DRY SUMMER (SUBSIDENCE)
EXTREME TEMP RANGE
PERMANENT ICE (EF)
Global Climate II
Mediterranean & British vs. China & Laurentian · Steppe Grasslands · Siberian Taiga · Tundra & Polar Ice Caps (28 Micro-Realms)
Mid-Latitude Asymmetry and the Boreal Forest (Köppen Groups C, D, E)
Beyond the tropics, climate distribution is heavily skewed by the clash between continental landmasses and prevailing winds. Group C (Warm Temperate) features an East/West divide: West Coasts host the Mediterranean (Cs) climate (dry summers, wet winters from Westerlies) and the marine British Type (Cfb). East Coasts host the warm China Type (Cwa/Cfa) receiving summer monsoon/hurricane rain. Inland lies the semi-arid Steppe (BSk) grasslands. Group D (Cold Snow Forest) exists only in the Northern Hemisphere due to landmass distribution, featuring the vast coniferous Siberian Taiga (Dc) with extreme annual temperature ranges, and the east-coast Laurentian Type. Finally, Group E (Polar) covers the treeless Tundra (ET) and frozen Ice Caps (EF).
I. Warm Temperate (Group C): Mediterranean vs. China Type
Group C: Warm Temperate
- Distinct summer and winter seasons
- Coldest month average temp: between $18^\circ\text{C}$ and $-3^\circ\text{C}$
- Warmest month is above $10^\circ\text{C}$
Mediterranean Climate (Cs)
SUMMER
WINTER
- The ONLY climate with winter rainfall & summer drought!
- Cs = Warm Temperate (C), Dry Summer (s)
- Known for abundant sunshine and clear skies
Med. Location Law
MEDITERRANEAN
CHINA TYPE
- Found exclusively on the WESTERN margins of continents
- Between $30^\circ\text{–}40^\circ$ N/S latitudes
- California, Central Chile, Cape Town, SW Australia, Mediterranean Basin
Wind Shift Engine
- Driven by the seasonal shifting of pressure belts
- Summer: Subtropical high shifts poleward $\to$ subsiding dry air
- Winter: Westerlies shift equatorward $\to$ bring cyclonic rain
Mediterranean Agriculture
- Sclerophyllous vegetation (thick, leathery leaves to retain water)
- World's orchard lands: Citrus fruits, Olives, Grapes
- Viticulture (wine making) is historically dominant
China Type Climate (Cw/Cf)
- Found on the EASTERN margins between $30^\circ\text{–}45^\circ$
- Opposite of Mediterranean: Summer is the wettest season!
- Influenced by onshore Trade winds & Monsoons
China Type Sub-Varieties
- China Type: Intense summer monsoon, typhoons in autumn
- Gulf Type: SE USA, no complete wind reversal, hurricanes
- Natal Type: More even rainfall from maritime air masses
II. British Type (Marine West Coast) & Steppe Grasslands
British Type Climate (Cfb)
- Found on WESTERN margins between $40^\circ\text{–}60^\circ$ N/S
- North of the Mediterranean zones
- NW Europe, British Columbia (Canada), Southern Chile, New Zealand
Year-Round Westerlies Rain
- Under the permanent influence of the Westerlies
- Rainfall occurs throughout the year (f = no dry season)
- Lots of cyclonic (frontal) drizzle; heavily overcast
Ocean Current Moderation
KEEPS PORTS ICE-FREE IN WINTER
- Warm ocean currents wash these coasts
- Makes winters anomalously mild for their high latitude
- Summers are cool (marine moderation)
Temperate Steppe (BSk)
- Located deep in continental interiors (Eurasia, N. America)
- Cut off from oceanic moisture (aridity)
- Extreme continentality $\to$ hot summers, freezing winters
Steppe Treeless Grasslands
- Too dry for forests, too wet for deserts $\to$ Grasslands
- Virtually treeless (unlike tropical Savanna)
- Downs (Australia), Canterbury (New Zealand), Pustaz (Hungary)
The Granaries of the World
WHEAT CULTIVATION
- Flat, treeless plains with incredibly fertile Chernozem soils
- Ideal for extensive, highly mechanized wheat farming
- Also prime regions for cattle & sheep ranching
Chinook Wind Impact
KEEPS PRAIRIES CLEAR FOR GRAZING
- In the North American Prairies, the hot Foehn-type Chinook wind
- Descends the Rockies in winter/spring
- Rapidly melts snow, a boon for ranchers!
III. Cold Snow Forest Climates (Group D) - Siberian & Laurentian
Group D: Microthermal
- Coldest month is below $-3^\circ\text{C}$; warmest month above $10^\circ\text{C}$
- Ground is snow-covered for several months
- Dominated by extreme cold winters
Northern Hemisphere ONLY
- Group D climates are entirely ABSENT in the Southern Hemisphere!
- Because there is no large landmass between $50^\circ\text{–}70^\circ\text{S}$
- Oceanic dominance prevents extreme winter cooling there.
Siberian Climate (Dc/Dd)
- Stretches across northern Eurasia and Canada
- Holds the record for the greatest annual temp range
- Verkhoyansk (Siberia): $-50^\circ\text{C}$ winter to $15^\circ\text{C}$ summer!
The Taiga (Boreal Forest)
- World's greatest reserve of softwood coniferous forests
- Pine, Fir, Spruce, Larch
- Trees are conical (to shed snow), evergreen, with needle-leaves
Economic Activity (Taiga)
& FUR TRAPPING
- Lumbering is highly commercial (pure stands of single species)
- Trees are felled in winter, dragged over frozen ground/rivers
- Fur trapping (Mink, Ermine) is a traditional economy
Laurentian Climate (Df)
- Found on EASTERN margins between $40^\circ\text{–}50^\circ\text{N}$
- NE North America (St. Lawrence basin), NE Asia (Japan, Manchuria)
- Rainfall throughout the year, but very cold winters
The Grand Banks Fishery
- Convergence of warm (Gulf Stream / Kuroshio)
- And cold (Labrador / Oyashio) ocean currents
- Creates abundant plankton $\to$ world's richest fishing grounds!
IV. Polar Climates (Group E) & High Altitude Zonation (Group H)
Group E: Polar Climates
- Located beyond the Arctic and Antarctic circles ($66.5^\circ$)
- Even in the warmest month, temperatures do not exceed $10^\circ\text{C}$
- Insolation is always extremely oblique (slanting)
Tundra Climate (ET)
- Brief, very cool summer (temps just above freezing)
- Subsoil is permanently frozen (Permafrost)
- Prevents tree roots from penetrating; completely treeless!
Tundra Vegetation
- Restricted entirely to Mosses, Lichens, and sedges
- Bloom rapidly during the brief summer thaw
- Supports reindeer/caribou and nomadic herders (Inuit, Lapps)
Ice Cap Climate (EF)
- Temperatures NEVER rise above freezing, even in summer!
- Greenland and Antarctica interiors
- Precipitation is meager (polar cold deserts) and falls as dry snow
Highland / Alpine (Group H)
- Climate governed by altitude rather than latitude
- Found in high mountain ranges (Himalayas, Andes, Rockies)
- Exhibits vertical zonation of climate from tropical base to tundra peak
The Treeline (Timberline)
- The latitudinal or altitudinal limit where trees can grow
- Roughly corresponds to the $10^\circ\text{C}$ summer isotherm
- Beyond this line, only Tundra vegetation survives
Master Group C,D,E Matrix
- Completes the Global Climate Systems
- Locks all geographical matching traps for Prelims
- The absolute culmination of the Climatology syllabus!
Core Distinctions
• Mediterranean (West Coast, 30°–40°): The ONLY climate with Winter Rainfall and Summer drought (due to shifting westerlies/subtropical highs).
• China Type (East Coast, 30°–45°): Experiences Summer Maximum Rainfall due to onshore trade winds and monsoonal influences, plus autumn typhoons/hurricanes.
• British Type (West Coast, 40°–60°): Highly moderated by ocean currents (Gulf Stream). Very mild winters, cool summers, and rainfall throughout the year from permanent Westerlies.
• Laurentian Type (East Coast, 40°–50°): Affected by cold continental winds in winter. Has freezing winters (unlike British type) but still gets year-round rain, supporting the world's richest mixing-current fisheries (Grand Banks).
• Savanna: Tropical. Tall grass, short scattered trees (Parkland). Wet summer, dry winter.
• Steppe: Temperate. Short grass, virtually treeless. High annual temp range.
• Taiga: Sub-Arctic. Vast coniferous forests (softwoods). Extreme winters.
• Tundra: Polar. Permafrost. Completely treeless (only moss/lichen).
Climate Systems II Matrix
Köppen Groups C, D & E Reference