Understand climate changes & other phenomena
about climate changes and other phenomena,and I hope my dear friends,
have a spare time to read these, if you haven’t came across one time or the
other about our climate changes,it’s effects, what El Niños or El Niñas are
all about and the consquences we are to face with it all.
Understand Climatic Changes with NOAA..( National Oceanic and Atmospheric Administration )
Thanks my dear Valerie Hadoux for the links.
In every walk of life, young and old alike, we shouldn’t stop learning!!!The El Niño Story
|What is an El Niño?
El Niño is characterized by unusually warm ocean temperatures in the Equatorial Pacific, as opposed to La Niña, which characterized by unusually cold ocean temperatures in the Equatorial Pacific. El Niño is an oscillation of the ocean-atmosphere system in the tropical Pacific having important consequences for weather around the globe.
| Among these consequences are increased rainfall across the southern tier of the US and in Peru, which has caused destructive flooding, and drought in the West Pacific, sometimes associated with devastating brush fires in Australia. Observations of conditions in the tropical Pacific are considered essential for the prediction of short term (a few months to 1 year) climate variations.
To provide necessary data, NOAA operates a network of buoys which measure temperature, currents and winds in the equatorial band. These buoys daily transmit data which are available to researchers and forecasters around the world in real time. In normal, non-El Niño conditions (top panel of schematic diagram), the trade winds blow towards the west across the tropical Pac:ific. These winds pile up warm surface water in the west Pacific, so that the sea surface is about 1/2 meter higher at Indonesia than at Ecuador.
The sea surface temperature is about 8 degrees C higher in the west, with cool temperatures off South America, due to an upwelling of cold water from deeper levels. This cold water is nutrient-rich, supporting high levels of primary productivity, diverse marine ecosystems, and major fisheries. Rainfall is found in rising air over the warmest water, and the east Pacific is relatively dry. The observations at 110 W (left diagram of 110 W conditions) show that the cool water (below about 17 degrees C, the black band in these plots) is within 50m of the surface.
El Niño can be seen in measurements of the sea surface temperature, such as those shown above, which were made from the TAO Array of moored buoys. In December 1993, the sea surface temperatures and the winds were near normal, with warm water in the Western Pacfic Ocean (in red on the top panel of December 1993 plot), and cool water, called the “cold tongue” in the Eastern Pacific Ocean (in green on the top panel of the December 1993 plot). The winds in the Western Pacific are very weak (see the arrows pointing in the direction the wind is blowing towards), and the winds in the Eastern Pacific are blowing towards the west (towards Indonesia). The bottom panel of the December 1993 plot shows anomalies, the way the sea surface temperature and wind differs from a normal December. In this plot, the anomalies are very small (yellow/green), indicating a normal December. December 1997 was near the peak of a strong El Niño year. In December 1997, the warm water (red in the top panel of the December 1997 plot) has spread from the western Pacific Ocean towards the east (in the direction of South America), the “cold tongue” (green color in the top panel of the December 1997 plot) has weakened, and the winds in the western Pacific, usually weak, are blowing strongly towards the east, pushing the warm water eastward. The anomalies show clearly that the water in the center of Pacific Ocean is much warmer (red) than in a normal December.
In the left hand panel, you see the sea surface temperature at the Equator in the Pacific Ocean (Indonesia is towards the left, South America is towards the right). Time is increasing downwards from 1986 at the top of the plot, to the present, at the bottom of the plot. The first thing to note is the blue “scallops” on the right of the plot, in the eastern Pacific. These indicate the cool water typically observed in the Eastern Pacific (called the “cold tongue”). Cold tongue temperatures vary seasonally, being warmest in the northern hemisphere springtime and coolest in the northern hemisphere fall. The red color on the left is the warm pool of water typically observed in the western Pacific Ocean. El Niño is an exaggeration of the usual seasonal cycle. During the El Niño in 1986-1987, you can see the warm water (red) penetrating eastward in the Spring of 1987. There is another El Niño in 1991-1992, and you can see the warm water penetrating towards the east in the northern hemisphere spring of 1992. The El Niño in 1997-1998 is a very strong El Niño. El Niño years are easier to see in the anomalies on the right hand panel. The anomalies show how much the sea surface temperature is different from the usual value for each month. Water temperatures significantly warmer than the norm are shown in red, and water temperatures cooler than the norm are shown in blue.
In the right-hand plot of sea surface temperature anomalies, it is very easy to see El Niños, with water warmer than usual (red) in the eastern Pacific, during in 1986-1987, 1991-1992, 1993, 1994 and 1997-1998. Notice the very cool water (blue), in the Eastern Pacific, in 1988-1989. This is a strong La Niña, which occurs after some (but not all) El Niño years. 1995-1996 was a weaker La Niña year. It is unusual for El Niños to occur in such rapid succession, as has been the case during 1990-1994.
El Niño/La Niña
Nature’s Vicious Cycle
El Niño/La Niña
|By Curt Suplee||Part 1 | 2 | 3|
It rose out of the tropical Pacific in late 1997, bearing more energy than a million Hiroshima bombs. By the time it had run its course eight months later, the giant El Niño of 1997-98 had deranged weather patterns around the world, killed an estimated 2,100 people, and caused at least 33 billion [U.S.] dollars in property damage.
Weekly Pacific Ocean Temperatures
Isaias Ipanaqué Silva knew none of that. All he and the other peasant farmers in the Peruvian hamlet of Chato Chico could see was that after weeks of incessant rain the adjacent Piura River had not stopped rising. The rainfall itself was no surprise. Every three to seven years, for as long as anyone could remember, the same rainfall had arrived after a pool of hot seawater the size of Canada appeared off the west coast of the Americas. The ocean would heat up right around Christmastime, so fishermen called the phenomenon El Niño, for the Christ Child. Then that titanic storm source would pour vast amounts of precipitation onto Peru’s normally arid northwestern coast.
But few had ever seen this much rain—five or six inches a day in some places.
Finally, on February 15, 1998, the river broke its banks. The sodden ground could hold no more, and water swept into the riverside homes of Chato Chico. The swirling torrent was first knee-deep and soon chest high. “Suddenly we were surrounded from all directions,” Ipanaqué Silva says. “It took all the little animals. Then my house just fell down completely.”
Hundreds of families splashed frantically through the muddy flood to save what they could. In most cases, says another villager, Rosa Jovera Charo, “we just grabbed clothes for the children.” Everything else—chickens and goats, pots and pans, religious icons and personal treasures—washed away. Compared with other places in Peru and around the world, the residents of Chato Chico were fairly lucky. Some were evacuated on barges, a few in helicopters, to a barren but dry refugee camp in the desert. Nearly all survived.
That was not the case some 60 miles [100 kilometers] to the south, in a 3-acre [1.2-hectare] pocket of one-room houses called Motse outside the city of Chiclayo. “We thought that the water couldn’t come here,” says Flora Ramirez, “but we lost practically everything.” Ramirez’s neighborhood was overrun in a matter of minutes. “They strung ropes from one house to another to rescue people,” recalls Manuel Guevara Sanchez. “Some spent three days on the roof. Those who knew how to swim brought them food.” When the flood finally receded, they could begin to count the dead: ten out of a village of just 150.
The runoff from the floods poured into the coastal Sechura Desert. Where there had been nothing but arid hardscrabble waste for 15 years, suddenly—amazingly—lay the second largest lake in Peru: 90 miles [145 kilometers] long, 20 miles [30 kilometers] wide, and ten feet [three meters] deep, with occasional parched domes of sand and clay poking up eerily from the surface.
In other areas the water simply pooled. The mosquitoes that thrived in these places caused rampant malaria—some 30,000 cases in the Piura region alone, three times the average for its 1.5 million residents.
Learn how wind and water drive El Niño and La Niña.
Peru was where it all began, but El Niño’s abnormal effects on the main components of climate—sunshine, temperature, atmospheric pressure, wind, humidity, precipitation, cloud formation, and ocean currents—changed weather patterns across the equatorial Pacific and in turn around the globe. Indonesia and surrounding regions suffered months of drought. Forest fires burned furiously in Sumatra, Borneo, and Malaysia, forcing drivers to use their headlights at noon. The haze traveled thousands of miles to the west into the ordinarily sparkling air of the Maldive Islands, limiting visibility to half a mile [0.8 kilometer] at times.
Temperatures reached 108°F [42°C] in Mongolia; Kenya’s rainfall was 40 inches [100 centimeters] above normal; central Europe suffered record flooding that killed 55 in Poland and 60 in the Czech Republic; and Madagascar was battered with monsoons and cyclones. In the U.S. mudslides and flash floods flattened communities from California to Mississippi, storms pounded the Gulf Coast, and tornadoes ripped Florida.
By the time the debris settled and the collective misery was tallied, the devastation had in some respects exceeded even that of the El Niño of 1982-83, which killed 2,000 worldwide and caused about 13 billion dollars in damage.
And that’s not the end of it. It is not uncommon for an El Niño winter to be followed by a La Niña one—where climate patterns and worldwide effects are, for the most part, the opposite of those produced by El Niño. Where there was flooding there is drought, where winter weather was abnormally mild, it turns abnormally harsh. La Niñas have followed El Niños three times in the past 15 years—after the 1982-83 event and after those of 1986-87 and 1995. Signs of another La Niña began to show up by June 1998.
El Niño/La Niña & PDO – Learn More About it
WMO El Niño/La Niña Update
El Niño/Southern Oscillation (ENSO) – La Niña, diagnostic discussion
Latest El Niño/La Niña Jason Data
NOAA’s El Niño Page
NOAA’s La Niña Page
What is La Niña?
The Effects of La Niña
activities such as deforestation and the burning of fossil fuels have
increased the concentrations of greenhouse gases in the atmosphere. Scientists
are concerned that higher greenhouse gas concentrations will lead to an
“enhanced” greenhouse effect which may lead to global climate change.
The Intergovernmental Panel on Climate Change
(IPCC) is an international group of scientists which advises policy
makers on the latest science of greenhouse climate change. In late 1995
the IPCC concluded that “the balance of evidence suggests a discernible
human influence on global climate.”