Unit 9, Chapter 27 Integrated Science
Mar 28, 2015
Unit 9, Chapter 27
Integrated Science
Unit Nine: Energy in the Earth System
27.1 Earth's Heating and Cooling27.2 Global Winds and Currents27.3 Weather Patterns27.4 Storms27.5 Weather and Climate
Chapter 27 Weather and Climate
Chapter 27 Learning Goals Learn how Earth’s rotation, Earth’s axial tilt, and distance
from the equator cause variations in the heating and cooling of Earth.
Learn how the heating of Earth’s surface and atmosphere by the sun causes convection cycles in the atmosphere and oceans, producing winds and ocean currents.
Learn about tools meteorologists use to predict weather, and how to read a weather map.
Make and test your own weather instrument. Model a Doppler radar system. Learn about the physical features that interact to form
the climate of each of six important land biomes.
Chapter 27 Vocabulary Terms longitude prevailing westerlies polar easterlies temperate forest stratiform cloud stratocumulus cloud taiga temperature inversion trade winds tropical rainforest tundra warm front
air mass El Niño-Southern Oscillation biome cold front Coriolis effect cumuliform cloud desert grassland gyres isobars jet stream latitude
27.1 Variations in Earth's Heating and Cooling
Key Question:
What causes seasons?
*Read text section 27.1 AFTER Investigation 27.1
27.1 Heating and Cooling Earth Satellite data is used to
map patterns of heating and cooling.
The National Oceanic and Atmospheric Administration (or NOAA) uses infrared photography to map how much heat is reflected or emitted from different areas of Earth each day.
27.1 LatitudeLatitude lines measure
distance from the equator.
These lines run parallel to the equator and are labeled in degrees north or degrees south.
27.1 LongitudeLongitude lines run vertically from the north pole to the
south pole.
The line that runs through Greenwich, England, is labeled 0 degrees longitude and is called the prime meridian.
Lines east of the prime meridian are numbered from 1 to 179 degrees east, while lines west of the prime meridian are numbered from 1 to 179 degrees west.
The 0- and 180-degree lines are not labeled east or west.
27.1 Temperature and LatitudeEarth’s temperature varies
with latitude.
At higher latitudes, solar radiation is less intense.
The same thing happens to the sun’s energy when it reaches the south pole at an angle.
27.1 Temperature and Rotation As Earth rotates, the portion of the globe facing the sun
warms as it absorbs more solar radiation than it emits. Earth constantly emits some of the absorbed energy as
infrared radiation. This emission of heat cools the dark side of the planet.
27.2 Global Winds and Ocean CurrentsThermals are small convection currents in the
atmosphere.
While thermals form on a local level, there are also giant convection currents in the atmosphere.
These form as a result of the temperature difference between the equator and the poles.
27.2 Coriolis Effect
Bending of air currents is called the Coriolis effect, after the French engineer mathematician Gaspard Gustave de Coriolis (1792-1843), who first described the phenomenon in 1835.
27.2 Global WindsThere are three important
global surface wind patterns in each hemisphere:— trade winds— polar easterlies— prevailing westerlies
27.2 Ocean CurrentsGlobal wind patterns and Earth’s rotation cause
surface ocean currents to move in large circular patterns called gyres.
27.2 Global Winds and Ocean Currents
Key Question: How do temperature and salinity cause
ocean layering?
*Read text section 27.2 BEFORE Investigation 27.2
27.3 Weather PatternsThree important factors
that shape the weather in a given region are:— temperature— pressure— water
A sling psychrometer can measure water in the air.
27.3 Phase changes of water Water in the atmosphere exists in all
three states of matter. High in the troposphere, there are
ice crystals. Tiny water droplets, much too small
to see, are suspended throughout the troposphere virtually all the time.
Other water molecules in the atmosphere are truly in the gas state, separate from all other molecules.
27.3 Cloud formationDifferent conditions
cause different clouds. Cumuliform clouds form
when convection causes rising pockets of air in the atmosphere.
Cumuliform clouds include:— cirrocumulus— altocumulus— cumulus— cumulonimbus
27.3 Cloud formationDifferent conditions
cause different clouds.
Stratiform clouds form when a large mass of stable air gradually rises, expands, and cools.
Stratiform clouds include:— cirrostratus— altostratus— nimbostratus
27.3 Cloud formationSometimes a cloud formation combines aspects
of both cumuliform and stratiform clouds. We call these clouds stratocumulus clouds.
27.3 Cloud formationCirrus clouds are thin lines of ice crystals high in
the sky, above 6,000 meters.They are just a thin streak of white across a blue
sky.
27.3 Precipitation A raindrop begins to form when water
molecules condense on a speck of dust.
At first it is round, but when it is large enough that it begins to fall, air resistance causes the underside of the drop to flatten, so that it looks more like a hamburger bun.
As it grows larger, it looks more like an upside down bowl with a thick rim.
If it hasn’t hit the ground by this point, it will break up into smaller droplets and the process repeats itself.
27.3 Air masses and fronts An air mass is a large body of air with consistent
temperature and moisture characteristics throughout. Changing atmospheric conditions and global wind currents
eventually cause these air masses to move.
27.3 Low and high pressure areas When a cold front moves
into a region and warm air is forced upward, an area of low pressure is created near Earth’s surface at the boundary between the two air masses.
A center of high pressure tends to be found where a stable cold air mass has settled in a region.
Isobars show areas with the same atmospheric pressure on map.
27.3 Weather PatternsKey Question:
How can we measure water content in the atmosphere?
*Read text section 27.3 BEFORE Investigation 27.3
27.4 Storms Thunderstorms arise when
air near the ground is strongly warmed and rises high into the troposphere.
As the air rises, it cools and condenses, forming a towering cumulonimbus cloud.
Eventually some of the cloud droplets become large enough to fall as rain.
a storm cell
27.4 Hurricanes Several conditions must be
present for a rotating system to become a hurricane:— wind speeds of at least 74
miles an hour.— warm ocean water must be
at least 46 meters deep.— the air must be warm and
moist to a point at least 5,500 meters above sea level.
a tropical cyclone
27.4 Tornadoes A tornado, like a hurricane, is a
system of rotating winds around a low pressure center.
An average tornado is tiny, compared with the average diameter of a hurricane.
However, the wind speeds of a tornado are much greater than those of a hurricane.
A tornado’s wind speed can reach 400 kilometers per hour.
a tornado
27.4 Storms
Key Question: How does
Doppler radar work?
*Read text section 27.4 BEFORE Investigation 27.4
27.5 Weather and ClimateClimate is defined as
the long-term average of a region’s weather.
Climate depends on many factors: — latitude— precipitation— elevation— topography— distance from large bodies
of water
27.5 Weather and ClimateScientists divide the planet into climate regions
called biomes.An example of a biome is desert.
27.5 Biomes
Key Question: How do zoos model climates?
*Read text section 27.5 BEFORE Investigation 27.5