Climate Processes Flashcards
What are the 3 characteristics of systems
-components (hill slope, river channels)
-a flow of energy which powers the components (inputs or outputs)
-internal regulation of their functioning (positive/negative feedback)
What is the different in climate and weather
Climate: average temperature/ weather of any area over 30yrs
Weather: day to day events in a climate system
What are the 4 layers of atmosphere
-troposphere (layer which we live, weather occurs and ghg are trapped)
-stratosphere (temperatures increase with height due to ozone layer
-mesosphere: no absorption of heat so temperature cools
-thermosphere: temperature rise again due to being heated by the sun
The ghg effect
-the natural ghg effect makes the earth warmer and livable, natural ghg keep earth at 33 degrees however extract ghg enhances these effects and increases temperature
Global ocean circulation patterns
-warm water from tropical equatorial regions into the north or south hemispheres in colder water
-the same the other way round
Facts about the suns main energy source
-solar energy: 1 trillion megaton atomic bomb per second
-energy emitted from the sun 3.9 x 10 (26) watts
Boltman law
-the total energy radiated per unit surface area of a black body per unit time is directly proportional to the fourth power of the black body’s thermodynamic temperature
-5.67 x10(-8) wm (-2) k(-4) X temperature
Weirns law
-the relationship between the temperature of a black body and the wavelength at which it produces the greatest amount of light
-constant equal to 2897 X temperature
What are the seasonal changes in the earths axis tilt
-there is a change in a radiation distribution from summer to winter due to the change in the earths axis tilt.
-longer radiation distribution is in January (perihelion) and shortest in July (aphelion)
-energy is highest in northern hemisphere in July and highest in Southern Hemisphere in January
Milankovitch cycle:
-periodic change in the orbital characteristics of earth
-axial precession: when the axis wobbles
-charge in obliquity: tilt in the axis (41yrs temp changes from 21.5-24.5 degrees)
-eccentricity: change in orbital shape (circle to oval)
What is direct and diffuse solar radiation
-direct: shortwave radiation taht passes uninterrupted through the atmosphere
-diffuse: shortwave radiation that is scattered or reflected downwards that has a interrupted path to the surface but does make it
Net radiation wave lengths equations:
Shortwave length: incoming SW-reflected SW
Net long wave: incoming LW-reflected LW
Net radiation: net SW + net LW
Energy balance equation
Net radiation: sensible heat + latent heat + subsurface heat
What happened to radiation in day and night
-moist day: most radiation goes into latent heat with little sensible heating of the atmosphere
-moist night: night has no SW radiation. Atmosphere is warmer and moist
What are the changes in relative humidity with temperature increase
Of teh temperature increases the water vapour amount stays the same but the relative humidity decreases
What is potential and actual evaporation
Potential: the amount that would be evaporated if there was no limit of water available
Actual: the amount actual evaporated
What is lapse rates and atmospheric stability
-rate of change in temperature with height through the lower layers of teh atmosphere
-adiabatic LR: what occurs as a parcel of air rises, decreases in pressure and temperature but increases in volume. Opposite for returning to earth
What happens with adiabatic relationships
-temp of parcel of air > surrounding air than the parcel of air is lighter than its environment it will rise
-temp of parcel of air = surrounding air than the parcel remains the still
-temp of parcel of air < surrounding air temp gah parcel of air is heavier and it will sink
Direct causes of precipitation
-air mass mixing (warm and cool air)
-increased water content
-dynamic cooling (cooling/warming due to expansion/compression or no heat added or subtracted
Causes of parcels of air to uplift
-convective lifting (thunderstorms)
-orographic lifting (over mountains)
-frontal wedging (contrasting air masses meeting)
-convergence (bumping of two opposing streams of air )
What are the visible signs of atmospheric moisture
-global cloud amount
-precipitation
-effective precipitation
-soil moisture
-global run off
What is the coriolis effect
-the wind deflects right in the northern hemisphere and left in the Southern Hemisphere causing a direction of wind. Wind speed increases closer to teh poles
What is the influence of surface friction
-friction reduces the wind speed whcih reduces coriolis force
-northern hemisphere: surface winds blow counter clockwise and inward into a surface low, and clockwise and out of surface high in the NH
-Southern Hemisphere: coriolis force acts to the left rather than the right. Causes winds of teh Southern Hemisphere to blow clockwise and inward around surface lows and the counter clockwise and outward around surface highs
What are teh cells in the atmospheric circulation systems
-polar (driven)
-Ferrell (movement of air from the other cells)
-Hadly (driven)
Causes of jet streams
-streams of air taht move up or down. Polar or subtropical jet streams
Causes:
-planets rotation, atmospheric heating
-latitudinal and vertical large gradients of temperature and pressure at the intersection of a colder air mass from the north with a warmer air mass from the south
What are rossby waves
Meandering jet streams in the upper westerlies
Upper and lower level convergence
-air sinks from zone of convergence (2 flows meet) towards the surface creating an area of high pressure. Therefor down wind of a ridge and up wind of a trough subsidence generally leads to good weather in the area of high pressure
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What are air masses
-large volumes of air with homogeneous thermal, moisture and stability characteristics formed by air sitting over an ocean or land surface for several days
What is a cold/warm/occluded front
-A cold front is defined as the transition zone where a cold air mass is replacing a warmer air mass
-A warm front is defined as the transition zone where a warm air mass is replacing a cold air mass
-An Occluded Front forms when a warm air mass gets caught between two cold air masses
Importance of oceans for climate
-ocean holds a large amount of heat, water and carbon dioxide
-global ocean circulation transports heat, water and co2 over large distances compared to the atmosphere
-compared to land, oceans are thermally conservative, no large variations in temperature and need 4x the heat required to raise the temperature of water compared to air
What happened in ocean acidification
-when co2 dissolves in the seawater it forms carbonic acid and as more co2 is taken up by the oceans surface the ph balance decreases moving towards a less alkaline and therefore more acidic state.
-rising acidity can drop she’ll formation and impact the ecology
The relationship between phytoplankton, dimeyhyl sulphide and cloud condensation nuclei
When P evaporate it goes into the atmosphere as DS with additional iron creating sulphate aerosols which form into a cloud
What is the CLAWS hypothesis of global climate regulation
-the hypothesis describes a feedback loop that begins with an increase in the available energy from the sun acting to increase the growth rates of phytoplankton by either a physiological effect or enhance photosynthesis
-clouds reflect sunlight into space-> cooling temperature Lower phytoplankton, less DMS->less clouds-> sunlight reaches earth->warmer temperatures more phytoplankton and DMS-> more clouds
How to observe data from the oceans
-bucket method: sample first few meters and deeper waters tk compared temperatures
-observing ships collect SST data
-ocean observing systems: forecast further conditions of teh sea
-Argo floats: robotic floats that are below surface, measured temperature, salinity, pressure and biochemical measurements)
Ocean circulation
-global wind patterns
-surface ocean circulation
-ocean gyres: large systems of circular ocean currents formed by global wind patterns and forced created by earths rotation. 5 major ones in major oceans
-equatorial and counter currents
-momentum transfer to ocean surface
-areas of upwelling cold water
What is Elkman current
-surface current that develops from steady wind at the ocean surface. As wind blows over the ocean a surface current develops due to the drag at the wind water interface.
-ekman spiral: indicates that each moving layer is deflected to the right of the overlaying layers movement
-as wind blows across the ocean it moves water because of friday ion at the ocean surface. It moves surface water away from the coast and replaces this water upwelling cold water
Deep ocean thermohaline circulation
