Category The Earth

Heatwaves in the ocean?

 

High temperatures and heatwaves across the globe saw records broken in July 2023 on land and in the oceans. The oceans serve as the Earth’s heat reservoir, absorbing substantial amounts of thermal energy as a result of their continuous interaction with the atmosphere. Under specific conditions. prolonged periods of unusually high temperatures in the oceans are called marine heatwaves. much like their atmospheric counterparts.

These higher temperatures could be driven by increased heat input from the atmosphere. decreased heat losses from the ocean or the transfer of warmer water masses through currents Over the past two decades these events have become more prevalent and widespread, having been observed in various areas of the global ocean, in both regional and large scales, at the surface of the ocean and at depth

In particular, recent data shows the occurrence of marine heatwaves surged by 34 percent between 1925 and 2016. While the exact mechanisms triggering marine heatwaves vary from region to region. there are two primary factors. In some instances, the atmospheric conditions themselves play a pivotal role. During such episodes. stagnant air masses and prolonged high temperatures in the atmosphere conspire to heat the ocean’s surface. setting the stage for a marine heatwave event. This pattern was notably evident during a 2012 North Atlantic event, which saw one of the highest sea surface temperatures ever recorded.

In other cases, the main driver is the movement of ocean currents, which transport relatively warm water masses to new areas. When these warm masses converge in specific regions, they cause a rapid and abrupt increase in the sea’s surface temperature. This was witnessed in the 2015 Tasman Sea (situated between Australia and New Zealand) event.

As the impacts of marine heatwaves reverberate across the globe, understanding the complex interplay between the oceans and the atmosphere is crucial for predicting the Occurrence of these extreme events. In the face of climate change, conserving and protecting our oceans becomes ever more critical. Therefore improving marine heatwave predictability is crucial to empower communities and ecosystems alike to adapt and build resilience. By better understanding the science behind marine heatwaves and taking collective action, people can work towards a more resilient and sustainable future for the oceans. (With inputs from agencies)

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IS THE ATMOSPHERE BUILT UP IN LAYERS?

Yes, the atmosphere has five layers. The lowest layer, closest to the surface of the Earth, is the troposphere. This is where weather is made, and most of the atmosphere’s gases are concentrated in it. Above it is the Stratosphere. No winds blow in this layer, nor are there any clouds. Beyond it lies the cold mesosphere, with very few gases. It is followed by the thermosphere, the thickest and hottest layer of the atmosphere, and lastly, the exosphere, on the edge of outer space.

Earth’s atmosphere is all around us. Most people take it for granted. Among other things, it shields us from radiation and prevents our precious water from evaporating into space. It keeps the planet warm and provides us with oxygen to breathe. In fact, the atmosphere makes Earth the livable, lovable home sweet home that it is.

The atmosphere extends from Earth’s surface to more than 10,000 kilometers (6,200 miles) above the planet. Those 10,000 kilometers are divided into five distinct layers. From the bottom layer to the top, the air in each has the same composition. But the higher up you go, the further apart those air molecules are.

Troposphere: Earth’s surface to between 8 and 14 kilometers (5 and 9 miles)

This lowest layer of the atmosphere starts at the ground and extends 14 kilometers (9 miles) up at the equator. That’s where it’s thickest. It’s thinnest above the poles, just 8 kilometers (5 miles) or so. The troposphere holds nearly all of Earth’s water vapor. It’s where most clouds ride the winds and where weather occurs. Water vapor and air constantly circulate in turbulent convection currents. Not surprisingly, the troposphere also is by far the densest layer. It contains as much as 80 percent of the mass of the whole atmosphere. The further up you go in this layer, the colder it gets.

Stratosphere: 14 to 64 km (9 to about 31 miles)

Unlike the troposphere, temperatures in this layer increase with elevation. The stratosphere is very dry, so clouds rarely form here. It also contains most of the atmosphere’s ozone, triplet molecules made from three oxygen atoms. At this elevation, ozone protects life on Earth from the sun’s harmful ultraviolet radiation. It’s a very stable layer, with little circulation. For that reason, commercial airlines tend to fly in the lower stratosphere to keep flights smooth. This lack of vertical movement also explains why stuff that gets into in the stratosphere tends to stay there for a long time. That “stuff” might include aerosol particles shot skyward by volcanic eruptions, and even smoke from wildfires. This layer also has accumulated pollutants, such as chlorofluorocarbons. Better known as CFCs, these chemicals can destroy the protective ozone layer, thinning it greatly. By the top of the stratosphere, called the stratopause, air is only a thousandth as dense as at Earth’s surface.

Mesosphere: 64 to 85 km (31 to 53 miles)

Scientists don’t know quite as much about this layer. It’s just harder to study. Airplanes and research balloons don’t operate this high and satellites orbit higher up. We do know that the mesosphere is where most meteors harmlessly burn up as they hurtle towards Earth.

The mesopause is also known as the Karman line. It’s named for the Hungarian-born physicist Theodore von Kármán. He was looking to determine the lower edge of what might constitute outer space. He set it at about 80 kilometers (50 miles) up.

The ionosphere is a zone of charged particles that extends from the upper stratosphere or lower mesosphere all the way to the exosphere. The ionosphere is able to reflect radio waves; this allows radio communications.

Thermosphere: 85 to 600 km (53 to 372 miles)

The next layer up is the thermosphere. It soaks up x-rays and ultraviolet energy from the sun, protecting those of us on the ground from these harmful rays. The ups and downs of that solar energy also make the thermosphere vary wildly in temperature. It can go from really cold to as hot as about 1,980 ºC (3,600 ºF) near the top. The sun’s varying energy output also causes the thickness of this layer to expand as it heats and to contract as it cools. With all the charged particles, the thermosphere is also home to those beautiful celestial light shows known as auroras. This layer’s top boundary is called the thermopause.

Exosphere: 600 to 10,000 km (372 to 6,200 miles)

The uppermost layer of Earth’s atmosphere is called the exosphere. Its lower boundary is known as the exobase. The exosphere has no firmly defined top. Instead, it just fades further out into space. Air molecules in this part of our atmosphere are so far apart that they rarely even collide with each other. Earth’s gravity still has a little pull here, but just enough to keep most of the sparse air molecules from drifting away. Still, some of those air molecules — tiny bits of our atmosphere — do float away, lost to Earth forever.

Credit: Science news for students

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WHAT IS EARTH’S ATMOSPHERE MADE UP OF?

Covering the surface of Earth like a thin blanket is a layer of gases that forms the atmosphere. It is made up of 78 per cent nitrogen, 21 per cent oxygen and 0.04 per cent carbon dioxide. The minute, remaining percentage is made of some other gases, water vapour and dust. We barely notice this all-enveloping atmosphere, but without it the Earth would be lifeless as the Moon.

Earth’s atmosphere is composed of about 78% nitrogen, 21% oxygen, 0.9% argon, and 0.1% other gases. Trace amounts of carbon dioxide, methane, water vapor, and neon are some of the other gases that make up that remaining 0.1%. While the earth’s atmosphere is mainly gases, it also contains tiny particles such as dust and pollen. Some unnatural particles also collect in the atmosphere and cause air pollution. These include anything from aerosols to carbon emissions from vehicles and power plants.

As humans, we rely on the atmosphere around us for life. We breathe it, we live in it—without it, we wouldn’t survive. Not only does the atmosphere around us need to be made of a certain composition for us to thrive, but it also needs to be one in which plants and food can grow, and one that protects us from the elements. Having oxygen we can breathe is just as important as being protected from the harsh sun rays, or the open expanses of space, and Earth has just the right location and atmospheric chemical composition to sustain life for humans and all other life forms that call Earth home.

Credit: Worldatlas

Picture credit: Google