Category Science

What are Hurricanes?

A hurricane is a giant, spiralling tropical storm in the Atlantic Ocean that can reach wind speeds of over 257 km per hour and unleash more than nine trillion litres of rain! It begins as thunderstorms that are set off by moist air rising over the warm ocean. If the water is warm enough, the thunderstorms join together, growing bigger as they begin to spiral across the ocean. As the hurricane grows, it spins faster and tighter around its centre, or ‘eye’, which remains a very calm area of low pressure. A hurricane can be as much as 800 km across and can take l8 hours to pass over. In the northern Indian Ocean hurricanes are known as cyclones and in the western Pacific Ocean, as typhoons.

Hurricanes are large, swirling storms. They produce winds of 119 kilometers per hour (74 mph) or higher. That’s faster than a cheetah, the fastest animal on land. Winds from a hurricane can damage buildings and trees.

Hurricanes form over warm ocean waters. Sometimes they strike land. When a hurricane reaches land, it pushes a wall of ocean water ashore. This wall of water is called a storm surge. Heavy rain and storm surge from a hurricane can cause flooding.

Once a hurricane forms, weather forecasters predict its path. They also predict how strong it will get. This information helps people get ready for the storm.

There are five types, or categories, of hurricanes. The scale of categories is called the Saffir-Simpson Hurricane Scale. The categories are based on wind speed.

  • Category 1: Winds 119-153 km/hr (74-95 mph) – faster than a cheetah
  • Category 2: Winds 154-177 km/hr (96-110 mph) – as fast or faster than a baseball pitcher’s fastball
  • Category 3: Winds 178-208 km/hr (111-129 mph) – similar, or close, to the serving speed of many professional tennis players
  • Category 4: Winds 209-251 km/hr (130-156 mph) – faster than the world’s fastest rollercoaster
  • Category 5: Winds more than 252 km/hr (157 mph) – similar, or close, to the speed of some high-speed trains

Credit: NASA

Picture credit: NASA

What is Meteorology?

No, it isn’t the study of meteors, although it does involve the study of other sorts of objects that fall from the sky. Meteorology is, by definition, the study of Earth’s atmosphere. The root of meteor is a variation on the Greek meteoron, which is a term dealing with any objects that originate in the sky.

Meteorology is an extremely interdisciplinary science, drawing on the laws of physics and chemistry (among others) to aid in our understanding of Earth’s atmosphere, its processes, and its structure. It is a study that dates to ancient times, when ancient civilizations made observations and kept records of weather conditions, both for agricultural purposes and out of a general curiosity about the world around them.

Over the centuries, the atmosphere has been studied for a variety of reasons, including agricultural knowledge, military defense and planning, and developing better warnings for severe weather systems like tornadoes and hurricanes. Technological advances, such as the development of scientific computing and an increase in the total number of meteorological observations being taken daily across the globe, have allowed for better forecasts (or at least the meteorological community likes to think they are better forecasts) and a much better overall understanding of our atmosphere.

Credit: Study.com

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What is Climatology?

Climatology is the study of the atmosphere and weather patterns over time. This field of science focuses on recording and analyzing weather patterns throughout the world and understanding the atmospheric conditions that cause them. It is sometimes confused with meteorology, which is the study of weather and weather forecasting. However, climatology is mainly focused on the natural and artificial forces that influence long-term weather patterns. Scientists who specialize in this field are called climatologists.

The first studies of climate can be traced back to ancient Greece, but climate science as it is now known did not emerge until the advent of the industrial age in the nineteenth century. The science of climatology grew as scientists became interested in understanding weather patterns. In recent times, climatologists have increasingly focused their research on the changes in Earth’s climate that have occurred since the industrial age. Earth has been growing warmer and warmer as human industry has expanded and released more carbon into the atmosphere. This effect, called global warming, is a particularly important object of study for climatologists. By studying global warming, climatologists can better understand and predict the long-term impact of human-caused climate change.

Credit: National Geographic Society

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What is Precipitation?

When water falls from clouds, whether it is in the form of rain, snow, sleet or hail, it is called precipitation. When the Sun heats up water on Earth’s surface, the water evaporates and travels into the atmosphere as water vapour. As the air rises and cools, this vapour becomes tiny drops of water again and falls to the ground as rain. If the temperature is below freezing, the droplets form tiny ice crystals that stick together to fall as snowflakes.

Precipitation is any liquid or frozen water that forms in the atmosphere and falls back to the Earth. It comes in many forms, like rain, sleet, and snow. Along with evaporation and condensation, precipitation is one of the three major parts of the global water cycle.

Precipitation forms in the clouds when water vapor condenses into bigger and bigger droplets of water. When the drops are heavy enough, they fall to the Earth. If a cloud is colder, like it would be at higher altitudes, the water droplets may freeze to form ice. These ice crystals then fall to the Earth as snow, hail, or rain, depending on the temperature within the cloud and at the Earth’s surface. Most rain actually begins as snow high in the clouds. As the snowflakes fall through warmer air, they become raindrops.

Particles of dust or smoke in the atmosphere are essential for precipitation. These particles, called “condensation nuclei,” provide a surface for water vapor to condense upon. This helps water droplets gather together and become large enough to fall to the Earth.

Credit: National Geographic Society

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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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