Chapter 7 Weather and Climate in the Environment

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Chapter 7Weather and Climate in the Environment

• Objectives
• Distinguish between climate and weather
• Explain climate types and differences
• Describe how weather elements are measured and
  reported
• Explain weather fronts, clouds, and storms
• List area of artificial weather modification

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Terms
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Climate and Weather

• Weather is the current condition of the
  atmosphere including temperature, wind, moisture,
  and atmospheric pressure
• The weather determines how we respond each day in
  the environment

• Climate is the weather that generally prevails
• Climate is an average of all of the weather
  conditions in a location
• Climate helps us plan for longer periods

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Climate Differences and Types

• Latitude
• Longitude
• Altitude
• Moisture
• Land and water temperature differences

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Latitude

• Latitude is the distance north or south from the
  equator
• The equator has a latitude of 0 degree, each pole
  is 90 degree from the equator

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Latitude
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Longitude

• Longitude is the distance between any location on
  the earth and the prime meridian line that passes
  over Greenwich, England
• Longitude lines are drawn north and south on a
  global or map
• Greenwich has been given a 0 degree longitude

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Altitude

• Altitude is the distance a point on the
  continental crust lies above sea level
• Elevation is a major factor in the temperature of
  area in the tropical and temperate regions

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Moisture

• Air in the tropical region over the ocean is much
  more likely to gain moisture and form
  precipitation than that in polar regions
• Areas long distance from oceans have less
  precipitation
• The polar areas have almost no precipitation
  because of the very cold temperature

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Land and Water Temperature Differences

• Land cools and heats faster than the water in the
  ocean
• Water stays near the same temperature year round
• Temperature differences between land and water
  are important in causing precipitation
• Wind moving over oceans gains moisture, as the
  wind moves over land and the elevation increases,
  the air cool
• Cool air can hold less moisture than warm air
  therefore, the moisture forms into precipitation

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Weather and the Environment

• All weather conditions affect the environment
• Extremes can cause considerable damage to crops,
  livestock, and other property
• Extremes also result in more energy being used to
  heat or cool our homes
• Four elements commonly measured about the weather
  are atmospheric temperature, moisture, wind, and
  air pressure

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Atmospheric Temperature

• Weather is measured in the atmosphere and known
  as atmospheric temperature
• Crop producers often decide when to plant seed by
  measuring the temperature of the soil

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Measuring Temperature

• Glass bulb thermometers
• Digital thermometers
• Bimetallic thermometers
• Thermocouple thermometers

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Temperature Scales

• Fahrenheit (F)
• Celsius (C)
• Kelvin (K)
• The common temperature scales vary based on the
  sea level freezing and boiling points of water
• Water freezes at 32 degree F and 0 degree C, with
  Kelvin, water freezes at 273 K and boils at 373 K
  

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Temperature and Living Organisms

• Organisms that live above the soil are more
  influenced by the atmospheric temperature
• Aquatic plants and animals are affected by the
  temperature of the water which they live
• Example, Tilapia will die in water that is below
  13 degree C
• Many plants and animals grow best in temperatures
  between 21-32 degree C

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Humidity

• Humidity is the amount of water in a per unit
  mass of air
• Air with high water vapor is said to have high
  humidity
• Dew point is the temperature of the air when dew
  begins to form
• Dew is often visible on plants in the early
  morning hours

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Humidity can damage structures
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Precipitation

• Precipitation is any form of moisture that falls
  to the earth rain, snow, or hail
• Precipitation is primarily measured as water
  using rain gauges
• Snow may be measured by the depth of accumulation
• A rain gauge is a tube that is open at the end one

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Rain Gauges
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Water Vapor

• Absolute humidity is the density of the water
  vapor in the air
• It is the amount of water vapor in a unit of air,
  often stated as grams of water per cubic meter of
  air

• Relative humidity is a comparison of the amount
  of moisture in the air with the ability of the
  air to hold moisture
• High relative humidity means the amount of water
  vapor the air can hold is approaching 100 percent
• Cool air can hold less water than warm air

Humidity is measured with several different
devices, such as hygrometers, psychrometers, and
sling psychrometers
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Atmospheric Pressure

• Atmospheric pressure is the pressure exerted by
  the atmosphere at a certain location
• Low air pressure is the sign of warm
• High air pressure results from cool air
• At sea level, the average air pressure is 14.7
  pounds per square inch
• Air pressure goes down with elevation
• Water boils at a lower temperature in higher
  elevations
• Food must be cooked longer and water must be
  heated longer to kill pathogens
• Air pressure is important in weather forecasting
• Low air pressure often means that storms may be
  approaching
• High air pressure usually indicates fair weather
• Atmospheric pressure is measured with a barometer
  

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This graph from a barometer shows a sudden drop
in air Pressure at the time of a severe storm
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Wind

• Wind is moving air
• The movement is caused by areas with high
  atmospheric pressure and low atmospheric pressure
• Wind moves from high to low pressure
• Wind is measured in two ways
• Direction is the direction the wind comes and is
  measured with a wind vane
• Speed is measured with an anemometer

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Wind being measured with an anemometer and a vane
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Clouds

• Clouds are visible aggregates of tiny water
  droplets or ice crystals in the atmosphere
• High clouds are made of ice crystals and are
  white
• Low clouds are dark and have more water vapor
  than high clouds

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Cirrus

• Cirrus clouds are white, high, and thin
• Cirrus clouds are above 20,000 feet

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Cumulus

• Cumulus clouds are large, dense, billowy clouds
• Cumulus clouds are often associated with fair
  weather but they can develop into cumulonimbus
  clouds by the upward movement of air
• Heavy rain, thunder, lightning, tornadoes, and
  hail are associated with the cumulonimbus cloud
  formations

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Stratus

• Stratus clouds are large layers or sheets of
  cloud
• Stratus clouds are usually below 6,600 feet
• Which produce a lot of precipitation

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Stratus
Cumulus
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Fog

• Fog is a cloud with its base at or very near the
  ground

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Storms

• Thunderstorms
• Winter storms
• Hurricanes
• Tornados

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Thunderstorms

• Typically occurring in warmer weather,
  thunderstorms can be violent combinations of
  gusty wind, hail, lightning and thunder, and rain

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Winter Storms

• Winter storms occur in cold weather and typically
  involve snow, freezing rain, and sleet

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Hurricanes

• Hurricanes are large, whirling storms that
  typically develop over water in the tropical
  region near the equator
• Hurricanes usually weaken rapidly once they reach
  land

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Tornadoes

• A tornado is the most powerful, violent type of
  storm
• The wind moves in a circular direction at speed
  up to 320 km/hr

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Artificial weather Modification

• Artificial weather modification means intervening
  in atmospheric processes to get certain weather
  results
• The aim is to make the weather meet the needs of
  people
• Rainmaking
• Frost prevention
• Fog and cloud dispersal
• Hail suppression

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Rainmaking

• Rainmaking is the process of artificial creating
  conditions in clouds to produce precipitation
• The process of adding materials to clouds is
  cloud seeding
• If the cloud temperature is above freezing, a
  solution of ammonium nitrate and urea is sprayed
  onto the bottom of the cloud
• If the cloud temperature is below freezing, dry
  ice and silver iodide may be dropped into a cloud
• Causing rain in one location may result in no
  rain in another
• U.S.A. have passed laws prohibiting rainmaking

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Frost Prevention

• One form of frost is visible as white crystal on
  plant leaves and other surfaces
• Several methods are used to prevent frost
  formation
• Large fan (not effective if the temperature drop
  below freezing)
• Large heater
• Water sprinkler system

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Fog and Cloud Dispersal

• Large fan and heater may be used to warm the fog
  and clouds so they dissipate
• Cloud seeding has also been used to reduce clouds
• Huge jet engine fans may be used on the ground at
  airports to keep the runway visible for landing
  airplanes

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Hail Suppression

• Silver iodide may be dropped into the clouds to
  keep hail from forming
• Waiting until hail has started is too late to
  protect a crop

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Royal Rainmaking

• Steps of rainmaking
• Triggering
• Fatten
• Attach
• Increasing rain
• Chemical used
• Exothermic chemical
• Endothermic chemical
• Nuclei chemical

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Usefulness of Rainmaking

• For agriculture
• For consumption
• For transportation
• For toxic reduction in the environment
• For electric production
• For wild fire quenching

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Rainmaking in the Future

• Missile
• Sprayer
• Super cooled cloud

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Tests

• What is the difference in weather and climate?
• What is latitude? How is latitude related to
  climate and weather?
• What are the major types of climate? What
  latitudes are involved in each type?
• What are the forms of precipitation?
• Distinguish between the major kinds of clouds
• What are storms? What are the common kinds of
  storms?
• What is artificial weather modification?