Unit 4 APES (4.4 - 4.9)

What are the 5 gases in the atmosphere

What are the 5 gases in the atmosphere

• nitrogen

• oxygen

• argon

• carbon dioxide

• water vapor

what percent of nitrogen is in atm

• 70%, but most is in gaseous form so its un-useable

what percent of argon is in atm

• 0.93%

• inert noble gas

what percent of carbon dioxide is in atm

• 0.04%

• most important greenhouse gas

• leads to global warming

• removed from atm by photosynthesis

what percent of oxygen is in atm

• 21%

• made by photosynthesis in plants, needed for respiration

what percent of water vapor is in atm

• 0.4%

• varies by region & condition

• acts as a greenhouse gas temp but less impactful than carbon dioxide

• quickly cycles through atm

5 layers of the earth

• exosphere

• thermosphere

• mesosphere

• stratosphere

• troposphere

exosphere

• outermost layer of earth, where atm merges with space

thermosphere

• the word therm = hottest temperature

• absorbs harmful x-rays & radiation

• produces northern lights bc of the charged gas molecules that glow under intense radiation from sun

mesophere

• middle layer, meso for middle

  • 60-80 km, not very dense

stratosphere

• second level, s for second

• 16-60 KM, less dense due to lack of pressure from layers above

• thickest layer of oxygen is found here

• absorbs UV-B & UV-C rays which mutate DNA of animals & cause cancer

troposphere

• tropo = change

• weather occurs here

• 0-16 km, most dense bc of pressure of other layers above it

• most of atms gas molecules are found here

• ozone here is harmful to humans, damages plant stomata, and forms smog

temperature gradient

• the amount of temperature change per unit of distance

• determines where layers of earth’s atm are based

temperature gradient of thermosphere

• temp increases due to absorption of solar radiation

temperature gradient of mesophere

• temp decreases bc of density decrease, leaving fewer molecules to absorb sun

• coldest place on earth

temperature gradient of Stratosphere

• temp increases bc of top layer of stratosphere is warmed by UV rays

temperature gradient of troposphere

• temp decreases as air gets further away from warmth of earth’s surface

what is atmospheric circulation and what are the three main steps?

• the movement of air around the planet

  • Energy from Sunlight

  • Density properties of air

  • Rotation of earth (coriolis effect)

steps of atm circulation

1. More direct sunlight @ equator warms air

2. Warm air rises, cools, and expands → H₂O vapor condenses into rain

3. Air continues to rise, cool, and expand

4. Cooling, expanding air spreads out

5. cool, dry air sinks back down to earth @ 30^o N & S → Deserts form here due to lack of moisture in air

what are the 5 main air properties

• Warm air rises

• Warm air holds more moisture than cold 

• Rising air expands & cools

• Cool air can’t hold as much H₂O vapor (condenses → rain)

• After cooling & expanding, air sinks

Coriolis Effect

• Deflection of objects traveling through atm. due to the spin of the earth

• causes moving objects to be deflected to the right in the Northern Hemisphere

• deflected left in the Southern Hemisphere.

How does the Coriolis effect work?

• Air @ 30^o moves back to L pressure of equator

• Wind between 0-30^o moves from E→ W 

  • b/c earth is spinning W→ E

• Wind between 30^o-60^o moves W→ E 

  • b/c earth spins faster @ 30^o than 60^o

Why does air move from 30deg to 0 and 60deg? How is low and high pressure indicated?

• it moves due to high pressure @ 30⁰ & low pressure @ 0 & 60

  • Air rising @ equator = low pressure,

  • air sinking down @ 30⁰ = high pressure

eastern trades

• 0 - 30 winds blow E → W

• Drives ocean current clockwise in N hemisphere

• counterclockwise in S hem

westerlies

• 30^o - 60^o: winds blow W→ E

• Drives weather patterns of N America

Watersheds

• All of the land that drains into a specific body of water

  • (river, lake, bay, etc.)

what determines a watershed

• slope

• ridges of land divide watersheds, creating different runoff directions

what characteristics play a role in how watersheds drain?

• vegetation

• soil composition

• slope

how does vegetation play a role in how watersheds drain?

• more vegetation = more infiltration and groundwater recharge

how does greater slope play a role in how watersheds drain?

• allows for faster velocity of runoff & more soil erosion

how does soil permeability play a role in how watersheds drain?

• determines runoff vs. infiltration rates

how do human activities impact watersheds, give examples of harmful human activity

• H₂O quality

• clearcutting

• urbanization

• dams

• mining

what is the Chesapeake Bay Watershed

• 6 state region

• drains into streams/rivers → eventually into Chesapeake Bay

• mix of fresh & salt water

• nutrients in sediment makes estuary habitats in bay highly productive

What ecosystem services do Chesapeake Bay Watershed habitats provide (Estuary and Wetland)

• tourism revenue

• water filtration

• habitat for food sources

• storm protection

what are the main Human Impacts on Chesapeake Bay

• Nutrient pollution leads to eutrophication

• Algae bloom due to increase of N/P

• Endocrine disruptors (from sewage treatment)

• Sediment pollution (deforestation, urbanization, tilling ag. fields)

How does sediment pollution affect Chesapeake Bay

• Increases turbidity which reduces photosynthesis

• covers over rocky streambed habitats

How does the algae bloom in Chesapeake Bay set off a series of events?

• Algae bloom due to increase of N/P → decreased sunlight → plants below surface die → bacteria use up O₂ for decomp. → hypoxia (low O₂) & dead zones

Effects of clearcutting on watersheds : soil erosion

• Caused by loss of stabilizing root structure

• Removes soil organic matter & nutrients from forest

• Deposits sediments in local streams

  • Warms water & makes it more turbid (cloudy

Effects of clearcutting on watersheds : Increased soil & stream temp.

• Loss of tree shade increases soil temperature

• Loss of tree shade along rivers & streams warms them

• Erosion of sediments into rivers also warms them

Insolation

• the amount of solar radiation reaching an area measured in Watts/m²

what does solar intensity of insolation depend on?

1. Angle: how directly rays strike earth’s surface

2. The amount of atmosphere sun’s rays pass through

How does earth’s orbit around the sun & tilt on axis affect it?

• changes angle of the sun’s rays

• causes varying insolation

• The tilt of the earth’s axis stays fixed during orbit

solstice vs equinox

• solstices : highest/lowest points of the sun throughout the year, or the longest days and nights || N or S hemisphere is maximally tilted toward sun, causing summer & winter

• equinoxes mark the start of spring/fall where the day and night are even in length || N & S hemispheres equally facing sun

What is the March & Sept. Equinox

• N & S hemispheres equally facing sun

Tilt of Earth’s Axis Causes Variation in

• Angle of Insolation (which changes intensity)

• Length of day

• Season

Albedo 

• proportion of light that is reflected by a surface

how is light affecting surfaces with high or low albedo

• high albedo → reflect more light, and absorb less (ice/snow) & less heat

• low albedo →reflect less light, and absorb more (water), & more heat

what happens when sunlight is absorbed by the surface

• it gives off heat or infrared radiation

Urban Heat Island

• urban areas are hotter than surrounding rural area due to low albedo of blacktop

what determines climate

• largely determined by insolation

• Higher latitudes receive less insolation

• Equator receives most intense insolation

how does geography affect climate

• Mountains: disrupt wind & produce rain shadow effect

• Oceans: moderate temperature & add moisture to the air

Rain Shadows

• a patch of land that has been forced to become a desert

• mountain ranges blocked all plant-growing, rainy weather

• imagine one side being lush, the other side being arid and dry

• the windward side is nice and moist, but then you pass onto the leeward side, which is dry asf bc it warms as it sinks

Gyers global surface currenr

• large ocean circ. due to global wind

  • clockwise in N hem

  • counterclockwise in S hem.

Upwelling Zones

• sreas of ocean where winds blow warm surface water away from a land mass, drawing up colder, deeper water to replace it

• Brings O₂ & nutrients to surface → productive fishing

Thermohaline Circulation

• Connects all of the world’s oceans, mixing salt, nutrients, and temperature throughout

El Nino Southern Oscillation (ENSO)

• attern of shifting atmospheric pressure & ocean currents in the pacific ocean between South America and Australia/Southeast Asia

  • Oscillates, or shifts regularly from El nino (warmer, rannier) to La Nina (cooler, drier) conditions along coast of South America

what is the normal conditions of the southern pacific?

1. eastern trade winds blow surface water from east to west

2. leads to upwelling on the west coast of SA → cooler weather & productive fisheries

3. moves warm equatorial waters toward Australia and SE asia → warmer & rainy weather

4. warmer conditions of the west pacific → low pressure system in the americas & eastern trade winds from east to west across the southern pacific, moving from high to low pressure.

how does el nino affect the southern pacific?

• trade winds weaken and reverse direction

• shifts warm water of equator from australia and se asia towards west coast of america

• warmer winters in north america and heavy rainfall/flooding in western us

• suppresses upwelling along coast of sa → better fishing conditions

• creates drought conditions bc the trade winds blow in reverse condition creating a low cooler pressure system in west pacific

how does la nina affect the southern pacific?

• restores eastern trade winds to normal direction & intensifies them

• stronger than normal upwelling along SA coast

• cooler & drier conditions to N & S america

• leads to warmer/rainier conditions in australia and SE Asia

what is the difference between la nina and le nino’s effects on the southern pacific

•  El Nino basically reverses the normal wind and ocean circulation directions, which brings warmer, wetter weather to the Americas, instead of to Australia and SE asia

• La nina restores the original wind and ocean current direction of East to west, and intensifies it

what are the effects of el nino as a whole?

• Suppressed upwelling & less productive fisheries in SA

• Warmer winter in much of N America

• Increased precip & flooding in Americas (W coast especially)

• Drought in SE Asia & Australia

• Decreased hurricane activity in Atlantic ocean

• Weakened monsoon activity in India & SE Asia

what are the effects of la nina as a whole?

• Stronger upwelling & better fisheries in SA than normal

• Worse tornado activity in US & Hurricane activity in Atlantic

• Cooler, drier weather in Americas

• Rannier, warmer, increased monsoons in SE Asia