Chapter 2 Climate

Weather: the combination of temperature, humidity, precipitation, wind, cloudiness, and other atmospheric condition occurring at a specific place and time. climate: long-term average pattern of weather→ the greatest constraint on organism

Physical environment=climate→ temperature and precipitation East ： High precipitation West ： low precipitation South ： high temperatureNorth ： low temperature

2.1 Earth intercepts solar radiation Solar radiation: electromagnetic energy→ a stream of photons or packets of energy→ wave or particle Sun (5800 ℃ ) short-wave radiation Earth (15 ℃ ) long-wave radiation

Greenhouse effect Greenhouse gas: water vapor (60 ﹪ ), CO 2 (32%)

Visible light→ Photosynthetically active radiation (PAR) Ultraviolet (UV) light: UV-A ( ), UV-B ( ) Infrared light : near infrared ( ), far infrared or thermal radiation ( )

2.2Intercepted solar radiation varies over earth’s surface Spatial variation high lat: sunlight over a larger area. travel through a deeper layer of air

Intercepted solar radiation varies over earth’s surface Spatial variation high lat: sunlight over a larger area. travel through a deeper layer of air Seasonal variation spring or vernal equinox( 春秋分 ) summer solstice ( 夏至 ):Tropic of Cancer winter solstice ( 冬至 ): Tropic of Capricorn

seasonal and daily solar radiation vary over earth

H L L

Mount Kilimanjaro, East Africa

2.3 Air temperature decreases with altitude Atmosphere pressure (air pressure): air’s weight act on earth’s surface→ P=F/A → total mass of air above that point

Air temperature decreases with altitude Atmosphere pressure (air pressure): air’s weight act on earth’s surface→ P=F/A → total mass of air above that point altitude↑ → pressure↓

Air temperature decreases with altitude Atmosphere pressure (air pressure): air’s weight act on earth’s surface→ P=F/A → total mass of air above that point altitude↑ → pressure↓ pressure ↓ → air density ↓ altitude↑ → pressure↓ → air density↓ Air temperature: altitude↑ → temperature↓ → environmental lapse rate( 直減率 )

air density ↑ → molecule collide ↑ →heat↑ Warming effect: primary reason

對流層 平流層 中氣層 增溫層

Adiabatic cooling ( 絕熱冷卻 ):air rise→ pressure↓ → expansion and cool The rate of adiabatic cooling:1 ℃ /100m of dry air or 0.6 ℃ /100m of wet air → the adiabatic lapse rate ( 絕熱直減率 )

2.4 Air mass circulate globally

Air mass circulate globally Coriolis force

2.5 Solar energy, wind, and earth’s rotation create ocean currents

2.6 Temperature influences the amount of moisture air can hold liquid→ gas (water vapor) Evaporation condensation: E=C→ saturated Vapor pressure: the amount of water can hold in air temperature→ absolute humidity saturation vapor pressure: the water content of air at saturation→ water vapor capacity: exceed → condensation temperature↑→ saturation vapor pressure↑ Dew point temperature: current= saturation Latent heat of evaporation ( 蒸發潛熱 )

2.7 Precipitation has a distinctive global pattern

Rainfall: southern hemisphere>northern hemisphere Intertropical convergence zone (ITCZ): near the equator, the northeasterly trade winds meet the southeasterly trade winds. →high precipitation ITCZ shift north and south, it brings on the wet and wet seasons in the tropics.

rainfall ： southern ＞ Northern coast ＞ interior continent

Wet season: summer Six month

2.8 Topography influences regional and local patterns of precipitation Rain shadow: 雨影

2.9 Irregular variation in climate occur at the regional scale The little Ice age: the mid-14th to the mid-19th century great plain of central North American →Earth orbit change in the tile of the axis and the shape of the yearly path about the sun Solar radiation: Sunspot activity ： 11 years Regional scale→El Niňo- southern oscillation (ENSO) → the oscillation in the surface pressure between the southeastern pacific and Australian-Indonesian

La Nińa 反聖嬰現象

ENSO index: air temp, surface temp, sea-level pressure, cloudiness and wind speed and direction

2.10 Most organisms live in microclimate Microclimate: the condition in which organism live.

Northern hemisphere→ south-facing slope → receive the most solar energy: warm, dry, variable condition. north-facing slope → receive the least solar energy: cool, moist, more uniform condition. Depression ： day: heat: sun; higher day time (summer) night: cool: terrestrial vegetation; lower night time (winter)