GEO2200C Exam 1 Study Guide How science works lines of evidence Premise prediction null hypothesis and then testing There are multiple lines of evidence including empirical modeling anecdotal and consensus Empirical evidence is necessary Uniformitarianism the past Latitude longitude degrees is at Greenwich England Weather Climate certain area Rotation vs revolution degrees relative to the sun Direct vs indirect radiation The present is the key to the past Processes that we see today we assume were also the same in Latitude a series of parallel lines from the equator measured in degrees 0 to 90 from north to south In Tallahassee our latitude is about 30 degrees Longitude run across latitude lines up and down measured in degrees 0 to 180 east to west 0 Weather is what is happening now whereas climate is basically the average of the weather in a The earth rotates on its axis and revolves around the sun Note our axis is tilted about 23 5 Direct radiation is when the suns light travels the shortest distance basically straight on sunlight Indirect radiation occurs when sunlight travels a further distance such as further from the equator For example at the equator there is approximately 2 5 times more energy than the poles Seasons solstice equinox etc There is a summer solstice in June and a winter solstice in December There are also spring and autumnal equinoxes The seasons result from the tilted axis of earth relative to the sun The winter solstice is the shortest day of the year where the summer is the longest day Atmosphere vertical structure Composed of the troposphere stratosphere mesosphere and thermosphere from bottom to top The temperature falls in the troposphere rises in the stratosphere falls in the mesosphere and rises again in the thermosphere Atmosphere gas composition 78 of the atmosphere is nitrogen 20 95 is oxygen water is 0 4 argon is 0 93 carbon dioxide is 0 0360 and so on Basically mainly made of nitrogen and oxygen There is an ozone layer above the troposphere that traps some short wave UV radiation Right now the ozone layer is thinnest above Australia The solar radiation that reaches earth s surface Radiation ultraviolet infrared UV and infrared rays have short wavelengths which are more harmful and more energetic The suns infrared radiation is felt as sensible heat The sun also gives off visible light and some UV Ozone Insolation radiation Conduction Transfer of heat between two substances that are in direct contact with each other Convection Climate change Transfer of heat by movements of fluids Has to do with greenhouse gases The earth has been warming since the end of the last glacial period There are many hypotheses including a major one that humans are responsible Yet the is no empirical evidence of this There is a major CO2 correlation as seen in Hawaii but this may be part of earths natural cycle Temperature has actually slightly decreased in recent history There are warm periods see throughout Minoan roman medieval and the late 20th century periods it looks like a pattern Looking back to the past 600 million years today s temperature looks relatively cool Greenhouse effect important gases Water carbon dioxide methane nitrous oxide and ozone Astronomical argument Milankovich and sunspots 21 000 year cycle Earth s combined tilt and elliptical orbit around the Sun precession of the equinoxes 41 000 year cycle Cycle of the 1 5 wobble in Earth s tilt 100 000 year cycle Variations in the shape of Earth s elliptical orbit cycle of eccentricity There are also 11 and 206 year cycles of solar variability sunspots Tectonic Landmass distribution Shifting continents continental drift causing changes in circulatory patterns of ocean currents It seems that whenever there is a large land mass at one of the Earth s poles either the north pole or south pole there are ice ages Undersea ridge activity Sea floor spreading associated with continental drift causing variations in ocean displacement Ocean atmosphere interchanges Ocean Currents Energy transfer of warm waters north and cold water south El Nino La Nina Southern Oscillation ENSO Pacific Oscillations Adiabatic effect As an air parcel rises it expands and cools As an air parcel falls it compresses and warms Sun s radiation budget The incoming radiation is 100 initially 20 is absorbed by clouds and the atmosphere 22 is reflected by the clouds 3 is reflected by earth s surface 5 is scattered by the atmosphere and about 50 is absorbed at earth s surface Albedo The color black has the lowest albedo it absorbs more and reflects less Fresh snow has an albedo of 80 95 the moon 6 8 forests 10 20 asphalt 5 10 water bodies 10 60 The 90 of the atmosphere is in the troposphere Low pressure means more storms earths average is 31 Atmospheric pressure Standard mb Isobars The normal standard pressure is 1013mb each other the winds are less strong If they are drawn closely spaced there are strong winds If they are drawn further away from Wind Winds results from different pressure systems The PGF is the pressure gradient force These pressure gradients result from an uneven heating of earth by the sun Note that when writing or saying wind direction you say where it is coming from not where it is going The Coriolis effect is the deflection of pressure systems to the right because of earths rotation High Low cyclonic anticyclonic movement High pressure systems rotate clockwise Low pressure systems like hurricanes rotate counterclockwise Global circulation Westerlies Trade Winds easterlies The westerlies where we are are between 30 and 60 degrees It pushes systems from east to west The Easterlies or trade winds are between 0 and 30 degrees and push systems from west to east Because of this the paths of hurricans often change at 30 degrees because of the change is circulation pattern At 30 degrees north and south as well as the poles there is high pressure At 60 degrees north and south as well as 0 degrees there is low pressure The jet stream drives pressure systems but pressure systems themselves determine surface Jet Stream winds Coastal winds Mountain winds katabatic then descends back over land At night cooler air goes down the valleys of mountains During the day warm up goes up During the day cooler air is brought inland where it is heated and then pushed back over the ocean At night cooler air is drawn out to sea where air is heated over the relatively warm water El Nino La Nina opposite effect El Ni o warmer winters across northern