Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Chapter 3 Air Temperature

Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Surface and Air Temperature Surface Temperature When solar radiation strikes the ground what happens to: Shortwave radiation? Longwave radiation ? Sensible heat flows? Latent heat transfer? Convection?

Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Temperatures Close to the Ground Temperatures on the ground usually more extreme than temperatures at standard height (4 ft.) Soil, surface, and air temperatures vary throughout the day

Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Surface and Air Temperature Environmental Contrasts: Urban and Rural Temperatures Surface materials influence temperature strongly Transpiration? Evapotranspiration? Why?

The Urban Heat Island City centers tend to be several degrees warmer than surrounding suburbs and countryside. Why? Albedo evapotranspiration

High-Mountain Environments Reduced air pressure  reduced oxygen to lungs Fewer air molecules  sun’s rays stronger Less CO 2 and water vapor  reduced greenhouse effect What do these graphs show?

Temperature Inversion: reversal of normal temperature pattern so that air temperature increases with altitude Occurs when cold marine air slips under warm air.

Daily and Annual Cycles of Air Temperature Insolation varies by season Net radiation varies daily Positive after sunrise Peaks at noon Decreases to negative by sunset Air temperature varies daily When is lowest temp? When max? Why

Land and Water Contrasts Temperature Ranges for Maritime and Inland?

Daily and Annual Cycles of Air Temperature

Annual Net Radiation and Temperature Cycles Annual cycle of daily insolation affects  net radiation, which affects  monthly mean air temperature Review sheet #16

Air temperature maps- high, low temp, gradients Isotherm? Temperature gradient: rate of temperature change along a selected line or direction

World Patterns of Air Temperature Factors Controlling Air Temperature Patterns Three main factors explaining world isotherm patterns: 1. Latitude affects annual insolation, temperatures, and seasonal temperature variation 2. Maritime-continental contrast 3. Elevation

Patterns to note: Large land masses in Arctic and subarctic zones are extremely cold Ice and snow reflect insolation Temperatures decrease from equator to poles Highlands are colder than surrounding lowlands. Temperatures in equatorial regions? Continents heat/cool faster than oceans

Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Temperature Structure of the Atmosphere Lapse Rate: rate at which air temperature drops with increasing altitude

Temperature Structure of the Atmosphere Aerosols: tiny particles present in the atmosphere

Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Temperature Structure of the Atmosphere Stratosphere and Upper Layers Stratosphere: What is happening to temperature? Contains ozone layer

Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Global Warming and the Greenhouse Effect Factors Influencing climatic Warming and Cooling Earth is getting warmer. Intergovernmental Panel on Climate Change: global warming is “unequivocal”, very likely caused by human activity Greenhouse Gases: Carbon dioxide (CO 2 ) Methane (CH 4 ) Chlorofluorocarbons (CFC’s) Tropospheric ozone (O 3 ) Nitrous oxide (N 2 O) What trends do you see in the graph? Temp ?

Global Warming and the Greenhouse Effect Greenhouse GasesSome pollutants have a cooling effect Some factors are natural Net warming effect of 1.6 W/m 2

Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Global Warming and the Greenhouse Effect The Temperature Record Reconstructing temperature records: Thermometers Historical data Tree rings Coral growth Ice cores

Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Global Warming and the Greenhouse Effect 2005 warmest year recorded since mid-19 th century 2005, 1998, 2002, 2003,2006 five warmest years since 1400 Earth’s temperature up: 0.6º C (1.1º F) in last 30 years 0.8º C (1.4º F) in last 100 years IPCC projects increase in global temperatures between 1.8º C (3.2º F) and 4.0º C (7.2º F) by 2100

Potential future effects of greenhouse warming???

Global Warming and the Greenhouse Effect International efforts to reduce greenhouse emissions? Solutions?