Climate Causes and Zones Climate Climate of a

Climate Causes and Zones

Climate �Climate of a region is dependent on: ◦ Latitude ◦ Atmospheric circulation cells ◦ Topography/Elevation

Latitude � The main factor influencing the climate of a region because different latitudes receive different amounts of solar radiation. � Equator receives the most solar radiation. � Polar regions receive the least solar radiation.

Atmospheric Circulation Cells �The position of a region relative to the circulation cells and wind belts has a great effect on its climate. �In an area where the air is mostly rising or sinking, there is not much wind.

Intertropical Convergence Zone (ITCZ) � the low pressure area near the equator in the boundary between the two Hadley Cells. ◦ air rises, cools and condenses to create clouds and rain � Climate along the ITCZ is warm and wet.

Cell Boundaries �Hadley and Ferrell ◦ 30°N and 30°S latitude ◦ air is warm and dry, it came from the equator where it lost most of its moisture at the ITCZ ◦ air is descending ◦ air warms and causes evaporation �Ferrell and Polar ◦ 50° to 60°N and S ◦ cold air from the poles meets warmer air from the tropics ◦ polar jet stream, shifts due to change in incoming sunlight ◦ South of jet stream = warmer and moister

Prevailing Winds �At the bases of the Hadley, Ferrell, and Polar Cells. �Influence the climate of a region by bring the weather from the locations they come from.

Continental Position � A maritime climate is strongly influenced by the nearby sea. � A continental climate is more extreme, with greater temperature differences between day and night and between summer and winter. The ocean’s influence in moderating climate can be seen in the following temperature comparisons. Each city is located at 37°N latitude, within the westerly winds.

Ocean Currents � The temperature of the water offshore influences the temperature of a coastal location, particularly if the winds come off the sea. ◦ cool waters of the California Current bring cooler temperatures to the California coastal region. ◦ in southern Alaska, the upwelling actually raises the temperature of the surrounding land because the ocean water is much warmer than the land.

Altitude �Air pressure and air temperature decrease with altitude. ◦ At higher altitudes, the air is less dense and air molecules are more spread out and less likely to collide and give off heat. �A location in the mountains has lower average temperatures than one at the base of the mountains.

Mountain Ranges �Have two effects on climate of surrounding regions: ◦ Rainshadow effect- brings a warm, dry climate to the leeward side of a mountain range. ◦ Separation of the coastal region from the rest of the continent. �The coastal region keeps a maritime climate, The Bonneville Salt Flats the inland/leeward side keeps a continental are part of the very dry climate. Great Basin of the Sierra Nevada of California. The region receives little rainfall.

Climate Zones �Climate zones are classified by the Köppen classification system. �Based on: ◦ Temperature ◦ Amount of precipitation ◦ Times of year when precipitation occurs �Vegetation is used as an indicator of climate type. �Köppen

Biomes �An intro to Biomes �Are regions of the world with similar climate, animals, and plants. �Organisms in a biome share certain characteristics around the world. �They have adapted to that environment in similar ways over time. ◦ Different species of cactus live on different continents, but they have adapted to the desert biome in similar ways.

Köppen classification system �Five major climate groups, A through E. �Subcategories are: ◦ forest (f) ◦ monsoon (m) ◦ wet/dry (w)