3.1 All biogeographic patterns are ultimately influenced by the geographic template

Ch. 3: PHYSICAL ENVIRONMENT (abiotic conditions: Water, Heat and

Rocks…)

• SOLAR RADIATION and TEMPERATURE REGIMES: Uneven Heating

• WINDS and RAINFALL (precipitation): Water!!!

• SOILS – an artifact (rocks + water + life!!)

• AQUATIC HABITATS

• MICROCLIMATES

Arctic Circle — 66° 33′ 39″ NTropic of Cancer — 23° 26′ 21″ NTropic of Capricorn — 23° 26′ 21″ SAntarctic Circle — 66° 33′ 39″ S

Terminology of Geography: latitude, longitude, meridian, parallel, equator, tropics, Arctic & Antarctic Circles…

Northern Hemisphere from Above

Earth:Circumference 24,902 miles

Diameter at equator: 7.926 miles, polar diameter: 7,900 mi

Length of 1° at equator = 69 miles

3.2 Average input of solar radiation to the Earth’s surface as a function of latitude

Earth revolves around the Sun = YearEarth axis is tilted.At any given time during summer or winter, one part of the planet is more directly exposed to the rays of the Sun, regardless of the time of day (i.e. the Earth’s rotation on its axis), This produces seasons.

Arctic winter: the North Pole is always dark, while the South Pole is illuminated.

Earth revolves around the Sun = One Year

http://www.classzone.com/books/earth_science/terc/content/visualizations/es0408/es0408page01.cfm?chapter_no=04

Sun is directly overhead on equator at spring and fall equinoxes (March 23, Sept 22), day = night all over Earth

Solstices: June 22 (summer in N hemi); sun is over Tropic of Cancer, 23.5°N

Solstices: Dec 22 (winter in N hemi); sun is over Tropic of Capricorn 23.5°S

Day length is determined by the length of time the Sun is above the horizon. Day length changes through the year as the orientation of the Earth to the Sun changes.

3.3 Seasonal variation in day length with latitude is due to the inclination of the Earth on its axis (1)

3.3 Seasonal variation in day length with latitude is due to the inclination of the Earth on its axis (2)

3.4 Vertical circulation of the atmosphere and wind patterns on the Earth’s surface

Three CONVECTIVE CELLS (Hadley Cells) in each hemisphere

Ascending: moist air releases moisture (rain)

Descending: dry air

WATER and WIND

Air masses, deflected by Coriolis effect, produce easterly trade winds of tropics and westerlies of temperate latitudes

These ZONAL WINDS initiate major CURRENTS in the oceans

3.5 Main patterns of circulation of the surface currents of the oceans

3.6 Factors causing rain shadow deserts (Part 1)

Climatic effects due to local geology:RAIN SHADOW across the mountains - WHY?

3.6 Factors causing rain shadow deserts (Part 2)

RAIN SHADOW: simple water physics!

3.7 Major climatic regions of the world

CLIM ATES: ZONALITY (and SEASONALITY)

SOILS

3.10 Schematic representations of the four major pedogenic regimes (Part 1)

SOILS: FOUR MAJOR REGIMES – 1 & 2

3.10 Schematic representations of the four major pedogenic regimes (Part 2)

SOILS: FOUR MAJOR REGIMES – 3 & 4

3.11 Schematic diagram depicting the relationships between major soil types and climate

3.12 World distribution of major soil types

3.13 Local elevational distribution of soil particle size and vegetation on a desert bajada

Lake Zones

3.14 Vertical temperature profiles of Lake Mendota, Wisconsin

AQUATIC HABITATS

3.15 Small-scale spatial and temporal heterogeneity of surface waters in the North Atlantic (Part 1)

AQUATIC HABITATS

3.15 Small-scale spatial and temporal heterogeneity of surface waters in the North Atlantic (Part 2)

3.15 Small-scale spatial and temporal heterogeneity of surface waters in the North Atlantic (Part 3)

3.16 How centrifugal force and the gravitational force of the moon cause the tides

AQUATIC HABITATS

3.17 A tide calendar for the northern Gulf of California (Sea of Cortez)

AQUATIC HABITATS

This image highlights major upwelling areas along the world's coasts in red. Upwelling occurs when winds blowing across the ocean surface push water away from an area and subsurface water rises up from beneath the surface to replace the diverging surface water. These subsurface waters are typically colder, rich in nutrients, and biologically productive. Therefore, good fishing grounds typically are found where upwelling is common. For example, the rich fishing grounds along the west coasts of Africa and South America are supported by year-round coastal upwelling.

  

http://www.marbella.es/medioambiente/images/stories/clima/upwelling.gif

What is El Niño? El Niño is the warming of sea-surface temperatures in the equatorial Pacific Ocean which influences atmospheric circulation, and consequently rainfall and temperature in specific areas around the world. El Niño is translated from Spanish as "the boy child". Peruvian anchovy fishermen traditionally used the term - a reference to the Christ child - to describe the appearance of a warm ocean current off the South American coast around Christmas. Over the years the term El Niño has come to be reserved for the sequence of changes in the circulation across the Pacific Ocean and Indonesian archipelago when warming is particularly strong. Approximately 14 El Niño events affected the world between 1950 and 2003. Amongst them was the 1997/98 event, by many measures the strongest thus far this century, although South Africa escaped the impact of it to some extend.

What is La Niña? La Niña is the cooling of sea-surface temperatures in the equatorial Pacific Ocean which influences atmospheric circulation, and consequently rainfall and temperature in specific areas around the world. La Niña, Spanish for "the girl", is the opposite of El Niño. SSTs in the equatorial Pacific become cooler than normal, giving rise to the term "cold event". This situation is reflected by negative SST anomalies. The Walker circulation intensifies and the SOI consequently becomes positive during this event.

What is ENSO? The changes in the Pacific Ocean are represented by the term "El Niño/La Niña", while changes in the atmosphere are known as the "Southern Oscillation". Because these two cannot be separated, the term ENSO is often used. ENSO refers to both El Niño and La Niña.

During normal years (non-ENSO years) relatively cold water occurs along the west coast of South America , an effect increased by upwelling of cold water along the Peruvian coast. The cold water then flows westward along the equator to Australia and is heated by the tropical sun. These normal conditions make the western Pacific about 3°C to 8°C warmer than the eastern Pacific.

During El Niño years, the area of warm water (usually over the western tropical Pacific near Australia ) cools down and the warm water is displaced eastward to the central Pacific. The upwelling off the Peruvian coast is suppressed and the SSTs in this region become warmer than usual.

3.18 Temperatures inside and outside the den of a bushy-tailed woodrat

MICROCLIMATES