The Effect of Revolution & Rotation on Climate & Weather

The movements of the Earth affect both climate and local weather.

The spinning of the Earth causes day to turn to night, while the rotation of the Earth around the sun once a year causes summer to become winter. Combined, these two movements of the planet dictate our daily weather and global climate by affecting wind direction, temperature, ocean currents and precipitation.

Weather and Climate

The immediate conditions of the atmosphere--temperature, pressure, humidity, precipitation, cloud cover and wind--at a given place and time, is what creates local weather. Climate, on the other hand, is the long-term change of the atmosphere based on analysis of weather records over at least 30 years. The two factors that most strongly affect climate and weather are temperature and precipitation.

Earth’s Revolution

As the Earth revolves around the sun, its axis is tilted from perpendicular to the plane of the elliptic by 23.45 degrees. It is on this axis that the earth rotates every 24 hours. Since the axis is tilted, different parts of the globe are tipped towards, or away from, the sun at different times of the year. This tilting causes the four seasons of the year. This tilting also creates opposite seasons in the Northern and Southern Hemispheres.

Seasons

The Earth's seasons are not caused by the distance from the sun, but rather, by the tilt of the Earth's axis. Summer is warmer than winter because the sun's rays shine more directly than during winter, and also because the days are longer than the nights. During the winter, the sun's rays hit the Earth at a steeper angle, producing shorter days. The equinoxes are days in which day and night are of equal duration, while the solstices are the days when the sun reaches its farthest northern and southern declinations, creating both the shortest and longest day of the year.

Earth’s Rotation

When the Earth rotates on its axis, it prevents air currents from moving in a straight line north and south from the equator. Instead, the Coriolis Effect caused by this rotation deflects winds to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. Between 30 and 60 degrees latitude, the winds moving toward the poles curve east, forming the prevailing westerlies, which are responsible for many of the weather movements across the United States and Canada.

Wind Currents

The global air circulation, and the Coriolis Effect, transfer warm air from low latitudes and cold air from high latitudes as wind moves from high pressure to low pressure. These global wind and pressure belts are important to Earth's climate, and determine the local geographical pattern of precipitation and temperature. Yet, for small, local weather systems such as thunderstorms, the wind will flow directly from high pressure to low pressure and is not affected by the Coriolis Effect.

References

• University of Wisconsin: Global Scale Circulation
• Global Environment: Weather and Climate
• Weatherquestions.com: What Causes Wind?
• NASA: Global Wind Patterns
• Enchantedlearning.com: The Seasons and Axis Tilt