# Modelling class/workshop

## Motivation

Many of us are using modelling more or less extensively as a part of our thesis and even if one wouldn’t be using any model, it would be very beneficial to have some knowledge about model set-up just to be able to read the literature and analyse the data. Also it is relatively easy to get access to different model codes in general and even set up an experiment. However, it might be often be that the user doesn't understand all (or maybe any of) the issues related to the set-up and in the worst case one might try to interpret some model artefacts as meaningful results. We hope this course could give some insight in these issues.

## The idea in short

• Learn how different processes are represented in different types of models
• Why and what does it mean in terms of using the model
• Additionally for those who are interested
• Run some rather simple sensitivity tests to get an idea how these things work in practise
• Test different parameterizations, grids, solar radiation, land-use, Coriolis parameter, slab vs. full ocean
• This could be done with 'tutor' idea, people who have previous modelling experience would join together with the less experienced ones

## Learning outcomes

• Learn some fundamentals of different type of models
• What type of questions can be answered with full climate models, ocean/atmosphere stand-alone, regional scale etc.
• Process approach: go trough some of the most challenging aspects in modelling and how are they solved in different type of models and what consequences does this have
• Topics:
• Model set-up/design, 1st day, how to build a model
• Basic equations
• Discretizations (Mats: unstructured grids, volume vs spectral, dis/advantages)
• approximations (non-hydrostatic vs hydrostatic)
• resolution
• coupling
• predictability (Francois Counillon)
• super-parameterizations
• Boundary conditions
• Initialization
• Conservation of properties
• Parameterizations for missing [physical] processes (rest of the week)
• Convection (Mats, Thomas T knows Steve)
• Mixing (Mehmet, Robert Hallberg, Alistair Adcroft, Markus Jochum)
• Topography (Pål Erik Isachsen)
• Internal waves (Jonas Nycander, Jarle Berntsen)
• Surface (Thomas knows a guy)
• Radiation (Thomas T)
• Cloud microphysics (Trond Iversen, Jon-Egill Kristjansson, from Oslo)
• Special topics for 1-1/2 day depending on time/lecturers
• sea-ice/land ice/carbon (Petra, Kerim, Pierre Rampal, Cristoph Heinze)
• Note: it's obvious that each of these topics could be made into a semester long class, so some narrowing down has to happen.

## Time Plan

The class would be based on lectures and discussion session about lectures and pre-assigned literature. The idealised order is given below. Some flexibility is of course possible.

### Detailed Time Plan [suggestions for Organisers]

Time Monday Tuesday Wednesday Thursday Friday
9-10 General Intro Lecture Lecture Lecture Lecture
10-11 Lecture Lecture Lecture Lecture Lecture
11-12 Discussion Discussion Discussion Discussion Discussion
12-13 Lunch Lunch Lunch Lunch Lunch
13-14 Lecture Lecture Lecture Lecture Lecture
14-15 Discussion Discussion Discussion Discussion Discussion
15-16 Lecture Lecture Lecture Lecture Lecture
16-17 Discussion Discussion Discussion Discussion Discussion

### Part I: General Intro (Mo)

The idea is to give a give a general overview of what models exists and what they are used for. It should lead towards the specific modelling problems that we picked for the following days. More philosophical thoughts on the limits of modelling both for making predictions and for gaining understanding are welcome, especially for the discussion slots on Monday.

Specific topics for Monday: (1 lecture for each)

• Basic Equations, approximation, predictability
• Discretization, resolution, parameterization, conservation of properties
• Initializations, Boundary conditions

### Part II: Topic days (Tu — Fr)

For a few selected topics, the following questions should be answered

1. On which scales to I have to consider which effects (and what happens if I don't)?
2. How is it treated in models of varying complexity?

In order to better tie the related topics together, the first (maybe shorter) lecture of the day could introduce the theme and suggest some links between the topics.

Specific topics for Tuesday (2 lectures for both or as the lecturer(s) want to separate)

• Coupling, nesting, super-parameterization
• Bathymetry/Topography, Internal waves

Specific topics for Wednesday (2 lectures for both or as the lecturer(s) want to separate)

• Mixing/Turbulence
• Convection

Specific topics for Thursday (2 lectures for both or as the lecturer(s) want to separate)

• Cloud Microphysics

Specific topics for Friday (2 lectures for both or as the lecturer(s) want to separate)

• Surface I: Air-sea interaction, from AGCM+slab-ocean / OGCM+prescribed wind stresses to coupled AOGCMs
• Surface II: EITHER Vegetation & land surface OR ice & snow depending on lecturer

### Timing

Preferably 25th-29th November, or if not then 27th-31th January

## Funding

Tore Furevik: typically around 50 Knok + travel and accommodation for all participants. This covers travel and accommodation for one or two lecturers plus some lecture fees at standard UiB rates.

## Questions to find out and solve

• Examples of the somewhat similar ones out there already?
• Stockholm University is offering a class titled "introduction to climate modelling"
• The University of Helsinki/Finnish met institute is offering a class, where they choose a different model each time and do some specific tests and write a short report. This class is also offered as a web-course for anyone interested.
• There is also a the European Earth System and Climate Modelling School lead by the NCAS & MPI-M, the length is similar.