IELTS Reading Practice Test 18

B Since the dawn of time, humanity has been making attempts to predict the weather using a variety of methods, ranging from observing the behaviour of animals to studying the movements of the stars. While some of these methods were based on superstition or folklore, others relied on careful observation and scientific principles. There were those that used consistent patterns. An example is the saying “Red sky at night, sailor’s delight. Red sky in the morning, sailor’s warning” comes to mind. This saying suggests that a red sky at sunset indicates good weather the following day, while a red sky at sunrise is a harbinger of poor weather conditions. More wild superstitions went like “Rain on your wedding day is good luck.” This belief sees precipitation on that special day as a sign of fertility and abundance. This, of course, wouldn’t always be true. Therefore, let us take a look at a more science-based approach to weather forecasting.

C Weather prediction is a complex process that involves gathering and analyzing information from a number of sources. It relies on analyzing the present situation just as much as looking at historical patterns and using extrapolation to make long-term predictions. One of the key sources of weather data is satellites, which supply information on cloud cover, temperature and precipitation across the globe — something that is hard to come by otherwise. Satellites also provide data on ocean temperatures and currents, which can in turn help predict the formation of hurricanes and other tropical storms. Of course, meteorologists are not limited to satellite feed alone. The more conventional approach, predominantly used in pre-space era, is weather stations located on the ground that measure variables like temperature, air pressure and wind strength.

D A notable tool in the tricky art of weather prediction is the weather balloon. These balloons are typically made of latex or similar synthetic material and are filled with a lighter-than-air gas such as helium to provide the lift needed to carry it and its cargo aloft. Once the balloon is launched, it ascends through the atmosphere, carrying with it an array of sensors and instruments. These typically include a radiosonde — a small box that contains sensors for data collection. As the balloon rises, it expands due to the decreasing atmospheric pressure. Eventually, the balloon reaches a point where the atmospheric pressure is equal to the pressure inside, stopping its rise. At this point, the balloon bursts and the radiosonde, along with other hardware, is released to fall back to Earth on a parachute. During its descent, the radiosonde sends data back to a ground station via radio waves. This data is invaluable when creating a vertical profile of the atmosphere. It is later collected and analyzed by meteorologists, who use computer models to create weather forecasts. These models take into account factors such as the rotation of the Earth, the influence of the sun and the movement of air masses.

E Such computer models are an integral part of modern meteorology. They use complex mathematical equations that crunch the given data to accurately simulate the behaviour of the atmosphere and make informed predictions. Probably the most widely used model is the Global Forecast System (GFS) maintained by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Other notable models include those made by European Centre for Medium-Range Weather Forecasts (ECMWF) and the Canadian Meteorological Centre (CMC). Once a model has generated a forecast, meteorologists review the data and make adjustments based on their own expertise and experience. They may also consult with other experts, such as oceanographers, to refine their predictions. Therefore, even highly-computerised, it still remains an art that is highly reliant on professional human input.

F One of the biggest challenges in weather forecasting is predicting the behaviour of severe weather events like hurricanes and tornadoes. Similar to most other weather occurrences, these are influenced by a variety of factors like temperature, precipitation and wind speed. To help with processing all these variables, meteorologists use radar and satellite data to track the movement of storms. In addition to anticipating such conditions, meteorologists also issue warnings and advisories when (and what kind of) severe weather is expected. This can include tornado notifications, hurricane and flash flood warnings. The latter are events of sudden flooding in a normally dry area, caused by an abnormally strong rainfall or the failure of certain infrastructure objects such as dams. The risk factor of such events is that they can reach dangerous levels of water within hours or even minutes.

G Looking back at the sheer amount of development weather forecasting has undergone over the years, you can’t help but wonder if we could really do without it. Today’s world hinges on accurately predicted weather: air and sea travel, construction and development, even planning a casual walk doesn’t go without looking up what the rest of the day might be like. So all we are left with is to hope that advances in technology and accumulated collective understanding of the atmosphere will reflect in the growing accuracy of these predictions.

Questions 28-34
Reading Passage 3 has seven paragraphs, A-G.
Which paragraph contains the following information?
Write the correct letter A-G for questions 28-34 .
NB You may use any letter more than once

28 far-reaching implications of weather forecasting ABCDEFG
29 a misconception held by many people ABCDEFG
30 an example of collaboration with another field of science ABCDEFG
31 how time-sensitive certain information can be ABCDEFG
32 a celestial body that affects the weather ABCDEFG
33 an overly artistic comparison ABCDEFG
34 a combination of high and low technologies complementing each other ABCDEFG

Questions 35-40
Complete the summary
Choose NO MORE THAN TWO WORDS for each gap.

Paying close attention to the way 35 behave has been one of the earliest methods of telling the weather. Of course, to make the predictions more consistent, people had to devise more complex approaches. Using 36  – that is, looking back at previous years to find a systematic trend – is one of the older methods that is still in use to this day. A more technologically advanced idea is to use balloons filled with helium. Said balloon carries a 37 whose sole purpose is to gather data on its way down to the ground. This would allow meteorologists to have a more comprehensive array of data.

Advancements in aerospace industry enable weatherpeople to reach new levels of precision in predicting the weather. Images from 38 provide invaluable information that practically completes the picture. One last touch is utilising 39 that are part of a purpose-made computer models. These process multiple factors and ensure even higher accuracy of forecasting. Finally, people rely on meteorologists when it comes to timely 40 about extreme weather phenomena such as floods and hurricanes.