Climate – a region’s weather conditions average over thousands of years
Includes temperature and moisture averages
1. Average temperature over the year2. Temperature range throughout the
year-difference between the hottest and coldest months of the year
The average yearly precipitation is less than the potential evapotranspiration.
Affected by the temperature – high temperature but low rainfall = arid
Examples - Deserts
Average rainfall is greater than the potential evapotranspiration
A lot of rain is not needed…as long as there is more rain than evapotranspiration
Examples - rainforest
Latitude – affects the temperature
Near poles – (high latitude) the angle of the sun changes a lot during the year, creating a wide temperature range, but cooler temperatures overall
Near equator – (low latitude) the angle of the sun is high most of the year, creating steady but warm temperatures all year long.
Latitude - affects moisture
Low pressure areas near equator and mid latitudes creates warm rising air, clouds and precipitation
High pressure areas near poles and 30o create dry sinking air and deserts.
See ESRT diagram wind and moisture belts
Large Bodies of Water -Marine climate –
Wind blows moist air from over the ocean of large lakes. Being near water will also make temperatures fluctuate less during year than an inland area of similar latitude (cooler summers and warmer winters) like Long Island
Large Bodies of Water –Continental climate –
Wind blows dry air over vast stretches of land. Being inland (far from water) will also make temperatures fluctuate more during year than an marine location of similar latitude (hotter summers and colder winters) like St. Louis.
Prevailing winds blow air masses across the US from southwest to Northeast (west to east)West coast – receives warmer wet air
(marine) East coast – mostly receives dryer air
(continental) except for Long Island (marine)
Lake effect snow – near great lakes in upstate NY because of wet air being clown from the great lakes
Ocean Currents Warmer water from the equator carried to higher
latitudes
Cooler water from near poles carried toward equator
See ESRT Surface Ocean Currents
ElevationHigher elevation have cooler
temperatures and more moisture because of increased cooling of the air and more condensation
Examples – Catskill and Adirondacks in NY
Mountains Mountains can block cold or warm air passing Windward side – “water” or “wet” side forces
air up and to condense, creating precipitation “Leeward side – “land” or “dry” side because
once the air passes over the mountain it descends, warms and precipitation stops. Examples –Champlain Lowlands are on the
leeward side of Adirondack Mountains. Also, Las Vegas desert is on the leeward side of the Sierra Nevadas.
Cloud Cover – Clouds near the
equator block some insolation, making it slightly cooler than the 30o latitude dry, cloudless areas.
Pollution adds particles to air that increases condensation, creating haze or clouds which decrease the transparency of the air (i.e cools it off)
Vegetation – Plants and trees increase transpiration, making areas humid and cooler from shade.
When deforestation occurs, the area gets much hotter and dryer
Jan. 2011 Regents