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92 Cards in this Set
- Front
- Back
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Why does the ocean contain more heat energy than the atmosphere?
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It's more dense, and has a higher specific heat capacity.
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In general, what drives Earth's climate?
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exchanges of heat and water between the ocean and atmosphere
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How does atmospheric pressure vary with altitude?
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It decreases rapidly as altitude is increased.
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What are the three zones of the atmosphere, from lowest to highest?
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troposphere, stratosphere, mesosphere
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What is the troposphere?
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the bottom ~12 km of the atmosphere (above sea level), where almost all vertical air movements occur, temperature decreases with altitude, and almost all weather takes place
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What is the stratosphere?
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the layer of atmosphere above the troposphere, between 12 and 45 km altitude consisting of very little air and slow diffusion of molecules, including the majority of the ozone
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When is the ozone layer the most depleted and why?
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In spring, icy clouds in stratosphere remove nitrogen compounds that normally react with free chlorines.
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What harmful effects does the dwindling of the ozone layer have?
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more sunburn, eye cataracts, skin cancers, and less phytoplankton and maybe plant growth
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How much is phytoplankton growth in the Southern Ocean affected by lack of ozone above?
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The growth rate has been reduced by 6-10%.
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What causes ozone depletion?
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Chlorofluorocarbons (CFCs), because of their long residence time (low reactivity) and their release of free Cl atoms in the stratosphere
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When were CFCs banned?
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the early 1980s
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What does ozone do in the lower atmosphere?
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It contributes to smog, but doesn't help absorb UV light.
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What effect does the temperature have on the saturation pressure of water vapor?
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Higher temperatures mean a higher saturation pressure.
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What is the maximum pressure of water vapor the atmosphere can hold called?
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saturation pressure
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At the same temperature, is moist or dry air heavier?
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Dry air is heavier.
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What happens to the temperature of air that rises?
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It cools by adiabatic expansion.
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Does water vapor form drops of water when the saturation pressure is the same as the actual pressure?
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No, it often supersaturates first.
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How does solid water form in the atmosphere when liquid water would have formed well before the temperature dropped to the freezing point?
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Without a catalyst like a dust particle, the water vapor becomes supersaturated for a while.
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What are clouds?
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extremely small water droplets that aren't big enough to condense and rain
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What are two ways water vapor can reduce the density of air?
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It has a small molecular weight, and a high latent heat of vaporization.
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What are atmospheric convection cells?
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semi-closed systems of rising and sinking air over geographical areas, with associated water transport
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What is the premise of water and heat budgets?
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The total amount of heat or water on Earth is not changing, so all inputs and outputs to and from all locations must balance out.
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What percentage of total evaporation and precipitation takes place in the ocean?
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93% of evaporation, but only 71% of precipitation
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How is the E-P balance over the entire oceans restored?
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via groundwater, river and stream runoff
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List five outcomes of sunlight falling on Earth.
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It can be backscattered (reflected) by clouds, the atmosphere, or the surface, or it can be absorbed by the surface or by the atmosphere.
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What are three ways the Earth can lose its heat absorbed from the sun?
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conduction into the atmosphere (sensible heat), evaporation of water into the atmosphere (latent heat), and infrared radiation that is either absorbed by the atmosphere or lost to space
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What causes the imbalance between the heat absorbed at the equator and the poles?
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The same amount of light is distributed over a larger surface area at the poles than the equator and must travel through more atmosphere and get absorbed.
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What causes the imbalance between the heat released at the equator and the poles?
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The poles are colder (but not much so on a thermodynamic scale).
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What causes the need for mechanisms to transfer heat from the equator to the poles?
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The imbalance of heat absorbed is greater than the imbalance of heat released.
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What are two ways latitudinal (meridional) heat transport takes place?
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Water vapor is carried to higher latitudes by convection cells where it condenses and possibly freezes, and warm water is transported poleward by ocean currents.
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What is the difference between weather and climate?
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Weather is on a short time scale, like hours or days, while climate is averaged over the entire year.
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How would global climate look on a nonrotating Earth?
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Moist air would evaporate at a low pressure zone at the equator, spread toward the poles, gradually losing water vapor and heat, and creating a high pressure system near the pole. It would then spread back towards the equator, creating equator-ward surface winds, heating and gaining water vapor to continue the cycle.
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How many convection cells does the rotating Earth have?
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six, three in each hemisphere
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What is different about atmospheric circulation on a rotating Earth?
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There are now three cells per hemisphere, the Hadley cells between 0° and 30°, Ferrel cells between 30° and 60°, and polar cells between 60° and the pole.
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Describe circulation in a Hadley cell.
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Air and water vapor rise and spread poleward; the Coriolis force deflects the air mass gradually eastward, so that when it reaches 30° (N or S), it is no longer travelling poleward. It sinks and returns to the Equator as the trade winds, coming from the east.
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How does circulation in a Ferrel cell differ from that in a Hadley cell?
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The air is deflected by the Coriolis force more, and surface winds travel towards the east (making them westerlies) and poleward.
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What are jet streams?
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fast west-to-east air currents in the top of the troposphere at around 60° but meandering around with weather
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What takes place between atmospheric convection cells?
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At the equator, the Intertropical Convergence Zone (doldrums) has lots of clouds and rain; at 30°, the horse latitudes have little rain and high atmospheric pressure; at 60°, polar fronts see high rainfall, while at the poles, especially Antarctica, there is very little rainfall because of high atmospheric pressure.
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What are the roaring forties?
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fast winds at around 40°S in Ferrel cells
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How do atmospheric convection cells vary seasonally?
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They migrate with the sun, but delayed a few weeks because of the oceans' thermal inertia.
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What causes the monsoon seasons of the Indian ocean?
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In July, the ITCZ moves into the Northern Hemisphere, causing moist winds to blow from the ocean to the Indian subcontinent, creating torrential rain. In January, cold, dry wind from the Himalayas blows across India, creating dry winters.
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Besides India, where do monsoons take place?
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east Asia, tropical Africa, and Northern Australia
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What generalized factors affect surface water temperature and salinity?
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solar radiation, heat transfer to and from the atmosphere, currents, vertical mixing, and river runoff
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What deviations from the ideal, latitudinally isothermal, arrangement of ocean surface temperatures exist?
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A band in the equatorial east Pacific (and the Atlantic, but less so) is colder than expected due to upwelling of deep water. Water on the west ends of oceans is warmer than the east ends because of western boundary currents. Polar temperatures are relatively constant because of melting and freezing of sea ice.
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What three properties primarily determine ocean surface salinity?
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the difference between evaporation and precipitation (E-P), runoff, and in some places up- and downwelling
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Where is ocean surface salinity the greatest?
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subtropical regions (high E-P) far from land (no runoff), like the central north Atlantic
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What determines evaporation and precipitation rates at different latitudes?
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Evaporation is related to ocean surface temperature, while precipitation is connected to atmospheric circulation.
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Why are evaporation rates lower at the equator than at subtropical zones?
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The equator has lots of cloud cover to block the sun, and is calmer, since winds enhance evaporation.
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Why does the Atlantic have higher salinities at similar latitudes than the Pacific?
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The mountain chains of North and South America block the clouds in regions with westerlies, so the air blowing from the Americas to the Atlantic is dry.
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Where can the most extreme salinities be found?
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in marginal seas, high in the Mediterranean, Arabian Gulf, and Red Sea, and low in the Baltic and SE Asia
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What are two examples of well-studied interannual climate variations?
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North Pacific Anomalies and the El Niño Southern Oscillation (ENSO)
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What are North Pacific Anomalies?
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Bodies of water in the Pacific randomly get 1-2° warmer or cooler, and affect Northern Hemisphere weather.
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How do North Pacific Anomalies affect weather?
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Warm anomalies force the jet stream and westerlies north around them, changing air circulation, and therefore temperatures and precipitation from California to the Rockies.
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What happens in El Niño?
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Warm water piled up by the trade winds in the western south Pacific travels east when the winds weaken in April, reaching Peru and Chile in December (El Niño means "the child"), inhibiting upwelling and dramatically decreasing primary productivity. It brings heavy rainfall to Peru and droughts to Australia and Indonesia, but returns to normal in 3-15 months.
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What causes the warm water near Indonesia to move east in El Niño events?
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It is already elevated slightly because of the trade winds, and gravity pushes it back east. The thermocline also slopes back and forth like a seesaw.
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What is La Niña?
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the overshooting of the return to normal conditions after an El Niño
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What effects does El Niño have outside of the South Pacific?
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droughts in India, Central America, Africa and Central Europe, and extra rainfall in SE Asia, California, the eastern US, Britain, France and Arabia
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When was the strongest El Niño on record?
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1982-3
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What are the general ways a landmass interacts with atmospheric circulation?
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It can block the wind (mountains) and act differently thermally than the ocean (heating up and cooling down more quickly).
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What are examples of interactions between the atmosphere and landmasses?
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land and sea breezes, the island effect, monsoons, and climate in the interior of continents
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Why does the ocean not change temperature easily when heat is added to it?
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Water has a high heat capacity, visible light can penetrate quite deep into the ocean, and wind mixes the ocean surface to distribute the heat evenly.
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What are sea breezes?
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During the day, coastal land heats up more than the ocean, so the air above it rises and the cooler air from the oceans comes ashore to take its place.
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What are land breezes?
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At night, the air above the land cools more quickly than the air above the sea, so it is pushed out to sea, and the air above the sea rises and returns over land in a cycle.
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How does coastal fog develop?
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Areas with upwelling have colder waters close to shore than farther out, so the sea breeze brings warm, moist air across cold water where some of the water vapor condenses and passes over land.
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Where in the world does coastal fog develop?
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the US West Coast, Maine, the eastern Canadian coast, and the west coasts of South America and Africa
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What is the mountain (island) effect?
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When a coastal mountain range impedes the progress of rain clouds, the windward (coastal) side of the mountain(s) will receive lots of rain while the leeward side receives close to none, becoming a desert.
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Where does the mountain (island) effect take place?
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California and Nevada (divided by the Sierra Nevadas), Chile and Argentina (the Andes), and Hilo and Kona on Hawaii island
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What are the six global ocean climate zones?
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equatorial, trades, subtropical, temperate, subpolar, and polar
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What properties do polar ocean zones exhibit?
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lots of ice, temperatures around freezing, low rainfall, and light winds except for coasts
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What properties do subpolar ocean zones exhibit?
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seasonal sea ice and low salinity waters due to ice exclusion of dissolved salts
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What properties do temperate ocean zones exhibit?
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strong westerly winds, high rainfall, and extratropical cyclones
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What properties do subtropical ocean zones exhibit?
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low winds and rainfall because they are between atmospheric zones, lots of beaches
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What properties do trade wind ocean zones exhibit?
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dry, low rainfall, lots of wind, and high evaporation and salinity
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What properties do equatorial ocean zones exhibit?
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warm surface waters, high evaporation, light winds, lots of clouds, and high continuous rainfall
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What determines the temperature range for a region of land?
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its proximity to oceans, whether it is downwind or upwind of those oceans, and ocean currents (Northern Europe)
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What parameters define terrestrial climate zones?
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seasonal temperature ranges and rainfall rates
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Why don't high and low pressure zones dissipate?
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The Coriolis effect deflects air moving toward or away from them.
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What is geostrophic flow?
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when winds flow clockwise around high pressure zones and CCW around low pressure zones (in the Northern Hemisphere)
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What does an isobaric chart map?
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contours of locations at the same atmospheric pressure
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What happens in the centers of high and low pressure zones?
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Low pressure zones have rising air that diverges at the top, making lots of precipitation, while high pressure zones have descending air that prevents precipitation
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How does a hurricane develop?
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A low pressure system in summer over water pulls water in until it flows geostrophically, gets warmer, and rises in a helical pattern as the pressure drops and wind speeds rise.
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Why do hurricanes have eyes?
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The low pressure rises higher in the atmosphere, where it pulls warm, dry air from above the hurricane.
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Which way do the winds of hurricanes flow in the Northern Hemisphere?
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counterclockwise, since it's a low pressure system
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How does a hurricane grow?
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If it flows over warm waters, its winds will cause lots of evaporation, and the latent heat is transferred to the hurricane system
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What determines the direction hurricanes travel in?
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The trade winds push them west, and the Coriolis force deflects them away from the equator.
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What is the most dangerous part of a hurricane?
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the storm surge, the wave that pushes ahead of it and can cause massive flooding
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Name three important hurricanes and their years of the late 20th century.
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Hurricane Andrew 1992, Hurricane Hugo 1988, and Hurricane Camille 1969
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Where do hurricanes form?
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all tropical oceans except the South Atlantic and eastern South Pacific, where waters are >26°C above 5° latitude.
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What are hurricanes called around the world?
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Indian and west Pacific: north of the equator are cyclones and south are typhoons; Baguios in Phillipines and Willy Willys near Australia; hurricanes in the Atlantic and west Pacific
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What problems could (and maybe have) come about with global warming and hurricanes?
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Higher sea level leaves more vulnerable, while hurricanes would happen more often and last longer, maintaining energy further north or south.
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How do extratropical cyclones form?
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When cold polar air from the east meets warmer temperate air from the west, the warm air goes on top and both swirl around each other due to the Coriolis effect, creating lots of precipitation and waves. Alternatively, a cold front can flow over a warm western boundary current.
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What is different between extratropical cyclones and hurricanes?
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Extratropical cyclones go eastward, are slower, have slightly lower wind speeds, and therefore cause lots of beach erosion because they concentrate their energy.
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