Lecture 1 - Energy and the Earth System
- Created by: sikemi__
- Created on: 03-05-21 10:28
View mindmap
- Atmospheres Lecture 1 - Energy and the Earth System
- Weather vs climate
- Both measured by the same quantity
- Weather - day to day condition of the atmosphere (incl. temperature, rainfall and wind)
- Deterministic view of the atmosphere
- Can only be predicted up to 20 days in advance theoretically
- Deterministic view of the atmosphere
- Climate - avg. weather conditions of a place (incl. temperature, rainfall and wind)
- Statistics based (can be done on longer timescales, if you know the boundary conditions for the climate system)
- Because you're interested in the development of the temperature means and variability
- Can be defined qualitatively (expected weather) or quantitatively(mean, variances, tendencies)
- Statistics based (can be done on longer timescales, if you know the boundary conditions for the climate system)
- Climate variability - the overall distribution of climatological parameters (air pressure, temperature, precipitation, ice cover, sea surface temp.) bounded by weather extremes
- Climate varies based on location - places on the coast e.g. San Francisco will experience air masses which will influence the temperature variations.
- Climate
- Open system, made up of spheres which interact with each other
- Biosphere
- Hydrosphere
- Geosphere
- Atmosphere
- Cryosphere
- Sources of energy
- Solar radiation
- Geothermal
- Burning fossil fuels
- Full moon radiation
- Radiation from stars
- Open system, made up of spheres which interact with each other
- Radiation
- Properties
- Electromagnetic waves which can travel through empty space
- Characterised by wavelength
- Transfers energy but doesn't displace or transport matter
- Moves at a constant speed (of light) regardless of frequency/wavelength
- The higher the frequency, the higher the energy
- Only form of energy that can't travel through space without matter
- The Sun and Solar Radiation
- Encompasses a range of wavelengths: ultraviolet, visible and infrared
- Radiation emitted from the Sun's photosphere
- A fraction of solar radiation emitted from the Sun drives climate system
- Sun creates energy through nuclear fusion
- Emission
- All matter with a temp. above absolute zero emits radiation (i.e. every real body emits)
- Black body - perfect absorber and emitter (e.g. Sun)
- Planck's Law describes black body emission
- Planck's Law - spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature T, when there is no net flow of matter or energy between the body and its environment
- Planck's Law describes black body emission
- The hotter an object, the smaller the wavelengths, the more radiation emitted
- Stefan-Boltzmann Law
- the total radiant heat power emitted from a surface is proportional to the fourth power of its absolute temperature
- Properties
- Weather vs climate
Comments
No comments have yet been made