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Flashcards in midterm 2 Deck (66):

why is the word radiative used in the definition of RF

b/c these factors change the balance of incoming solar radiation and out going infrared radiation with in the earth's atmosphere


what makes RF positive or negative

positive - the energy of the earth-atmosphere system will increase leading to a warming
negative - energy decreases leading to cooling


what is the climate sensitivity parameter and how is RF related to GMST

delta T_E =lamda x RF
where lamda is the climate sensitivity parameter


what is the major contributor of net RF

green house gasses mainly CO2


how is the energy of the earth affected when emissivity increases

surface of the earth gets more energy for atmosphere (everything else is constant) so it will increase


RF created by increasing emissivity is



What is the most abundant greenhouse gas in the earths atmosphere

Water vapor


why is water vapor not present in IPCC RF

human activities only have small direct influence on the amount of water vapor


list two reasons why CO@ conncentration changed

combustions of fossil fuels, gas flaring and cement production


2 sources of CH4 changes

agriculture, natural gas distribution and land fills



fertilizer used and fossil fuel burning


what factors created the most positive RF and negitive

positive CO2
negative aerosols
both are due to humans


define positive and negative feedback

a process in which changing one quantity changes the second and the change in the second quantity in turn changes the first
positive amplifies the first quantity and negitive reduces it


example of positive feedback

ice melts, reduce reflectivity, more radiation, more radiation received at the earths surface increasing temperature
Warmer ocean temperature leads to increase evaporation, so there’s more water vapour in the atmosphere. This will lead to increased cloud cover, so there will be more absorbed infrared radiation, and therefore a higher temperature.


examples of negitive feedbacl

water vapor, increase in cloud cover, more reflected solar radiation decreases temp


what was the sea level during the last glacial period

4-6 m higher


what does IPPC conclude about the feed back of glacial-interglacial CO2 variations

glacial-interglacial CO2 variations have a strong positive feedback on climate variation


did CO2 variations triggered the end of the glacial periods



do current atmospheric concentration of CO2 exceed the natural range

very likely


can the rise of GMST since 1950 be reproduced without including anthropogenic greenhouse gases

very likely it cant be reporduced


was marine carbon cycle responsible for glacial-interglacial CO2 variations

very likely


will GMST be significantly influenced by a natural orbital induced forcing during coming centuries

virtually certain


what caused the low atmospheric CO2 concentration during glacial times

we dont know


what caused the ice ages and other important climate changes before the industrial era

dont know


what are milankvich cycles

-Changes in the tilt (or obliquity)of the Earth’s axis;
-changes in the eccentricity of the orbit (due to variations
in the minor axis of the ellipse);
-changes in the direction of the axis tilt (precision or wobbling) at a given point of
the orbit (precision or wobbling).


do milankvich cycles change the global annual mean of solar radiation

no, can be very marginal or not much


how eccentricity changes can lead to onset of glacial period

summers become colder and snow from the pastwinter does not melt away in summer and an ice sheet start to grow as more and more ssnow accumulates


when will the next glacial period start

about 30,000 years


variables that define weather/climate

temperature, humidity, precipitation


define weather

measurements of variables in a short period of time


define climate

time averaged measurements of the variables over a long period of time


what is the main variable in defining global climate

mean surface temperature (land and water) averaged over a few years


did we have global warming in the past

yes, both warming and cooling


what methods do scientists use to measure past climate

climate proxies, tree rings, stable isotopes, Deuterium (symbol D or 2H), isotope of oxygen ( 18O), desert and marine aerosols


what does current warming mean

rise in mean global surface temperature (MGST)


What kind of core samples were used, where they were taken and what was maximum drilling depth? What period these samples cover

Ice cores, at Vostok station in East Antarctica, 3,623m, the past 420 ky


what is an isotope

variants of chemical elements, having the same number of protons and electrons but with different number of neutrons


what proxies were used for measuring temp and [CO2]

Isotope of hydrogen (deuterium) and isotopes of oxygen for temperature;
bubbles of entrapped air which include composition of gases in air including CO2 concentration


example of time range corresponding to the following: Global warming trend:
Global cooling trend:
No change in temperature

Global warming trend: [140K-130K] BP
Global cooling trend: [130K-200K] BP
No change in temperature [420K-0]


What atmospheric parameters were found to be well coordinated to temp pattern

CO2, CH4


4 phases of matter

solid, liquid, gas, plasma


what phase has the lowest kinetic energy



define an objects internal energy

the total kinetic and potential energy stored in the molecules of the object


how can the eternal energy of an object be changed

by heating, cooling, or applying work


what is heat

amount of energy transferring b/w two objects of different temperatures


how can heat be transferred

conduction: Energy transfer through particle collisions and interactions
convection: energy transfer through the bulk movement of a material
Radiation: energy transfer from EM waves


define black body

an object that is a perfect emitter and absorber of radiation


Define Stefan-Boltzmann Law

Law is applicable for Black Body radiation. The amount of energy radiated is:
Flux of energy =epsilon sigma temp ^4
F = W/m^2


what is the solar constant

flux of radiative energy emitted by the sun at a planet's mean distance from the sun


If you put some object which has some temperature remotely in the Universe (very far from all other objects in the Universe), what would be temperature trend for the object and why?

the object will continue to lose energy as radiation until it is at thermal equilibrium with the universe


what doesnt the temp of earth continue to lose energy?

The Earth is not isolated it is close to the Sun. Solar radiation input compensates the earth energy losses and it keeps temperature of the Earth constant


What is Albedo?

the fraction of incoming energy that is reflected by an object


how does a grey body differ from a black body

BB absorbs 100% radiation at any
GB absorbs some fraction of incoming radiation. some maybe transmitted or reflected


what is emissivity

the ratio of the energy radiated by a grey body to the amount of energy radiated by black body at the same temperature.


formula for radiative energy flux of a grey body

F = εσ T4


What is the difference in interaction of solar and Earth radiation with earth atmosphere?

it is transparent to solar radiation but absorbs a substantial amount of the earth's radiation


describe the green house effect

the atmosphere behaves like a GB. it absorbs a part of the Earth's radiation and emits is in all direction giving the earth an extra flux of radiative energy.


what are max and min concentrations of CO2 during 400000 years before 1750

Min~180 ppm; max~300 ppm


what are max and min concentrations of CH4 during 400000 years before 1750

Min~350 ppb; max~700 ppb


[0.5] What is the current (2005) concentration of CO2

380 ppm


What is the current (2005) concentration of CH4

1900 ppb


what is the increase in CO2 concentration from 1750 to 2005

278 to 380 ppm
RF=1.66 Wt/m2


what is the increase in CH4 concentration from 1750 to 2005

715 to 1775 ppb, ~150%,
RF = 0.48 Wt/m2


what is the increase in N2O concentration from 1750 to 2005

270 to 319 ppb, ~18%,
RF = 0.16 Wt/m2


what is RF

the energy balance of the earth-atmosphere system is influenced when factors that affect the climate are altered
the rate of change per unit area of the globe as measured at the top of the atmosphere


what are atmospheric aerosols

small particles produced from natural or anthropogenic processes
primary particles are released directly into the atmosphere
secondary particles are created from gas to particle conversions from precursor gases