Hurricanes, typhoons, cyclones.... tropical storms are full of energy
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Hurricanes, cyclones, and typhoons are all the same weather phenomenon; we just use different names for these tropical storms in different places. In the Atlantic and Northeast Pacific, the term “hurricane” is used, in the Northwest Pacific it is a “typhoon”, and “cyclones” occur in the South Pacific and Indian Ocean. Tropical storms can’t form outside the tropics - water temperatures are too cold. Sea surface temperature must be at least 27°C, and this temperature is actually required to a depth of at least 50 m. The warm tropical atmosphere heats up the water at the ocean surface and begins to evaporate it. The trapped water vapour in the air rises up through the atmosphere.
When the rising air cools, and the water vapour condenses into liquid water, the heat is released back into the atmosphere. The warm air rushes upward, because it has a lower density than its surroundings. This then draws air up from below, and speeds up the rising air near the surface. Surface air around the growing disturbance rushes in to replace it. A satellite image from the National Oceanographic and Atmospheric Administration shows Hurricane Katrina bearing down on the Gulf Coast on Aug. 28, 2005.
As this cycle continues, more warm, moist air is drawn into the developing storm, and more heat is transferred from the surface of the ocean to the atmosphere.
This continuing heat exchange creates a wind pattern that spirals around a relatively calm centre, or eye, like water swirling down a drain.
What is the worst-case scenario for climate change? The geological record shows that when the atmosphere suddenly changes, there are big effects on living things. Five major mass extinction events are recorded in the rock record of the last 600 million years. The biggest extinction was at the end of the Permian , around 252 million years ago. It is called the End-Permian mass extinction. Only about 8% of species survived to live on in the Triassic Period. This photo shows geologists investigating tilted sedimentary rocks at Shangsi in South China. Triassic rocks (at the top right) lie over the older Permian rocks. Each mass extinction in the rocks matches with a change in the chemistry of the rocks called a ' carbon excursion '. Some of the carbon excursions are 'negative CEs' and some are 'positive CEs'. Negative CEs indicate that lots of gaseous carbon compounds escaped into the air, causing warming. These are sometime...
What do scientists mean by the " Greenhouse Effect "? When the Sun's energy arrives at the Earth, it travels through the air. Some is reflected back to space, but some hits the Earth and warms it. The warm Earth gives off infrared radiation with various wavelengths. Some of those waves can pass back out of the air to space, but some are absorbed by certain gases in the air. The gases then re-emit the energy into the air. If there are more of those gases, less heat escapes into space. An extreme case has happened on Venus. Concentrated 'greenhouse gases' on Venus have caused the surface temperature to rise to 735 Kelvin (462 degrees C; around 900 degrees F) Carbon dioxide levels in the atmosphere have risen quickly since people began burning large quantities of fossil fuels. There was carbon dioxide in the air before that, at around 270 parts per million. Without any carbon dioxide, the Earth wo...
Coal, oil and natural gas are fossil fuels . When they are burned, they change the Earth's atmosphere. How is that possible? C oal is a good example. Coal was formed hundreds of millions of years ago . Geologists say that a three-metre (10-foot) coal seam took between 12,000 and 60,000 years to form . Ancient trees and other plants lived, died and were fossilised. All those plants took carbon dioxide out of the atmosphere. Some larger coal seams are, for example, 10 metres thick. They took around 40,000 years to form, but have been mined and burned in a little over 100 years. The fastest rise of CO 2 in the air seen in the ice core record (800,000 years) is 20 ppm in 1000 years. The CO 2 level in the atmosphere is now rising at around 20 ppm per decade . The carbon joins up with oxygen when it burns. Eac...
