Weather and climate: heat Flashcards
globally is the earth in energy balance|?
yes almost but climate change impacts it
energy moving between poles and tropics
define energy
capacity for doing work
what is energy measured in?
joules J
define energy flux
rate of transfer of energy
joules per second
Watt W
energy flux per unit area =
Watts per square metre Wm-2
what is the first law of thermo dynamics?
energy cannot be destroyed nor created
transferred one place to another
transformed one place to another
eg radiation > heat> mechanical
name 4 mechanisms for energy transfer?
Radiation
Conduction
Convection
Advection
define radiation
emission or transmission of energy in the form of waves or particles
feel the heat on fire
conduction definition
molecular impact without transfer of matter
soils rocks
heat travelling up rod in fire
convection definition
heat transfer (vertical) in a fluid movement of the substance itself
air water
eg smoke off fire
advection definition
heat transfer (horizontal) in a fluid movement of the substance itself
air water
why is advection important in climate systeM?
forms orographic cloud
and precipiatation of water from clouds as part of hydrological cycle
it involves moving matter from one place to another taking energy with them
define thermodynamics
deals with relations betwenn heat and other forms of energy
what is the second rule of thermodynamics?
entropy of an isolated system will increase with time
the degradation of energy movement is explained by what?
entropy
what does entropy describe?
the spontaneous dispersal of energy
how much or how widely energy is spread out at specific temp
measure of the unavilability of a systems heat energy for conversion into mechanical work
what does low entropy mean?
lots of heat to do work
what does high entropy mean?
little heat energy to do work
when will entropy increase inside a system?
when heat energy flows from hot to cold areas of a system the entropy increases as heat energy is dispersed throughout greater volume and therefore less able to do work
what will entropy do when theres an imbalance of energy?
changes this
hot to cold
high pressure to low
give an example of entropy
heat added to a gas (heat is internal energy)
kinetic energy increases of gas atoms
temp also increases (measure of internal energy)
define specific heat capacity
the amount of energy added to a substance in form of heat to 1 unit of mass and cause an increase of 1 degree temp
what does a high specific heat capacity mean?
needs more energy to heat up water
can store more energy
what has a greater specific heat capacity out of air, waiter and dry soil?
water
~4.5 times greater
name 3 things with low specific heat capacity?
dry air (atmosphere)
paper
gas
Name 3 things with high specific heat capacity?
ocean water
ice at 0 degrees
iron
water bodies and specific heat capacity
higher than lands so needs more energy
higher transparency - energy distributed over greater volumes (slower response to energy fluxes)
higher ability to redistribute energy through fluid movement
temp change is less than of land even if same energy inputted
Land and specific heat capacity?
lower specific heat capacity than ocean
no mixing between layers
opaque surface
define continentality
difference in temp of ocean and continent and many factors influence this
what is the most important influence on temperature of a place?
angle of suns rays
tilt of earths axis
(as latitude increases so annual range but they have lower annual minimum)
what is the unit for atmospheric pressure?
millibar mb
1mb = 100 N m-2
pressure decreases logarithmically with height
where is 99.9% of the atmosphere located?
below 50km in stratosphere and troposhere
(~50% of atmosphere is below 5km)
Tropopause height varies
the height of the tropopause varies, how come?
polar regions its 9km
equitorial regions its 18km
define elevation
point on surface
define altitude
airborne objects above surface
what happens as altitude increases?
decrease in pressure
decrease density
less mass to absorb energy
lower mean temps
night time cooling greater
more rapid diurnal (Day time) changes in temp
describe factors of atmospheric gases?
COMPRESSIBLE
density is highest at surface because of the weight of the air (pressure)
CAN EXPAND
under influence of lighter pressure or higher temps (release of pressure)
what happens to temp in tropopause?
decreases with height
what happens to temp in stratosphere ?
increases with height (ozone and chemical reactions increase energy in system)
