Chapter 7 Weather and Climate Define climate in terms of temperature and precipitation.
Describe the factors that affect climate. A region’s average weather pattern, which can change over time, determines its climate. rain shadow – a region on the side of the mountain where air becomes dry and descends
sunspot – a dark area that appears temporarily on the sun’s surface Climate is the average weather pattern of a region.
Climate may vary from season to season. Latitude or distance from the equator effects climate due to insolation.
Tropical zones, equator to 30° N or S, tends to be hot and wet.
Latitudes around 30° are often hot and dry.
Between 30° and 60° summers are warm and winters cold. Draw Conclusions
What type of plants might live in areas of low precipitation?
Plants that live in areas of low precipitation have adapted to dry conditions, such as cactuses that can store water. Critical Thinking
How would you dress for a trip to the South Pole?
Polar regions are cold and dry. Dress to stay warm, because the body will lose heat quickly there. Clothing that is in layers will help conserve heat. Layers are important because, if you do become warm enough to sweat, you can remove some of the layers. Temperature and precipitation are the two main factors.
Temperature can be affected by latitude, distance from water, ocean currents, winds, altitude, and mountain ranges. Regions within a large landmass have a Continental climate.
Hot summers, Cold winters, And low precipitation. A maritime climate can be found by large bodies of water.
Warm summers Mild winters And high annual rain fall Global winds move water in currents across the surface of the ocean.
Areas near warm currents tend to have warm temperatures.
The prevailing winds that blow west to east push air masses and fronts across the United States. At higher elevations there is less air pressure therefore the air has less energy which means it will be cooler.
Mountain ranges block much of the air from passing by them.
Rain shadows are created when winds blow clouds up a mountain side and rain. The leeward side receives the dry air. Dust, ash, and gases from erupting volcanoes can block sunlight, causing a cooling effect.
Draw Conclusions Suppose you live on the windward side of a coastal mountain range. A warm current flows along the coast. Describe the climate of your region. The climate would be warm, moist, and rainy.
Critical Thinking As you climb a mountain, you may pass through several climate zones? How is this possible. As you climb up the mountain it becomes colder due to the low air pressure. The lower pressure and lower temperatures cause changes in the climate.
Evidence suggests a climate change due to variations in sunlight and plate tectonics.
The energy output of the Sun varies.
The Sun has a sunspot cycle every 11 years, which is related to the Sun’s magnetic field.
During sunspot activity the Earth’s average temperature rises. Fossil evidence tells us that very cold areas were once closer to the equator. Draw Conclusions Scientists have learned that northern Europe once had a warm, wet climate. What led scientists to draw this conclusion?
Fossil evidence and evidence of plate tectonics are proof that northern Europe was once closer to the equator.
Critical Thinking
What changes in the Sun might account for warm periods in Earth’s history?
Warm periods might have been caused by an increase in the Sun’s brightness or in sunspot activity.