Global Earth Systems Exam 1 (Jamie’s flashcards)

Littoral Desert

where cold ocean currents reduce evaporation and cool the air on nearby coastlines, normally on west coasts

Where is precipitation inhibited?

• areas of subsidence, like the interior of large landmasses

• Leeward side of mountain ranges

• Littoral deserts

Where are heavy precipitation zones associated with uplift?

• along polar front zone

• ITCZ

• Warm land masses in summer

• Where air is mechanically forced up, like mountain ranges

Cloud condensation nuclei

• organic or inorganic, natural or anthropogenic particles that water condenses on, causing rain

• Without these, the air can become supersaturated

Relative humidity

• Ratio of actual vapor pressure to saturation pressure at the temperature at 100%, it normally rains

Where is water on land?

• ~ 75% in ice sheets (Greenland and Antarctica)

• <1% in lakes, soils, and rivers

• Rest in groundwater

Energy needed to heat water from 0C to 100C

419 kJ/kg

Water on earth

• Oceans >70%

• Clouds cover ~50%

• Only natural substance to exists in 3 states at surface

• Cycles readily between different components of the Earth system

Monsoons

• a pattern of wind circulation that changes with the season

• Generally wet summers, dry winters

• Linked to different heat capacities of land and water and the north- south movement of the ITCZ

• Ex: in Southeast Asia, there is a large landmass north of the Indian Ocean near the equator

Radiation incident of land vs water and what it means

Land: radiation absorbed or reflected at the surface

Ocean: radiation penetrates further than on land

• this means the ocean absorbs more energy over the same area as land with less temperature change (but more volume in ocean)

Thermal conductivity

rate at which energy passes through a column of a given material

Albedo of ocean vs. land

Ocean is less than land, so it absorbs more and reflects less solar radiation

Latitudinal distribution of incoming solar radiation is modified by

• seasonal changes of temperature input

• Land- ocean contrasts in thermal behavior

Solar radiation at high latitudes

• energy spread out over more area

• Energy passes through more area

• Incident angle causes lower intensity which causes the poles to be cooler

3 qualities of incoming radiation

• varies with latitude (causes temperature differences)

• Radiation comes in parallel waves

• Incident angle varies with latitude

Why does land distribution affect airflow? What does this cause?

• land changes temperature more rapidly than water due to lower heat capacity

• ITCZ more narrow and consistent over oceans

• Greater season differences in Northern Hemisphere (Earth’s top heavy)

Specific Heat

• 4.186 J/gK of water

Residence time (constituents)

• amount in the oceans / flux in or out of the ocean

• Average length of time on elements spends in the ocean

Heat budget

the total amount of heat received by Earth and lost by radiation and reflection; the amount in is the amount lost

Latent heat of evaporation

• amount of heat required to change 1g of water from liquid to gas

• Water has the highest of any known liquid

Heat capacity

The amount of heat/energy required to raise the temperature of a quantity of matter by 1C

latent heat of fusion

amount of heat required to change 1g of water from ice to liquid

Seasonality and N-S (or US) temperature gradient

season change weakens or strengthens the N-S temperature gradient in different hemispheres

Why are wind patterns considered simplified

• winds are not continuous around the globe

• Wind do not blow continuously

• Convective uplift in ITCZ occurs in clusters of small cells

• Areas of subsidence are concentrated in localized zones that vary with season

Winds in polar regions

easterly winds circulating around a polar high pressure area

Winds at mid-lats, subtropics, equator

• Mid-lats: westerly winds

• Subtropic: easterly trade winds

• Equator: doldrums

Coriolis effect

-opponent force acting on a body in motion

Caused by rotation of earth

Deflection right in Northern Hemisphere and left in Southern (from equator)

Inertial force

What causes coriolis effect

• rotation of Earth (once per day)

• If earth is broken down into discs, the ones at the equator move faster than the ones at higher latitudes; circumference is longer but the same 360 must be covered in the same time

Intertropical convergence zone (ITCZ)

• region of weak and variable winds where trade winds of the two hemispheres converge

• Generally associated with the zone of the highest surface temperature and as the climate equator between 3N and 10N

Coriolis effect near equator

to weak to generate rotation air masses

Polar Front Zone

• ~ 60 latitude

• Where air from the poles meets air from the tropics

• Sharp temperature gradient

Doldrums

nautical term for a belt of light, variable winds near the equator

How is heat moved

• ocean and air currents (equator to poles)

• Solar radiation

• Change in state

• Evaporation: heat loss

• Condensation: heat gain

Atmospheric convergence vs. divergence

Convergence: where winds meet at the bottom of the troposphere

Divergence: where winds separate at the bottom of the troposphere

What stops air from continuing to rise in areas of uplift?

tropopause forms a barrier due to density stratification in the stratosphere

Coriolis effect and atmospheric circulation

• air affected because it has mass

• Air is deflected before reaching pole from equator (sinks about 1/3 the way there)

• Descending air deflected right, back to equator

• Heats up at the equator and rises again

Atmosphere structure

Bottom: troposphere

Stratosphere

Mesosphere

Thermosphere

How is it moved: sensible vs latent heat

Sensible: convection and conduction

Latent: change in state

Where is there a solar radiation on surplus? A deficit?

Surplus: equator (~30S to ~30N)

Deficit: above and below equator (-30S + and ~30 N+)

thermosphere

O2 absorbs short wavelength UV

mesosphere

• ozone and heating decline

• Temperature decreases with altitude

Stratosphere

• the stratified second layer of atmosphere ~10 to 50 km in altitude

• Lower pressure than troposphere

• No convection due to stable thermal structure (warmer higher up)

• Ozone blocks UV radiation

Troposhere

• constrains ~ 80 % of atmospheric mass

• Well mixed by convection

• Temperature decreases with altitude

• Thermal instability leads to atmospheric circulation

Causes of horizontal atmospheric circulation

caused by uneven solar heating with respect to latitude and powered by sunlight

Effect of pressure on vertical air movement

• compressed air becomes warmer and rises

• Decompressed air becomes cooler and sinks

• Rising air experiences less pressure and cools

• Descending air experiences more pressure and warms

Describe air movement

• air warms and rises at the equator

• Loses moisture at it expands and cools

• Cool air moves toward equator to replace it

• Creates zones of low and high pressure

3 global changes on short timescales

• greenhouse gases and global warming

• Stratospheric ozone depletion

• Deforestation and biodiversity loss

2 causes for global warming

• primarily fossil fuel combustion

• Some deforestation

Evidence that global warming is caused by humans

Carbon isotopes in the atmosphere, 13^C/12^C and radioactive 14^C

What do ice cores show?

Unprecedented increase in greenhouse gases

Why do we know the increase in greenhouse gases is due to humans?

Ocean circulation and configuration of landmasses

Why do we know climate change data is not wrong

Multiple data sets are independent of each other, so problems with one is not applicable to the others

What absorbs UV-B radiation?

Stratospheric Ozone

What caused the hole in the ozone?

Chlorine containing compounds formed from anthropogenic CFCs

Why does ozone hole primarily occur over Antarctica in spring?

• atmospheric circulation

• Chemistry

• Availability of sunlight

How do human impacts reduce landscape complexity?

Clearing forests and grasslands reduces biodiversity, resulting in extinctions

Tropical rainforests

Most biodiversity terrestrial habitats that are rapidly being cleared

What does rainforest clearing result in?

Largest and most significant loss of species

Time needed to recover stratospheric ozone depletion atmospheric CO2 increase mass extinction of species

Ozone depletion: ~50 to 150 years

CO2 increase: over 1 million years at current rates

Mass extinction: tens of million years to never

How to determine which global scale change is most concerning?

Based on the time it takes to recover

3 global changes on long timescales

Glacial-interglacial cycles in Quaternary (ka)

Mass extinction at K-T boundary (Ma)

Solar luminosity changes (Ga)

Order of geologic time intervals

eons>eras>periods>epochs

Why do temperature, CO2, and CH4 vary over glacial-interglacial cycles?

Atmospheric CO2 increase mass

Milankovitch cycles

Alvarez Impact hypothesis

• too much indium at K-T boundary to be deposited in normal circumstances

• ~200km crater near chicxulub supports impact hypothesis

Causes in changes in solar luminosity

-Stellar nucleosynthesis, which is H to He to Fe

4 H —> 4^He + energy

He takes less space than 4H, causing the core to contract and heat up

Why is solar luminosity increase?

The rate of nuclear fusion and emission of energy from the sun is increasing

Faint young sun paradox

solar luminosity was too low for liquid water before 2 billion years ago

BUT! We had liquid water

Thought that greenhouse gases made earth warm enough for liquid water

Gaia hypothesis

posits Earth is a self regulating system in which biota play an integral role in optimizing conditions for their continued survival; does not require a collective consciousness

Problems with Gaia hypothesis

Difficult to test

Unlikely biota can cope with all possible disturbances

System

An entity composed of diverse but interrelated parts that function as a complex whole

Types of system components

• reservoirs of matter

• Reservoirs of energy

• Attributes of a system

• Subsystems composed of sub components

State of a system

set of attributes characterizing a system at a particular time

Couplings

links between components of a system in which changes to one affects the other

Stable vs unstable equilibrium

stable needs a large disturbance to affect equilibrium state, while unstable is easily permanently changed

Perturbation vs forcings

Perturbations are temporary and forcings are more persistent

Ex: volcanic eruption vs solar luminosity

Daisy world climate system

a very simple hypothetical planet used to show how the biota can self regulate

essence of Gaia

• evolution of the biota and its material environment is tightly coupled process

• Active feedback processes operate

• Positive and negative feedback

• Solar energy sustains the Earth system geophysology

• Biological regulation occurs in the context of physical changes in the environment

Essence of Gaia active feedback processes

arises from coupling between biotic and physical/geological processes

Essence of Gaia Geophysiology

term also used to explain this global self-regulation

Essence of Gaia biological regulation occurs in the context of physical changes in the environment

• increase in solar luminosity changes tectonic activity

• Not really at homeostasis, fluctuates around a fixed point

• Better considered homeorrhesis (or homeostasis I can’t read it)

Daisyworld stats

• gray soil and white daisies

• No clouds or greenhouse gases

• Surface temperature determined by albedo

• Daisy growth dependent on planet temperature

What does this show

More daisies increases albedo and lowers temperature

What does this show

Shows that daisies have an optical temperature range

What does this show?

Shows daisy and temperature relationship with the interactions of optimal daisy growth

A is stable equilibrium while B is unstable

If temperature changes, the line will move

Lessons from Daisyworld

Planetary climate systems are not necessarily passive in response to internal and external influences

Responses are feedback loops

What causes Earth’s moderate temperature?

Greenhouse effect

Planetary albedo

Convection

Process in which heat energy is transferred by motions of a fluid, bottoms particles warm and move up, cooler particles sink to warm

Radiation movement

moves as a stream of photons from an energy source

What is the speed of electromagnetic radiation?

Speed of light, 3×10^8 m/s

Blackbody radiation

an object emits radiation with a 100% efficiency across the entire electromagnetic spectrum

Stefan-Boltzmann Law

the energy flux emitted by a black body is related to the fourth power of the body’s absolute temperature

Flux

• amount of energy or material that passes across a given area per unit time

• A vector quantity, so the only part that matters is perpendicular to a given area

How much energy input?

A- highest solar energy input

B- moderate solar energy input

C- very little solar energy input

Differences in latitudinal albedo

tropics have low albedo due to oceans

Polar regions have high albedo due to ice

Albedo and solar energy input

albedo differences amplify differences in solar energy input as a function of latitude

Solar constant for Earth(s) and other planets

S earth: 1360 W/m²

Other planets: varies by 1/r²

Greenhouse Effect One Layer model

1. Atmosphere transparent to visible photons

2. Planetradiates heat (infrared photons upwards; atmosphere opaque to infrared photons

3. Atmosphere radiates infrared protons equally in all directions

Why are CO2 and water vapor greenhouse gases?

Infrared radiation absorption and emissions affects the rate of molecular rotation and vibration

Greenhouse gases

water vapor

Carbon dioxide

Methane

Nitrous oxide

Ozone

Freons

Why are minor greenhouse gases still important?

They absorb wavelengths CO2 and water vapor do not