1. Section 1: INTRODUCTION
1.1 Where are the tropics and what makes them special?
1.2 The amount of energy received by the earth
1.3 Moisture in the tropics
1.4 Basic equations

2. 1.1 Where are the tropics and what makes them special?
Arbitrary definitions for where they are:
Geography: Tropics are the region of the earth bounded by the tropic of Cancer (23.5oN) and the tropic of Capricorn (23.5oS). These are the latitudes where the sun reaches the zenith just once a year at the summer solstices.
Equal Halves: The region between 30N and 30S would divide the earth into two equal halves. Defined this way, the tropics would be the source of all the angular momentum of the atmosphere and most of the heat. But this is not meteorologically sensible.
Processes: Riehl (1979) chose to define the “meteorological” tropics as those parts of the world where atmospheric processes differ significantly from those in higher latitudes (see next slides).
Riehl (1979) Climate and Weather in the Tropics, Academic Press.

3. Contrasting processes
Figure 1.1

4. Land and ocean contrasts
Figure 1.2:
Markedly non-uniform distribution of land and ocean areas in the tropics may be expected to have a large influence on the meteorology there

5. Annual Mean Rainfall
Figure Precipitation peaks in the tropics

6. Mean Meridional Circulations
Figure There are no walls between the tropics and extratropics!

7. 1.2 The amount of energy received by the earth
Solar Radiation Received at TOA
Figure 1.5
Solar absorbed
Outgoing radiation
Northward transport of energy
Northward transport by atmosphere
Figure 1.6

8. 1.2 The amount of energy received by the earth
Figure 1.7

9. 1.2 The amount of energy received by the earth
Figure 1.8(a)

10. 1.2 The amount of energy received by the earth
Figure 1.8(b)

11. 1.2 The amount of energy received by the earth
Figure 1.9

12. 1.3 Moisture in the tropics
Figure 1.10

13. 1.3 Moisture in the tropics
Figure 1.11

14. 1.3 Moisture in the tropics
Figure 1.12

15. 1.3 Moisture in the tropics
Figure 1.13(a)
Figure 1.13(b)

16. 1.3 Moisture in the tropics
Figure 1.14

23. 1.4 Basic equations
Adiabatic, Frictionless Equations in Pressure Coordinates
where