Category Science

              It is possible to simulate the conditions of certain climates inside a greenhouse. Glass and other materials can be used to create a space within which the heat and light from the Sun is intensified, making it much warmer than it is outside. The temperature, humidity and air movement can be controlled, recreating the atmosphere of a particular climate.

           Climate simulators (or climate models) are complex computer programmers which simulate the Earth’s climate system, including the atmosphere, ocean, land surface and ice, and the interactions between them. The computer programme represents the climate in terms of key quantities such as atmospheric temperature, pressure, wind, and humidity at locations on a three dimensional grid. The atmospheric grid covers the Earth’s surface and extends from the surface to the upper atmosphere. A similar grid for the ocean extends from the ocean’s surface to the ocean floor. By solving the relevant mathematical equations the computer is able to calculate how the state of the atmosphere and ocean evolves in time.

                 At present, a typical simulator of global climate has grid boxes with horizontal dimensions of approximately 100-200 km; this is known as the “spatial resolution”. Simulators used to predict daily weather use much higher spatial resolution, but typically only simulate a specific region (e.g. the UK). Simulators with higher resolution are more accurate, but they also take longer to run and require larger computers.

To test scientific understanding

              Scientists use climate simulators to test and improve their understanding of the climate system. By comparing the simulated climate with observations of the real world, scientists can identify where a simulator needs improvement.

To predict future climate

              Climate simulators are used to predict how climate may change in the future. For example, scientists can implement expected future conditions, such as a higher concentration of greenhouse gases in the atmosphere, and use the simulator to predict how such a change may affect the climate.

              Climate simulators are not perfect and scientists are careful to study, quantify and communicate their accuracy and reliability along with particular results. However, climate scientists are confident that climate simulators can accurately represent many fundamental aspects of the climate system for several reasons.

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            Parts of India and Southeast Asia have a monsoon climate. In these areas, it changes very suddenly from a wet to a dry season, according to the direction of the prevailing wind. The dry period is extremely hot, and the powerful monsoon winds that blow in from the sea bring torrential rain, often without warning. Such violent extremes of weather can make daily life very difficult, with heavy flooding, damage to property and loss of life commonplace.

            A monsoon often brings about thoughts of torrential rains, similar to a hurricane or typhoon. But there is a difference: a monsoon is not a single storm; rather, it is a seasonal wind shift over a region. The shift may cause heavy rains in the summer, but at other times, it may cause a dry spell.

            A monsoon (from the Arabic mawsim, which means “season”) arises due to a difference in temperatures between a land mass and the adjacent ocean, according to the National Weather Service. The sun warms the land and ocean differently, according to Southwest Climate Change, causing the winds to play “tug of war” eventually switching directions bringing the cooler, moister air from over the ocean. The winds reverse again at the end of the monsoon season. 

            A wet monsoon typically occurs during the summer months (about April through September) bringing heavy rains, according to National Geographic. On average, approximately 75 percent of India’s annual rainfall and about 50 percent of the North American monsoon region (according to a 2004 NOAA study) comes during the summer monsoon season. The wet monsoon begins when winds bringing cooler, more humid air from above the oceans to the land, as described above.

            A dry monsoon typically occurs between October and April. Instead of coming from the oceans, the winds tend to come from drier, warmer climates such as from Mongolia and northwestern China down into India, according to National Geographic. Dry monsoons tend to be less powerful than their summer counterparts. Edward Guinan, an astronomy and meteorology professor at Villanova University, states that the winter monsoon occurs when “the land cools off faster than the water and a high pressure develops over the land, blocking any ocean air from penetrating.” This leads to a dry period. 

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          The polar climate is very dry and windy, as well as being exceptionally cold. Inland, it is nearly always below freezing, and temperatures often reach -40°C (-40°F). Only near the coasts do temperatures reach about 10°C (50°F) in the summer.

          Both the Arctic (North Pole) and the Antarctic (South Pole) are cold because they don’t get any direct sunlight. The Sun is always low on the horizon, even in the middle of summer. In winter, the Sun is so far below the horizon that it doesn’t come up at all for months at a time. So the days are just like the nights—cold and dark.

          Even though the North Pole and South Pole are “polar opposites,” they both get the same amount of sunlight. But the South Pole is a lot colder than the North Pole. Why? Well, the Poles are polar opposites in other ways too.

          The Arctic is ocean surrounded by land. The Antarctic is land surrounded by ocean.

          The ocean under the Arctic ice is cold, but still warmer than the ice! So the ocean warms the air a bit.

          Antarctica is dry—and high. Under the ice and snow is land, not ocean. And it’s got mountains. The average elevation of Antarctica is about 7,500 feet (2.3 km). And the higher you go, the colder it gets.

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          Some relatively small areas have their own climate, which differs slightly from the climate surrounding it — a microclimate. Cities often have a microclimate, due to the concentration of buildings, people and vehicles generating heat. This creates a “heat island” — a warm mass of air that sits over the city, making it up to 6°C (11°F) warmer than the surrounding area.

          Microclimate, any climatic condition in a relatively small area, within a few metres or less above and below the Earth’s surface and within canopies of vegetation. The term usually applies to the surfaces of terrestrial and glaciated environments, but it could also pertain to the surfaces of oceans and other bodies of water.

          The strongest gradients of temperature and humidity occur just above and below the terrestrial surface. Complexities of microclimate are necessary for the existence of a variety of life forms because, although any single species may tolerate only a limited range of climate, strongly contrasting microclimates in close proximity provide a total environment in which many species of flora and fauna can coexist and interact.

          Microclimatic conditions depend on such factors as temperature, humidity, wind and turbulence, dew, frost, heat balance, and evaporation. The effect of soil type on microclimates is considerable. Sandy soils and other coarse, loose, and dry soils, for example, are subject to high maximum and low minimum surface temperatures. The surface reflection characteristics of soils are also important; soils of lighter colour reflect more and respond less to daily heating. Another feature of the microclimate is the ability of the soil to absorb and retain moisture, which depends on the composition of the soil and its use. Vegetation is also integral as it controls the flux of water vapour into the air through transpiration. In addition, vegetation can insulate the soil below and reduce temperature variability. Sites of exposed soil then exhibit the greatest temperature variability.

          Topography can affect the vertical path of air in a locale and, therefore, the relative humidity and air circulation. For example, air ascending a mountain undergoes a decrease in pressure and often releases moisture in the form of rain or snow. As the air proceeds down the leeward side of the mountain, it is compressed and heated, thus promoting drier, hotter conditions there. An undulating landscape can also produce microclimatic variety through the air motions produced by differences in density.

          The microclimates of a region are defined by the moisture, temperature, and winds of the atmosphere near the ground, the vegetation, soil, and the latitude, elevation, and season. Weather is also influenced by microclimatic conditions. Wet ground, for example, promotes evaporation and increases atmospheric humidity. The drying of bare soil, on the other hand, creates a surface crust that inhibits ground moisture from diffusing upward, which promotes the persistence of the dry atmosphere. Microclimates control evaporation and transpiration from surfaces and influence precipitation, and so are important to the hydrologic cycle—i.e., the processes involved in the circulation of the Earth’s waters.

          The initial fragmentation of rocks in the process of rock weathering and the subsequent soil formation are also part of the prevailing microclimate. The fracturing of rocks is accomplished by the frequent freezing of water trapped in their porous parts. The final weathering of rocks into the clay and mineral constituents of soils is a chemical process, where such microclimatic conditions as relative warmth and moisture influence the rate and degree of weathering.

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          In the most mountainous regions of the world, the climate will often be very different from that of the land that surrounds them. The freezing climate of the Himalayas, for example, is surrounded by desert, warm temperate, and monsoon climates.

          Lower down, the climate may be milder (temperate), suitable for lots of different plants and trees to grow, which in turn, provide food for a wide variety of animals. Higher up, plants and animals are fewer: they have to be highly adapted to survive, as the climate becomes much harsher. It’s windy and cold. Frozen ground means that there is not much water available and the soil is shallow. Humans also struggle to cope at high altitude (a fancy word for great height), because the air becomes much thinner, meaning that there is less oxygen available for your body to use.

          Mountain weather conditions can change in a split second! Well, maybe not quite that quickly but in just a few minutes clouds can gather and a thunderstorm begins. That’s why mountaineers have to be ready for anything; they pack their rucksacks really carefully and carry emergency kit like tents and extra food. Professional climbers always tell other people what their plans are so, if they go missing, search and rescue teams know where to look!

          Mountains also receive lots and lots of rainfall. This is because air travelling over land is forced up and over any mountains in its path – it can’t tunnel! This air cools as it rises causing the condensation of any water vapour it was carrying into huge clouds (made up of tiny droplets) ready to burst at any moment.

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