unit 3

what is climate?

• study of how the sun’s energy is trapped + transported across earth

• average weather + variability in a location

• temperature, humidity, precipitation etc

greenhouse effect

• slows down loss of energy into space

  • keeps warm enough for life, human intervention → global warming

• earth absorbs solar radiation (earth heats)

• radiation also emitted from earths surface (earth cools down)

  • hotter = more radiation emitted

1. Sunlight enters Earth's atmosphere.

2. Earth's surface absorbs sunlight and warms up.

3. Earth releases heat as infrared radiation.

4. Greenhouse gases absorb and re-emit some of that heat.

5. Some heat escapes into space, while some returns toward Earth's surface.

greenhouse gases

H2O

CO2

CH4

N2O

radiative balance

• earth heats up enough to where it emits as much radiation as it absorbs

earths climate system

earth atmosphere

alt inc → pressure decrease

lowest alt.

1. troposphere (coldest)

2. stratosphere (warm)

3. mesosphere (warm)

4. thermosphere (cold)

• mostly N

• next biggest O

• small argon

• CO2

trade winds

• equator: receives direct sunlight (warmer)

• poles: angled sunlight (earth tilt = cold)

• trade winds = blow toward equator

  • NE t.w (northern hem)

  • SE t.w (southern hem)

• westerlies: W→ E

• coriolis effect (E rotation = curve wind)

• global circulation: moves heat around

hydrosphere

• all liquid water in earths surface

  • oceans, lakes, rives, groundwater

  • water transports better than air

• thermohaline circulation (?)

el nino

• warm sea surface T in east equator pacific

• normal behavior = cool NE + SE trade pushes warmth away from EEP

• el nino = cold air from both sides cause heat to swell in 1 area

cryosphere

• albedo

  • snow + ice so white they reflect alot of sun energy back to space

lithosphere

• continents heat and cool more than oceans

• topography

  • mountains influence wind pattern

    • colder → inc elevation

• volcanism

  • injects particulates (tiny solid/liq particles suspended in air)

  • that black solar radiation = cooling

biosphere

all organisms living near Earth’s surface

• organisms heavily influence water + carbon cycle

• plants influence albedo

carbon cycle

biological

• plants absorb CO2 + sunlight releasing O2

• animals eat plants + animals to pass carbon through food chain

• microbes break down dead plants + animals releasing CO2

global carbon reservoirs

• atmosphere holds CO2 interacts w/ land + ocean

• oceans absorb CO2 + store in plankton remain

• ancient plant + animal remains form fossil fuels

carbon budget + human impact

• emissions: human activities add to atmosphere (fossil fuel burning, deforestation, etc.)

• uptake: new plant growth and air-sea gas exchange

feedbacks

positive: change in one component = enhanced by change it does on other

• inc CO2 = respiration for animal remain inc = CO2 increase

• CO2 inc = surface T inc = ice cap melp = earth albedo decrease = surface T inc

negative feedback: change in one component reduced by change it does on others

• ex: inc CO2 = plants grow faster = less CO2

climate variability

• [add more of this]

• climate has varied in past → rate of modern climate change = alarmingly fast

Milankovitch cycles

• eccentricity

  • (how much Earth's orbital path around the Sun departs from a circle)

• tilt

  • (earth tilt due to orbital plane more tilt = more extreme temps)

• precession

  • (wobble of earths axis)

weathering (chem, phys, feedbacks, O2, CO2)

• breakdown and fragmentation of rocks

• chemical

  • chemical alteration in presence of water/air

• physical

  • mechanically fragmented without change in composition

  • joints (fracturing with no faulting)

  • bedding + cleavage

  • roots

  • exfoliation (outer layer of rock flake away in thin sheets/slabs)

  • frost wedging (ice expands as it freezes + crack expands + frag)

• more Si = weathers least

• olivine → pyroxene → amphibole → biotite → muscovite/quartz/feldspar

• calcium P feldspar → sodium

• feedbacks (positive)

  • chemical removes material + loosens grain = weaken rock →

  • physical frags weaken rock →

  • frag inc surface area exposed to air and water →

  • inc area = inc rate of chemical weathering

• feedback (negative)

  • CO2 inc

  • climate warms + plants/microorg. grow faster

  • weathering inc

  • CO2 dec

erosion

• removal of weathered mat from source

• water

  • like water + coffee (top is ground coffee and bottom is liquid coffee and other substance)

  • soil is feldspar at the top and kaolinite clay and other at the bottom

• ex

  • granite made of crystals that decay @ diff rates

  • cracks form + biotite + magnetite decay

  • decay progresses + rocks disintegrates

mass wasting

• collapse of hillsides

• angle of repose

  • particles dropped in pile create angle of repose based on size (cone shaped)

    • fine sand has a shallower angle than pebbles

    • water saturated sand keeps grains apart = less cohesive

soil

residue of chemical weathering

• soil retains water + remain wet

• plants + microorgs produce acids

• most valuable natural resource

  • food supply

  • buildings on soil

  • tropical soil = valuable aluminum ores

  • soil + climate linked (need soils to study climate)

gradient

1. O horizon = decomposing org matter

2. A horizon = weathered mineral grain + org matter

3. E horizon = max dissolution + max remove mineral grain + org matter

4. B clay minerals (Fe and Al, calcite) combination of phys transport from upper, water infiltrating, + in place weathering

5. C horizon: unweathered / slightly weathered parent

6. bedrock

translocation: minerals/grains may move through soil

transformation: precipitates form from fluids within pores in soil

factors

• time

• climate

  • more annual precipitation = calcite pushed down/dissolved = taller / lush vegetation (forest)

• topography

• parent material

  • more Si = slower weathering (hematite, quartz, clay)

  • less Si = faster (halite, calcite, olivine)

• organisms

where is earths water

reservoir = storage for water

• most in ocean

• then glaciers

• underground water

• lakes

• atmosphere

• biosphere

hydrologic cycle

• models the movement of water from one reservoir to another

hydrology and climate

• relative humidity

  • amount of water vapor in the air (% water the air could hold if saturated)

  • warm air holds more than cold

    • warm air cools = supersaturated (water condenses) → clouds

orogenic rain shadow

1. wind carry warm air over oceans (gains moisture)

2. moist air + mountains = rises + cools (rain/snow)

3. result = rainy windward slope

4. air passes over mountain, cold air has no more moisture + sinks

5. dry slope/rain shadow formed (desert)

precipitation

runoff

• water flowing due to gravity not evaporation or infiltrating soil

• Half the global runoff is carried in the 70 largest rivers

  • half of that is carried in the Amazon alone.

    • amazon most, Mississippi least

• surface reservoirs = lakes + wetlakes

  • dry period = low reservoir low runoff

  • wet period = high reservoir high runnoff

  • dams and natural reservoirs only release water slowly despite dry/wet periods

ground water

groundwater = part of subsurface water in saturated zone (phreatic)

water table

• boundary between unsaturated zone (vadose) and saturated (phreatic)

• vadose (higher up)

  • water + air both occupy pore spaces

  • soil + weathered bedrock

• phreatic (lower)

  • water fills all pore spaces

• easy to pump out but slow to recharge

• pumping exceeds recharge → resource depletes

porosity

porosity

• percent rock volume that is pores (spaces)

  • porosity increases with increased sorting

  • independent of grain size

permeability

• ability to allow fluids to pass through

• interconnectedness of pores

  • decreases with decreasing grain size, porosity, and sorting

infiltration

• surface water infiltrates into unsaturated zone

  • gravity + capillary forces, moves into water table

• groundwater moves by gravity + pressure difference along a head gradient

• ground water moves from high head to low head not always downhill

recharge

• addition of water that causes water table to inc

• inc evap/withdrawal by pumping lowers table

cone of depression

• water pumped faster than it can recharge

• salt water is denser than fresh

  • too much pumping = water supply might turn brackish as salt pulled into pump

aquifer

• any permeable saturated layer that can transport water

unconfined

• upper bound defined by water table

confined

• upper bound is aquitard

• ogallala aquifer

• karst aquifer

• edwards aquifer

aquitard

• impermeable layer prohibiting flow of water (ex shale layer)

artesian well

• well that brings ground water up without pumping

• under pressure within surrounding layers of impermeable rock

springs

• ground water discharge feature

• forms wherever the land surface intersects water table