Hydroclimatology Flashcards
what’s the difference between climate and weather?
Climate- 30 year average of atmospheric information such as rainfall, temperature and pressure
Weather - shorter term variability about these average conditions
How is incoming radiation filtered by the atmosphere and earth surfaces? (3)
- reflected or absorbed by the atmosphere or earth surfaces
- reflected not involved in earths climate system (back to space)
- absorbed radiation allows conversion between energy types, heat production and exchange which drives the global climate system
Name the 2 components that reflection of incoming radiation is made up of?
Clouds
Molecules and dust/aerosols
What is the largest agent of reflection and radiation filtering in the earth system?
Clouds
+ reflecting 20% of incoming solar radiation
What is Rayleigh scattering?
When incoming radiation is reflected by water vapour, dust and air molecules
Difference between direct and diffuse radiation?
Direct - travelling in the same beam direction
Diffuse - travelling in all directions so produced less shadow
What is the difference between the wavelengths it ozone/ aerosols and water vapour?
Ozone/ aerosols - short wavelengths
Water vapour - longer wavelengths
What is ‘global’ radiation?
The sum of diffuse and direct radiation
How to calculate net shortwave radiation
Total absorbed - total reflected = net shortwave radiation
What is the ratio of radiation absorbed and reflected at the earth surface?
Absorbed 70%
Reflected 30%
Explain how the balance of outgoing longwave radiation prevents overheating?
- trapping LW radiation gives earth a warmer temperature
- loss to space prevents overheating
What is global warming?
Addition of greenhouse gases to the atmosphere, more molecules to trap outgoing long wave radiation
Difference in shortwave radiation between the tropics and the poles?
Tropics recieve more shortwave radiation than they emit
Poles emit more than received
What happens to the shortwave radiation absorbed at earths surface?
- > 50% re emitted as long wave radiation
- the rest is used to drive the surface energy balance providing linked to the hydrological cycle
What is latent heat?
Where heat is transferred to drive a phase change with no change in temperature
What is sensible heat?
Where heat transfer ones increase the temperature
Difference in the energy used from latent and sensible heat on land and water?
- latent: used to change state of water
- sensible: used to change temperature of atmosphere
What is ground heat flux energy used for on land and water?
To change the temperature of ground surface
What is net radiation used for?
Direct heat transfers e.g latent heat flux and sensible heat
How does latent heat flux link energy and water balances?
- evaporation from the ocean
- soil evaporation and transpiration from plants
Where is most of the earths heat stored?
In the oceans
How does the atmosphere remain saturated?
- evaporation increases water vapour conc in atmos
- condensation reduces it
When these two values are equal
Name 3 main types of humidity?
- absolute humidity
- relative humidity
- specific humidity
Define absolute humidity
Total amount of water vapour in the atmosphere (doesn’t take temperature into account)
