Earth Science Unit 7
Climate = region's long term weather pattern
Weather = short term condition of region, daily changes in atmosphere
Factors that affect climate of region:
Angle of insolation
Global wind patterns
Heat absorption (Specific heat)
Topographic
Average yearly temperature = hot/cold it is in a region throughout the year
Yearly temperature range = Highest monthly average temperature through lowest monthly average temperature
Average yearly precipitation = average amt of precipitation that falls in a region
Yearly precipitation range = highest to lowest monthly average precipitation
Earth’s axis = tilted by 23.5°
As earth revolves around the sun, where the tilt is facing changes → different seasons throughout the year
Angle of insolation = angle of the sun’s rays striking the Earth
Higher angles of insolation = sun shines more directly
Lower angles of insolation = sun shines indirectly
Duration of insolation = total amt of time the sun’s rays struck the earth on any particular day
Higher angle of insolation = Higher duration of insolation
Throughout the year, highest angle of insolation & duration of insolation changes based on the lines of latitude it lays on → unequal heating of Earth’s surface
Climate varies with latitude since direct sunlight = more solar radiation → warmer temperatures
Lower angles of insolation = larger area is covered
Sun shines more directly between the Tropic of Cancer (23.5°N) and the Tropic of Capricorn (23.5°S) (These are lines of latitude) These areas are known as tropical climates = areas in this region have long, warm summers & short, mild winters
Less solar radiation → cooler temperatures
Sun shines indirectly above the Artic Circle (66.5°N) and the Antarctic Circle (66.5°S)
These areas are known as polar climates → long, cold winters and short, mild summers
Between the latitudes 23.5°N/S and 66.5°N/S, angle of insolation changes from high to low throughout the year
Sun’s rays doesn’t directly shine onto this area but it is enough for these areas to get warmed in specific seasons
These areas are known as temperate climates = experiences all four seasons
Insolation = Incoming Solar Radiation
Based on the Northern Hemisphere:
Vernal (Spring) Equinox - March 21st or 22nd
Summer Solstice - June 21st or 22nd
Autumnal (Fall) Equinox - September 22nd or 23rd
Winter solstice - December 21st or 22nd
Low latitudes = High angle of insolation → warmer temperatures
Higher latitudes = lower angle of insolation → cooler temperatures
Ocean currents = continuous flow of water
Surface ocean currents are driven by prevailing winds which are driven by the heat from the sun
Deep ocean currents are driven by differences in temperature and salt content (salinity)
Global ocean conveyor belt = connected system of deep & surface ocean currents which circulate around the globe on a 1000 year time span
Warm currents originate at the equator and flows towards the poles
Cool currents originate at the poles and flow towards the equator
Ocean currents change the climate of locations that are alongside the coasts of continents
Warm water transfers heat to the air → warmer air
This warmer air passes over land → warmer region
Cold water absorbs heat from the air → cooler air
The cooler air passes over land → cooler region
Warm currents that move towards the north and south cause cold regions to be warmer than what it would typically be without warm currents
Cold currents that move towards the equator cause hot regions to be cooler than what it would typically be without cold currents
Wind = movement of air across Earth’s surface due to uneven heating of the Earth by the sun
Wind currents:
As air is heated, it rises which creates a region of low air pressure
As air cools, it sinks which creates a region of high air pressure
Air flows from an area of high pressure to low pressure
Wind currents form wind cells = convection currents of rising & sinking air in the atmosphere
The equator has a low-pressure zone due to direct heating of the sun’s rays causing the heated air to rise
The heated air will cool down once it rises high enough in the atmosphere and it eventually sinks along 30°N/S latitude
The sinking air will warm and travel towards 60°N/S or towards the equator where it eventually rises in both areas
The poles have high-pressure zone due to very cold air sinking and traveling towards 60°N/S where it eventually rises.
Wind belts form alongside some lines of latitudes due to rising and sinking air
There are three low pressure/wet belts at 0° 60°N and 60°S
At these latitudes, air rises and create regions of low pressure
As the air rises, it expands and cools → condensation → wet (rainy) regions
There are two high pressure/dry belts at 30°N and 30°S
At these latitudes, air sinks and create regions of high pressure
As the air sinks, it contracts and warms → regions of dry/arid weather
Between the wind belts though,
Prevailing winds = the wind blows in the same general direction alongside the Earth’s surface
These cause the movements of the surface ocean currents & affect the climates of different regions
Prevailing winds curve as they travel over Earth’s surfaces due to rotation of the Earth (Coriolis Effect)
Prevailing winds create four climates alongside the wind belts:
Locations near the equator are hot and wet since they’re areas of low pressure which results in high amts of precipitation
Locations near the 30°N and 30°S are hot and dry since they’re areas of high pressure which result in low amounts of precipitation
Locations near 60°N and 60°S are cool and wet since they’re areas of low pressure which result in high amounts of precipitation
Locations near the poles are cold and dry since they’re areas of high pressure which result in low amounts of precipitation
When warm and moist prevailing winds hit a mountain chain, the wind is forced up the mountain → change in climate on one side from the other
Windward side - Climate = more humid
Leeward side - Climate = more drier
The drier area is called a rain shadow
Average surface temperature is also affected by specific heat, color, and texture
Heat energy is transferred by:
Conduction = Heat transferred from one material to the other through physical contact
Convection = Heat transferred through the movement of a fluid (liquids or gasses)
Radiation = Heat transferred through electromagnetic waves like solar radiation
Different Earth materials heat up and cool down at different rates due to differences in specific heat
The amount of heat energy to raise the temperature of 1 gram of a substance by 1°C is called the specific heat of that substance
Higher specific heat value = longer it takes for the substance to heat up or cool down
Large bodies of water can affect the climate of coastal cities
Since the water heats up slowly in the summer and cools down slowly in the winter months → coastal cities having a smaller annual temperature range (less extreme temperatures) than cities further inland
Radiation will be reflected or absorbed depending on the color of the material
Dark colored material absorb more radiation
Lighter colored material reflect more radiation
Smooth surfaces reflect more radiation
Rough surfaces absorb more radiation
Earth’s atmosphere traps heat with the help of greenhouse gases so that the average surface temperature is high enough for life to survive
Examples of greenhouse gases:
Water vapor (H2O)
Carbon dioxide (CO2)
Nitrous oxide (N2O)
Methane(CH4)
Trapping of heat by greenhouse gases is called the Greenhouse Effect
Sun emits radiations in the form of electromagnetic waves (light)
Some is reflected off Earth’s atmosphere
Some reaches Earth’s surface
The radiation that reaches the Earth’s surface is absorbed by the land and water which causes Earth’s surface to heat up
The Earth then radiates the absorbed heat back into space in the form of infrared radiation which is trapped in the atmosphere
Since the industrial Revolution, carbon dioxide in the atmosphere has increased
Release of greenhouse gases through human activity = greenhouse gas emissions
Increasing emissions → increase in Earth’s average surface temperature (global warming)
Burning fossil fuels and contributing to deforestation increases the amount of carbon dioxide there is in the atmosphere
Increase in average surface temperature → change in climate patterns, more specifically:
Changes in precipitation
More droughts & heatwaves
Stronger and intense hurricanes
Sea level will rise 1-4 feet by 2100
Increase in Earth’s global temperature → melting of the ice caps → sea level rising
Coastal cities are at risk of being flooded due to the ice caps melting
Different features of Earth (snow, ice, land, ocean, clouds) have different albedos
Albedos = percentage of solar radiation reflected back into space
Land and ocean have low albedo = they absorb more energy than they reflect
Snow, ice, and clouds have high albedos which mean they reflect more energy than they absorb
without ice caps, the oceans would absorb large amts of sunlight and become much warmer → change in climate & ocean current patterns
As the altitude of the atmosphere increases → the air pressure and water vapor content decreases
80% of the mass of the atmosphere is found in the troposphere
Altitude increase → temperature in each layer of atmosphere increases or decreases based on the layer
Ozone (O3) is formed when ultraviolet light strikes oxygen(O2) in the stratosphere
Ozone layer absorbs harmful ultraviolet radiation and prevents it from reaching Earth’s surface
Air mass = large body of air that take on the characteristics of their source region (where they came from) which are temperature, pressure, and humidity
Movement of air masses is determined by winds
Air masses are identified by letters that describe the temperature and humidity characteristics they embody
c = continental (dry & formed on land)
m = maritime (humid & formed on water)
T = tropical (warm & formed at low latitudes near the tropics)
P = polar (cool & formed at high latitudes near the poles)
A = Artic (cold & formed at higher latitudes closest to the poles)
Jet stream = strong wind current that flows in the upper levels of the troposphere
These wind currents move west to east
The jet streams move southward during the winter and northward during the summer and this helps move air masses and their fronts to the east.
Front = boundary between two air masses
Cold front
Warm front
Occluded front
Stationary front
The moist, less dense, warmer air will always be forced to rise over the drier, denser colder air
This would mean that the hot air mass will always rise over the cold air mass
Air masses’ symbols will always point at the direction their heading
Cloud = large collection of very tiny droplets of water or ice crystals that float in the atmosphere
Warm air rises → expands and cools and water vapor condenses (turns into a liquid)
Condensation nuclei = microscopic particles of dust or salt in the atmosphere where droplets & ice crystals can form
Cold fronts move quickly → weather changes quickly along a cold front & the more severe the weather becomes
Warm fronts moves slower than cold fronts → weather changes slowly = light precipitation
Barometric pressure (atmospheric pressure) = pressure within the atmosphere of Earth
Measured with a barometer in millibars (mb)
Normal barometric pressure at Earth’s surface = 1000 millibars (mb)
Values above 1000 mb = high pressure
Values below 1000 mb = low pressure
On weather station model, barometric pressure is written with 3 digit code
Formula to find true barometric pressure:
Above 500 - place a 9 at front & place a decimal point before the last number
Below 500 - place a 10 at front & place a decimal point before the last number
Barometric trend tells us how much the pressure has changed over the past 3 hours
Formula to find true barometric pressure 3 hours ago:
Trend is negative - Add a decimal before the last number of the trend and add it to the current barometric pressure
Trend is positive - Add a decimal before the last number of the trend and subtract it from the current barometric pressure
Difference in air pressure between locations → air movement
High pressure areas causes wind to move clockwise and outward
Low pressure areas causes wind to move counterclockwise and inward
Isolines show air pressure, isolines that connect equal air pressure values are called isobars
Isobars are close together → wind speed increases
Sea breeze = Wind moves from the ocean towards the lands due to warm air from the land rising, condensing and cooling down and sinking towards the ocean
Land breeze = wind moves from land out to sea since in the night, the ocean takes long to cool down so the warm air will rise from the ocean, form clouds and the cooler air will sink onto the land
Dew point temperature = the temperature where condensation begins
Warm air needs to cool down in order to begin condensation
Relative humidity = percentage of water vapor in the air
Warm air holds more water vapor than cooler air
Relative humidity is 100% = air is fully saturated with water vapor
Sling psychrometer measures the relative humidity and dew point of the air
It involves a dry bulb thermometer & wet bulb thermometer
Determine the difference of the dry and wet bulb temperatures:
Subtract the wet bulb temperature from the dry bulb temperature
Use the dew point temperature chart to find dewpoint
Use the relative humidity chart to find relative humidity
Weather station model represents the current weather conditions for a specific location
Cloud cover (Percent) is represented by a pie graph
Amount of the circle that is shaded = the percentage of the sky covered by clouds
Temperature (Fahrenheit), also known as dry-bulb temperature, is found on the left upper corner of a weather station model
Visibility (Miles) = Greatest distance at which objects can be seen, it is found underneath the temperature
Present weather = atmospheric conditions (precipitation) It is found right beside the visibility
Dewpoint = Temperature at which air would be saturated with water vapor, It can be found beneath the visibility
When the air temperature and the dew point temperature are the same or close enough, this indicates high humidity
Wind direction is measured with a wind vane, determined by the direction the wind is coming from, this is placed attached to the pie graph
Wind speed is measured in knots
1 knot = 1.15 mph
A whole feather = 10 knots
A half feather = 5 knots
Measures with an anemometer
Precipitation = amt of rain or snow that has fallen in the past 6 hours, measured by a rain gauge, it is found below the barometric trend
Barometric Pressure is measured with a barometer and it is found above the barometric trend.
Climate = region's long term weather pattern
Weather = short term condition of region, daily changes in atmosphere
Factors that affect climate of region:
Angle of insolation
Global wind patterns
Heat absorption (Specific heat)
Topographic
Average yearly temperature = hot/cold it is in a region throughout the year
Yearly temperature range = Highest monthly average temperature through lowest monthly average temperature
Average yearly precipitation = average amt of precipitation that falls in a region
Yearly precipitation range = highest to lowest monthly average precipitation
Earth’s axis = tilted by 23.5°
As earth revolves around the sun, where the tilt is facing changes → different seasons throughout the year
Angle of insolation = angle of the sun’s rays striking the Earth
Higher angles of insolation = sun shines more directly
Lower angles of insolation = sun shines indirectly
Duration of insolation = total amt of time the sun’s rays struck the earth on any particular day
Higher angle of insolation = Higher duration of insolation
Throughout the year, highest angle of insolation & duration of insolation changes based on the lines of latitude it lays on → unequal heating of Earth’s surface
Climate varies with latitude since direct sunlight = more solar radiation → warmer temperatures
Lower angles of insolation = larger area is covered
Sun shines more directly between the Tropic of Cancer (23.5°N) and the Tropic of Capricorn (23.5°S) (These are lines of latitude) These areas are known as tropical climates = areas in this region have long, warm summers & short, mild winters
Less solar radiation → cooler temperatures
Sun shines indirectly above the Artic Circle (66.5°N) and the Antarctic Circle (66.5°S)
These areas are known as polar climates → long, cold winters and short, mild summers
Between the latitudes 23.5°N/S and 66.5°N/S, angle of insolation changes from high to low throughout the year
Sun’s rays doesn’t directly shine onto this area but it is enough for these areas to get warmed in specific seasons
These areas are known as temperate climates = experiences all four seasons
Insolation = Incoming Solar Radiation
Based on the Northern Hemisphere:
Vernal (Spring) Equinox - March 21st or 22nd
Summer Solstice - June 21st or 22nd
Autumnal (Fall) Equinox - September 22nd or 23rd
Winter solstice - December 21st or 22nd
Low latitudes = High angle of insolation → warmer temperatures
Higher latitudes = lower angle of insolation → cooler temperatures
Ocean currents = continuous flow of water
Surface ocean currents are driven by prevailing winds which are driven by the heat from the sun
Deep ocean currents are driven by differences in temperature and salt content (salinity)
Global ocean conveyor belt = connected system of deep & surface ocean currents which circulate around the globe on a 1000 year time span
Warm currents originate at the equator and flows towards the poles
Cool currents originate at the poles and flow towards the equator
Ocean currents change the climate of locations that are alongside the coasts of continents
Warm water transfers heat to the air → warmer air
This warmer air passes over land → warmer region
Cold water absorbs heat from the air → cooler air
The cooler air passes over land → cooler region
Warm currents that move towards the north and south cause cold regions to be warmer than what it would typically be without warm currents
Cold currents that move towards the equator cause hot regions to be cooler than what it would typically be without cold currents
Wind = movement of air across Earth’s surface due to uneven heating of the Earth by the sun
Wind currents:
As air is heated, it rises which creates a region of low air pressure
As air cools, it sinks which creates a region of high air pressure
Air flows from an area of high pressure to low pressure
Wind currents form wind cells = convection currents of rising & sinking air in the atmosphere
The equator has a low-pressure zone due to direct heating of the sun’s rays causing the heated air to rise
The heated air will cool down once it rises high enough in the atmosphere and it eventually sinks along 30°N/S latitude
The sinking air will warm and travel towards 60°N/S or towards the equator where it eventually rises in both areas
The poles have high-pressure zone due to very cold air sinking and traveling towards 60°N/S where it eventually rises.
Wind belts form alongside some lines of latitudes due to rising and sinking air
There are three low pressure/wet belts at 0° 60°N and 60°S
At these latitudes, air rises and create regions of low pressure
As the air rises, it expands and cools → condensation → wet (rainy) regions
There are two high pressure/dry belts at 30°N and 30°S
At these latitudes, air sinks and create regions of high pressure
As the air sinks, it contracts and warms → regions of dry/arid weather
Between the wind belts though,
Prevailing winds = the wind blows in the same general direction alongside the Earth’s surface
These cause the movements of the surface ocean currents & affect the climates of different regions
Prevailing winds curve as they travel over Earth’s surfaces due to rotation of the Earth (Coriolis Effect)
Prevailing winds create four climates alongside the wind belts:
Locations near the equator are hot and wet since they’re areas of low pressure which results in high amts of precipitation
Locations near the 30°N and 30°S are hot and dry since they’re areas of high pressure which result in low amounts of precipitation
Locations near 60°N and 60°S are cool and wet since they’re areas of low pressure which result in high amounts of precipitation
Locations near the poles are cold and dry since they’re areas of high pressure which result in low amounts of precipitation
When warm and moist prevailing winds hit a mountain chain, the wind is forced up the mountain → change in climate on one side from the other
Windward side - Climate = more humid
Leeward side - Climate = more drier
The drier area is called a rain shadow
Average surface temperature is also affected by specific heat, color, and texture
Heat energy is transferred by:
Conduction = Heat transferred from one material to the other through physical contact
Convection = Heat transferred through the movement of a fluid (liquids or gasses)
Radiation = Heat transferred through electromagnetic waves like solar radiation
Different Earth materials heat up and cool down at different rates due to differences in specific heat
The amount of heat energy to raise the temperature of 1 gram of a substance by 1°C is called the specific heat of that substance
Higher specific heat value = longer it takes for the substance to heat up or cool down
Large bodies of water can affect the climate of coastal cities
Since the water heats up slowly in the summer and cools down slowly in the winter months → coastal cities having a smaller annual temperature range (less extreme temperatures) than cities further inland
Radiation will be reflected or absorbed depending on the color of the material
Dark colored material absorb more radiation
Lighter colored material reflect more radiation
Smooth surfaces reflect more radiation
Rough surfaces absorb more radiation
Earth’s atmosphere traps heat with the help of greenhouse gases so that the average surface temperature is high enough for life to survive
Examples of greenhouse gases:
Water vapor (H2O)
Carbon dioxide (CO2)
Nitrous oxide (N2O)
Methane(CH4)
Trapping of heat by greenhouse gases is called the Greenhouse Effect
Sun emits radiations in the form of electromagnetic waves (light)
Some is reflected off Earth’s atmosphere
Some reaches Earth’s surface
The radiation that reaches the Earth’s surface is absorbed by the land and water which causes Earth’s surface to heat up
The Earth then radiates the absorbed heat back into space in the form of infrared radiation which is trapped in the atmosphere
Since the industrial Revolution, carbon dioxide in the atmosphere has increased
Release of greenhouse gases through human activity = greenhouse gas emissions
Increasing emissions → increase in Earth’s average surface temperature (global warming)
Burning fossil fuels and contributing to deforestation increases the amount of carbon dioxide there is in the atmosphere
Increase in average surface temperature → change in climate patterns, more specifically:
Changes in precipitation
More droughts & heatwaves
Stronger and intense hurricanes
Sea level will rise 1-4 feet by 2100
Increase in Earth’s global temperature → melting of the ice caps → sea level rising
Coastal cities are at risk of being flooded due to the ice caps melting
Different features of Earth (snow, ice, land, ocean, clouds) have different albedos
Albedos = percentage of solar radiation reflected back into space
Land and ocean have low albedo = they absorb more energy than they reflect
Snow, ice, and clouds have high albedos which mean they reflect more energy than they absorb
without ice caps, the oceans would absorb large amts of sunlight and become much warmer → change in climate & ocean current patterns
As the altitude of the atmosphere increases → the air pressure and water vapor content decreases
80% of the mass of the atmosphere is found in the troposphere
Altitude increase → temperature in each layer of atmosphere increases or decreases based on the layer
Ozone (O3) is formed when ultraviolet light strikes oxygen(O2) in the stratosphere
Ozone layer absorbs harmful ultraviolet radiation and prevents it from reaching Earth’s surface
Air mass = large body of air that take on the characteristics of their source region (where they came from) which are temperature, pressure, and humidity
Movement of air masses is determined by winds
Air masses are identified by letters that describe the temperature and humidity characteristics they embody
c = continental (dry & formed on land)
m = maritime (humid & formed on water)
T = tropical (warm & formed at low latitudes near the tropics)
P = polar (cool & formed at high latitudes near the poles)
A = Artic (cold & formed at higher latitudes closest to the poles)
Jet stream = strong wind current that flows in the upper levels of the troposphere
These wind currents move west to east
The jet streams move southward during the winter and northward during the summer and this helps move air masses and their fronts to the east.
Front = boundary between two air masses
Cold front
Warm front
Occluded front
Stationary front
The moist, less dense, warmer air will always be forced to rise over the drier, denser colder air
This would mean that the hot air mass will always rise over the cold air mass
Air masses’ symbols will always point at the direction their heading
Cloud = large collection of very tiny droplets of water or ice crystals that float in the atmosphere
Warm air rises → expands and cools and water vapor condenses (turns into a liquid)
Condensation nuclei = microscopic particles of dust or salt in the atmosphere where droplets & ice crystals can form
Cold fronts move quickly → weather changes quickly along a cold front & the more severe the weather becomes
Warm fronts moves slower than cold fronts → weather changes slowly = light precipitation
Barometric pressure (atmospheric pressure) = pressure within the atmosphere of Earth
Measured with a barometer in millibars (mb)
Normal barometric pressure at Earth’s surface = 1000 millibars (mb)
Values above 1000 mb = high pressure
Values below 1000 mb = low pressure
On weather station model, barometric pressure is written with 3 digit code
Formula to find true barometric pressure:
Above 500 - place a 9 at front & place a decimal point before the last number
Below 500 - place a 10 at front & place a decimal point before the last number
Barometric trend tells us how much the pressure has changed over the past 3 hours
Formula to find true barometric pressure 3 hours ago:
Trend is negative - Add a decimal before the last number of the trend and add it to the current barometric pressure
Trend is positive - Add a decimal before the last number of the trend and subtract it from the current barometric pressure
Difference in air pressure between locations → air movement
High pressure areas causes wind to move clockwise and outward
Low pressure areas causes wind to move counterclockwise and inward
Isolines show air pressure, isolines that connect equal air pressure values are called isobars
Isobars are close together → wind speed increases
Sea breeze = Wind moves from the ocean towards the lands due to warm air from the land rising, condensing and cooling down and sinking towards the ocean
Land breeze = wind moves from land out to sea since in the night, the ocean takes long to cool down so the warm air will rise from the ocean, form clouds and the cooler air will sink onto the land
Dew point temperature = the temperature where condensation begins
Warm air needs to cool down in order to begin condensation
Relative humidity = percentage of water vapor in the air
Warm air holds more water vapor than cooler air
Relative humidity is 100% = air is fully saturated with water vapor
Sling psychrometer measures the relative humidity and dew point of the air
It involves a dry bulb thermometer & wet bulb thermometer
Determine the difference of the dry and wet bulb temperatures:
Subtract the wet bulb temperature from the dry bulb temperature
Use the dew point temperature chart to find dewpoint
Use the relative humidity chart to find relative humidity
Weather station model represents the current weather conditions for a specific location
Cloud cover (Percent) is represented by a pie graph
Amount of the circle that is shaded = the percentage of the sky covered by clouds
Temperature (Fahrenheit), also known as dry-bulb temperature, is found on the left upper corner of a weather station model
Visibility (Miles) = Greatest distance at which objects can be seen, it is found underneath the temperature
Present weather = atmospheric conditions (precipitation) It is found right beside the visibility
Dewpoint = Temperature at which air would be saturated with water vapor, It can be found beneath the visibility
When the air temperature and the dew point temperature are the same or close enough, this indicates high humidity
Wind direction is measured with a wind vane, determined by the direction the wind is coming from, this is placed attached to the pie graph
Wind speed is measured in knots
1 knot = 1.15 mph
A whole feather = 10 knots
A half feather = 5 knots
Measures with an anemometer
Precipitation = amt of rain or snow that has fallen in the past 6 hours, measured by a rain gauge, it is found below the barometric trend
Barometric Pressure is measured with a barometer and it is found above the barometric trend.
