AOSC 684/484

**Climate System Modeling**

Web: http://www.atmos.umd.edu/~zeng/AOSC684

Course outline

Fundamentals in building computer
models to simulate the components of the climate system: atmosphere,
ocean, land-surface, cryosphere, terrestrial and marine ecosystems, and the
biogeochemical cycles embedded in the physical climate system. Simple to state-of-the-art research
models to tackle problems such as the Daisy World, El Nino and global
warming.

A main goal of the course is to help students to relieve the 'fear' of sophisticated models via a hands-on simple-to-complex approach. The course will be conducted as 50% lecture and 50% lab in which students will build numerical models, analyze the model structure both in terms of programming and scientific content, and apply the models to various problems. Basic knowledge of programming language such as Fortran, C, Python, Matlab, or IDL is preferred, but prior knowledge of numerical modeling or climate is not required.

Course content

- The climate system
- Atmosphere
- Ocean
- Land
- Cryosphere
- Biosphere and biogeochemical cycles
- A survey of climate modeling
- Fundamentals of building a computer model: zero dimensional models
- Numerical solution of a simple ODE (force-damped equation and global warming)
- Numerical instability
- Behavior under different forcings: step function, diurnal/seasonal
- Multivariate ODE's; Chaos
- A zero-D coupled ocean-atmosphere model: multiple time scales
- Importance of modularity
- (optional) Daisy world
- Fundamentals of building a computer model: one dimensional models
- Numerical solution of PDEs:
- Wave equation; finite differencing; CFL criterion
- 2D models
- Energy balance model
- Atmosphere, ocean and land models
- Numerical solution of the shallow-water equation (SWE) and its applications:
- Gaussian forcing and spinup;
- SST forcing: seasonal cycle and interannual variability (ENSO)
- An intermediate complexity model: manageable yet realistic models; the QTCM model
- Anatomy of an atmospheric GCM (CCM3)
- Dynamics and Numerics
- Physical parameterizations
- Land surface model
- Carbon cycle models
- Terrestrial carbon and dynamic vegetation models: the VEGAS example
- Box ocean carbon models
- Framework of an Earth System model
- Coupling strategy: spatial aspects
- Coupling strategy: temporal aspects
- Applications

**Instructor**: Prof. Ning Zeng (CSS
2417, phone 301-405-5377)

Office hours: by appointment/drop by

Textbook

Introduction to Climate Modelling, by Thomas Stocker , 182pp, Springer 2011. ISBN-13: 978-3642007729.

**Reference books**:

Introduction To Three-dimensional Climate Modeling (2nd edition) by Warren M. Washington, Claire L. Parkinson

Mathematical Modeling of Earth's Dynamical Systems: A Primer by Rudy Slingerland and Lee Kump, Princeton University Press,2011, 248 pages, ISBN-13: 978-0691145143.

McGuffie, K. and A. Henderson-Sellers: A climate modelling primer, 2nd ed. Chichester ; New York : Wiley, c1997.

Trenberth, K. E., ed., 1993: Climate system modeling, Cambridge Univ. Press, New York, 817 pp.

** AOSC684 and AOSC484 **:

**Grading method**:

Each student is expected to work on a project of his or her choice. A few set of homeworks in the form of highly-simplified numerical modeling will explore the concept of numerical instability, approximation of differential equations, etc. There will be no formal exams.

Homeworks/quiz 70%

Project 30%

**Project**

Any project related to the numerical modeling of the climate system, either a component or coupled components such as ocean-atmosphere interaction is welcome. This semester we will encourage the students to choose research-like topics. It is my hope that some of these projects can lead to results publishable in professional journals. In order to achieve this goal, the instructor is prepared to work closely with each student on topic selection, experiment design, and result analysis.

Possible project ideas (to be expanded/refined):

Why is W. Africa so climatically sensitive?

The future of the Sahel

Sudden climate change in the Sahara during the Holocene: solar forcing or ocean-land-vegetation interaction?

Global warming: Shift of storm tracks at 2xCO2; zonally symmetric vs asymmetric experiments; Mediterreanean: drier because the northward shift subtrop high?

Global Warming: transient CO2, atmosphere/mixed layer ocean

Global Warming: emission, coupled carbon-climate modeling

What determines the northern limit of monsoons?

Causes of climate change over the last
1000 years?

Using space aerosols to counter global
warming: dust at the Lagrangian point

**Homework #1**

Think of some project ideas and discuss with people around you on its feasibility such as:

Is it of scientific merit?

Do you have the tools/models?

Do you have enough time to finish it?