BIOL 2140 Exam # 3 Study Guide Lectures: 1 - 12Lecture 1 (October 27)Global climate patterns -moisture and temperature are key factors that reflect biological communities. Insolation patterns- amount (intensity) of sunlight received in one area vs another. Insolation is responsible for determining moisture and temperature in a given area. Solar energy-irradiation= sunlight, heat Sun provides a lot of energy! 25%- reflected by clouds and gases (reflectivity=albedo)25%- absorbed in the atmosphere (into greenhouse gases)50%- reaches earth What happens if we didn’t have the greenhouse effect? -the earth would be very cold! Differential insolation- drives weather and climate What is the difference between weather and climate? Weather- atmospheric conditions at the moment Climate- long-term characteristic weather patterns/averages Regions of intensity in a globe model: High intensity= solar energy hits concentrated on a small area (equator) region of greatest warming. Lower intensity- the same amount of solar energy hits spread over a broader area, due to shallow angle of impact= less warming ( poles) Equatorial conditions: 1. Solar energy hits the air and water, causing the air and watermolecules to move faster = higher kinetic energy 2. As the water molecules increase in kinetic energy, more of themgain the “escape velocity” to break their hydrogen bonds andevaporate into the air as vapor; the various other gases in the airare similarly imparted with energy such that they too move faster,causing them to be more spread out = the air mass is less denseand begins to rise3. As the air and water gases rise upward through the atmosphere,there is less and less weight of atmospheric gases pushing onthem from above = the volume of the air mass expands, justbecause it isn’t being squeezed as much anymore (the moleculesare able to move even further apart, but simply due to the releaseof pressure rather than a gain of kinetic energy)4. All else being equal, this expansion in volume (due only toreduction in pressure) causes the temperature of the air mass tofall, simply because the molecules aren’t colliding with each otheras frequently anymore• This is called adiabatic cooling, and it explains why the air that is releasedout of a car tire is cool• The opposite effect, where an increase in pressure (squeezing) causes thegas body to warm, is called adiabatic heating– 5. What happens to water molecules when they cool?• They form hydrogen bonds = condense into water dropletsGlobal summary: Land masses disrupt temperature distributionOcean is hottest along the equator, and cooler towards the polesEquator: warm air and water rise =low pressure system; air cools and drops rainHeat (water vapor, other greenhouse gases) transported polewardPoles: Dry air kinetically cools and sinks =high pressure system, little rainif warming patterns existed without rotation? -convection currents Uneven insolation pattern is responsible for the earth’s very broad climate patterns– A warm, humid, rainy equatorial region vs. cold, dry polar regionsHeat is absorbed by water and other atmospheric gases, which rise at the equator and carry the heat with them to the poles– If not for this redistribution of heat, the earth’s temperature gradient would be even stronger: even hotter at the equator and even colder at the poles. Lecture 2 (October 29) Insolation and wind The sun creates air movement aka wind Air is warmed the most at the equator, causing it to rise– As the air lifts upwards it cools adiabatically due to the reduction in atmospheric pressure around it, and drops rain– High in the atmosphere the air diverges to the north and south(where else can it go?), carrying heat with it toward the poles– The air currents collide and descend at the poles (again, whereelse can the air go?)– As the air descends it warms adiabatically due to the increasing atmospheric pressure around it– Once it hits ground level, the air is forced to spread back across the surface of the earth to the equator.The Coriolis Effect- As the air is doing all this moving around driven by solar energy, the earth’s rotation causes it to be deflected (or to appear to be deflected) into a curve. The Coriolis Effect is due to the shape and rotation of the earth combined with the laws of inertia. The deflection is to the right in the northern hemisphere, and to the left in the southernEarth rotates toward the east Objects sitting near the poles have lower inherent eastward velocity (momentum) compared toobjects sitting near the equatorAs these objects move toward the equator, they are increasingly slow relative to the surroundings, and thus appear to drift west…when really the surface of the earth is just drifting faster east. – North/south motion: simple velocity differences in momentum• Objects moving toward the equator (away from a pole) effectively move slower and slower east as they go• Objects moving away from the equator (toward a pole) effectively move faster and faster east as they go relative to the surfaceof the earth– East/west motion: conservation of angular momentum• Eastbound objects move relatively faster than the surface of the earth =fling away from earth’s core = drift toward the equator• Westbound objects move relatively slower than the surface of the earth = fall toward earth’s center = drift toward the polewarmer air = water vaporcooler air = water droplets (condensation)Earth’s rotation breaks up air movement to explain why we tend to have forests vs. deserts where we do by latitudeEarths tilt creates seasons! The region of most intense solar heating + evaporation (intertropical convergence) shifts north and south of the equator = seasonsWe call the region of the earth that receives the maximum solar intensity for at least a part of the year the tropics (= between 23.5°N and 23.5°S)Ocean currents influence climate The Gulf Stream is responsible for? -keeping Europe warm for its latitudeWater warms as it moves west along the equator• The Coriolis force turns it to the right, as it also slams against the east coast of North America• This causes a jet of water to shoot up the coast, like squeezing a bar of soap from your hand a boundary current known as the Gulf Stream• The warm Gulf Stream water moves north so rapidly that it still retains most of its heat when itreaches the Arctic• There it finally slows and cools, releasing its heat into the air to blow across