Climate

1. Climate Chapter 25 Earth Science

2. Section 1: Climate and Climate Change Introduction • This section: • Presents temperature and precipitation as the two major factors used to describe climate. • Explains how latitude, proximity to large bodies of water, and topography affect climate.

3. 1. Climate vs. Weather • The average weather conditions for an area over a long period of time are referred to as climate. • Different from weather in that weather is the condition of the atmosphere at a particular time. • Weather conditions, such as temperature, humidity, wind, and precipitation, vary from day to day. • Climates are described by using average temperature and precipitation. • To estimate the average daily, monthly, or yearly temperature, add the high and low temperatures of the day, month, or year and divide by two • Using only average temperatures to describe climate can be misleading. • Yearly temperature range, or the difference between the highest and lowest monthly averages, is also used

4. Climate vs. Weather (cont.) • Another major factor that affects climate is precipitation. • It is also described by using monthly and yearly averages and ranges. • As with temperature, average yearly precipitation alone cannot describe a climate. • The months that have the largest amount of precipitation are important for determining climate. • Extremes of temperature and precipitation as well as averages have to be considered. • The factors that have greatest influence are latitude, heat absorption and release, and topography.

5. Climate vs. Weather (cont.) • Five major climate types based on temperature and precipitation: • Tropical • Warm to hot year-round and can be wet part or all of the year • Dry • Hot and cold regions with low rainfall • Temperate • Warm to hot in the summer and cool in the winter, with moderate rainfall. • Continental • Cool to warm in the summer and cold in the winter, with precipitation in the summer or year-round • Polar • Cold year-round

6. 2. Factors that Influence Climate • Latitude • In general, hot climates are found near the equator, very cold climates near the poles, and temperate climates are in the mid-latitudes. • The correlation between climate and latitude occurs because Earth is a sphere. • Because Earth’s surface is curved, each point faces in a slightly different direction relative to the sun. • In a 24-hour period, every point along a single line of latitude receives the same amount of energy from the sun • But low latitudes closer to the equator receive more than high latitudes closer to the poles.

7. Factors that Influence Climate (cont.) • Heat Absorption • Because land and water heat up and cool down at different rates. • Water takes longer to heat up and it retains heat longer. • As a result, coastal regions tend to be more moderate with more stable temperatures that those inland • Wind pushes warm water from the equator to the poles and cold water from the poles to the equator • Reflectivity of, or albedo, of surface materials. • Dark-colored materials like water and soil absorb more sunlight than light-colored materials like ice. • Dark surfaces heat up more than light surfaces • Earth reflects more sunlight when there is more ice.

8. Factors that Influence Climate (cont.) • Surface Features • Regions at high elevation tend to have cooler climates than those at low elevation. • Occurs in part because air temperature decreases with altitude • Air expands as it rises and cools as it expands • Mountains redirect air currents by channeling or blocking winds • Precipitation patterns are also affected • When warm, humid air reaches a mountain range, it rises and cools, resulting in high precipitation on one side of the range. • Can result in extremely wet climates on one side and extremely dry climates, or rain shadows, on the other