The Atmosphere - Science Chapter 7 (Markus version) PDF

The Atmosphere =================================== The Atmosphere ============== 1. Light or radiant energy travels as a form of electromagnetic radiation to the Earth. Other forms of electromagnetic radiation are x-rays, microwaves, satellite waves and UV rays are s...

The Atmosphere =================================== The Atmosphere ============== 1. Light or radiant energy travels as a form of electromagnetic radiation to the Earth. Other forms of electromagnetic radiation are x-rays, microwaves, satellite waves and UV rays are screened and blocked by the atmosphere. Though some UV radiation does enter as UV A and B. 2. It retains heat creating a relatively stable climate. 3. Contains O~2~ needed for CELLULAR RESPIRATION & CO~2~ needed for PHOTOSYNTHESIS The Atmosphere ============== 4. Gravitational force keeps atmospheric gases close to the Earth's surface; 5. 99% of atmospheric gases are found within the first 30km of the atmosphere's total 10,000km 1. ##### [COMPOSITION OF THE ATMOSPHERE]  1. ##### [COMPOSITION OF THE ATMOSPHERE] - Water vapour is important in meteorology since it is responsible for the formation of clouds, Precipitation and fog. - The degree to which it is present (RELATIVE HUMIDITY) can be as much as 4% of air volume - Air also contains suspended solid particles: dust, pollen, soot, smoke... - There are 5 main layers from the Earth's surface Layer ========================== **s** 1. Troposphere: - 0-15 km away; - clouds/storms occur here; - Temperature decreases with altitude. - Helicopters fly in this layer. 2. Stratosphere: Layer ===== **s** - 15-50 km away; - Contains the Ozone Layer which absorbs sun's UV light (a form of electromagnetic radiation); - Temperature increases with altitude (opposite of troposphere) due to the ozone layer's influence; - Less air particles with altitude; - Jets and planes fly at this level 3. Mesosphere: Layer ===== **s** - 50-80 km away; - Contains very few air particles; - Coldest layer; - Temperature \< -80°C 4. Thermosphere: Layer ===== **s** - 80-500 km away; - Absorbs most of the solar rays; - Temperature as much as 1800°C; - Meteors burn rapidly when contact this layer causing shooting stars; - Polar auroras found at this level Layer ===== **s** 5. Exosphere: - 500 km+; - Practically devoid of air so temperature can't be measured; - Satellites are found here Atmospheric circulation -------------------------------------------- 2. ATMOSPHERIC CIRCULATION Atmospheric circulation -----------------------  1. Warm, humid (lighter) air at the Equator rises (low-pressure zone) 2. Air moves towards the poles 3. Air cools becoming heavier and then falls over cold, dry regions (high-pressure zone) 4. Cold air from the poles moves towards the Equator while step 3 is happening - Northern hemisphere winds are - Southern hemisphere winds are 1. Polar Cells: air starts at the poles then proceeds towards the 60th parallel. It hits the Ferrel cells, warms up and loops back over towards the poles. 2. Ferrel Cells: warms air moves towards the poles then rises at the 60th parallel, loops over and moves back towards the 30th parallel. 3. Hadley Cells: warm air over the Equator (0 parallel) rises and moves towards poles, cooling and dropping at the 30th parallel (fig.7.7 (p.227).  1. Polar easterlies: wind moving westward between polar and 60th parallel 2. Westerlies: wind moving eastward between 60th and 30th parallel 3. Trade Winds: Westward moving between Equator and 30th parallel - Prevailing winds are an important component of weather. Storms, rain and other phenomenon move from West to East in Quebec because we are under the influence of Westerlies. - Jet streams are very strong high altitude winds (especially in winter) ; they travel West to East around the globe between circulation cells. - Two jet streams per hemisphere: - \(1) Subtropical: At the 30th parallel - \(2) Polar: Near the 60th parallel   - It encourages cloud formation and precipitation. - A strong depression can occur over tropical warm waters forming huge spirals moving as fast as 360 km/hr leading to CYCLONES, HURRICANES or TYPHOONS. 3. GREENHOUSE EFFECT - It is a process by which the Earth retains a certain amount of solar heat that is essential to life. - Certain greenhouse gases (CO~2~, CH~4~, N~2~O, etc.) have always been part of the - It is like a greenhouse roof, these gases retain some of the sun's heat and release some of it. - Process: 1. Solar rays reach the Earth, heating the ground 2. Ground releases some of this heat, in the form of infrared radiation, into 3. Some of this infrared radiation is trapped and returns to Earth's surface  - For example: **CO~2~**: it is naturally released by forest fires, volcanic eruptions and cellular respiration; it is absorbed by plant growth and oceans; in the last century the balance has been offset by COMBUSTION of HYDROCARBONS (Fossil fuels: oil, natural gas, coal) which dramatically increase the release of CO~2~ into the atmosphere; the more CO~2~ is released, the more heat will be trapped thus contributing to climate change, i.e. abnormal modifications - Another example: **CH~4~**: it is 21 times more potent than CO~2~ in creating a trapping effect; it is released by farm animals when they digest grass or any greenery, through manure, paddy (Pads) field rice farming, decomposing waste (dumps), natural gas distribution, melting of the permafrost, etc. - Another example: **N~2~O**: (nitrous oxide) from fertilizer use, combustion of biomass, industrial uses (ex. nylon production) - Between 1850 and 2005, Earth's average temperature increased by 0.76°C. An increase of 2.0°C would bring serious disruptions (droughts, floods, heat waves and rising ocean levels). +-----------------------------------+-----------------------------------+ | | | +-----------------------------------+-----------------------------------+ | - - - - | - - - | | | | | | | | | | | | - - | +-----------------------------------+-----------------------------------+ 4. THE CONTAMINATION OF THE ATMOSPHERE 1. SO~2~ (When combined with water, it creates sulfuric acid) and NOx (nitrogen oxides) are contaminants found in ACID RAIN and SMOG. 2. Hg, As, Pb from hydrocarbon combustion, waste incineration and glass making. 3. CFC from refrigeration systems and aerosol cans, destroys ozone layer. 4. Dust and solid particles from factory chimneys and vehicle exhaust can enter lungs ### THE THINNING OF THE OZONE LAYER ### SMOG 1. NOx (from car exhaust or factories) + UV Rays → low altitude O~3~ + N~2~ 2. Low altitude (tropospheric) O3 + NO2 or SO2 → smog #### ENERGY RESOURCES - The wind's mechanical energy and then into electricity - A renewable resource. Wind turbines can be up to 120 m in height. Huge blades turn in the wind, activating an electric generator in the body of the turbine; electricity that is produced descends the turbine tower and is directed to a distribution centre then to our homes, businesses, etc. - Advantage: considered eco-friendly; no greenhouse gases produced - Disadvantage: eye sore. Wind speed is unpredictable thus the energy produced is not necessarily consistent. Its energy cannot be stored so it must be used with another more reliable system , for instance with hydroelectricity - ~~Sun is important: solar energy i.e. light and heat. The sun and the moon are also~~ - The Sun (star) is 75% Hydrogen and 25% Helium. Its core is 15 million °C. This core create NUCLEAR reactions that transform H into He and creates light. Solar energy (includes radiant energy-light) is transported by electromagnetic waves. It takes 8 min to travel between the Sun and the Earth. - Although solar radiation contains all of the electromagnetic spectrum waves , only visible light, some infrared, and a minute amount of UV rays reach the Earth's surface. #### SOLAR ENERGY 1. Passive heating systems: no specialized devices needed. A building made of heat absorbing materials (ex. concrete) is positioned southwards in a way to maximize sun penetration. 2. Photovoltaic cells: panel-shaped silicon containing structures that absorb the sun's rays. Electrons (Negatively charged particles) in the panel become activated creating an electric current. Can be used on houses, highway signs and satellites. 3. Solar collectors: sun exposed glass panels transfer their heat to water in copper pipes, heated water can be used. It is effective in heating air, house water and pools.