Energy Efficiency Review Efficiency refers to the ability of an energy conversion reaction to convert energy from one form to the next without losing too much heat to the environment (electrical to light, chemical to mechanical, and etc.) An energy conversion that doesn t lose any heat at all would have a 100% efficiency rating (= 1) Efficiency = (Work Output/Work Input) x 100% Example: A fluorescent lightbulb converts light at 25% efficiency. 0.25
Global Climate Tuesday, September 8 th, 2015
Disaster in Kenya (2003) Western Kenya: Heavy rains led to floods (roads/homes), death, mudslides and disruption of water services (pipes damaged at a water treatment plant), as well as increased cholera Northern Kenya: no summer rains, drought for 3 years. Crops died, no water, increased deaths, risk of starvation national disaster In conclusion, global processes drive rainfall patterns. Depends on the seasonal position of the sun, wherever the sun strikes most directly, water evaporates and forms clouds which drop rain.
Climate = average weather (conditions of the atmosphere like temperature, humidity, clouds, precipitation, wind speed, atmospheric pressure) that occurs in a region over decades Cannot predict weather, but we can make observations Regional differences determine which organisms can live where. Look at processes that affect the distribution of heat/precipitation. 1. unequal heating of the earth by the sun 2. atmospheric convection currents 3. rotation of Earth 4. Earth s orbit around the sun on a tilted axis 5. ocean currents
Earth s Atmosphere Consists of 5 layers pull of gravity on gas molecules 1.Troposphere Densest layer, where weather occurs 2.Stratosphere less dense, ozone, more UV so warmer 3.Mesophere 4.Thermosphere blocks X ray and UV radiation 5.Exosphere
Earth s Atmosphere
Sun passes through the atmosphere to heat the earth unequally Uneven warming pattern has three primary causes 1. Angle at which sun s rays hit Earth 2. Amount of surface area that the rays are distributed 3. Albedo (percentage of incoming sunlight that is reflected higher, less light absorbed)
Unequal heating affects air circulation in the atmosphere Properties of air determine how it circulates in the atmosphere. 1. Density determines air s movement (less dense rises, denser air sinks) 2. Water vapor capacity maximum amount that can be in the air at one time (saturation point) 3. Adiabatic heating or cooling higher in atmosphere, decreases pressure, decreases temperature or lower in atmosphere, higher pressure, increases temperature 4. Latent heat release when heat is released as water vapor condenses into liquid
Unequal heating affects air circulation in the atmosphere Atmospheric convection currents = global patterns of air movement due to unequal heating
Earth s rotation also has an effect on climate (direction of prevailing winds & seasons) As the earth rotates, moves faster at equator than ends. The faster equator rotation speeds cause deflection of objects also known as Coriolis Effect. Area of earth s surface that receives the most sun/hours of daylight changes throughout the year as the earth orbits creating predictable seasons.
Ocean Currents Gyres: large scale patterns of water circulation Spread heat in the ocean like convection currents in the atmosphere Upwelling: movement of water towards the surface Thermohaline circulation: ocean water circulation pattern (between surface and deep water) Affect temperature of nearby landmasses Current concerns increased air temperatures could accelerate glacier melting stop thermohaline circulation
Variations in climate affect the distribution of species around the globe Species are adapted to local temperature and precipitation patterns Biomes: particular combination of annual temperature and precipitation Three categories = Tundra/boreal forest, temperate, and tropical. Climate diagrams can be helpful to visualize patterns of temperature and precipitation. Indicate the growing season Relationship between temperature, precipitation and plant growth Humans use the different biomes