Global Temperatures
Now that you understand how incoming solar radiation is treated as it enters the Earth's atmosphere and impacts the surface, let's look at the global distribution of that energy.
While the processes that reflect, scatter, transmit, absorb, and emit energy are the same no matter where you are on Earth, the amounts of insolation associated with of each of those processes, or rates of each process, are dependent upon two factors that vary considerably across the surface of the Earth:
1) Amount of incoming solar radiation
2) Amount/thickness of atmosphere
Measuring Global Surface Temperature - What Geographers See
Log in to BBLearn, and under Module 3, go to the Study Area. Under Interactive Animations, Chapter 4, select the animation titled "Seasonal Changes in Land Surface Temperatures: Land Surface Temperature."
This animation is created with remotely-sensed data from the sensor called MODIS. The sensor has special equipment to measure the thermal radiation that is emitted back towards space from the Earth's surface and its atmosphere, and converts that radiation to a temperature value. Make some observations about Land Surface Temperature (LST) over the course of each year to answer the questions below.
1) What places have the highest LSTs? Where are they in relationship to the equator?
2) How is the distribution of LSTs different in the northern hemisphere versus the southern hemisphere?
3) What is the seasonality of the highest LSTs globally? Which months do they occur where?
4) Observe the places that have the lowest LSTs and are the coldest year-round. Are these places generally higher in latitude, or lower?
As discussed in Module 1 on Earth-Sun relationships, the poles have the lowest angle of incidence of anywhere on Earth (for the 6 months of the year they have sunlight, anyway). This low angle of incidence translates to the lowest amount of insolation received; the more directly overhead the Sun is in the sky, the more insolation a location is receiving. A good analogy is thinking of the Sun as a flashlight beam on a dark night: the more area you try to cover with the beam, the weaker the light is. Additionally, insolation must travel through much more atmosphere at the poles, allowing for increased reflectance, scattering, and atmospheric absorption of energy before it ever reaches Earth's surface.
Another factor that impacts global energy distribution and global temperatures is water. Recall that the surface of our planet is about 70% water; this high ratio of water to land impacts how energy is distributed through ocean currents and land-water heating differences.
While the processes that reflect, scatter, transmit, absorb, and emit energy are the same no matter where you are on Earth, the amounts of insolation associated with of each of those processes, or rates of each process, are dependent upon two factors that vary considerably across the surface of the Earth:
1) Amount of incoming solar radiation
2) Amount/thickness of atmosphere
Measuring Global Surface Temperature - What Geographers See
Log in to BBLearn, and under Module 3, go to the Study Area. Under Interactive Animations, Chapter 4, select the animation titled "Seasonal Changes in Land Surface Temperatures: Land Surface Temperature."
This animation is created with remotely-sensed data from the sensor called MODIS. The sensor has special equipment to measure the thermal radiation that is emitted back towards space from the Earth's surface and its atmosphere, and converts that radiation to a temperature value. Make some observations about Land Surface Temperature (LST) over the course of each year to answer the questions below.
1) What places have the highest LSTs? Where are they in relationship to the equator?
2) How is the distribution of LSTs different in the northern hemisphere versus the southern hemisphere?
3) What is the seasonality of the highest LSTs globally? Which months do they occur where?
4) Observe the places that have the lowest LSTs and are the coldest year-round. Are these places generally higher in latitude, or lower?
As discussed in Module 1 on Earth-Sun relationships, the poles have the lowest angle of incidence of anywhere on Earth (for the 6 months of the year they have sunlight, anyway). This low angle of incidence translates to the lowest amount of insolation received; the more directly overhead the Sun is in the sky, the more insolation a location is receiving. A good analogy is thinking of the Sun as a flashlight beam on a dark night: the more area you try to cover with the beam, the weaker the light is. Additionally, insolation must travel through much more atmosphere at the poles, allowing for increased reflectance, scattering, and atmospheric absorption of energy before it ever reaches Earth's surface.
Another factor that impacts global energy distribution and global temperatures is water. Recall that the surface of our planet is about 70% water; this high ratio of water to land impacts how energy is distributed through ocean currents and land-water heating differences.
Assignment
Log into BBLearn, and under Module 3, Mastering Assignments, use the MapMaster to complete the activity "Assignment 3.3: Energy and Temperature."