Hurricane Rita’s intensity dropped to a surface wind speed of 145 mph and continued to gradually weaken over the next 36 hours prior to landfall. Rita tracked west northwest on the 23^rd and made landfall at the Texas Louisiana border early on the 24^th at a category 3. Hurricane force winds were sustained more than 150 miles inland.

http://www.ncdc.noaa.gov/special-reports/rita.html



El Niño

El Niño is the name given to a change in the flow of water currents in the Pacific Ocean near the equator. El Niño in Spanish means the child. It was given that name because if often occurs around Christmas. Although El Niño takes place in a small portion of the Pacific, it can affect the weather in large parts of Asia, Africa, Indonesia, and North and South America.

The rotation of Earth and the exchange of heat between the atmosphere and the oceans create wind and ocean currents. At the equator, trade winds blow westward over the Pacific, pushing surface water away from South America toward Australia and Indonesia. These strong trade winds bring life giving monsoons to eastern Asia. As warm surface water moves west, cold water from the deep in the ocean rises to replace it.

Every three to five years, the trade winds slacken or reverse direction allowing winds from the west to push warm surface water eastward toward South America. This change is called the Southern Oscillation and is caused by a shifting pattern of air pressure between the eastern and western ends of the Pacific Ocean. The warm, moist air that slams into South America coast brings heavy rains and storms. At the same time, countries on the western Pacific, such as Australia, Indonesia, and the Philippines, have dry weather.

Another type of weather that follows El Niño is La Niña which in Spanish means the girl. La Niña and El Niño are opposite. El Niño is a warming trend that raises the water temperature as much as 5.6 degrees Celsius above normal and La Niña is a cooling of the waters that drops the temperature of the water as much as 8 degrees Celsius below normal.

http://www.scienceclarified.com/El-Ex/El-Ni-o.html

What is a Thunderstorm?

     A thunderstorm is millions of droplets of water vapor in the atmosphere that produce lightning, rainfall, winds, hail, and thunder. Thunderstorms form when instability in the atmosphere cause cumulonimbus clouds to form. Towards the tops of the thunderstorm water droplets become supercooled and is a region know as the anvil. This is where the thunderstorm can’t go any higher because the stratosphere is stable. The cloud starts to spread out along the bottom of the stratosphere. Dust is sucked into the cloud when growing so the supercooled water droplets come in contact with it and turn into to ice.

     If enough ice particles collide and clump together, a small hailstone will form. Forced by gravity, the hailstone falls toward the earth. If the updrafts are strong enough, the hailstone will be sucked back to the top of the storm and get bigger. This process continues until the hailstone is too large and the updraft can’t support it anymore. This causes it to fall to the earth.

     Lightning occurs when the ice particles in the cloud rub each other and cause friction which in turn charges the water droplets. Once enough charge builds between the ice particles rubbing against each other and the ground, the stage is set for lightning. A single lightning can heat the air around it to 30,000 degrees Celsius. This intense heating occurs so rapidly that air density cannot respond. The rapid rise in air temperature is accompanied by an increase in air pressure that generates a shock wave. The shock wave goes outward and produces thunder. This explains why it’s called thunderstorm.

http://michael.bsch.au.com/whatisstorm.html

Cumulus Congestus Clouds

Cumulus congestus clouds are thick fluffy clouds. Basically, water vapor starts condensing at a particular altitude, and as it rises further, it tends to drift upwards in the Earth's atmosphere. These factors play a significant role in giving the clouds its fluffy appearance. A congestus cloud has the ability to cover a significant vertical distance, which gives it a gigantic appearance. Cumulus congestus clouds are characteristics of areas of the atmosphere that are undergoing convection. They are often characterized by sharp outlines and great vertical development. Because cumulus congestus is produced by strong updrafts, it is typically taller than it is wide, and don’t reach higher than the lower troposphere.

It is the largest of the four possible species of Cumulus. Congestus can develop from the smaller humilis and mediocris species when the atmospheric conditions are unstable. This means that the way the air temperature changes with latitude tends to encourage the rising column of warm, moist air at the centre of the cloud to keep lifting higher and higher. Such convection makes the cloud swell to dreadful proportions.

Cumulus congestus clouds are also called towering cumulus. The tops of them look like cauliflower and sometimes light rain can fall from them. Congestus clouds are in the last stage of development. This stage of Cumulus is when it is at the point of maturing into a Cumulonimbus cloud. Once the top of the cloud begins to glaciate, its droplets freezing into ice crystals, the crisp edges of it soften and become more blurred. This is the point at which the cloud has officially turned into a Cumulonimbus cloud and thunderstorms with rain, hail, thunder and lightning can occur.

http://amsglossary.allenpress.com/glossary/search?id=cumulus-congestus1

The Great Tri-State Tornado

On March 18 1925, the U.S. was hit with its worst tornado. The Great Tri-State tornado started out from the Ozarks in southeastern Missouri, headed eastward through southern Illinois, and then lifted in southwestern Indiana after a duration of three and a half hours. The tornado was rated as a F5 on the Fujita scale. It traveled at an average speed of 62mph which is approximately double the speed of an average tornado. The wind speeds of the funnel were 261 to 318 mph. Strong frame houses were swept away by the tornado. Automobiles looked like missiles flying through the air which were thrown in excess of 109 yards.

In total, there were 652 deaths and over 2000 people injured. The number of deaths was double the number of the second worst tornado in U.S. history.The tornado traveled the distance of 219 miles which is the longest recorded in history. It destroyed 15,000 homes and damaged more than 164 square miles. Due to the tornado about $16.5 million in damage was caused. Today it would be about almost $2 billion in damage as a result of today’s prices.

The tornado was the worst because it had longest path in history and destroyed 50% more than an average tornado. In that era, there were no warning systems within towns. There were also ineffective communications with other towns because phone and telegraph services were immediately cut off by the tornado. People didn’t even realize a tornado was in its way until it was right in front of them.

http://www.suite101.com/content/worst-tornado-in-us-history-a37716

Katrina

Hurricane Katrina is one of deadliest storms to hit the U.S Coast. It ripped through the Gulf Coast in 2005 and became the largest hurricane to hit the United States. Major damage was done to Louisiana, Mississippi, and Alabama. Due to the hurricane, 1836 lives were lost and more than $89.6 billion in damage was caused. The oil and forest industries suffered a major blow with interruption in oil supply and loss to the forest industry amounting to $5 billion. Katrina is the costliest hurricane of U.S. history.

Due to a tropical wave and the remains of a Tropical Depression 10, Katrina formed over the Bahamas on August 23, 2005. It then upgraded to a tropical storm on the 24^th, from where it moved to Florida as category 1. After weakening over land, it gained intensity as it moved to the Gulf of Mexico. On the 28^th it grew from a category 3 to a category 5 hurricane with winds up to 160 mph which caused severe damage along the Gulf Coast. The pressure measurement recorded Katrina as the fourth most intense hurricane.  On the early hours of August 29^th the storm weakened and was classified as a category 4 storm. Moving slowly at 12 mph with wind blowing at 155 mph, Katrina caused far greater damage than a fast moving storm would have done.

The main reason for the great loss of life and property in New Orleans was the failure of its levee system due to the system design flaws and lack of maintenance. Nearly every levee in New Orleans was broken or ruptured which caused the flooding of 80% of the city.

http://www.buzzle.com/articles/hurricane-katrina-facts-and-information.html

Earthquake Triggers Tsunami

     On March 28, 1964, an earthquake of a magnitude of 9.2 hit Prince William Sound, Alaska. It is the largest earthquake to hit the United States. The earthquake and a following tsunami took 128 lives and caused about $311 million in damage. The tsunami took 113 lives and the earthquake took 15. Effects were severe in many towns such as Anchorage, Chitina, Glennallen, Homer, Hope, Kasilof, Kenai, Kodiak, Moose Pass, and others. Anchorage held the most severe damage to property. About 30 blocks of homes and commercial buildings were damaged or destroyed in the downtown area. Many schools and stores were damaged beyond repair. Duration of the shock was about 3 minutes.

     Landslides in Anchorage caused heavy damage too. The largest landslide occurred at Turnagain Heights. An area of about 130 acres was demolished by displacements that broke the ground into many deranged blocks that were collapsed and tilted at all angles. This slide destroyed about 75 private houses. Water mains and gas, sewer, telephone, and electrical systems were disrupted throughout the area. Due to the earthquake vertical displacement took place which caused a tsunami. There was no time for warning and within minutes huge tsunami waves destroyed local towns and fishing villages. The tsunami destroyed many towns along the Gulf of Alaska. It left serious damage at Alberni, Canada, along the West Coast of the United States, and in Hawaii. The maximum wave height recorded was 67 meters at Valdez Inlet.


     In my opinion, I believe the earthquake didn’t cause as much damage compared to others even though it triggered a tsunami. I would think that with the magnitude of 9.2, the earthquake would have caused much more damage and the cost would be much greater to repair.

 

http://earthquake.usgs.gov/earthquakes/states/events/1964_03_28.php

Hurricane Andrew

     Hurricane Andrew is part of a group of hurricanes that have been the most destructive in the United States. On August 14, 1992, it started as a tropical wave that moved from the west coast to Africa. Three days later, August 17, it became a tropical storm now known as Hurricane Andrew. As it moved west-northwestward, the development of Andrew was slow. By August 21, it was between Bermuda and Puerto Rico turning west into a better atmosphere. It rapidly started strengthening reaching hurricane strength of Category 4 on the 23. When Andrew passed through the Bahamas it weakened but shortly after regained its Category 4 strength. A day later, it burst straight towards Florida and continued west toward the Gulf of Mexico where it then made a northern turn. This movement led Andrew to Louisiana as a Category 3 hurricane and then it made a northeastward turn to the Mid-Atlantic states where it diminished.


     Andrew is the third most intense hurricane that has hit the United States in record. From the reports of the barometer they have established that Andrew’s central pressure was 27.23 inches. An automated station at Fowey Rocks reported 142 mph sustained winds with gusts to 169 mph. Andrew produced a 17 ft. near the landfall point Florida and tides of 8 ft in the Louisiana coast. It also created a tornado in southern Louisiana.

     Due to the hurricane’s disaster, 23 life’s were lost and $26.5 billion in damage which $1 billion was accounted to Louisiana and the rest to Florida. The damage in the Bahamas was estimated to be $250 million.

     I was amazed by how much damage the hurricane caused. $26.5 billion is a lot of money lost. I would have expected a higher death rate but thankfully it wasn’t.

Tornados

Tornados

     As I was searching for a topic to write about I came upon an article about tornados that caught my attention. A tornado is a violent destructive windstorm occurring over land and characterized by a long funnel-shape cloud. It is formed of winds of high speeds usually going in a counter-clockwise direction (in the Northern Hemisphere) that produce a partial vacuum.

     I have always wondered how a tornado is formed and through this research I have finally informed myself about it. Before a thunderstorm forms, there is an area in the lower atmosphere of horizontal spinning air caused by a change in wind direction and an increase in wind speed and height. When the thunderstorm starts to develop, the updraft lifts this area of spinning air, changing its direction from horizontal to vertical. At this point, there is a large area of rotation, from two to six miles in diameter, where the tornado typically forms. A wall cloud will form, which is a low mass of clouds that rotate. Finally the tornado forms and is accompanied by high winds and damaging hail.

     Tornadoes destruction can be severe and can arrive with little or no warning. A tornado can completely destroy a house or an office building in less than a second. Even those buildings that are not in the tornado’s direct path can suffer damage from the lightning and hail that accompany it. In the United States, there is an average of 910 tornadoes per year and cause an average of 80 deaths and over 1,500 injuries. A weak tornado has maximum wind speeds of 110 mph and lasts up to ten minutes. The average tornado measures around 250 feet in width and travels approximately one mile.

     I have never experienced a tornado but through this research I have been informed that a sum of weather activities have to occur for a tornado to develop. I found the developing of a tornado to be very interesting.

http://www.weatherexplained.com/Vol-1/Tornadoes.html