Category Geography

How does the Sun create weather?

The energy (heat) that the Earth receives from the Sun is a major cause of different weather Conditions. The Sun’s energy in different parts of the Earth depends on where a place is in the world, the time of year and the time of day.

The energy that the Earth receives from the Sun is the basic cause of our changing weather. Solar heat warms the huge air masses that comprise large and small weather systems. The day-night and summer-winter cycles in the weather have obvious causes and effects.

The effects of currently observed changes in the Sun – small variations in light output, the occurrence of solar particle streams and magnetic fields are very small in the Earth’s lower atmosphere or troposphere where our weather actually occurs. However, at higher altitudes, the atmosphere reacts strongly to changes in solar activity. The ozone layer, at an altitude of 25 kilometers (16 miles), and the ionosphere, which extends upwards in a series of layers above 60 kilometers (37 miles), are produced by solar ultraviolet light and X-rays which ionize the thin air at these altitudes. Although the visible light of the Sun is stable, large variations in X-ray and ultraviolet radiation accompany solar activity, and these variations on the Sun cause major changes in the ionosphere. Some meteorologists believe that the ionospheric changes in turn influence the weather in the lower atmosphere, but the physical mechanism by which this may occur has not been definitely identified. There is much research under way or possible relationships between solar activity and the weather.

Credit: A Meeting with Universe

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What is Atmospheric circulation?

It is the uniform pattern in which air moves around our planet’s atmosphere. It happens because the Sun heats Earth more at the equator than at the poles, and it is also affected by the spinning of the Earth.

Solar radiation that reaches the Earth passes through the atmosphere and is either absorbed or reflected by the atmosphere and Earth’s surface. Most of this absorption happens on Earth’s surfaces, which increases the temperature of both land and water. A small amount of heat in the first few centimeters of the atmosphere is transferred from the surface by conduction, the process of molecules colliding and transferring energy. Because air molecules are farther apart than they are in liquids or solids, they do not collide as frequently as in liquids and solids, and air is a poor conductor of heat. Most heat is transferred in the atmosphere by radiation and convection.

Sunlight absorbed by Earth’s surfaces is re-radiated as heat, warming the atmosphere from the bottom up. This heat is absorbed and re-radiated by greenhouse gases in the atmosphere, resulting in the greenhouse effect. Warmed air expands and becomes less dense than cool air, so warmed air near the surface of the Earth rises up. Cooler air from above sinks and air moves horizontally to replace the rising warm air, which we experience as wind over the surface of the Earth. This transfer of heat because of density differences in air is called convection.

Patterns of air movement are further complicated because of Earth’s spin. Air moving from the equator towards the poles does not travel in a straight line, but is deflected because of the Coriolis effect, adding to the complexity of atmospheric circulation patterns.

Credit: Understanding Global change

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What creates different weather conditions?

The weather depends on the way the air moves (wind), the moisture if carries (humidity), and its temperature (warmth). These are controlled by changes in air pressure. As air heats up, it becomes thinner and lighter. It rises upwards, creating an area of low pressure beneath it, which pulls in air from around to fill the empty space. As the air rises, it cools, forming clouds. But the cooler the air gets, the denser and heavier it becomes until eventually it starts to sink. The high pressure created pushes air down towards the ground, causing it to fan out and blow away everything in its way, stopping   the formation of clouds. This is why clear blue skies occur on high air-pressure days.

Weather comes in all different forms, and it changes by the day. It could be sunny one day and raining the next. It could even be sunny, rainy, cloudy, and stormy in one day.

Temperature

It’s getting hot out there. When you talk about the heat of the air outside on a summer day, this is the temperature. Measured with a thermometer in Fahrenheit, Celsius, or Kelvin, the temperature tells you how fast the air molecules and atoms are moving. Fast-moving molecules and atoms mean the temperature is high, while slow-moving molecules in the air create a low temperature.

Humidity

The moisture or dryness of the air is humidity. It’s an important weather aspect. Without it, humans wouldn’t be able to survive. However, the amount of water vapor, or humidity, in the air needs to have balance. Too little or too much water vapor in the air causes health issues and can be dangerous.

Precipitation

Precipitation is just a big word to describe how water falls to the ground. It can be rain, snow, sleet, ice, hail, or drizzle. The form these water or solid particles take depends on other weather factors. For example, if the temperature is cold, below 32 degrees, precipitation comes to the surface in the form of snow. If the weather is nice and warm, water comes down in the form of rain.

Wind

Air moves. All you must do is walk out your door to feel that. The movement of air is created by how the sun heats the Earth, and then convection tells you how air moves in predictable patterns. Therefore, meteorologists have some idea of how a storm will move or the type of weather you’ll have in a week.

Credit: Your Dictionary

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What is wind?

Wind is moving air, ranging from a light, gentle breeze to a very strong and fast-moving storm capable of great destruction. Air moves because the Sun warms some places more than the others, creating differences in air pressure, which causes the air to be pushed around in the form of air currents.

Differences in atmospheric pressure generate winds. At the Equator, the sun warms the water and land more than it does the rest of the globe. Warm equatorial air rises higher into the atmosphere and migrates toward the poles. This is a low-pressure system. At the same time, cooler, denser air moves over Earth’s surface toward the Equator to replace the heated air. This is a high-pressure system. Winds generally blow from high-pressure areas to low-pressure areas.Wind is the movement of air caused by the uneven heating of the Earth by the sun. It does not have much substance—you cannot see it or hold it—but you can feel its force. It can dry your clothes in summer and chill you to the bone in winter. It is strong enough to carry sailing ships across the ocean and rip huge trees from the ground. It is the great equalizer of the atmosphere, transporting heat, moisture, pollutants, and dust great distances around the globe. Landforms, processes, and impacts of wind are called Aeolian landforms, processes, and impacts.

The boundary between these two areas is called a front. The complex relationships between fronts cause different types of wind and weather patterns.

Credit: National Geographic Society

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IS THERE ANY UNDERWATER VOLCANO IN THE ISLAND OF MAYOTTE?

In 2018, seismometers around the world detected mysterious rumbles emanating from a usually quiet area in the Indian Ocean between Comoros and Madagascar. At the time, researchers were astonished to find a 2,690-foot-tall underwater volcano, which is about 1.5 times the height of the One World Trade Center in New York.

The volcano was formed after the largest underwater eruption ever detected and now, scientists suspect that the volcano draws its lava from the deepest volcanic magma reservoir known to researchers.

Scientists first took notice of volcanic activity about 31 miles east of the French island of Mayotte in 2018 when seismic hums, or low-frequency earthquakes, were detected by seismometers all over the globe. However, the huge underwater volcano shocked scientists because only two seismic events had been recorded near Mayotte since 1972. Before that, a layer of 4,000-year-old pumice in a lagoon nearby is the only additional evidence of an eruption ever found. After researchers noticed that the island was moving eastward about 7.8 inches a year, they installed ocean-bottom seismometers and GPS systems to track the island’s fascinating geological activity. To understand the origin of the tremors that began in 2018, the study’s lead author Nathalie Feuillet, a marine geoscientist at the French National Center for Scientific Research, along with her team embarked on a mission—dubbed MAYOBS1—aboard the French research vessel Marion Dufrense in 2019.

Credit : Smith sonian magazine

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WHY IS THE ARCTIC AND ANTARCTICA ARE DIFFERENT?

Any mention of our polar regions – the Arctic and Antarctica – perhaps conjures up images of floating icebergs and blindingly white ice sheets. Sure, that’s common to them but they are also different from each other in many ways.

The Arctic: A variety of landscapes and animals

Home to the North Pole, the Arctic lies in the Northern Hemisphere, and is the northernmost region of Earth. The Arctic usually refers to the area within the Arctic Circle, and spans the Arctic Ocean and parts of Scandinavia, Russia, Canada, Greenland, and Alaska (a U.S. State). It is not always covered in ice, and comprises mountains, rivers, lakes, hills, etc. It hosts several types of land animals and vegetation.

Antarctica: Just ice cover and barely any land animal

Our planet’s southernmost continent, Antarctica is where the South Pole is situated. It is almost entirely covered in ice, and hardly has any vegetation or large rivers or lakes to boast of. With barely any land animals, the largest creature to dwell on land is a wingless insect that’s about half an inch. There are hardly any trees there but Antarctica has its share of lichens, moss, algae, etc.

No penguins in the Arctic

Considering videos show glistening penguins diving into the water and launching themselves back on to ice-covered land adorably, it is easy to imagine that they inhabit both the polar regions. However, these flightless birds are found only in the Southern Hemisphere, and predominantly in Antarctica. None in the Arctic!

No polar bears in Antarctica

It is called a polar bear, after all, but the name is slightly misleading. It is an animal that lives in just one polar region – the Arctic. So, there are none in Antarctica. And, the next time someone asks you if polar bears hunt penguins in the wild, you can confidently tell them that can never happen because the two never get to meet each other!

A continent without permanent residents

Only a country can have permanent residents. And since Antarctica, though a continent, has no country, it has no permanent residents. It is not home to any indigenous community either. That does not mean Antarctica has just tourists. It hosts researchers and scientists at research stations set up by many countries for experiments, especially in summer. In winter, the numbers dwindle. Hard to imagine people queuing up to be a resident in a place with punishing temperatures! On the other hand, the Arctic does host permanent residents, especially indigenous groups, since it spans several countries. In fact, it has been inhabited for thousands of years.

Summers and winters

Due to the way our planet is tilted, the poles receive less light and heat from the sun than other regions of the world. The two seasons- summer and winter – are unique. Both the polar regions have long and cold winters and short summers. During summer, the poles have daylight since the sun does not set, and in winter, it is dark since the sun does not rise. However, since the Arctic and Antarctica are in the opposite directions, when one region experiences summer, the other experiences winter, and vice-versa.

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