Climate modelling Flashcards
Why do we use climate models?
- test understanding
- prediction or projections
- attribution
- decision making
What is a climate model?
A computer programme that simulates the 3D behaviour of the atmosphere, oceans and land surface
What do computer programs integrate?
Various equations to determine the time and space-deponent evolution of the climate system
When is numerical integration used?
When an equation is too complicated to solve analytically
What elements are calculated in models?
double check this future emily
- Atmoshpere and ocean circulation
- Atmoshperic radiation budget
- Hydrology and water phase change
- Energy flow in rocks and soils
What is the AGCM?
Atmospheric General Circulation Model
What it the OGCM?
Ocean General Circulation Model
What is the AOGCM?
Coupled Atmosphere-Ocean General Circulation Model
What is the ESM?
Earth System Model
How have models progressed?
- AGCM … prescribed the oceans and land surface
- OGCM … simple atmospheric calculations (wind stress and heat supply)
- AOGCM … used extensively in climate change experiments
- ESM
What must you do before running a climate model?
Define the initial conditions
What is discretisation?
The splitting of continuous quantities into discrete units e.g. spilling the earth up into a grid cells for models
What is the typical resolution of models?
1º x 1º x 60 altitudes levels …. equivalent to 125 km x 125km x 100’s m
What is the problem with discretisation?
- Numerical diffusion (flattening of graphs)
- Don’t have information everywhere on the grid
- causes a reduction in resolution (detail)
What is parameterisation?
The simplification of processes in terms of simpler equations with physically or empirically derived parameters