Exam 2 Flashcards
Coriolis Force
Affects wind direction The apparent deflection of wind and objects relative to the Earth’s surface caused by the rotation of Earth. Deflection right in Northern hemi, left in southern hemi, direction shift increases with latitude.
Three-Cell Model
Geostrophic Flow
Occurs when pressure gradient force = Coriolis force. Air flows parallel to lines of equal pressure. Rare in nature
Gradient flow results from:
a nonuniform pressure gradient
Surface winds are NOT parallel to isobars because:
of friction, reduces wind speed, and therefore reduces Coriolis force
Anticyclones
air diverges from high pressure areas at surface and is deflected by Coriolis force. Clockwise N, counter S. Effect: descending air that warms and creates clear skies.
Cyclones
Air converges toward low pressure center at surface and is deflected by Coriolis force. Counter N, Clockwise S. Effect: ascending air that cools to form clouds.
Unclosed pressure systems are…
elongated areas called troughs and ridges
Single Cell Model
General movement of atmosphere. Heating at equator causes air to expand upward and diverged towards the poles, eventually sinking to the surface and returning to the equator. Easterly surface winds.
Define easterly winds
From east to west
Define westerly winds
From west to east
Three Cell Model
Divide each hemisphere into three cells: Hadley cell, Ferrel cell, Polar cell. With different air circulation patterns. Describes climate patterns.
Hadley Cell
Intense heating at equator creates the equatorial low belt of pressure. Pressure and wind model considered close approx of real world.
ITCZ
Intertropical Convergence Zone, region around equator where trade winds of N and S hemispheres come together
Ferrel Cell
Circulates surface air between subtropical highs and subpolar lows (middle). Deflected by Coriolis, causing westerlies.
Polar cell
circulates surface air between polar highs and subpolar lows. Deflected by Coriolis, causing easterlies.
How accurate are Ferrel and Polar cells?
Does not capture real world well.
Semi-permanent pressure cells
Instead of cohesive pressure belts, there are semi-perm high and low belts that fluctuate seasonally.
Monsoons are caused by:
continental surface heating; seasonal thermal differences between land masses and large bodies of water.
Winter monsoons
Dry air flows southward from the Himalayas. Offshore flow.
Summer monsoons
Moist air is drawn northward from the equatorial oceans. Onshore flow.
Land cools or heats _______ than water
faster
Sea breezes are caused by:
heating and cooling differences between land and ocean
How do sea and land breezes travel?
Land breeze: during day, land is warmer so air expands and rises and moves towards sea.
Sea breeze: during night, water is warmer, so air moves back to land.
Air mass
a volume of air with uniform temp and humidity affecting vast area
continental polar air mass (cP)
source: high-latitude continental interiors.
properties: cold, dry, stable, minimal cloud cover
continental arctic air mass (cA)
source: highest latitudes of Asia, North America, Greenland, Antarctica.
properties: extremely cold and dry and stable. minimal cloud cover.
Maritime polar air mass (mP)
source: high-latitude oceans
properties: cold, damp, cloudy, somewhat unstable
continental tropical air mass
source: low-latitude deserts
properties: hot and dry, very unstable
maritime tropical air mass (mT)
source: subtropical oceans
properties: warm and humid
Walker Circulation
normally trade winds move equatorial surface waters westward, causing higher surface temps and a difference in sea surface height
Warm water creates a surface ______ pressure
low
El Nino
weakening or reversal of Walker circulation
La Nina
strengthening of Walker circulation
El Nino occurs every:
two to seven years
El Nino Southern Oscillation
ENSO, the change in atmospheric pressure caused by the sea surface temperature change during El Nino events
Southern Oscillation Index
SOI, difference in pressure between Tahiti and Australia. Positive/stronger than average during La Nina, Negative/weaker than average during El Nino
Teleconnections
Relationships between weather or climate patterns at two widely separated locations. Because pressure systems affect not just local but also the overall jet stream
North Atlantic Oscillation
Changing difference in pressure between the two semipermanent cells in the atmosphere above the Atlantic Ocean: Bermuda Azores High and the Icelandic Low
Positive phase of NAO Index
pressure gradient greater than normal, intensification and northward shift of polar jet stream, Hanover will have mild wet winter
Negative phase of NAO index
pressure gradient less than normal, weakened polar jet stream, Hanover will have increased cold air outbreaks
Front
Boundaries between different air masses
Mid latitude cyclones occur at:
fronts
Four types of fronts
cold, warm, stationary, occluded
Cold front
mass of cold air displacing warm air upward, associated with heavy precipitation and rapid temp decrease
Warm front
warm air overrunning cold air, associated with shallow clouds and light precipitation
Stationary front
neither air mass is displacing the other
Occluded front
two cold fronts meet, warm air between is displaced up
Koeppen System
climate classification based on temperature and precipitation. Multi-tiered, lettered, first letter responds to latitude, continentality, and topography.
What do the three letters in Koeppen System stand for?
Classification, winter, summer
Climograph
graphical representation of a location’s basic climate: monthly average temperature and monthly average precipitation
Fast carbon cycle
short term carbon movement, largely the movement of carbon through life forms on Earth, the biosphere. Balance between photosynthesis and respiration/decay.
Net primary productivity
net carbon consumed by plants both on land and in the oceans
How much carbon in fast cycle?
100 gigatons per year
Slow carbon cycle
Long term carbon movement, carbon fluxes between rocks, soil, ocean, and atmosphere. Carbon is sequestered in ocean sediments or organic matter embedded in mud.
How is carbon sequestered into ocean sediments? In what form?
As calcium carbonate
Vast majority of carbon exists as ______, but ______ also contain carbon
carbon dioxide; methane, CFCs, aerosols
Global Warming Potential
GWP, a measure of the total energy that a gas absorbs over a particular period of time compared to carbon dioxide. Used to make comparisons across greenhouse gases.
Carbon dioxide equivalent
amount of CO2 that would cause the same radiative forcing as a given type and amount of a different greenhouse gas. Multiply tons of gas by relevant GWP.
Climate change is modeled three ways:
- integrated assessment models: human systems
- climate models: natural systems
- assessing impacts, adaptation, and vulnerability
Global Climate Model
GCM, complex computational models that simulate the Earth’s climate using basic geophysical equations to simulate fluid flow on a spherical surface
IPCC projections depend on:
- emission scenarios = RCPs
- socioeconomic change = SSP
RCP
Representative Concentration Pathway: greenhouse gas concentration trajectories. Number indicates radiative forcing (W/m2) by 2100.
SSP
Shared Socioeconomic Pathway: narrative outlining broad characteristics of global future: population, GDP, urbanization, education level, technology development
Paleoclimate
past climates
Paleoclimate proxies
climates across the broader history of Earth are assessed through indicators of past climates from geological or biological records. Temporally expansive, limited accuracy.
Prediction of future climates are temporally ___ spatially _____ and ______ accuracy
temporal and spatial coverage limited by computational resources and understanding of the climate system. Limited accuracy.
Examples of paleoclimate proxies
18O/16O ratio in ice cores (higher = warmer), width of tree rings indicate favorability of growing conditions like temp and precip
Do variations in solar output change climate?
sun spots and solar flares, impact is negligible. sun is getting hotter over billions of years, but no impact on human timescales.
Types of Milankovitch cycles
eccentricity: how elliptical Earth’s orbit is
obliquity: how tilted Earth’s axis is
precession: wobble of the axis
Do Milankovitch cycles/changes in Earth’s orbit change climate?
100,000 year cycles, not of concern on human timescales
Current warming in context.
Earth’s climate has experienced significant changes in the past, but the rate of change of warming we’ve experienced/will witness is orders of magnitude faster than anything the planet has seen. Today’s CO2 level is the highest in the last 3 million years.
IPCC
Intergovernmental Panel on Climate Change, goal to provide policymakers with most authoritative and objective assessments. Assessment reports published every 6 years.
externality
impact on individual or societal production and consumption possibilities from a human activity that are not accounted for by agents responsible for the activity
mitigation
human intervention to reduce the sources or enhance the sinks of greenhouse gases
sequestration
the uptake of carbon containing substances in terrestrial or marine reservoirs
What gas is responsible for the greatest percentage of greenhouse gas emissions?
CO2 from fossil fuel and industry
What economic sector is responsible for the greatest percentage of greenhouse gas emissions?
electricity and heat production
What region is responsible for the greatest percentage of greenhouse gas emissions?
Eastern Asia total, North America historically and per capita
Mean emissions dominated by _____, median by _____
US, Europe
What is COP?
Conference of Parties, convened under UN Framework Convention on Climate Change for negotiating international binding limits on greenhouse gases
What happened at COP 21?
The Paris Agreement, reduce emissions so that the rise in global temps is limited to no more than 2 degrees celsius, commitments to nationally determined contributions, “name and shame”
What happened at COP 26?
Glasgow Climate Pact. Reaffirms the Paris Agreement temperature goal, urge rapid reductions, check in because developed countries are falling short on supporting developing countries
Six Americas
Scale of opinions on climate change: alarmed, concerned, cautious, disengaged, doubtful, dismissive
Majority of Americans __________ climate change
believe in
Rebut: Climate has not significantly warmed since 1998
1998 unusually warm due to a strong El Nino, need to look at a larger time period
Rebut: The observed temperature record is unreliable
Temperature record is processed by 3 different agencies, 2 of which have open source code, and a variety of scientists. Also more data, more stations = more accurate
Rebut: Antarctica is gaining ice
yes sea ice is growing (because reduced ozone increases stratospheric cooling and winds) but Antarctica has been losing land ice at an accelerating rate
Rebut: Temperature leads CO2
yes AND because it’s a positive feedback loop
Rebut: the models are unreliable
yes, there are large uncertainties in climate models. climate models are not effective locally or over short time periods for this reason. but all models to date are unable to recreate observed temp without increasing CO2 levels
Rebut: Scientists predicted global cooling
though aerosols reduced global temps from the 40s-90s, most climate studies at the time still predicted global warming, did not believe that large increased in aerosols could cause the next glacial
Rebut: scientists say increased number/strength of hurricanes, but no observed
we don’t have a good way to measure this, particularly because of relatively low numbers of hurricanes
Rebut: sea levels will rise 216 feet
alarmism, only if you melt all ice on Earth, which would take forever and tons on CO2
Rebut: collapse soon, uninhabitable Earth
alarmism, bold claim without bold evidence
Geoengineering
deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change
two types of geoengineering
solar radiation management and carbon dioxide removal
Solar Radiation Management
reflect a small percentage of the sun’s light and heat back into space. Could be quick, but does not address root issue. Largest impediments: need for global consensus and unintended consequences
Carbon Dioxide Removal
remove CO2 from the atmosphere. address root cause, slower but higher confidence. Largest impediments: questionable effectiveness and cost
Types of SRM
stratospheric sulfate aerosols, big mirrors, marine clouds, paint it white
Types of CDR
iron fertilization in ocean, greening the desert, carbon capture and storage underground or in deep ocean
positive feedback mechanism
feedback magnifies further change in a variable
negative feedback mechanism
feedback inhibits further change in a variable
feedback mechanism
systems in which changes in one variable lead to changes in another
Longwave radiation feedback
negative feedback: as surface and atmosphere warm, amount of energy it emits increases, stabilizing surface temperature
Ice-Albedo feedback
positive feedback: surface temp increases, snow cover decreases, albedo decreases, absorption of solar radiation increases, surface temp increases
Atmospheric water vapor feedback
positive feedback: surface temp increases, evap increases, atmospheric absorption of longwave radiation increases, longwave emission to surface increases, surface temp increases
US Clean Power Plan
the cornerstone of US emissions reduction legislation, to keep up our contributions, is and has always been tied up in legal challenges.
Climate change impacts defined
effects on natural and human systems
Climate change exposure defined
the presence of people, ecosystems, resources, or assets that could be adversely affected
Climate change hazard defined
the potential occurrence of a natural or human-induced impact that may cause damage to health, ecosystems, or property
Climate change risk defined
the potential for adverse consequences for human or ecological systems, recognizing diversity of values and objectives in such systems
Climate change vulnerability defined
the propensity to be adversely affected
Adaptation
altering our behavior, systems, ways of life as a way of dealing with and protecting from the impacts of climate change
Radiative forcing
difference in energy entering Earth’s atmosphere and energy leaving Earth’s atmosphere, can force changes in the Earth’s climate
What is the largest reserve of carbon on Earth?
deep ocean
Mitigation is most effective at the _____ scale, while adaptation is most effective at the _____ scale
global, local
We are currently living in an _______ of an ice age
interglacial
Climate is defined over periods of at least:
30 years
Key Conclusions of IPCC AR6
- observed impacts of climate change are widespread and consequential
- differences in vulnerability and exposure are caused by nonclimatic stressors and inequalities
Oceanic Nino Index
defined by departures from average sea surface temperatures, positive during La Nina and negative during El Nino
Air mass source regions
high or low latitudes most likely
