Southern AERA Quarterly Activity Bulletin of the South Carolina Department of Natural Resources- Southeast Regional Climate Center
Volume 3, No. 1
The 7th Annual Sky Awareness Week (SAW) celebration will be held April 20-26, 1997. Once again, the theme will be centered on
Since 1991, 42 states and the District of Columbia have issued proclamations in support of this growing national celebration. The National Weather Service, the National Weather Association, the National Science Teachers Association, the International Weather Watchers, and the Weather Channel TM are among the many organizations supporting this effort!
SAW 97 will provide many opportunities for teachers, students, parents, home schoolers, senior citizen centers, nature center staff, meteorologists and others to look toward the sky. In doing so, they can (1) learn how to read the sky (first by learning cloud types and their weather, and then by forecasting from them); (2) understand sky processes (water cycle, sky colors, rainbows); (3) appreciate the sky's natural beauty; (4) protect the sky as a natural resource (it's the only one we have); and (5) learn about sun safety. Also, SAW falls during the same week as National Science and Technology Week and National Mathematics Awareness Week, and around the same time as Earth and Astronomy Day. To enhance multi-disciplinary study, we will be linking dozens of schools across the United States, Canada and elsewhere in a sky data exchange using electronic mail and/or the Internet throughout the school year. SAW 97 encourages people across the Nation and around the world to notice the myriad of cloud types, ranging from fair weather cumulus puffs to high-flying cirrus streamers. Late spring is a time when most people experience their most dramatic and changeable skies. In addition to making their own weather forecasts, just as farmers and explorers used to do, people will notice that the sky is not the same color blue every day. The changes, albeit subtle, are often tied to the movement of weather systems and accumulations and transport of atmospheric pollutants. The list of "things" in the sky also includes birds, airplanes, hot air balloons, and the sun moon and stars. We can appreciate all of these and gain an upbeat feeling just by LOOKING UP!
For more information about SAW 97 contact :
HOW THE WEATHERWORKS
1522 Baylor Avenue
Rockville, MD 20850
A comprehensive sky study guide, cloud charts, cloud postcards, and other low-cost sky related materials are available for purchase.
El Nino/Southern Oscillation
Many climatic hazards affect our lives every year. Climatic hazards familiar to us include hurricanes, tornadoes, and severe winter storms. Although these hazards can have devastating effects on us, we know how to prepare for them and take measures to lessen their impacts. One climatic hazard that is less commonly known is the El Nino/Southern Oscillation (ENSO). Nonetheless it is important to study and understand all climatic hazards. The purpose of this exercise is to introduce and familiarize students with ENSO and its impacts on a global scale as well as on a local scale.
Discussion - Definitions and Background
El Nino is a Spanish word meaning "the Christ Child." The term was originally used by fishermen to describe a disruption in the flow and temperature of ocean currents along the coast of Ecuador and Peru, South America. Oddly enough this event usually occurred around Christmas time, hence giving its name. ENSO occurs typically every four to seven years and lasts an average of a few months. This event has local and global consequences, some of which can be very devastating. The areas that are most directly affected are the countries bordering the tropical Pacific Ocean. However, in addition to the direct impacts there are indirect impacts referred to as teleconnections. These "teleconnections" have been felt in Australia, Indonesia, Southern Africa, India and the United States.
What exactly is the El Nino/Southern Oscillation? The ENSO is the result of interactions between the ocean and the earth's atmosphere. The impacts of the El Nino were first noticed along the west coast of South America. During normal conditions the warm currents on the surface of the ocean are deflected or pushed westward into the eastern Pacific by the equatorial trade winds. The trade winds are driven by a difference in air pressure in the eastern and western portion of the Pacific Ocean. Normally the atmosphere above the eastern portion of the Pacific is dominated by a high pressure zone, while a low pressure zone dominates the west. As the pressure rise in the east, it falls in the west and vice versa. This "seesaw" of relative air pressure is known as the Southern Oscillation.
The trade winds normally blowing from the southeast to the northwest drive the surface ocean currents westward, causing cold, nutrient-rich waters from the ocean depths to rise to the surface. This process, known as upwelling, causes dry arid conditions along the coastal plain as well as providing the base for the fishing economy in Peru.
During El Nino years the trade winds weaken as a result of the pressure in the eastern portion in the Pacific decreasing, as the air pressure in the western portion rises. As the winds weaken or reverse, the warm water found in the eastern Pacific Ocean flows back to the east as a slow-moving wave. These warm surface waters rise over and push below the cold ocean currents which build up along the coast of Peru. As a result the nutrients that provide the base for the anchovy population are killed off. In return, marine birds that feed on the anchovies are also killed. The depletion of the anchovy stock is detrimental to the fishing economy in Peru. Another direct impact includes heavy rains which cause flooding on normally dry land.
The most powerful ENSO ever recorded in the Twentieth Century occurred in 1982-1983. While torrential rains plagued the western Pacific, a serious drought occurred in Indonesia and Australia. The United States weather patterns also changed as a result of the 1982-83 ENSO including severe storms around the Gulf Coast, Midwest and West Coast, as well as causing a hurricane in Hawaii. These weather disruptions had a negative impact on the fishing and agricultural industries, costing the United States millions of dollars. Unusual weather patterns continued through the winter and summer seasons. Heavy rains continued along the Gulf coast and into the Midwest causing significant flooding. Agricultural fields were eroded, cattle and poultry were killed, and buildings and homes were destroyed. For these reasons, ENSO related scientific research has increased. Scientists are using direct global observations to study ENSO and use the data to predict future climatic conditions. Long-term forecasts will make it possible to better prepare for future ENSO conditions.
The 1982-83 ENSO was not predicted and no unusual weather conditions were present before hand to warn scientists of its arrival. The previous El Ninos had been preceded by stronger than normal easterly winds along the equator which the scientists could directly observe. Now, scientists are using historical data and direct global observations and putting them into prediction models using mathematical equations. Two ENSO events, the 1986-87 and the 1991-92 event, were successfully predicted. Models can assist farmers, the fishing industry and government officials to plan ahead for an upcoming ENSO event.
1. What are the indirect impacts of ENSO that affect other parts of the world called?
2. In which direction do the trade winds that influence ENSO blow?
3. What is the process called where cold nutrient rich waters rise up from the depths of the ocean?
4. The atmosphere above the eastern portion of the Pacific Ocean under normal conditions is dominated by a ________ pressure zone, while a _________ pressure zone dominates the west.
5. The "seesaw" effect of air pressure driving the trade winds is known as what?
6. During El Nino years do the trade winds weaken or grow stronger? Why?
7. El Nino's occur on the average every _______ years.
8. What industries are the most severely affected by ENSO?
9. In what country were El Nino conditions first observed?
10. What are some of the impacts of the 1982-1983 ENSO in the United States?
11. Find these words horizontally and vertically in the puzzle:
Southern AER is a quarterly publication of the Southeast Regional Climate Center. Funding is provided by a grant from the National Oceanic and Atmospheric Administration.
Weather and Climate Resources for the Classroom
For El Nino Education Modules on the Internet
For El Nino Theme Pages on the Internet
For Extended Range Predictions of ENSO on the Internet
For Other El Nino Sites and Resources
El Nino Trivia
Did you know that...
Permission is granted for the reproduction of materials contained is this pub lication.
Southeast Regional Climate Center
S.C. Department of Natural Resources
1201 Main Street, Suite 1100
Columbia, South Carolina 29201
The South Carolina Department of Natural Resources prohibits discrimination on the basis of race, color, sex, national origin, disability, religion, or age. Direct all inquiries to the Office of Human Resources, P.O. Box 167, Columbia, SC 29202.