Meridional Circulation PatternsAtmospheric Cells, Jet Streams, Adiabatic Cooling and Warming,Horse Latitudes

Coriolis Force

Ocean currents move heat to higher latitudes on east coasts, and cold polar water towards the equator on west coasts.

Latitudinal Belts of Average Annual Precipitation

Geographic Distribution of Average Annual Precipitation

Rainshadow Effect

Earth’s Annual Elliptical Orbit around the SunAngle of Inclination of Axis is currently about 23.5° (wobbles between 22° and 24.5° every 41,000 years)

Perihelion — at present, earth is closest to sun during winter in the northern hemisphere (11,000 years ago it was closest to the sun during summer in the northern hemisphere) (22,000 year cycle). Orbit itself shifts <——>

Angle of inclination varies cyclically from 22° to 24.5° with a periodicity of about 41,000 years (currently about 23.5°)

Earth’s orbit changes from relatively circular to more elliptical and back again over a 95,000 year cycle.

Milankovitch Cycles

Daylength (Photoperiod) changes seasonally, but differently at different latitudes — no change in daylength at equator

AnnualMarch ofAverageMonthlyPrecipitation(seasonalPatterns ofPrecipitation)

ClimographsPlot averageMonthly TemperatureAgainstAverage MonthlyPrecipitation

Two plots of temperature against moisture. (a) Climographs for an area in Montana where the Hungarian partridge was introduced successfully and a Missouri locality where its introduction failed, compared to the average climatic conditions of its European geographic range. Apparently Missouri summers are too hot and/or too wet for these birds. (b) Plots of temperature versus relative humidity in 1927 and 1932 in Israel superimposed on optimal (inner rectangle) and favorable (outer rectangle) conditions for the Mediterranean fruit fly.

Geographic Distribution of Climates

Trifluoromethyl Sulfur Pentafluoride: SF5 CF3

During the past few decades, a new greenhouse gas molecule has begun to appear in Earth’s atmosphere.Air trapped in glaciers before 1960 does not containSF5 CF3. It must be man-made, but we don’t know where

it is coming from.

Each molecule traps as much heat as 18,000 CO2

molecules. SF5 CF3 is increasing at rate of 6% per year.

Moreover, this molecule is extremely stable with a half life of 1,000 years.

The Interface between Climate and Vegetation

Plant Life Forms and BiomesTundraTaiga (northern coniferous forest, spruce forest)Temperate Deciduous Rain forestTropical Rain forestTropical Deciduous forestTropical Scrub forest Temperate grassland and savannaChaparralDesert (warm, cold)Mountains (complex zonation)

Distribution of Major Vegetation Types

Geographic Distribution of Climates

Idealized Thermal Profile

Daily March of Temperature

Microhabitats

Leaves droop(wilt) which reduces solar heat load

Leaves in shade present their full surface to collect as much incoming solar radiation as possible.

Similarly, desert lizards position themselvesperpendicular to the sun’s rays in early morning,when environmental temperatures are low, but during the high temperatures of midday, these same lizards reduce their heat load by climbing up off the ground into cooler air, facing directly into the sun, thereby reducing heat gained.

Temperature profiles in a growing cornfield at midday.

Microhabitat Selection

Plants buffer temperatures and humidites for animals (also wind). An aphid lives in a 2mm thick microhabitat with 100% humidity.

Soils act similarly: temperature and moisture content are more stable deeper down.

Wind operates to increase thermal exchange (“wind chill” effect) and also has a desiccating effect.

Wind Velocities

Primary Productivity versus Average Annual Precipitation

Net Primary Productivity and World Net Primary Production for Major Ecosystems

__________________________________________________________________ Net Primary Productivity

per Unit Area (dry g/m2/yr) World Net ––––––––––––––––––––––––– Primary

Area Normal Production (106 km2) Range Mean (109 dry tons/yr)

__________________________________________________________________

Lake and stream 2 100–1500 500 1.0Swamp and marsh 2 800–4000 2000 4.0

Tropical forest 20 1000–5000 2000 40.0 Temperate forest 18 600–2500 1300 23.4Boreal forest 12 400–2000 800 9.6 Woodland and shrubland 7 200–1200 600 4.2Savanna 15 200–2000 700 10.5Temperate grassland 9 150–1500 500 4.5Tundra and alpine 8 10–400 140 1.1Desert scrub 18 10–250 70 1.3

Extreme desert, rock, ice 24 0–10 3 0.07Agricultural land 14 100–4000 650 9.1

Total land 149 730 109.0Open ocean 332 2–400 125 41.5Continental shelf 27 200–600 350 9.5Attached algae, estuaries 2 500–4000 2000 4.0Total ocean 361 155 55.0

Total for earth 510 320 164.0__________________________________________________________________