Climate Zones and Climate Change

1: Climate Zones and Climate Change

1. Climate Classification

diving climates based on long term patterns of temp, precipitation and seasonal variation

Tropical Wet

• Code A

• Subtype: Af

• located in ITCZ

• high temperature all year

• small anual temperature range (steady temperature)

• heavy rainfall all year

• NO dry season

• Ex: Singapore, Amazon River Basin in South America

Tropical Monsoon

• Code A

• Subtype: Am

• Warm temperatures year-round

• Short dry season followed by extreme rainy monsoon season

• seasonal wind shifts

• Ex: Southwestern India and Phillippines

Tropical Savanna

• subtype: Aw

• warm temperatures year-round

• pronounced, longer dry season (low sun season)

• lower precipitation and seasonally concentrated

• Open grasslands with scattered trees

Subtropical Desert

• Code B

• Subtype: BWh

• Location: 20 to 30 degree latitude

• Very hot summers, mild winters

• Extremely low annual precipitation

• High daily temperature range (hot days, cold nights)

• Sparse, drought adapted vegetation

Midlatitude Cold Desert

• Code B

• Subtype: BWk

• extremely dry conditions like BWh

• Cold winter (often dropping below freezing) due to higher latitude or inland location

• Sparse Vegetation

• Ex: Great Basin Desert, Gobi Desert

Subtropical Steppe / Hot Semi Arid

• Code B

• subtype: BSh

• Hot, semi-arid climate (a dry region that receives more rain than a true desert, but still loses more moisture to the air than it gets from precipitation)

• supports continuous short grasses and shrubs

• Ex: Parts of West Africa

Midlatitude Steppe / Cold Semi Arid

• Code B

• Subtype: BSk

• semi-arid climate with cold winters and warm summers

• Low rainfall supporting grassland and prairie enviroments

Humid Subtropical

• subtypes: Cfa and Cwa

• hot,humid summers and mild winters

• sufficient rainfall year-round ( or summer- concentrated in Cwa)

• eastern side of continents (Southeastern US, Eastern China)

Mediterranean

• subtypes: Csa (Hot-Summer), Csb (Warm Summer)

• hot and warm, dry summers and cool, wet winters

• strongly influenced by seasonal shifts in subtropical high-pressure systems

• ex: Spain, Southern Italty, Los Angeles

Marine West

• subtypes: Cfb (warm-summer) , Cfc (cool-summer)

• mild summers and cool-to-mild winters

• narrow annual temperature range

• frequent cloud cover and steady rainfall distributed throughout the year

• Ex: London, Paris

Humid Continental - Hot summer

• subtypes: Dfa, Dwa

• hot summers and cold, snowy winters

• rainfall occurs year round or summer dominated

• strong seasonality

• Ex: Chicago, Detroit, New York City

Humid Continental - Warm/ Cool Summer

• subtypes: Dfb, Dwb

• shorter, milder summers and longer, cold winters

• heavy seasonal snowfall

• supports mixed and deciduous forests

• ex: Minneapolis, Toronto

Subartic / Taiga

• subtype: Dfc, Dfd, Dwc, Dwd

• very short, cool summers and extremely cold, long winters

• massive auunual temperature ranges

• low precipitation

• dominted by boreal coniferous forests

• Ex: Alaska, Canada

Tundra

• subtypes: ET

• short, cool growing season where at least one month averages above freezing 0 degress

• permanently frozen subsoil (permafrost)

• supports low growing plants like mosseds, lichens and grasses (no tree growth)

Ice Cap

• subtype: EF

• permanent frost with no month averaging above freezing

• covered continuously by thick ice sheets

• extremely low precipitation (polar desert)

Highland Climates

• Code H

• governed by elevation rather than latitude

• rapid drops in temp and changes in precipitation as altitude increases

• features complex microclimates and stacked vegatation zones

Group A

Tropical Climates

• Characterized by high temperatures year-round (every month averages above 64 degrees and heavy rainfall

Group B

Dry (Arid and Semi- Arid) Climates

• Characterized by potential evaporation exceeding annual precipitation; very little moisture.

Group C

Temperate/ MIld Midlatitude Climates

• Characterized by moderate temperatures, distinct summer and winter seasons, with average cold-month temperatures between 27 F and 64 F

Group D

Continental / Sever Midlatitude

• Characterized by large annual temperature ranges, warm to hot summers, and freezing winters (at least one month average below 0. Found almost exclusively in the Northern Hemisphere.

Group E

Polar Climates

• Characterized by enduring cold; the average temperature of the warmest month is below 50 F

Climate type

reoccuring combination of long term temp and precipitation charactersitics that’s mapped geographically and combared across locations

Climographs

displays a locations annual temp and precipitation that can, be mapped geographically and compared across other locations

small anual temperature range

limited seasonal contrast

temperature remains steady

large annual temp range

stronger seasonality

temperature changes

very hot summers and very cold winters

Vertical Zonation

systematic change in climate and vegatation with increasing elevation

Tierra Caliente “hot land”

0 - 3,000 feet

low elevations

75 F to 80 F

Tierra Templada “temperate land”

3,000 to 6,000

intermediate elevations

65 F to 75F

Tierra Fria “cold land”

6,000 to 12,000

higher elevations

55 F to 65 F

Tierra Helada

12,000 - 15,000

permanent snow and ice may occur

highest elevation

20 F to 55 F

elevation can…

reproduce climate contitions found at higher latitudes

aspect, slope, moisture, and exposure modify the exact boundaries of these zones

Factors controlling Climate

1. Latitude : determines angle and seasonal distrubution of incoming solar radiation

2. Ocean Currents

3. Prevailing winds

4. Maritime Influence

5. Continentality

6. Altitude

NOTE: factors interact with eachother

Causes of temperature extremes

driven mainly by strong continentiality

Causes of Preciptation extremes

rely on moisture sources, wind patterns, storms, tophography

Causes of Polar Ice/ Tropical Storms

ocean-atmosphere shifts and warm surface waters

Short term v Long term

short term weather/climate fluncations occur WITHIN broader long-term climate trends

Climate conclusions require…

evaluating long-enough time periods

noting that brief cooling periods or year to year swings do not disprove overall warming or cooling trend

Paleoclimatology

study of past climates and causes of climate change

using proxy measures

Proxy measures

• indirect indicators that substitute for direct measurements

tree rings, ocean sediments , ice cores, coral reefs , relic soil, and pollen

Each proxy has different strengths, limitations, geographical covers and time resolotion

confidence increases when independent proxies produce consistent evidence

Dendrochronology

dating and analysis of past events using tree rings

wide rings=favorable conditions

narrow rings=unfavorable

useful for constructing recent year by year climate variablity

growth may be influenced by factors other than climate

Palynology (Pollen Analysis)

examines pollen preserved in successive sediment layers in lake bottoms and bogs

• using radiocarbon daying

• identifies plant specifies adapted to cooler or water enviorments

changing pollen provide evidence of past climate

Geological Indicators of Past Climate & Climate Change

Glacial Landforms: revealformer ice-sheet with evidence of glacial retreat

Speleothems: cave deposits analyzed through growthlayers, carbon and oxygen isotopes

Ice Cores: air bubbles trapped bubbles preserve ancient atmosphere.valuable for climatic evidence and atmospheric compositiond data

Atmospheric Aerosols

suspended particles in the air that alter incoming solar radiation

• Cooling drivers, solar variability, greenhouse gases and human- impacts, positive feedback loops, and wate vapor and cloud feedbacks.

Cooling Drivers (Aerosols)

Volcanic Europtions: inject ash/ aerosols if reached stratospehere cooling lasts for years

Asteroid Impacts: block sunlight with massive particle clouds — > global cooling

Human- made: Fossil Fuel combustion releases particles that scattered sunlight, cooling

Solar Variability

sunspot activity affects solar wind and solar output (fewer sunspots lead to cooler periods)

Greenhouse gases and human impacts

greenhouse gases levels track temp shifts

increases tried to anthropogenic sources

Positive feedback loops

mechanism ampliefies intial change

ice-albedo feedback

water vapor

cloud complexityy

Ocean Storage

• oceans store vast amounts of greenhouse gases

• marine organisms trap carbon via photosynthesis and building calcium-carbonate shells

Gas storage, circulation, and atmospheric feedbacks affect eachother

Rising wate temp limit gas storage, while shifting currents change heat distribution

Evidence of Current Anthropogenic Climate Change

atmosphere: average air temp increasing, hottest in years

ocean: surface waters warming, acidic

polar regions: glaciers and sea ice shrinking warming in artic

weather patterns: extreme weather events more common

biosphere: species changing migration patterns of crop yields are experiencing negative affects

Anthropogneic Climate Change

cannot be explained by natural factors alone

Greenhouse gases: main driver

Aerosols (human and Volanic): provide slight cooling affect, masking GHG warming

Climate Models (GCMs and ESMs)

GCMs: computer simulations

ESMs: extend GCMs by intergration deep ocean circulation models