The Earth and its Atmosphere

Temperature and the Seasons

Why?

Solar Radiation

• Solar Constant

• Atmospheric Effects

• Angle of the Sun

• Length of the day

Solar Angle = angle above the horizon

Earth orbits the Sun once every 365 1/4 days as if it wereriding along a flat plane. We refer to this imaginary surfaceas the ecliptic plane and to Earth’s annual trip about the

plane as its revolution. Earth is nearest the Sun (perihelion)on or about January 3 (147,000,000 km). Earth is farthest

from the Sun (aphelion) on or about July 3 (152,000,000 km).

The latitudinal position of the subsolar point is the solar declination, which can be visualized

as the latitude at which the noontime Sunappears directly overhead.

What date is this?

Daily Insolation - top of the atmospere.

• 75º N in June gets more sun than the Equator

• Compare meridional gradient of insolation by seasons

• Very little tropical seasonality

Controls - Temperature

• Latitude

• Land and Water

• Ocean Currents

• Elevation

Mean July Temp (F.)

Mean January Temp (F.)

One of the most immediate and obvious outcomes of radiation gain or loss is a change in the air temperature. The map depicts differences between mean temperatures in January and July through the use of isotherms,

which are lines that connect points of equal temperature.

Certain geographical factors combine to influence temperature patterns across the globe. These factors include latitude, altitude, atmospheric circulation patterns,local conditions, continentality, (the effect of an inland location that favors greatertemperature extremes) and ocean current characteristics along coastal locations.

Data

Air Temperature

Local Variations

microclimates