CH. 16 – THE ATMOSPHERE

Meteorology

Study of atmosphere & its dynamic processes (weather)

Weather – state of atmosphere at a given place for short period of time

Meteorology

Climate - compilation of weather over time for a region

- changes gradually

Ex: Ice Age vs. present

Global warming

Elements of Weather

1) 2) 3) 4) 5) 6)

Heating the Atmosphere

Radiation – energy transmitted through space

Different types of energy travel at different wavelengths

Heating the Atmosphere

All objects give off radiation:

Hotter object = shorter wavelength

Cooler object = longer wavelength

Steps for heating the atmosphere:

1) Short wavelength solar radiation passes through atmosphere (uv & visible range)

2) Earth’s surface absorbs solar radiation & heats up

Steps for heating the atmosphere:

3) Earth emits infrared radiation

4) CO2 & H2O vapor absorb infrared radiation

- “selective absorbers”

Earth-Sun Relations

Causes annual variations in seasons at a given latitude

Rotation = Earth spins on axis

Revolution = Earth’s elliptical orbit around sun

Earth’s axis:

Tilted 23 ½ o off vertical to plane of the ecliptic

- points to North Star

Most intense sunlight = solar rays striking Earth’s surface at 90o

Earth-Sun Relations

Know for each season:

1) date

2) location of vertical rays of sun

3) nickname

Controls of Temperature

1) Latitude controls:

a) Intensity = sun angle

Most intense = 90o

Lower sun angles = less intense

Latitude

b) Amount = length of daylight hours

At night, Earth emits radiation w/o collecting anymore

- coolest temp. = _____________

Latitude

Summer vs. WinterMore daylight hours = Earth builds

up surplus of energy (hot temp’s)Less daylight hours = Earth loses

more energy than it gains (cold temp’s)

Latitude

Affects annual temperature rangei) Closer to equator = ____ annual

temp. rangeii) Closer to poles = _____ annual

temp. rangeWhy?

Temperature Range

Difference between high & low temperatures

- daily, monthly, annual

Controls of Temperature

2) Amount of water vapor

Water vapor acts as a “blanket”- critical to daily temperature

range

Arid vs. Humid Regions

Arid regions:

Daily temp. range is__________

Humid regions:

Daily temp. range is __________

Cloudy vs. Clear Nights

Cloudy night:

Daily temp. range is__________

Clear night:

Daily temp. range is __________

Controls of Temperature

3) Land vs. water

____ heats more in summer

Land cools more in winter

Land has more variable annual temperature range than water

Controls of Temperature

4) Elevation – land height above sea level

Cooler temp’s at higher elevations b/c:

a) Further from main heat source (“radiator”) = Earth’s surface

Elevation

b) Less water vapor available in atmosphere

Why?

Controls of Temperature

5) Geographic Position

- prevailing westerly wind directions between 30o & 60o latitude

- both hemispheres!

Ex: East Coast vs. West Coast

Geographic Position

“Landlocked” cities have _______ annual temp. ranges

Coastal cities have ______ annual temp. ranges

Global Temperature Distribution

Figures 16.32 & 16.33Isotherm = line connecting points

of equal temp’sNOTE:1) Isotherms run __________

Why?

Global Temperature Distribution

2) Isotherm pattern is more ______ in Northern Hemisphere

Why?

Global Temperature Distribution

3) Ocean surface currents alter general east-west trend of isotherms

“Gyre” = circular pattern of ocean currents

Ocean Circulation

Poleward-moving currents are _______

Equatorward-moving currents are _______

Ex: Gulf Stream vs. California Current

Ocean Circulation

Affects temperature mean at similar latitudes

Ex: England vs. Newfoundland