Revision Part 1 Flashcards
What is albedo?
Reflection coefficient
Where would radiation inversion most likely to occur?
Deserts - no clouds, no moisture (water retains heat longer)
Planetary albedo?
31% (the other 69% is absorbed by the atmosphere, materials on the surface)
Radiative power
The hotter the object becomes the higher its radiative power (rate at which it emits radiation)
Terrestrial radiation
The radiation emitted by the planet.
The heating of the atmosphere is due to
Longwave radiation, infrared (+15C on average)
Greenhouse effect definition and which gases are involved?
The absorption of infrared radiation by certain gases and re-radiated.
Water vapour, carbon dioxide, methane, nitrous oxide and ozone.
Advection
Horizontal movement of the air (wind), redistributing the energy within it
Turbulence
Mechanical movement of air transfer from top and bottom to top of the friction layer. The lapse rate in the boundary layer (friction layer) will eventually adopt the DALR.
At the upper level of the friction layer an inversion can occur.
Why is water vapour important?
It regulates air temperature by absorbing thermal radiation from the sun and earth.
Humidity capacity of air is determined by
Temperature; the hotter the air the more water vapour it can hold
Relative humidity
The ratio of the amount of water vapour in the air compared to how much it can hold at its present temperature (%)
Dew point
The temperature to which a sample of air must be cooled for it to become saturated (any further cooling will cause condensation)
Mixing ratio
The ratio in g/kg of water vapor to dry air (the hotter it gets the hotter the mixing ratio - exponentially)
Relative humidity approximation
RH % = 100 - 5 x (temp - dew point spread)
Dry bulb temperature
The ambient or outside air temperature (OAT)
Wet bulb temperature
It is the lowest temperature to which the ambient air (flowing around a moistened thermometer bulb) can be cooled by the evaporation of water. The great the humidity around the thermometer, the less room for evaporation.
Needs heat (from the atmosphere) and a place to go.
Adiabatic expansion
No energy can pass into or out of the system (idealization - process is so fast , very isolated, or if the system is very large)
Lapse rates - fixed values
- the rate at which temperature drops off with altitude.
SALR - 1.8 Deg C per 1000ft (it depends at the rate that latent heat is released internally , once it gets saturated some of it is going to condense to liquid water (releasing heat)
DALR (not completely dry) - 3 Deg C per 1000ft (constant)
Absolutely stable
ELR <1.8°C / 1000 ft = absolutely stable
Absolutely unstable
ELR > 3°C/1000ft = absolutely unstable
Conditionally unstable (stable if dry, unstable if saturated)
ELR is between 1.8 and 3 = conditionally unstable
Lapse rates - stable or unstable
Flat line? Fast lapse rate (unstable) fluffy clouds (Cu), fierce clouds (Cb), unstable, showers .
Steep line? Slow lapse rate ( stable) smooth, stratus
Good base
Gap between the OAT and the wet bulb temperature divided by DALR - SALR = cloud base