Climate Change and Climate Modeling

Climate Change and Climate Modeling

Sample Syllabus

Instructor: T.A.:

Office: Office:

Phone: Phone:

email: email:

Course web page:

Textbook web page:

Office hours:

Prof.: To be announced or by appointment.

T.A.: To be announced in discussion section.

Global environment issues involving climate change due to human activities or natural climate variations are presented for students with a background in the sciences. This course provides a quantitative introduction to the new science of climate modeling, which attempts to understand and predict these climate changes. The El Niño phenomenon will be used as a primary example of natural climate variation for which predictions with climate models are now possible. Global warming will be the focus for human-induced change.

Recommended Text(s)

Neelin, J. D.,Climate Change and Climate Modeling (Cambridge University Press, 2010)

Grading

Problem sets (3) 30% (including parts done in discussion section)

Midterm 30%

Final exam 40%

Prerequisites

This course is intended for students majoring in any science area (including biological sciences). Some basic calculus and physics preparation is required, but no background in atmospheric sciences is necessary.

Web-based material on problem sets

Some of the problems sets will include accessing web based material from climate research groups that is not controlled by the instructor; it is recommended to access this well in advance of the deadline. Some problem sets will have a problem that can be done as an exercise in discussion section.

Course Outline

*Sections in [ ] will not be covered or will be abbreviated this year

Note to instructors: for a 10-week (quarter system) course, with lectures of 2h40min/week, a midterm occupying one lecture, and review sessions 1.5 lectures: certain sections should be abbreviated as in this example, or equivalent.

Chapter 1 Overview of Climate Variability and the Science of Climate Dynamics

• Climate dynamics, climate change and climate prediction

• The chemical and physical climate system

Chemical and physical aspects of the climate system

El Niño and global warming

• Climate models - a brief overview

• Global change in recent history

Trace gas concentrations

A word on the ozone hole

[Some history of global warming studies]

Global temperatures

• El Niño: An example of natural climate variability

[Some history of El Niño studies]

Observations of El Niño: the 1997-98 event

The first El Niño forecast with a coupled ocean-atmosphere model

• Paleoclimate variability

Chapter 2 Basics of Global Climate

• Components and phenomena in the climate system

Time and space scales

Interactions among scales and the parameterization problem

• Basics of radiative forcing

Blackbody Radiation

Solar energy input

• Globally averaged energy budget—first glance

• Gradients of radiative forcing and energy transports by atmosphere and ocean

• Atmospheric circulation

[Vertical structure]

Latitude structure of the circulation

Latitude-longitude dependence of climate features

• Ocean circulation

Latitude-longitude dependence of climate features

The ocean vertical structure

The ocean thermohaline circulation

• Land surface processes

• Carbon cycle

Chapter 3 Physical Processes in the Climate System

• Conservation of momentum

Coriolis force

Pressure gradient force

Velocity equations

Application: geostrophic wind

[Pressure-height relation: Hydrostatic balance]

Application: pressure coordinates

• Equation of state

Equation of state for the atmosphere: Ideal gas law

Equation of state for the ocean:

[Application: height-pressure-temperature relation]

Application: thermal circulations

Application: sea level rise due to oceanic thermalexpansion

• Temperature equation

Ocean temperature equation

Temperature equation for air

[Application: the dry adiabatic lapse rate near the surface]

[Application: decay of a sea surface temperature anomaly]

Time derivative following the parcel

• Continuity equation

Oceanic continuity equation

Atmospheric continuity equation

[Application: coastal upwelling]

Application: Equatorial upwelling

Application: Conservation of warm water mass in an idealized layer above the thermocline

• Moisture equation and salinity equation

Conservation of mass applied to moisture

Sources and sinks of moisture, and latent heat

[Conservation of mass applied to salinity]

• Moist processes

Saturation

Saturation in convection; Lifting condensation level

The moist adiabat and lapse rate in convective regions

[Moist convection]

• [Wave processes in the atmosphere and ocean]

[Gravity waves]

[Kelvin waves]

[Rossby waves]

• Overview

Chapter 4 El Niño and Year-to-Year Climate Prediction

• Recap of El Niño basics

The Bjerknes Hypothesis

• Tropical Pacific climatology

• ENSO mechanisms I: Extreme phases

• Pressure gradients in an idealized upper layer

Subsurface temperature anomalies in an idealized upper layer

• Transition into the 1997-98 El Niño

Subsurface temperature measurements

Subsurface temperature anomalies during the onset of El Niño

Subsurface temperature anomalies during the transition to La Niña

• El Niño mechanisms II: Dynamics of transition phases

Equatorial jets and the Kelvin wave

[The Kelvin wave speed]

[What sets the width of the Kelvin wave and equatorial jet?]

Response of the ocean to a wind anomaly

[The delayed oscillator model and the recharge oscillator model]

ENSO transition mechanism in brief

• El Niño prediction

Limits to skill in ENSO forecasts

• El Niño remote impacts: teleconnections

• Other interannual climate phenomena and prospects for seasonal-to- interannual

climate prediction

Hurricane season forecasts

Sahel drought

North Atlantic oscillation and annular modes

Chapter 5 Climate Models

• Constructing a Climate Model

An Atmospheric model

Treatment of sub-grid scale processes

Resolution and computational cost

An ocean model and ocean-atmosphere coupling

Land surface, snow, ice and vegetation

Summary of principal climate model equations

Climate system modeling

• [Numerical representation of atmospheric and oceanic equations]

[Finite-difference versus spectral models]

[Time-stepping and numerical stability]

[Staggered grids and other grids]

[Parallel computer architecture]

• [Parameterization of small scale processes]

[Mixing and surface fluxes]

[Dry convection]

[Moist convection]

Sea ice and snow

• [The hierarchy of climate models]

• Climate simulations and climate drift

• Evaluation of climate model simulations for present day climate

Atmospheric model climatology from specified SST

Climate model simulation of climatology

Simulation of ENSO response

Chapter 6 The Greenhouse Effect and Climate Feedbacks

• The greenhouse effect in Earth’s current climate

Global energy balance

A global-average energy balance model with a one-layer atmosphere

Infrared emissions from a layer

The greenhouse effect: example with a completely IR-absorbing atmosphere

The greenhouse effect in a one-layer atmosphere, global average model

Temperatures from the one-layer energy balance model

• Global warming I: example in the global-average energy balance model

Increases in the basic greenhouse effect

Climate feedback parameter in the one-layer global average model

• Climate feedbacks

Climate feedback parameter

Contributions of various feedbacks to global average temperature response

Climate sensitivity

• The water vapor feedback

• Snow/ice feedback

• Cloud feedbacks

• [Other feedbacks in the physical climate system]

Stratospheric cooling

[Lapse rate feedback]

• [Climate response time in transient climate change]

Transient climate change versus equilibrium response experiments

A doubled-CO2 equilibrium response experiment

The role of the oceans in slowing warming

Climate sensitivity in transient climate change

Chapter 7 Climate Model Scenarios for Global Warming

• Greenhouse gases, aerosols and other climate forcings

Scenarios, forcings and feedbacks

Forcing by sulfate aerosols

Commonly used scenarios

• Global-average response to greenhouse warming scenarios

• Spatial patterns of warming for time-dependent scenarios

Comparing projections of different climate models

Multi-model ensemble averages

Poleward amplification of warming

Summary of spatial patterns of the response

• Climate response time in transient climate change

Transient climate change versus equilibrium response experiments

A doubled-CO2 equilibrium response experiment

The role of the oceans in slowing warming

Climate sensitivity in transient climate change

• Ice, sea level, extreme events

Sea ice and snow

Land ice

Extreme events

• Summary: the best-estimate prognosis

• Climate change observed to date

Temperature trends & natural variability: scale dependence

Is the observed trend consistent with natural variability or anthropogenic forcing?

Sea ice, land ice, ocean heat storage and sea level rise

• Emissions paths and their impacts

• The road ahead