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| sources of climate information from natural or human archives used to estimate climate conditions prior to modern period. |
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| When was the little ice age? |
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| How long is it between interglacial periods? |
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| 100,000 years. (125, 225, 325…) |
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| extended period of cold climate including glacials and interglacials |
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| times of ice accumulations, cold spells, 90,000 years |
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| times of ice retreat, brief warm spells, 10,000 yrs |
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| times with no permanent ice on earth |
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| when did the last glacial maximum ed? |
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| tectonics and ocean circulation, orbital ariations, solar variability, atmospheric factors (volcanoes, greenhouse gas fluctuations) |
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| how do plate tectonics affect climate change? |
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| land masses move, change ocean flow and landmass concentration. |
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| how do ocean currents affect climate change? |
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| sinking, cold, salty water from artic and antarctic goes south in atlantic, warm water goes north. change in directions changes climate. |
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| 100,000 years. earths orbit around sun varies from nearly circular to an elipse. circle = warmer |
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| 41,000 yr cycle. earth’s axial tilt varies from 22 to 24 deg. if it’s tilted more, the poles get more sun. |
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| 26,000 yr cycle. axis wobbles and changes the orientation of hemispheres toward the sun. eventually, aphelion is dec 4th instead of july 4th. |
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| solar flares, sun spots, irradiance go up every 11 yrs. high 1991, 2001. low 1996. |
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| atmospheric perturbations |
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| natural and anthropogenic short term climate change. pinatubo, el nino, la nina. |
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| water, NOx, CO2, Methane, CFCs |
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| gases transparent to shortwave, but absorb and reemit longwave radiation |
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| What causes increase in CO2? |
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| fossil fuel burning, fires, deforestation, cement making |
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| What causes increase in Methane? |
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| as ocean warms, thaws frozen Deep Sea Methane Hydrate. also, Rice, livestock, coal mining |
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| What causes increase in N2O? |
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| Internal combustion, fertilizer, manure |
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| effects of greenhouse gases on energy budget |
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| less heat escapes to space, more LW radiation emission of atmo to earth, increased LW absorbtion by atmo |
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| Why is NOx worse than CO2? |
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| Higher GWP, absorbs more LW, longer atmo lifetime. |
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| Historical Data record length |
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| since 221 BC in China, whole world since 1000. |
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| What does Historical Data measure? |
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| observations of weather phenomena, data through measurement and indirect observations (planting season length) |
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| firsthand accounts, usually dated, from most inhabited places |
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| calendars might be off, language/handwriting, exaggeration, etc |
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| What do tree rings measure? |
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| temperature and moisture of growing seasons |
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| How long is tree ring record? |
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| doesnt damage living tree, dead trees preserve well and can be compared to living, high resolution |
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| they only record growing seasons (in temperate zones) so can’t see winter. tropical trees have no rings. only available where trees are. |
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| what do ice cores measure? |
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| atmo composition, wind speed, volcanoes, temperature |
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| length of ice core record |
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| found on 6 continents, can be cross-references, traps actual bubbles of atmo, accurate |
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| expensive, melting can ruin layering, can be altered by wind or ice flow |
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| What do ocean/lake sediments measure? |
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| microorganisms, pollen, plankton for climate history |
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| how long is ocean/lake sediment record? |
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| pros of ocean/lake sediments |
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| show what plants grew, temp of earth, conditions in climate for these fossils to be abundant |
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| cons of ocean/lake sediments |
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| water currents can mix record, really hard to do |
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| calcium carbonate skeletons’ growth rings. reflect conditions of oceans – nutrients, temperature, sea level, storms |
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| how long is coral record? |
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| fine resolution, easy to see year bands, record composiiton of ocean and temp |
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| areas with little seasonability – no banding. no way to tell monthly from yearly in high seasonability |
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| what is measured in caves? |
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| precipitation record, seasonal length, |
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| influenced by geography, ground water chemistry |
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| What does IPCC say causes global warming? |
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| increase in anthropogenic greenhouse gases |
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| what do climate models do? |
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| day to day weather forecasts, analysing local severe weather, predicting future climates, modeling the atmos of different planets |
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| what are global circulation models? |
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| simulation of atmospheric circulations and interannual oscillations. used to forecast climate trends |
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| A2 (a divided world, independent nations, uncontrolled pop growth, slow tech changes, regionally oriented) |
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| B1 (integrated, ecofriendly. rapid econ growth, slow pop growth, clean, efficient tech) |
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| what is the high forecast for temp change? |
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| what is the low forceast for temp change? |
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| what is the middle forecast for temp change? |
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| consequences of global warming |
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| more frequent heat waves, more intense and longer droughts, shifting crop patterns, extended wildfire season, more intense storms, melting glaciers, changing sea level, increase in water vapor, expansion of malaria |
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| what and when is kyoto protocol? |
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| 1997. 159 country signatories, 38 mandated to reduce emissions, voluntary limits on developing countries (China!) aims for reduction of 5.2% below 1990 levels by 2012 |
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| in Copenhagen, 2009, global agreement on climate change |
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| CFLs, (90bil lbs of CO2) Moving thermostat 2F (2,000lbs/fam) recycling (2400lbs/fam), inflate tires, eat less meat, farmers markets |
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| what is the control for diurnal energy cycles? |
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| insolation, earth’s rotation |
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| equation for net radiation |
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| what determines daily cycle of temperature? |
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| daily cycle of net radiation |
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| what happens to increase temperature? |
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| what happens to decrease temp? |
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| net radiation goes negative |
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| what happens to radiation at night? |
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| terrestrial radiation emitted surpasses terrestrial radiation emitted to surface by atmo |
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| what does net radiation graph look like? |
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| like temp graph, but shifted down and to left |
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| what happens at sunrise to net rad and temp? |
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| some solar radiation appears, but it is still negative for awhile, so temp still decreases, coldest about 2 hrs after sunrise |
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| What happens when net radiation = 0 in morning? |
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| minimum temp, then increase |
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| what makes the net radiation go positive in morning? |
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| as sun moves higher in sky, more solar radiation reaches surface, net rad = positive |
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| when does solar radiation peak? what’s going on with temp? |
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| peaks at noon, when sun is highest in sky. maximum net radiation of the day. temp still increasing |
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| what happens in late afternoon? |
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| the sun moves lower in the sky, net radiation decreases to 0, at 0, maximum temperature (3pm) |
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| what happens in evening to net radiation? |
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| net radiation goes negative again, temp starts to decrease. |
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| what do clouds do to net radiation? |
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| decrease daytime temp by lowering insolation and increase night time temp by rereflecting LW |
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| what month is net rad highest? |
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| what month is temp highest? |
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| what month is the min of net radiation? |
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| what are controls of latitudinal variations in energy? |
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| daylength and solar altitude angle |
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| what happens to net radiation at poles during winter? |
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| net radiation goes negative for whole time |
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| the heat required to raise 1g of water by 1C |
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| What has a low Specific heat? |
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| what has a high specific heat? |
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| what does water do to temp variability |
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| why doesnt land retain temperature? |
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| no mixing of surface and inner soil, the surface is opaque and there is no evaporation |
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| why does water retain temperature? |
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| surface transparent, greater mixing, greater evaporation |
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| an ordered, interrelated set of things and their attributes. distinct from surrounding environment, linked by energy flow. |
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| energy and matter flow freely in and out of system |
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| shut off from the environment, self contained |
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| amplifies or encourages response (snowball) |
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| arctic feedback if warming continues |
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+, warming melts ice which reduces aledo which reduces refelction
-, more evap=more snow=increased albedo |
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| Carbon feedbacks if warming continues |
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| +, CO2 dissolves in cold water = water sinks = resurfaces and escapes in warmer water
-, phytoplankton take up CO2, more phyto when warm |
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| Ocean feedbacks to warming |
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+, warming releases CO2bubbles
-, more evaporation/clouds, more albedo, more phyto to eat CO2 |
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+, warmer = more rain = rocks weathered into atmo and ocean
-, warmer = more plants = less CO2, |
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| threshold (tipping point) |
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| when a system can no longer resist changeee |
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| any ongoing process or discrete event that alters the energy of the system |
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| why is arctic sea ice at tipping point? |
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| permanent blue ice melting, cant be recovered in annual cycle, still reaching an ice minimum even with cold 08 winter. feedback leads to more ocean warming, methane burps from melting ice, more warming. |
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