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54 Cards in this Set
- Front
- Back
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Define: Climate
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Aggregate of environmental conditions involving heat, moisture, and motion typical of an area
110.1.1 |
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Define: Climatology
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The scientific study of climate
110.1.1 |
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Define: Climatological normal
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The arithmetic mean of the observed values of a climatic element over a specified period of time
110.1.1 |
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List and describe the three scales of climate
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Macroclimate:
- processes of a global or continental scale Mesoscale: - characterized by the size of a major landform up to several hundreds of kilometers Microclimate: - take place near the ground along the vertical axis 110.1.2 |
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Describe the influence of macrogeography on climate
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Consists of all those events and processes that are large enough to be considered on a world or continental scale
110.2.1 |
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List the factors influencing climate
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- mountains and plains
- widespread vegetation - large lakes and enclosed seas 110.2.2 |
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List the principle elements of macrogeography
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- Central Plains
- Boreal Forest - Eastern Mountains - Western Highlands - Arctic Canada - Lakes and Oceans 110.2.3 |
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Describe the interaction with the atmosphere of the Central Plains (Mountains and Plains)
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- climate varies gradually from north to south
- airstreams can move at will in all directions - Arctic airstreams can move southward while Tropical airstreams can move northward 110.2.4 |
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Describe the interaction with the atmosphere of the Eastern Mountains (Mountains and Plains)
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-considerably less extensive than western highlands
- not a very effective climatic barrier - macroclimatic effects not clearly known - produce marked variation of mesoclimates 110.2.4 |
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Describe the interaction with the atmosphere of the Western Highlands (Mountains and Plains)
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- stretches from Alaska to Central America
- barriers to westerly winds - affects movement of traveling cyclones - prevents warm and humid Pacific air masses from invading the continent without considerable modification 110.2.4 |
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Describe the interaction with the atmosphere of the Gulf of Mexico (Gulfs, Lakes, and Oceans)
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- important source region of moisture for air masses from the south
- accounts for moderate precipitation of eastern North America 110.2.4 |
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Describe the interaction with the atmosphere of the Gulf of Alaska (Gulfs, Lakes, and Oceans)
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- great generator of storms
- dumps vast quantities of snow and ice on southern Alaska - provides much of seasonal rainfall in the Pacific Northwest 110.2.4 |
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Describe the interaction with the atmosphere of the Hudson Bay, Great Lakes, and Arctic Ocean (Gulfs, Lakes, and Oceans)
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Hudson Bay:
- source region for deep arctic air masses during winter Great lakes: - considerably modify traveling air masses Arctic Ocean: - permanently ice-covered 110.2.4 |
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Describe the interaction with the atmosphere of the Pacific Ocean (Gulfs, Lakes, and Oceans)
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- key element in our climate
- considerable percentage of water vapor/heat that reaches central/eastern North America originate there - complete control of weather west of the Rocky Mountains 110.2.4 |
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Describe the interaction with the atmosphere of the Atlantic Ocean (Gulfs, Lakes, and Oceans)
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- dominates climate of eastern North America
- moderating temperatures and extensive persistent advection fog are common - warm Gulf Stream often cause intense low pressure systems to form rapidly 110.2.4 |
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Describe the interaction with the atmosphere of Vegetation Cover
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Mainly western highlands, central plains, and boreal forest
- winds subject to frictional drag of vegetation - encourages development of turbulence as a lifting agent - source of much of evaporation - vegetation absorbs most of solar radiation and emits most of terrestrial radiation 110.2.4 |
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Describe the heat exchange mechanisms
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Radiation:
- emission or transfer of energy in form of electromagnetic waves Advection: - warm air passes over cool surface or vice versa Convection: - as air rises, it expands and cools Conduction: - transfer of heat between two bodies in contact Precipitation: - vapor condenses and warms air with release of latent heat and vice versa 110.3.1 |
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Describe how Radiation affects the temperature cycle
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- daytime heating
- nighttime cooling - reflection (albedo) and angle incidence create uneven heating - amount affected by seasonal variations 110.3.2 |
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Describe how Advection affects the temperature cycle
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- modifies the magnitude of vertical transfers
- leads to changes in temp and humidity over short periods 110.3.2 |
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Describe the Other Factors which affect the temperature cycle
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Proximity to water:
- cooler during day in spring/summer, warmer during fall/winter Distance from coast: - warmer during day in spring/summer, cooler during fall/winter Topography: - different surfaces absorb heat at different rates Altitude: - higher altitudes have cooler temps due to atmospheric lapse rates 110.3.2 |
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Describe factors affecting surface humidity
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Density of the air:
- humid air is less dense Temperature of the air: - warm air holds more moisture Source of moisture: - ie. Great Lakes vs. Arizona desert Seasonal variations - winter, higher along coast, very dry interior - summer, higher everywhere, highest near Great Lakes, St. Lawrence, Mississippi 110.4.1 |
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Describe the water balance
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P=N+E
Precip equals total evaporation plus surface runoff 110.4.2 |
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Describe the role of clouds
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- form of water storage
- first step in precipitation formation process - act as solar screen by blocking short wave radiation and reradiating terrestrial terrestrial radiation - short life expectancy 110.4.3 |
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Explain the difference between quasi-stationary and traveling disturbances
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Quasi-stationary:
- quasi-permanent - may last weeks or months Traveling: - transient - last only a few days 110.5.1 |
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Name the 5 quasi-stationary systems
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- Aleutian Low
- Icelandic Low - Arctic High - Pacific High - Bermuda High 110.5.2 |
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Describe the Aleutian Low
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- over NE Asia in summer
- over Aleutian islands in winter - affects BC and WA coasts during winter - maritime Arctic flow during winter - mild, humid winters 110.5.3 |
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Describe the Icelandic Low
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- near Iceland in winter
- moves westward in summer - affects much of eastern Canada - graveyard of cyclones for the Atlantic ocean 110.5.3 |
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Describe the Arctic High
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- important in the spring
- brings flow of Arctic air over central and eastern Canada - replaces the Icelandic Low 110.5.3 |
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Describe the Pacific High
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- controls air flow over coastal BC and western US during summer
- responsible for cool and clear summers of western coast 110.5.3 |
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Describe the Bermuda High
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- plays major role for eastern continent climate
- persistent in spring and summer - feeds in warm, very humid trade winds - gives hot, humid spells of summer 110.5.3 |
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Name the travelling disturbances
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- cyclones: Pacific lows, Alberta lows, Central US lows, Atlantic coast lows, cold arctic lows (synoptic)
- anticyclones: traveling warm highs, blocking highs, cold arctic highs (synoptic) - hurricanes and tropical storms (tropical cyclones) - showers and thundershowers 110.5.4 |
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Describe the traveling disturbances
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Synoptic systems:
- traveling cyclones and anticyclones, or lows and highs Tropical cyclones: - form as small, shallow low pressure systems over tropical oceans between 9 and 35 degrees from equator Showers and thunderstorms: - products of mesoscale phenomena - typically no more than tens of km across 110.5.5 |
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Describe Pacific lows
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- fast moving
- develop over Pacific along maritime Arctic front - deep and occluded when reaching BC and Yukon 110.5.5 |
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Describe Alberta lows
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- fast moving
- form in lee of Rockies - formed most often in Alberta -develops on Arctic or Maritime front, often involves both 110.5.5 |
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Describe Central US lows
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- also known as Colorado lows
- fast moving - forms in central US - enters Canada between MB and QC, usually over Great Lakes - develops over Polar front - usually involve tropical air streams 110.5.5 |
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Describe Atlantic Coast lows
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- fast moving
- forms along US seaboard - intensifies over Gulf Stream warm waters - enters Canada over Atlantic provinces and QC - involves tropical air streams 110.5.5 |
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Describe Arctic cold lows
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- slow moving
- forms within Arctic air - usually found over northern territories - occasionally drift south 110.5.5 |
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Describe 'Other Cyclones' in the context of travelling disturbances
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- can be quite complex in their structure
- common to be a pair of lows travelling east, involving the Arctic and Maritime front - deep cyclones can involve all three fronts 110.5.5 |
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Describe travelling warm highs
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- more common in summer and fall
- moves across southern Canada/northern US - usually involves mA or mP air from Pacific - usually clear, dry weather - accumulates smog if slow-moving - widespread radiation fog, especially in fall 110.5.5 |
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Describe blocking highs
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- slow moving
- occasionally form directly across westerlies - once formed, are persistent - may dominate flow for days or weeks - upsets normal synoptic system movement - cause large anomalies in temp - can produce extensive smog 110.5.5 |
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Describe cold Arctic highs
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- shallow
- rare in July/August, but common elsewise - moves southeastward from NW Canada - brings cold, windy, and clear in winter - brings cool, dry weather with few CU in summer 110.5.5 |
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Describe tropical cyclones
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- forms between June and November in North Atlantic
- can become tropical storms or hurricanes - copious amount of rainfall - affects continental east coast to the Mississippi valley - becomes smaller and weaker as they travel northward over colder waters - can intensify in northern latitudes if merging with a cold front 110.5.5 |
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Describe showers and thundershowers in the context of travelling disturbances
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- are a feature of synoptic systems
- usually accompany fronts - will form without fronts in an unstable air mass - usually forms in rows when formed from summer convection - can produce severe weather 110.5.5 |
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List the 10 macroclimatic zones in North America
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- Pacific Coastal
- North Pacific Coastal - Cordilleran and Plateau Provinces - Prairies and Great Plains - Gulf States - Great Lakes/St. Lawrence/Northeastern States - Atlantic Canada - North Atlantic - Boreal - Arctic 110.6.1 |
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Describe the Pacific Coastal macroclimatic zone
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- west of crest line of Coast Range and Cascade Mountains
- onshore flow of Pacific airstreams - cool, drier summers - mild, rainy winters - less rain in southern areas 110.6.2 |
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Describe the North Pacific Coastal macroclimatic zone
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- extension of Pacific Coastal from central BC to Alaska
- onshore flow of Pacific airstreams - cooler average temps than southern region - less sunshine than southern region - high precipitation amounts 110.6.2 |
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Describe the Cordilleran and Plateau Provinces macroclimatic zone
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- from Interior BC to southern Alberta
- high precip amounts on western slopes due to westerly winds - mild and rainy winters, except for invasions of cold air masses from interior - warm, dry summers near the coast - very hot, dry summers in southern interior 110.6.2 |
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Describe the Prairies and Great Plains macroclimatic zone
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- from southern AB to Great Lakes in east and Gulf States in south
- exposed to both cold arctic and warm subtropical air due to lack of W-E barrier - large annual temp range - dry winter, moderate precip in spring and early summer - clear and cold winters, little snowfall but windy - summer warm in south, cooler north 110.6.2 |
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Describe the Gulf States macroclimatic zone
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- dominated by proximity to the Gulf of Mexico
- relative warm year round - occasional below freezing temps - rarely above 35C in summer - high relative humidity 110.6.2 |
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Describe the Great Lakes-St. Lawrence/NE States macroclimatic zone
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- climate markedly modified by Great Lakes
- day to day weather quite variable - abundant and regular precipitation regime - seldom persistent wet or dry spells - long, warm springs and summers - affected by Bermuda High in summer - April/May have lowest precipitation/humidity - directly affected by most major systems - lake-effect snowfall highly pronounced in some areas 110.6.2 |
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Describe the Atlantic Canada macroclimatic zone
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- essentially a continental climate
- all coastal regions markedly cool in summer - lies in converging track of most major systems - precipitation both abundant and reliable - late spring and short summers - advection fog common on south-facing coasts - frequency of storms increase in fall - increased cyclonic activity in winter, with heavy precipitation 110.6.2 |
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Describe the North Atlantic macroclimatic zone
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- floating ice predominates for 8 months of the year
- water temp below 4C - ocean effect limited to near shore line - widespread fog in winter with east winds - predominant winds very cold westerly flow - precipitation heavier to the south - high precipitation amounts due to Atlantic storms - summer brief and cool, with warm and dry westerly winds, and cool and wet easterly winds 110.6.2 |
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Describe the Boreal macroclimatic zone
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- stretches from Alaska to Labrador
- area of spruce, fir, pine, larch, etc - cold in winter and spring - late spring due to snow on ground - cool in summer and fall - 3 sub-zones: forest tundra, woodland, closed forest - mean annual temp below 0C - precipitation normally light 110.6.2 |
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Describe the Arctic macroclimatic zone
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- north of tree line
- treeless, ice caps, permanently frozen ground - permanently ice-covered Arctic ocean - continual cooling in winter due continuous darkness - temps recover rapidly in summer due snow melt and continuous daylight - precipitation generally light 110.6.2 |
