Presentation on theme: "Aim: What are some of Earth’s wind patterns? I. Winds and Pressure Belts A. Convection cell – when air circulates by rising in one place and sinking at."— Presentation transcript:
Aim: What are some of Earth’s wind patterns? I. Winds and Pressure Belts A. Convection cell – when air circulates by rising in one place and sinking at another. 1. Convection cells occur because cooler, more dense air sinks toward the earth’s surface, pulled by earth’s gravity, causing the warmer, less dense air to rise.
B. Pressure belts are produced due to convection. 1. Low pressure belts are found at the equator and 60 o N and S latitudes. a. Air rises and converges. Thus, called zones of convergence. 2. High Pressure Belts are found at the poles and 30 o N and S latitudes. a. Air descends and diverges. Known as zones of divergence.
C. Coriolis Effect – rotation of earth causes winds to deflect. 1. In the northern hemisphere, winds are deflected to the right. 2. In the southern hemisphere, winds are deflected to the left. 3. Winds are a result of air moving from regions of divergence (high pressure) to areas of convergence (low pressure). GAME
D. Trade Winds – winds flowing toward the equator between 30 o and 0 o in both hemispheres. (NE and SE trades) 1. Doldrums – where trade winds of N & S hemispheres meet at the equator. Very weak winds in this area. E. Westerlies – winds located between 30-60 o in North and Southern hemispheres.
F. Jet Streams – occur high in the troposphere and low in the stratosphere. 1. Due to great difference in air temperature. Why do great differences in air temperature cause high speed winds? 2. These winds are found at an altitude of 10-15 km, are about 100 km wide, and are 2-3 km thick. These winds may reach a speed of 500 km per hour!!!!
G. Local winds – not part of the global wind belts. 1. Breeze – gentle wind that extends over distance of less than 100 km. a. Sea breeze – occurs during the day. when air over the water blows towards the land due to temperature and pressure differences. b. Land breeze - occurs at night. When air over the land moves towards the water due to temperature and pressure differences.