F 311 1st Edition Exam #1 Study GuideWeek 2- How objects gain / loose heat: Conduction, convection, radiation, and waterevaporation / condensationConduction: Transfer of energy through matter. Transfer and distribution of neat energy from atom to atom within a substance. Convection: Transfer of heat energy in a gas, liquid or solid by movement of currents. Radiation: Electromagnetic waves directly transporting energy through space. Everything in the universe is either losing or gaining energy through radiation. Temperature and electromagnetic radiation: Temperature is created by the collision ofmolecules Under higher pressure, molecules collide morefrequently, generating more heat and with greater energy molecules move faster colliding more frequently All objects “shine” (emit radiation)Measuring Energy:  The unit of energy flow per unit of area: W/m2 a Watt (W) is a J/s (a rate of flow) where a Joule (J) is an energy unit (an amount of energy, 1 Newton of force over a m distance) Radiation wavelength, energy and temperature:  Energy is measured as W/m2 Different types of electromagnetic radiation have different wavelengths Radiation with longer wavelengths has lower energy, meaning it “shines” less and has lower temperatures The wavelengths of visible light range from 400 nm (violet)to 700 nm (red) Hotter objects shine brighter (emit more energy persecond), and shine at shorter wavelengths.Greenhouse effect: Greenhouse effect results from gases absorbing longwave radiation, warming up, and then emitting the radiation to space Shortwave radiation not reflected by the atmosphere passes through and heats the earth’s surface, causing the surface to shine longwave radiation Gases (water, CO2 , CH4 , N2O) absorb longwave radiation that would be leaving back to space, which causes the gases to warm up (like a blanket).  The gases keep warming up, emitting longwave radiation that warms the atmosphere and surface of the earth (i.e., the “greenhouse” effect).  The atmosphere can’t hold onto infinite amounts of heat – as it warms, it emits more energy until we have a balance of: Incoming radiation = Outgoing radiation The greenhouse effect in anutshell Earth is about 30oC warmer with its greenhouse effect than it would be without it. 2/3rds of our “warmth” depend on this! Some greenhouse is good but to much is bad Solar input variation:  Sun doesn’t warm Earth evenly because of the curvature of the earth. Sunlight that strikes at an angle is spread across a greater surface area, and is a less intense heat source than a beam impinging directly. Light coming onto a slope is proportional to the sin of the angle between the slope and the sun Light=Sunlight*sin h  Earth's tilt of 23.5o and revolution around the sun creates seasonal heating patterns. At solstice, tilt keeps one polar region with 24 hours of light and the other with 24 hours of darkness At equinox, tilt provides exactly 12 hours of night and 12 hours of day everywhere. At one location, the influence of slope angle and aspect make little difference in summer, but huge difference other times:“Adiabatic” cooling (or heating) Adiabatic “lapse rate”: About 3 ⁰C/1000ft (9.8⁰C/1000 m) for dry air  About 1.5 ⁰C/1000 (5⁰C/1000 m) for saturated air  Lower lapse rate for saturated because air is warmed as water vapor condenses and releases heat Taking a fixed mass of air, and raising or lowering its pressure (and volume) compress and it heats. Energy budgets:  Incoming and outgoing energy must balance on average ut there are huge differences from placeto place  Way more solar heating in tropics. Some places (deserts) emit much more than others (high cold clouds over rainforests) Incoming solar minus outgoing longwave. Must be balanced by horizontal transport of energy by atmosphere and oceans!- Clearcutting:clearcutting increases day time temps and lowers night time temps (montana example)Week 3 Patterns of Water Inputs and Outputs across Space and Time Probabilities:  A once-in-a-century event really means a 1% chance of the event in any year. 1% probability for an event this year = 99% probability of no event. Probability of a 5-year span with no event = 0.99 x 0.99 x 0.99 x 0.99 x 0.99 = 0.951 (95%).  Probability of a 100-yr span with no event = (0.99)100 = 0.366 (37% chance of no event) Cool rule: Whatever the “return interval” of an event, there’s a 37% chance of no event within that intervalClimate of Rockies:  Summer: warm moist air moves from the gulf bringing in air masses  Fall/winter/spring: pacific front storms origninating from Alaska are stripped of air moisture from sierra nevadas and rockies. Airtic air masses engulf the middle of the continentForest Water Balance and the Role of Trees Water flows in forests:1. Precipitation 2. Interception, infilatration, overland flow 3. Uptake4. Transpiration/ evaporation Watershed:  streamflow(yield or dishcharge)= precipitation - interception loss - evaporation loss - transpiration loss Weir:More streamflow raises level of water in pond measuring water level can lead to calculating streamflow. Changes in watershed flows (fluxes) after cutting trees, Fraser experimental forest: Cutting 40% of the watershed increased streamflow from 30 to 38 cm/yr More snow accumulates in the cut strips, because leaves do not intercept it. Intercepted snow evaporates. Cutting trees usually increases water flow in streams – effect increases with precipitation Hydrologic response follows Canopy responseHow much water is used by trees (interception + transpiration)? Transpiration results from potential differences from the water to the air through the tree; moderated by the leaf pores or stomataPotential: Things go from higher potential, to lower potential. Things go downhill.How Transpiration Works At night, temperature is cooler, and relative humidity is higher Air has no ‘suction’ when Stomata are closedWater potential: Energy per mol in pressure units, relative to pure water. Vapor pressure deficit is A) The amount of water the air could hold, minus B) The amount of water currently in the air In soils, water moves downhill. It can also be “sucked” into tiny poor spaces, because it “sticks” to surfaces (like in a test tube).Water movement up trees: 1) The air is drier than the leaf 2) The leaf is drier