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Flashcards in Midterm 1 Deck (18):

Differentiate b/w climate and weather.

weather is the state of the atmosphere in a short period of time, weather includes the temperature, humidity, and precipitation on the hourly scale.
climate s the atmospheric conditions over a long period of time. time averaged, is more perdictable


what is the main variable used to describe global warming?

The main variable describing global warming is surface temperature averaged over earth in centuries


list and describe the paleoclimate proxies?

sediment cores - taken from marine sediment , thickness of sediments and organic composition of the deposits can be used to infer about the past climate.
Pollen - well preserved, can provide info about the vegetation at that time, can infer past climates based on plant distribution
Tree rings - tree growth is influenced by climate and can be seen in ring width and isotopic composition.
Stable isotopes - the ratio of O18:O16 is influenced by climate
coral reefs - composed of calcium carbonate, can us oxygen ratio to predict the water temp and the location.
ice cores, aersols, ash layers and insolation can also be used


proxies for temp and CO2 proxies

temp. - deuterium isotopes, ice cores, marine sediments
CO2 - ice cores


differentiate b/q mechanics and thermodynamic

mechanics considers one particle while thermodynamics considers multiple


define plasma

a mixture of electrons and cations at very high temp


what is heat?

a form of energy indicated by Q.


What are the methods for heat transfer?

Conduction refers to heat exchange, where high speed particles are colliding with low speed particles, until eventually approximately all particles are travelling at the same speed.
Convection is heat transfer by motion of a fluid (either water or gas) , where the heated fluid is moving away from the source of heat through bulk motion. Radiation is the transfer of heat by electromagnetic waves, carrying energy from origin to spaces around it


Define a black body

any object that is a perfect emitter and absorber of radiation, will absorb and emit all radiation it comes in contact with


Stefan - Boltzmann law

F = σT4. It gives the total energy being emitted at all wavelengths by the blackbody, the area under the Planck Law.
two principles: all objects emit radiant energy proportional to the temp raised to the 4th


Solar constant?

the energy flux from the sun at the earth's mean distance from the sun


thermal equilibrium

two systems in contact will come to the same temperature after a period of time, all objects want to be in a state of equilibrium


what is albedo?

the percent of energy reflected away from an object, for the earth it is 0.306 and for mercury it is 0.068


why do we need albedo?

b/c the atmosphere is gaseous, they cannot be approximated as black bodies, not all the solar radiation will reach the surface.


first lay of thermodynamics

the change in the internal energy of a system is equal to the heat added or lost and the work done on the system.


grey vs black body

BB absorbs all radiation grey absorbs a fraction and emits a fraction. it may transmit and reflect some



F = εσ T4


greenhouse effect

atmosphere absorbs a fraction the the earths radiation, acting as a grey body radiates it in all directions. so earth receives this radiations as well as the solar flux