Category: Winds

Earth's Emergency Heat Valve: The Hurricane

6/2/2022

Vicki Cobb
The Master Chef of Kids' Hands-on Science

Earth has a problem. The sun creates hot spots over land, in the air and in the water. That’s why there are winds, weather, and currents in the ocean as Earth tries to even out the heat, moving warmer masses of air and water to cooler areas.

During hurricane season ( from June 1-November 30), only 10 or 11 of the 80 tropical disturbances off the west coast of Africa (where most of our hurricanes originate) become large enough storms to be given a name. Only two or three of them hit the United States. They are not frequent but they are massive wind storms that can destroy life and property.

Do they do anything good at all? As far as the Earth is concerned, these largest of all storms are a safety valve to rapidly move heat that has been accumulating in the oceans up to the stratosphere (from 7 to 31 miles above the Earth’s surface). From there it will be transported through the air to over the North Pole. It’s the way Earth stops a fever.

Once a hurricane forms, it must have an ocean surface that is at least 80°F to keep moving and to grow. Under the storm, huge amounts of warm water become water vapor. Warm moist air rapidly rises through the spinning winds of the hurricane, up to the stratosphere. When moist air reaches the frigid (-70°F) stratosphere the water vapor quickly condenses to liquid water (rain) releasing its heat. This heat makes surrounding air molecules move faster forming winds.

How do hurricanes cool off the oceans? How do they move the heat? Here’s a clue: Wet your finger and wave it in the air. How does it feel? Pretty cool, I bet! That’s because the heat from your finger changes liquid water into water vapor (a gas) as your finger dries. Water vapor molecules store this extra heat. They rise because they are lighter than other air molecules.

So, a hurricane is a heat engine that moves water vapor from the ocean’s surface high enough to condense back into liquid water and release heat safely to the stratosphere forming rivers of wind that move it to the poles.

Scientists predict that global warming will increase the number and the power of the hurricanes as the ocean surfaces become increasingly warmer during our summers.

This diagram of the anatomy of a hurricane shows the direction of the winds. The blue represents cold air descending while the pink shows warm moist air rising. The outflow surface clouds form as water condenses into a "table-top" cloud, releasing heat that becomes wind. Kelvinsong via Wikimedia

Hurricane Isabel (2003) as seen from orbit during Expedition 7 of the International Space Station. The eye, eyewall, and surrounding rainbands, all characteristics of hurricanes, are clearly visible in this view from space. Image courtesy of Mike Trenchard, Earth Sciences & Image Analysis Laboratory, NASA Johnson Space Center

Vicki Cobb's How Could We Harness a Hurricane? offers questions and provides new points of view that may just change peoples' thinking by showing young readers the work scientists and engineers are doing to avoid future disasters. The book includes hands-on experiments that make science fun, be it at home or in the classroom. Here's a link to the book' s Trailer.

How Could We Harness a Hurricane was named a 2018 Best STEM Book K-12 by the National Science Teachers Association and the Children's Book Council.

Vicki is a member of iNK's Authors on Call so you can invite her to your classroom via iNK's videoconferening Zoom Room. Click here to find out more:

MLA 8 Citation
Cobb, Vicki. "Earth's Emergency Heat Valve: The Hurricane." Nonfiction Minute,
iNK Think Tank, 24 Apr. 2018, www.nonfictionminute.org/
the-nonfiction-minute/Earths-Emergency-Heat-Valve-The-Hurricane.

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Climate Change: The Facts and the Consequences

4/28/2022

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Dorothy Hinshaw Patent
Nature’s Animal Ambassador

The polar jet stream can travel at speeds greater than 100 miles per hour (160 km/h). Here, the fastest winds are colored red; slower winds are blue. NASA/Goddard Space Flight Center

No one can honestly deny that our climate has been changing in recent years. Before the winter of 2018-2019, California had only a year’s water supply stored in its reservoirs. Wildfires have become an annual threat throughout much of the west, while the Midwest and East Coast have experienced record-setting winters. These problems are due to complex interactions among temperature, winds, and water currents.

A major change is the warming of the atmosphere. The earth’s atmosphere has been getting warmer since the late 1800s, when factories started spewing out carbon dioxide. Because natural variations also affect the temperature, a graph showing the temperature over time is a jagged line. But the trend is consistently upward and follows the graph of increasing carbon dioxide in the atmosphere due to human activities. That’s strong enough evidence that we are at least a large part of the problem, and the vast majority of climate scientists are urging countries of the world to reduce their carbon dioxide emissions.

A major player in the world’s weather is the jet stream, which helps circulate the atmosphere around the world about every two weeks. This flow of fast-moving air speeds across North America from west to east, separating cold arctic air from warmer, more southerly air. The jet stream used to run in a fairly direct arc across the northern United States. But in recent years it has become less stable, dipping southward in the eastern U.S. to bring frigid winters to the Northeast while arching northward in the West, carrying warm, dry air there. Scientists believe that the rapid melting of the Arctic ice brought about by global warming is part of the cause for the jet stream’s instability.  However, climate trends are controlled more by the oceans. Scientists estimate 95% of the heat from global warming is being stored in the oceans, increasing water temperatures even into the depths.

As global warming continues, so will climate change. The melting of sea ice and glaciers is already raising the sea level. While scientists don’t blame climate change for devastating Hurricane Sandy, Sandy’s extreme coastal flooding was made worse by the increase in sea level that’s already occurred. As time goes on, coastal cities around the world will be at increasing risk for more severe storm damage.

Because warm air holds more moisture than cold air, storms are becoming more severe, increasing blizzards and flooding storms. Some agricultural regions that depend on reliable rainfall may soon be unable to grow crops, disrupting the food supply.

Climate change is complicated, but because it affects us all, we need to learn about it.  The Environment Protection Agency has questions and answers about climate change.

Oceans cover 71% of the Earth’s surface and contain 97% of the water on our planet. This chart shows how this water has absorbed the vast majority of the increased atmospheric heat due to global warming.

This chart shows how carbon dioxide in the atmosphere has increased since 1960. The measurements are made near the top of Mauna Loa on the island of Hawaii, thousands of miles away from any land-based major pollution.

Calculations of global warming prepared in or before 2001 from a range of climate models. The projections assume no action is taken to reduce emissions.

Yellowstone National Park’s majestic geologic wonders and remarkable wildlife draw millions of visitors each year. But there was a time when these natural treasures were in great danger, all because after years of unrestricted hunting, one key piece of the puzzle had been eliminated—the wolf.

Now, more than a decade after scientists realized the wolves’ essential role and returned them to Yellowstone, the park’s natural balance is gradually being restored. Dorothy Hinshaw Patent's text supplemented by spectacular full-color photographs show the wolves in the natural habitat that was almost lost without them. Click here to find out more.

Dorothy Hinshaw Patent is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.

MLA 8 Citation
Patent, Dorothy Hinshaw. "Climate Change: The Facts and the Consequences."
     Nonfiction Minute, iNK Think Tank, 17 Apr. 2018,
     www.nonfictionminute.org/the-nonfiction-minute/
     Climate-Change-The-Facts-and-the-Consequences.

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Earth's Emergency Heat Valve: The Hurricane

Climate Change: The Facts and the Consequences

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