ENGAGE
Convection and Heat Flow in the Atmosphere - More Hot Air...
Most of us can think of an example from our daily life that demonstrates convection. Whether it's the warmer water near the surface of the lake we're swimming in, or the greater warmth near the ceiling compared to the floor, we've all learned that heat rises.
And as we discussed on the previous module on ocean circulation, cold, denser fluids descend. So much of what we discussed regarding density driven ocean circulation applies to the atmosphere as well. But instead of the ocean currents, here we'll explore the atmospheric currents--wind.
In the atmosphere, the motions of rising and falling gases of differing temperature, humidity and densities create the winds which are further directed by the larger forces of Earth's rotation and corresponding Coriolus force.
In the atmosphere, there are two main causes for air density to decrease; Increased temperature and increased water vapor caused by evaporation both decrease the density of air and cause it rise.
As the water vapor-rich warm air rises, it also expands and correspondingly cools. This cooling permits water vapor to condense. This way the atmosphere releases heat high in the atmosphere that it gained through evaporation at the surface.
So, here we see one simple, but very powerful method in which our planet moves heat from where it's hot to where it's not; This convection driven evaporation-condensation system, called latent heat flux, accounts for 23% of Earth's net heat budget.
All these varied forces interact to create complex, but distinct and predictable patterns of wind, weather and climate around the globe. Let's explore some of the online resources the help us to visualize and better understand and appreciate weather, whether or not you're a meteorologist.
Convection and Heat Flow in the Atmosphere - More Hot Air...
Most of us can think of an example from our daily life that demonstrates convection. Whether it's the warmer water near the surface of the lake we're swimming in, or the greater warmth near the ceiling compared to the floor, we've all learned that heat rises.
And as we discussed on the previous module on ocean circulation, cold, denser fluids descend. So much of what we discussed regarding density driven ocean circulation applies to the atmosphere as well. But instead of the ocean currents, here we'll explore the atmospheric currents--wind.
In the atmosphere, the motions of rising and falling gases of differing temperature, humidity and densities create the winds which are further directed by the larger forces of Earth's rotation and corresponding Coriolus force.
In the atmosphere, there are two main causes for air density to decrease; Increased temperature and increased water vapor caused by evaporation both decrease the density of air and cause it rise.
As the water vapor-rich warm air rises, it also expands and correspondingly cools. This cooling permits water vapor to condense. This way the atmosphere releases heat high in the atmosphere that it gained through evaporation at the surface.
So, here we see one simple, but very powerful method in which our planet moves heat from where it's hot to where it's not; This convection driven evaporation-condensation system, called latent heat flux, accounts for 23% of Earth's net heat budget.
All these varied forces interact to create complex, but distinct and predictable patterns of wind, weather and climate around the globe. Let's explore some of the online resources the help us to visualize and better understand and appreciate weather, whether or not you're a meteorologist.
EXPLORE
Teachers' Domain
Here's a TD animated video resource that demonstrates how the physics principles we have been exploring are coupled in the inseparable interface between the ocean and atmosphere; Ocean Temperatures and Climate Patterns.
And the TD-hosted NOVA interactive resource, Giving Rise to The Jet Stream, illustrates nicely the complexities of the interacting forces that create Earth's weather.
The Jet Stream and Horizontal Temperature Gradients is another TD interactive resource that helps to demonstrate how different forces interact to create the weather patterns that are distinct to various regions.
Ocean Temperatures and Climate PatternsGiving Rise to The Jet StreamThe Jet Stream and Horizontal Temperature GradientsEXPLAIN
- What are some of the differences in winds and weather associated with latitude on Earth?
- How do temperature differences between the poles and equator (thermal gradient) affect wind velocities in the Jet Stream?
- What forces work together to create the Walker Cell?
- Why is it difficult to discuss weather apart from the role of the ocean?
- How do these TD digital resources serve to enhance student learning?
EXPLORE SOME MORE...
YouTube
From YouTube, here are some of the basics presented as the Six Principles of How Weather Works, by Weather School. A more technical and informative YouTube video, Global Circulation, shows graphically where and how the patterns of weather occur across the planet.
And just try not to be mesmerized by this amazing composite of a year's worth of satellite data showing water vapor motion across the planet; Water Vapor Circulation on Earth.
EXPLAIN
- What is the primary force that causes weather?
- How does the differential heating of the planet contribute to wind and weather patterns?
- How do the seasons affect the position and behavior of the atmospheric circulation cells?
- What role does Earth's rotation play in creating wind and weather?
- Monitor the atmosphere over Alaska by satellite in near-real-time. A picture's worth a thousand words.
- For the more scientifically ambitious, try NASA's Atmospheric Science Data Center for lots of great information and resources.
EVALUATE
- What resources so far have been the most engaging for you? Your students?
