Textbook Notes (368,432)
Canada (161,877)
Geography (106)
GG101 (32)
Chapter 4

GG101 Chapter 4 Notes.docx

5 Pages
Unlock Document

James Hamilton

GG101 Chapter 4 Notes- Atmosphere and Surface Energy Balances Energy Esssentials  Solar energy heating Earth’s atmosphere and surface is unevenly distrubted by latitude, and fluctuates seasonally  Refer to: flow diagram of shortwave and longwave radiation  Transmission: the passage of shortwave and longwave energy through either the atmosphere or water o Shortwave: includes radiation inputs (UV light, visible light, and near-infrared wavelengths) o Longwave: OUTPUTS such as thermal infrared  Insolation Input: insolation is the single energy input driving the Earth-atmosphere system o Solar energy (watts per square metre) is distributed unevenly throughout the world o Insolation decreases poleward from about 25 degrees latitude in both North and South hem’s o Consistent daylength and high Sun altitude produce average annual values of 180-220 W/m^2 throughout equatorial and tropical latitudes o Greater insolation occurs in low-latitude areas due to lack of clouds: Sonoran, Saharn, Arabian, Gobi, Atacama, Namib, Kalahari, Australian  Scattering (Diffuse Radiation): the process of insolation encountering increasing density of atmospheric gases as it travels toward the surface; the downward component of scattered light o Atmospheric gases and physically interact with insolation o Gas molecules redirect radiation, changing direct of light movement WITHOUT altering wavelength o Rayleigh Scattering: The shorter the wavelength, the greater the scattering and vice versa  Small gas molecules in the air scatter shorter wavelengths of light  Thus, the shorter wavelengths of visible light- the blues and violets- scatter the most and dominate the lower atmosphere  A blue sky prevails because there are more blue than violet wavelengths in sunlight  A sky filled with smog and haze appears white b/c the larger particles associated with air pollution act to scatter all wavelengths of visible light  Refraction: a bending action where insolation passes through various mediums, shifting direction in speed o Think: a ray of light passing through a prism/crystal- rainbows are created this way (reflected at precise angles towards witness) o Mirage: an image that appears near the horizon where light waves are refracted by layers of air at different temperatures (and consequently of different densities) o The atmospheric distortion of the setting Sun iis also a product of refraction  Refraction also causes the sun’s image to appear 4 minutes before it rises above horizon  Albedo and Reflection o Albedo: the proportion of K that is reflected or scattered from the surface and/or the atmosphere o Reflection: a portion of arriving energy bounces directly back into space without being absorbed or performing any work o Albedo: the reflective quality or intrinsic brightness of a surface (mirror vs dirt?)  i.e. dark colours have lower albedos, lighter colours have higher albedos o ERB- Earth Radiation Budget: sensors in satellites that measure Albedo concentration (19-38% in areas between tropics, and 80% near the polar regions)) o Earth and its atmosphere reflects 31% of all insolation when averaged over a year; comprised of clouds, land, ocean and reflections o Snow and ice also contribute to higher albedo o Albedo (reflective shortwave radiation/incoming shortwave radiation)*100%  24% absorbed in atmosphere, 31% reflected/scattered back to space, 45% reaches surface and is absorbed  Clouds, atmospheres and the atmosphere’s albedo o Cloud-Albedo forcing: an increase in albedo caused by clouds; yet clouds act as insulation, trapping longwave radiation from Earth and raising minimum temps o Cloud-greenhouse forcing: an increase in greenhouse warming caused by clouds o Eruption of Mount Pinatubo in the Philippines: caused 15-20 megatons of sulfur dioxide to be injected into the stratosphere; an average cooling of 0.5 degrees C was caused o Industrialization is producing a haze of pollution that is increasing the reflectivity of the atmosphere, including sulfate aerosols, soot and fly ash, and black carbon o Emissions of sulfur dioxide and subsequent chemical reactions in the atmosphere from sulfate aerosols  This pollution causes both atmospheric warming and surface cooling through reduction in insolation reaching ground and water surfaces (global dimming)  Absorption: the assimilation of radiation by molecules of matter and its conversion from one form of energy to another o Insolation in all forms that is NOT part of the 31% reflected from Earth’s surface and atmosphere is absorbed  Converted into longwave radiation or chemical energy by plants in photosynthesis o Warmer surfaces radiate more total energy at shorter wavelengths- the hotter the surface, the shorter the wavelengths that are emitted  Conduction, Convection and Advection o Conduction: molecule-to-molecule transfer of heat energy as it diffuses through a substance  As molecules warm, their vibration increases, causing collisions that produce motion in neighbouring molecules  Solids, liquids and gases conduct sensible heat directionally from areas of higher temp to those of lower temp  Example: heating of surfaces and overlying air, and soil temps o Convection: when physical mixing involves a strong vertical motion  Example: atmospheric and oceanic circulation, air mass movements and weather systems, internal motions deep within Earth that produce a magnetic field and crust movement o Advection: horizontal motion dominates  Example: horizontal movement of winds from land to sea and back, fog that forms and moves to another area, and air-mass movements from source regions o Solid, Liquids and Gases: remember particle theory…evaporation Energy Balance in the Troposphere  The earth-atmosphere energy system budget naturally balances itself in a steady-state eq’m  The greenhouse effect and atmospheric warming o Some of Earth’s
More Less

Related notes for GG101

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.