Fluent Essays

Hello, you need to finish two assignments.You need to use the required reading to finish the questions for reading.And you need to finish the backer 2016 word document by using the Backer PDF reading materials required_reading.docx quesiton_for_reading.docx becker_2016.doc becker_2016_on_the_trail_of_el_nino.pdf Unformatted Attachment Preview Chapter 16: Chapter 17: Chapter 18: Chapter 19: Chapter 20: 1.Flannery Ch. 16. Measured air temperatures over the last several decades may have been cooler than expected due to Group of answer choicesa. a.atmospheric aerosols that are reflecting incoming solar radiation b. lower ozone concentrations in the stratosphere that are causing cooling c. greater frequency of forest fires d. all of the above e. most of the above 2.Flannery Ch. 17. How much of a reduction in carbon emissions is required to stabilize Earth’s climate? Group of answer choicesa. a.20\% b. 40\% c. 55\% d. 70\% 3. Flannery Ch. 18. Which species will benefit from global warming? Group of answer choicesa. a. poison ivy b. polar bears c. parasites that cause malaria d. kudzu 4.Flannery Ch. 19. Species typically adjust to climate change by migrating. Why is migration more of a problem for flora and fauna today? Group of answer choicesa. human modified landscapes make it impossible for many species to migrate b. climate change is happening too quickly for the flora and fauna to migrate c. flora and fauna are slow to react to current changes in climate d. all of the above 5. Flannery Ch. 20. Which deep sea creature was not discussed by Flannery in ‘Boiling the Abyss?’ Group of answer choicesa. megamouth shark b. giant squid c. angler fishes d. gulpers 6. Flannery Ch. 21. Which of the pack of jokers is least likely to occur this century? Group of answer choicesa. release of methane clathrates b. shutting down the gulf stream c. collapse of the Amazon rain forest d. shutting down the Antarctic circumpolar current 7. When the walker circulation slows down, what happens? Group of answer choicesa. La Niña event b. El Niño event c. NAO event d. PDO event 8. A very strong SST (sea surface temperature) gradient from east to west in the tropical Pacific is indicative of … Group of answer choicesa. a. La Niña event b. El Niño event c. NAO event d. PDO event 9. A Magic Gate is most likely associated with Group of answer choicesa. a. La Niña event b. El Niño event c. a sustained change in the PDO phase d. a sustained change in the NAO phase a and d b and c 10. How will global warming impact oscillations in the climate system Group of answer choicesa. a.oscillations will increase b. oscillations will decrease c. it is not clear how oscillations will change with climate warming Homework #6 Emily Becker, 2016 On the Trail of El Nino (10 points) 1. What is an El Niño? What is a La Niña? Make sure to discuss the Walker Circulation and the Southern Oscillation. (2 points) 2. How do scientists forecast and track an El Niño or a La Niña? (2 points) 3. Did NOAA scientists correctly predict the 2016 El Niño? What did they get wrong and Why? (2 points) 4. What are oscillations in the climate system? Describe the climate oscillations discussed in this article. (2 points) 5. What are the key take away points regarding the climate system and future climate change? (2 points) W E AT H E R On the Trail of El Niño This fickle and influential climate pattern often gets blamed for extreme weather. A closer look at the most recent cycle shows that the truth is more subtle By Emily Becker sad1016Beck3p.indd 68 8/23/16 5:47 PM Illustration by Yuko Shimizu sad1016Beck3p.indd 69 October 2016, ScientificAmerican.com 69 8/23/16 5:47 PM Emily Becker is a contract research scientist at the National Oceanic and Atmospheric Administration’s Climate Prediction Center in College Park, Md., where she specializes in climate diagnostics and prediction. She also writes a monthly blog at NOAA that tracks El Niño, La Niña and other climate phenomena. C ALIFORNIA GROWS MORE THAN 90 percent of the tomatoes, broccoli and almonds consumed in the U.S., as well as many other foods. These crops require a lot of water. In the spring of 2015, after four years of little winter rain, the state was in a severe drought. Reservoirs were far below capacity, and underground aquifers were being heavily tapped. Mountain snowpack, an important source of meltwater throughout the spring and summer, was nearly gone in many areas. Not surprisingly, then, when the National Oceanic and Atmospheric Administration announced that an El Niño climate pattern was setting up over the Pacific Ocean, California farmers and their neighbors took note. Conventional wisdom said that El Niño brings plentiful rains to the Golden State. El Niño is the warm half of a cycle of warming and cooling in the tropical Pacific Ocean’s surface waters. The cycle recurs about every three to seven years; the cool half is called La Niña. When either phenomenon arises, it generally prevails for six months to a year. During El Niño, the warm waters heat the air above them, causing changes to the atmospheric circulation that affect the entire world. NOAA, where I conduct climate research, can usually see an El Niño or La Niña coming in advance of when it will have its strongest influence on global weather. Californians’ hopes were high, and yet the effects that usually occur with an El Niño there and elsewhere do not happen all the time. During the 20 El Niño seasons since NOAA began tracking them in 1950, only about half brought above-average precipitation to California during its rainy season: December, January and February. In some cases, the effects are the opposite of what is expected. Forecasters have become good at predicting a developing El Niño or La Niña, but they still struggle with predicting the regional weather changes that might result. In early 2015, as California dried out further, forecasters faced several burning questions: Would the coming El Niño be a big one? Would it save California? For that matter, would it amp up hurricanes in the Pacific and reduce hurricanes in the Atlantic, bake Australia, fuel forest fires in Indonesia, or make the upcoming winter disappear in the Northeast, as some El Niños had done in the past? And could we know ahead of time? Being able to answer such questions would greatly help farmers, forecasters, emergency planners and the general public prepare for extreme weather, and investigators are trying hard to pin down the data that are needed. Yet as the tale of how the most recent, extreme El Niño unfolded demonstrates, the science is tricky. ~ MARCH 2015: EL NIÑO IS HERE EARLY SIGNS of a developing El Niño occur under the ocean surface. Winds across the tropical Pacific typically blow from east to west—the trade winds that reliably have carried sailing ships across the great ocean. These winds keep the surface water in the eastern and central Pacific slightly cooler and pile up warm water in the western side, toward Indonesia. Occasionally these winds can weaken, allowing slow waves of warmer western waters to begin to travel back eastward along the equator toward South America over many months. That can kick off an El Niño or feed one that has already begun. To me and other meteorologists, it looked like the developing 2015 El Niño was going to be a big one. Over the past several months we had seen sea-surface temperatures that were warmer than average in the tropical Pacific, including the Niño 3.4 region in the central Pacific, which we track as a leading indicator. El Niño, though, is part of a phenomenon that couples changes in the ocean to changes in the atmosphere—the El Niño/Southern Oscillation—so we were also monitoring the atmosphere for signs that it was responding to those increased ocean temperatures. Water even just a few degrees higher than usual holds a tremendous amount of heat, which warms the air above the ocean, coupling the changes in the ocean to the atmosphere. During El Niño, the warmer central-eastern Pacific takes over as the engine affecting an atmospheric pattern called the Walker Circulation [see box on opposite page]. With a strong source of rising moist air now much farther east, the surface winds weaken, sometimes reversing altogether and blowing west to east. This atmospheric reaction is the Southern Oscillation, and it is essential to El Niño, helping it sustain and strengthen itself. In March the effects of the warmer tropical Pacific had taken IN BRIEF The media, and even meteorologists, tend to say that certain kinds of extreme weather are caused by El Niño or La Niña, but the patterns are not always consistent. For example, the 2015–2016 El Niño did not bring expected heavy rains to southern California, much needed to reduce the drought there. The 2015–2016 El Niño was among the three strongest ever recorded. It af- fected weather across the globe, including a warmer winter in the northeastern U.S. But global warming, as well as other climate patterns, could have also contributed. Forecasters predict La Niña will prevail during the 2016–2017 winter, which often happens after a strong El Niño. La Niña also increases the probability of some extreme events. 70 Scientific American, October 2016 sad1016Beck3p.indd 70 8/23/16 5:47 PM BASICS Walker Circul at Cause and Effect A Neutr al An El Niño or La Niña climate pattern arises when Pacific Ocean temperatures change, relative to neutral conditions (illustrations). In winter 2016 a strong El Niño altered the jet stream across the U.S. and made precipitation more or less likely in certain regions worldwide (map). El Niño or La Niña? Winds Pacific oce a n Thermoc Warm line Cooler th a 50 m n norma ● Warm water in the western Pacific A typically heats air that rises, rains out and circulates eastward when it hits the stratosphere. It descends and travels west, helping to trap warm water there. If the surface winds weaken over several months, warm water can drift back eastward, changing the Walker pattern and pushing warm water down deeper, kicking off an El Niño B . If the east-west surface winds get stronger instead, even more warm water moves west and deepens there as well, setting up La Niña C . The atmospheric reaction to these water flows, ever changing over a time frame of months, is called the Southern Oscillation. Stratosphere (altitude: 15 kilometer s) ion Cool l sea surf ace Depth: 1, 000 mete rs an norm al sea surf ace Warmer th B El N iño ● ● C La Niñ a What Happened in 2016 El Niño helped to push the subtropical jet stream’s path across the U.S. south in early 2016. The shifting jet, and a changing mix of warm and cool seawater (yellow and blue), led to enhanced or limited precipitation in certain regions (blue and pink pattern overlays). Other factors also influenced global weather, however, as they do every year. COMPLICATING FACTOR: Arctic Oscillation This atmospheric pattern in the northern Atlantic changed state as 2016 began, allowing cold air up in the Arctic to drift down into the Northeastern U.S., cooling what had begun as a warm winter. COMPLICATING FACTOR: Climate Change SOURCE: NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (map) As the atmosphere and oceans warm overall, that could change the nature of El Niño and La Niña, as well as how much those patterns may affect local weather, but meteorologists are not yet sure how. Subtropical jet stream Niño 3.4 region Sea-Surface Temperature (December–February) Average Cooler Warmer –1 C � 0 +1 +2 Equator +3 Precipitation (Relative to average) Drier Wetter (≥ 1.8 inches) Illustration by George Retseck, Map by Jen Christiansen sad1016Beck3p.indd 71 Cross sections shown above COMPLICATING FACTOR: Madden-Julian Oscillation This area of storminess travels eastward along the equator, usually crossing the Pacific in a few weeks. It temporarily strengthened and weakened El Niños impacts in winter 2016. October 2016, ScientificAmerican.com 71 8/23/16 5:48 PM 2 hold. The Walker Circulation was weakening. We also saw bursts of westerly wind over the tropical Pacific, which can encourage warmer surface waters to move eastward. Heat deeper in the Pacific Ocean was high, too, which could help extend the atmospheric coupling. After 12 months of watching, noaa issued an El Niño Advisory. Game on. MAY 2015: PROBABILITIES RISE By May, noaa had determined there was a 90 percent chance that the current El Niño would continue through the summer and an 80 percent chance that it would continue through the end of 2015. The agency was confident in its prediction because seasurface temperatures in the equatorial Pacific remained substantially above average during April. The same was true for water below the surface, in the upper 300 meters of the ocean. The atmospheric re­­sponse had strengthened, too. But what weather effects might we see? And what would happen in California? El Niño typically exerts its strongest impacts on temperature and rain in the early winter, which was still six months away. Some signs suggested that this El Niño would be like other strong ones in the past. Drought and heat waves in Australia were rearing up (autumn was giving way to winter there). And the western Pacific cyclone season was off to a roaring start, with seven named storms by May; the average is two. JULY 2015: FULL SWING As July commenced, n  early all the computer models were in agreement, and the ocean and atmosphere continued to be­­have ac­­ cording to plan. El Niño was well established, and forecasters were convinced that it would become very strong. The threemonth-average sea-surface temperature in the Niño 3.4 region was ex­­pected to peak near an all-time high, matching that of the two previous, strongest El Niños on record: 1997–1998 and 1982–1983. Southern Californians who remembered the 1997–1998 winter anticipated pounding storms and surf. During the 1982– 1983 and 1997–1998 El Niños, winter conditions shifted the Pacific subtropical jet stream—a band of eastward-flowing air ~ EL NINO’S EFFECTS can be inconsistent. In winter 2016 it did not bring extra rain to central California as hoped, offering no help to a years-long drought (1). But heavy snow in the mid-Atlantic states, like the January 2016 blizzard, has happened during El Niños before (2). high in the atmosphere above the U.S. that often influences weather—south toward southern California. Powerful storms, fed with moisture from the warmer waters, provided heavy, reservoir-filling rains—as well as landslides along a soggy coast. Farmers and residents hoped that the new El Niño would deliver plentiful precipitation by December. Forecasters gave a 60 percent chance that during the upcoming 2015–2016 winter, regions of southern California, as well as the Gulf States, would see rain amounts in the upper third of the historical record. This forecast was derived in part by monitoring several different signals, including El Niño, and comparing them with past trends to see if the odds of a certain outcome might be shifting. OCTOBER 2015: UNEXPECTED WINDS In October, hope for California was high. We were closing in on the peak of the 2015–2016 El Niño, and it still ranked among the strongest in our records. Yet we were seeing something unexpected. The surface winds along the Pacific equator, im­­portant for maintaining the high sea-surface temperatures, had not weakened as much as they had during past strong El Niños. In 1997–1998 the winds weakened so much they re­­versed, blowing from west to east during October and November, moving even more warm water from the far western Pacific into the central Pacific and feeding the El Niño. We humans have a tendency to expect that the outcome of a set of circumstances will always be the same, but variability happens in nature all the time. In coastal northern California, a strong El Niño year averages about 40 rainy days per winter, compared with about 26 during a non–El Niño winter. Yet the winter of 1965, one of the six strongest El Niños, had fewer rainy days than the non–El Niño average. In these times of global warming, we also had to wonder whether that was playing a JUSTIN SULLIVAN Getty Images (1); MATT MCCLAIN Getty Images (2) 1 72 Scientific American, October 2016 sad1016Beck3p.indd 72 8/23/16 5:48 PM role, too. If it was, prediction of El Niño’s effects would become that much more difficult. JANUARY 2016: A LOT GOING ON By January, E  l Niño had put up some impressive numbers. In December the Niño 3.4 index broke the record for that month at 2.32 degrees Celsius above average, surpassing the 2.24 de­­ grees C of December 1997. El Niño is ultimately measured on seasonal timescales, though, so the average of the sea-surface temperature anomaly (the departure from the long-term aver­ age) over three months is what we really pay attention to. From October to December 2015, the anomaly was 2.3 degrees C, tied for first place with 1997. Outside of California, the effects of El Niño were mostly oc­­ curring as expected. Much more rain than is typical fell in east­ ern Africa during the “short rains” season (October through De­­ cember). Southern Africa had continued dry conditions. Uru­ guay, southern Brazil and Paraguay experienced a lot of rain, and northern South America had been dry. Australia’s typical El Niño impact is dryness over most of the continent from about July to December, but in 2015 there had not been a clear rainfall deficit, except in parts of eastern Australia. It is possible that a record warm Indian Ocean had a strong counter­ effect—a reminder that the climate system has many moving parts, so expected impacts from El Niño are not guaranteed. Closer to home, the Northeast was very warm, as anticipat­ ed. Michelle L’Heureux, my fellow meteorologist at noaa, wrote in her blog: “For the first time ever my extended family did our Christmas gift exchange outside on my aunt’s patio in the Wash­ ington, D.C. area.... We abandoned hot cider in favor of tropical beverages. Some of us wore t-shirts and sandals. We played catch with the dogs.” As in Australia, El Niño was not the only cause of the unusual weather in Washington. An atmospheric pattern known as the Arctic Oscillation—epitomized by the “polar vortex” of winds that circle the Arctic—had entered a strong state. Unlike some recent winters, when the vortex was weak and allowed cold air to pour down into the U.S., during December 2015 it had been strong, trapping the frigid air way up north and allowing warm air from the southern U.S. to drift northward. Several other non–El Niño oceanic and atmospheric phenom­ ena could also have influenced weather in one part of the globe or another. One is the Madden-Julian Oscillation (MJO), an area of storminess that circles the equator, traveling eastward and last­ ing for weeks. It can temporarily enhance the effects of El Niño but can also reduce them. As I wrote in January, “Clearly, the question of how the MJO and El Niño act to reinforce or weaken each other is still up for debate.” Then there is the Pacific Decadal Oscillation, a relation be­­ tween the surface temperatures of the eastern and western North Pacific that often prevails for 15 years or more before switching to a different state. All these patterns affect one an­­other. And of course, climate change is a wild card that could influence any of these patterns in still unpredictable ways. L’Heureux’s warm Christmas, and the extremely warm Nov­ ember and December across eastern North America, seemed to stem from a combination of El Niño, the bottled-up cold air near the Arctic and an active Madden-Julian Oscillation, plus a large component that cannot be explained even by those fac­ tors. De­­spite screaming headlines in daily newspapers and bold declarations by television weather forecasters, all saying El Niño was causing the extreme weather, it is not possible to point to a single storm, or cold snap, or heat wave and say, “That’s El Niñ ... Purchase answer to see full attachment