Weather and Climate of Latin America. Topics: Latitude and altitude zones Orographic effects Ocean...

Weather and Climate of Latin America

Topics:

• Latitude and altitude zones • Orographic effects• Ocean currents • Wind and pressure patterns• Precipitation patterns• Hurricanes• Hurricane Mitch

Latitudinal Zones

Altitudinal zonation

Temperature drops 3.5 degrees (F) for every 1000 ft gain in elevation

In each elevation zone, Climate, vegetation, agriculture, lifestyles vary

Peru map

Tierra Nevada (permanent snow and ice)No permanent human occupants

– When some snow/ice melt, keeps water reserves high

– Rodents, small carnivores, condor

Tierra Helada 12000 – 1 5 000 ft.“páramo” in northern Andes; “puna” in

Andes of Peru and Bolivia– Mining, herding of sheep, llamas,

alpacas– Deer, vicuña, guanaco

Tierra Fria: 6000 – 12000 ft.

Lower elevations: maize and beans;

higher elevations: tubers

Sheep herding, wheat. barley, broad beans, alfalfa, fruit trees, dairy cows

Major population centers: Bogotá, Quito, La Paz, Sucre, Cuzco

Tierra Templada 2500 – 6000 ft.

– Absence of frost

– Coffee and cacao

– Sugar cane, citrus, cotton, tomatoes, sweet potatoes, squash, maize

Tierra Caliente (sea level to 2500 ft.)

– Year-round high temps

– High diversity; disease and pest problems

– Cacoa, manioc (cassava), sweet potatoes, peanuts

Orographic Effect

• Mountains force air to lift, cooling temperatures, forcing cloud and precipitation formation

• Windward side of mountain is wet

• Lee side of mountain is in rainshadow (dry)

• Patagonian desert is in rainshadow of southern Andes

examples:

• Puerto Rico– Windward side :

San Juan : – 60 “ annually

– Leeward side : Ponce: 36 “

• Buenaventura, Colombia (windward):

394 cm

• Cali, Colombia (leeward) :

97 cm

Ocean Currents

• Currents affect temperatures of coastal landmasses

• Currents affect humidity of coastal landmasses – (cold currents: dry; warm currents: wet)

3 cold currents

• California current– Aridity of

northwestern Mexico

• Falkland/Malvinas current– Cold, arid Patagonia

• Peru (Humboldt) current– El Niño

• Equatorial Counter Current (Pacific)

• Brazil Current

• North Equatorial Current (Atlantic)

• Gulf Stream

4 warm currents

Wind and pressure patterns

Pressure belts:1. Equatorial Low (15°N - 15°S)

– Rising air; warm, wet, cloud cover all year

2. Subtropical Highs (centers 30°N, S)– Descending air, dry, lack of cloud cover– Clockwise circulation in N. Hem,

counterclockwise in S. Hem.

3. Subpolar Lows (centers 55 °N, S)– Rising air, cool, wet

4. Polar High (poles)– Descending dry air

• Belts shift seasonally with subsolar point

– Causing wet and dry seasons

• When equatorial low is present: wet season• When subtropical high is present: dry season

Resulting wet/dry seasons:

• Caribbean, S. Mexico, Central America:– Wet season: May – October (summer)– Dry season: November – April (winter)

• South America:– Central (Brazil, Eastern Bolivia):

• Wet season: November – April (summer)• Dry season: May - October (winter)

Wind patterns

• Winds blow from high to low pressure; clockwise and counterclockwise around highs and lows

• Northeast Tradewinds

• Southeast Tradewinds

• Intertropical Convergence Zone (Doldrums)

• Westerlies

Guajira

Atacama

Patagonia

Hurricanes

Progression:Tropical disturbances– disorganized storms

Tropical depressions23 mph

Tropical Storms39 mph

Hurricanes (Tropical Cyclone) 74 mph

• Originate in tropics over warm oceans– “typhoon”– “baguio”– “cyclone”

• N. Hem: August - September

• S. Hem: January - March

• Eye wall (100 inches/day)

• Very low pressure in center

Forward right flank

• High winds (>120 km / hr)

• Heavy rainfall (25 cm - several meters / day)

• Storm surge

Saffir-Simpson Scale

CATEGORY DAMAGE WINDS STORM SURGE

1 minimal 74 -95mph 4 -5 ft.

2 moderate 96 -110 6 -8 ft.

3 extensive 111-130 9 -12 ft

4 extreme 131 -155 13 -18 ft

5 catastrophic > 155 > 18 ft

Hurricane Mitch 1998at the time, (2nd) most deadly hurricane in western

hemisphere

Hurricane Date Areas Struck Deaths

"The Great Hurricane"

October 10-16, 1780

MartiniqueSt. Eustatius

BarbadosShips

22,000

Hurricane Mitch Oct 26 - Nov 4,

1998

Central America:HondurasNicaragua

11,000+ (3 million homeless)

Galveston, Texas

September 8, 1900

Galveston Island 8,000

Hurricane Fifi September 14 -

19, 1974 Honduras 8,000

Dominican Republic

September 1-6, 1930

Dominican Republic

8,000

Hurricane Flora Sep 30, 1963 - Oct 8, 1963

HaitiCuba

7,200

Martinique September 6,

1776 Point Petre Bay 6,000

1864 Calcutta Cyclone, In, 1864dia

Death Toll: 60,000

1922 Swatow Typhoon, China, 1922

Death Toll: 60,000

1882 Bombay cyclone, India, 1882

Death Toll: 100,000

1991 Bangladesh cyclone, 1991

Death Toll: 138,866

Cyclone Nargis, Myanmar, 2008

Death Toll: 140,000

1970 Bhola cyclone, Bangladesh (East Pakistan)               

Year: 1970      

Death Toll: 500,000

Great Backerganj Cyclone of 1876, Bangladesh

Death Toll: 200,000

Super Typhoon Nina, China, 1975   

Death Toll: 210,000

1737 Calcutta cyclone, India, 1737    

Death Toll: 300,000

1881 Haiphong Typhoon, Vietnam, 1881

Death Toll: 300,000

1839 Indian Cyclone, 1839      

Death Toll: 300,000

10-22-98

tropical depression

10-26-98

Category 5; central pressure 905 mb

(sustained 6 hours)

180-200 mph winds

(sustained 15 hours)

44 ‘ waves

10-31-98 inland to Guatemala

Orographic rain (1-2 ‘ per day; total 75 “)

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