Meridional Circulation Patterns Atmospheric 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 Sun Angle 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

Annual March of Average Monthly Precipitation (seasonal Patterns of Precipitation)

Climographs Plot average Monthly Temperature Against Average Monthly Precipitation

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: SF 5 CF 3 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 contain SF 5 CF 3. It must be man-made, but we don’t know where it is coming from. Each molecule traps as much heat as 18,000 CO 2 molecules. SF 5 CF 3 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 Biomes Tundra Taiga (northern coniferous forest, spruce forest) Temperate Deciduous Rain forest Tropical Rain forest Tropical Deciduous forest Tropical Scrub forest Temperate grassland and savanna Chaparral Desert (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 themselves perpendicular 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/m 2 /yr) World Net –––––––––––––––––––––––––Primary Area Normal Production (10 6 km 2 ) Range Mean (10 9 dry tons/yr) __________________________________________________________________ Lake and stream2100– Swamp and marsh2800– Tropical forest – Temperate forest 18600– Boreal forest 12400– Woodland and shrubland 7200– Savanna 15200– Temperate grassland 9150– Tundra and alpine 8 10– Desert scrub 18 10– Extreme desert, rock, ice 24 0– Agricultural land 14100– Total land Open ocean332 2– Continental shelf 27200– Attached algae, estuaries 2500– Total ocean Total for earth __________________________________________________________________