AP®︎ Environmental Science: Topic 4.7 Flashcards

Solar energy received by Earth, the principal external energy source driving surface warming and most atmospheric processes

The amount of solar energy received per unit of surface area

Direct rays strike nearly perpendicularly and concentrate energy, while oblique rays strike at a slant and spread energy over a larger area

The location where sunlight strikes Earth perpendicularly and the Sun is directly overhead at solar noon

Earth’s rotational axis is tilted about 23.5° from perpendicular to its orbital plane, causing seasonal changes in sun angle and day length

A point in Earth’s annual orbit marking an extreme in seasonal solar angle and day length

Around June 20–22, the Northern Hemisphere has its longest day, the Southern Hemisphere its shortest, and the subsolar point is at 23.5° N.

Around December 20–22, the Southern Hemisphere has its longest day, the Northern Hemisphere its shortest, and the subsolar point is at 23.5° S.

A point when neither hemisphere is tilted toward the Sun, the subsolar point is at the equator, and day and night are approximately equal

Around March 19–21, an equinox beginning astronomical spring in the Northern Hemisphere and autumn in the Southern Hemisphere

Around September 21–23, an equinox beginning astronomical autumn in the Northern Hemisphere and spring in the Southern Hemisphere