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21 Cards in this Set
- Front
- Back
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Troposphere |
- lowest part of the atmosphere - zone where the air is constantly in motion, mixing and moving as part of a global pattern of atmospheric circulation -- weather - temperature decreases with altitude - not fixed in height -- declines in height moving toward the poles |
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Stable isotope ratio |
- do not decay over geological time - stable isotopes most commonly used in climate science are oxygen (18O and 16O), hydrogen (1H), deuterium (2H), and carbon (13C and 12C) - oxygen and hydrogen isotopes --> measure temperature and ice volume. - O18/O16 ratio depends on the surrounding environment. Cycles in the ratio mirror climate changes in geologic history. Ratio in colder climates is always O18 heavy, since O16 stays trapped in ice. - carbon isotopes --> estimate past levels of carbon dioxide (CO2) in the atmosphere --> infer global weather patterns |
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Foraminifera (forams) |
- marine invertebrates that use carbon and oxygen from the surrounding water to construct their calcium carbonate (CaCO3) shells - isotopic composition of these shells reflects the isotopic composition of the seawater they lived in. Layers of foraminifera that accumulate over time on the seafloor (dead) reflect the changing isotopic composition of seawater as the polar ice caps expand and contract. - data used to estimate both the volume of ice locked away at the poles and the temperature of the oceans - benthic forams = bottom-dwelling, planktonic forams = surface-dwelling |
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climate proxy |
- sources of climate information from tree rings, ice cores, corals, lake and ocean sediments, etc. that are used to estimate climate conditions of the past - used when direct meteorological measurements are not available - can use data to infer things about climate |
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stomata |
- Leaf structures regulate plant respiration and respond to environmental change. Can use as a proxy for CO2 - small pores in a leaf that take in CO2 from atmosphere and release water. - Useful relationship bw number of stomata per unit area on a leaf (stomatal density) and concentration of CO2 in atmosphere: when CO2 concentrations increase, stomatal density decreases -- fewer stomata limits water loss and reduces possibility of infection; when CO2 decreases, stomatal density increases -- enhances photosynthesis |
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temperature anomaly |
- departure from a base period that usually covers a much longer period of time at the same location (usually more than 1, preferably more than 30 yrs) - positive anomaly -- observed temp was warmer than the reference value; negative anomaly -- observed temp was cooler than the reference value |
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hothouse climate |
- world with no permanent ice caps and average global temps much higher than they are today -- typically referring to the Cretaceous Period (~145 to 65 million yrs ago) - intense and extensive volcanism --> CO2 levels 4-8 times higher than today's |
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radiative forcing |
- imbalance that develops at top of the atmosphere between the amt of incoming radiation from the sun and the outgoing radiation from the earth - radiant energy the sun produces has been nearly constant for millions of years (slight variation due to growth and decay of sun spots) - Earth's climate system either augmented or diminished by related changes in another part of the system -- ex: melting Arctic sea ice with high albedo is replaced by ocean water with low albedo, and bc darker water can absorb more of the sun's incident radiation, the environment warms up |
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S/4 |
- avg amt of energy that strikes the earth - earth = sphere and rotates once on its axis every 24 hours; in this time, earch receives S/4, or 342Wm^-2 amt of energy flux |
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Wien's (Displacement) Law |
- measures peak intensity of emitted radiation: wavelength of maximum emission in meters = constant ("b") / temperature of object in Kelvin ("T") - objects of diff temps emit spectra that peak at diff wavelengths; black body radiation curve for diff temps peaks at a wavelength inversely proportional to the temp - earth = "perfect black body," total amt of energy never lost (not quite, but fine). Peak intensity of emitted radiation on Earth follows Wien's law |
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Stefan's constant; Stefan-Boltzmann Law |
- F = (SBconstant)T^4 - constant = 5.67 x 10^-8 w/m^-2 - energy radiated by blackbody emitted radiation increases non-linearly with temp |
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dry greenhouse gas |
- gases become more dry higher up in the atmosphere - bc the concentration of gas varies in diff parts of the atmosphere, greenhouse gases do not have a consistent effect - a lot of water in the atmosphere from both water vapor and clouds can effectively act as greenhouse gases |
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intertropical convergence zone (ITCZ) |
- represents the "thermal equator," or line of max avg temp at any time during the year. - surface air flows in from both north and south to replace the air rising by convection and creates zone of surface convergence; trade winds of the N and S hemispheres come together; essentially a cloud layer of hot air rising - typically produces low atmospheric pressure - zone is not fixed in place, but moves back and forth across the equator with the shifting of seasons and is affected by warm ocean currents |
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heat capacity |
- amt of energy or heat needed to raise a substance's temp by 1 degree C - ability of water to store large amts of energy with only a small increase in temp and a much longer time to change temp = high heat capacity. oceans have 100x the heat capacity of land - the atmosphere is more effective in moving heat; ocean is more effective in storing heat |
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polar jet stream |
- wind system that moves like a belt of air around the arctic circle -- farther up in the northern hemisphere, fairly high in the atmosphere - occurring at convergences of air masses - northward moving air is deflected over the polar air mass and to the right by the Coriolis effect - polar vortex: upper level low-pressure area lying near Earth's poles - the rossby/planetary waves create vortexes moving air masses further south, bringing arctic air south - the frequency of polar vortexes are slowing down and cooling trends are decreasing |
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vertical ocean stratification |
- layers in the ocean dependent on temperature, physical gradients in light, and salinity - natural stratification: vertical water column formed due to the varying densities of water, with less dense, warmer water toward the surface and more dense, colder water toward the bottom. salinity causes water to sink - varying dense layers of the water mix through upwelling, a process in which deep, cold water rises to the surface, replacing that surface water with nutrient rich cold bottom water - layers act as barrier in water mixing. but as temp rises, ocean becomes more stratified --> potential reductions in upwellings/downwellings-- more diff for nutrient rich water to reach the surface and for oxygen to reach the lower depths of the ocean |
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Eckman transport |
- wind flows across ocean, friction bw wind and sea's surface sets water in motion --> transports heat around the globe - Coriolis effect deflects upper layer of ocean ~45 degrees to the wind (to the right in the N hemisphere), surface water flowing in this direction applies stress to water underneath, etc etc --> net transport of the water current = to the right. overall progressive spiral of deflection from original surface current - helps us understand where there is more ocean biological productivity -- more nutrients! |
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snowball earth |
- earth froze over completely (snowball) or almost (slushball) several times during Protorezoic period (2500-542 million years ago) - scientists found that albedo (reflection) exceeded major thresholds, which allowed ice to spill beyond the poles, past mid-latitudes, and as far as the equator. albedo helped create positive feedback for cooling: initial cooling event, snow and ice increase albedo, positive feedback loop for cooling, little water vapor bc cold temps, little or no hydrological cycle |
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methane hydrate |
- molecule of methane gas trapped by water molecules - not super abundant but has the potential to be released in a number of places - could have major impacts w melting ice, with could lead to increased levels of methane escaping from these hydrates. esp bad considering methane has a much higher warming potential |
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permo-triassic crisis = "The Great Dying" |
- huge supercontinent, Pangea, straddles the equator. extreme interior desertification--a lot of volcanic activity, released high levels of CO2, released deep sea methane, 12 degrees C warmer, oxidizing atmosphere lowers O2 levels, shut down of thermohaline circulation in the ocean increased anoxia (oxygen decrease) |
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global conveyor belt circulation = thermohaline circulation |
- constantly moving system of deep ocean circulation driven by both temp and salinity (thermo - temp, haline = saline) in the ocean and wind driven currents on the surface. - high salinity is driven by evaporation and the effect of ice expelling salts - cold, salty water is dense and sinks to the bottom of the ocean; travels south. warm water is less dense and remains on the surface of the ocean. - a whole cycle takes approx 1,000 yrs to complete - deep-water leg of the journey: 1) controls transportation of heat from tropics to poles. as cold water sinks to the ocean floor, it creates a mass deficit that is filled by warm surface water drawn in from the subtropics. 2) as the Arctic Ocean warms, some of this energy is stored in these deep-ocean currents, for sooo long. - global circulation begins where cold, dense, relatively low-salinity Arctic seawater sinks from the surface and flows southward along ocean floor, in contrast to circulation in the atmosphere; warms in pacific and indian oceans; warm water transferred back toward poles --> tropipcs are cooled and poles are warmed and energy balance of climate system is maintained! |
