Climate

CLIMATE: A BRIEF INTRODUCTION Weather: short-term physical condition of the atmosphere at a given time and place Ex: temperature, precipitation, air pressure, wind direction. Climate: a region’s average weather conditions over a long time. (years) Based on average temperature and precipitation values Factors affecting Climate: Latitude Way most important! Elevation Topography Ocean Currents Atmospheric Circulation Greenhouse Effect

Latitude and Climate In general, as latitude increases, solar intensity decreases Why? It’s all about the angle!! The larger the solar angle, the more concentrated the sun’s rays are!

Latitude and the Seasons At any given location, the solar angle varies throughout the year, altering climate and creating “seasons” Solstice: (6/21 or 12/21) The sun is directly over 23.5° N (Tropic of Cancer) Or… The sun is directly over 23.5° S (Tropic of Capricorn) Which Hemisphere receives more direct sunlight? What season is it in the other Hemisphere? Equinox: (3/21 or 9/22) The sun is directly over the Equator Both hemispheres experience 12 hours of daylight

Elevation As we go higher in the troposphere, the atmosphere cools at the environmental lapse rate with an average 6.5°C/Km Therefore the higher the elevation, the colder the climate! (Basically)  As a parcel of air move up through the troposphere it expands as the air pressure decreases and cools “adiabatically.” (without heat transfer) Higher elevations usually also have more precipitation than surrounding areas.

Topography: The Rain Shadow Effect Windward: The direction the wind is coming from Leeward: The direction the wind is blowing As air approaches a mountain range, the mountains act as large ramps pushing the air up. This causes the air to expand and cool. Eventually the dew point temperature is reached and clouds/precipitation form. ****The Rain Shadow Effect: Warm dry habitats on the leeward side of mountain range****

Ocean Currents: Distributing Heat Ocean currents influence climate by distributing heat from place to place Warm water moves from the equator towards the poles Cold water moves from the poles towards the equator

Global Circulation Global air circulation is affected by the properties of air, water, and land. As air is heated it becomes less dense and rises leaving behind a low pressure zone Figure 5-5

Convection Cells Heat and moisture are distributed over the earth’s surface by vertical currents, which form six giant convection cells at different latitudes. Figure 5-6

The Greenhouse Effect What is the greenhouse effect? Natural warming of the atmosphere depending upon the concentration of greenhouse gasses What are some greenhouse gases? H2O CO2 CH4 (Methane) N2O (nitrous oxide) O3 (Ozone) Wrong

Greenhouse effect Important gasses H2O CO2 CH4 N2O O3 Solar energy (light) that reaches the earth is converted into (heat) infrared. This infrared radiation has a hard time passing through the gasses in our atmosphere thereby trapping heat and keep the planet about 30 degrees (Celsius) warmer Important gasses H2O CO2 CH4 N2O O3

Climatograms Definition: Graphs that summarize monthly measurements of temperature and precipitation. Useful to give a rough idea of the climate in a certain area. Due to these abiotic factors, a characteristic type of vegetation adapts, which in turn supports a characteristic variety of animal life. Resulting in a community of both plants and animals known as a… BIOME!