Modeling the Earth's Climate and Its Variability

by Holland; Joussaume; David

• ISBN13: 9780444503381
• ISBN10: 0444503382
• Format: Hardcover
• Copyright: 1999-12-13
• Publisher: Elsevier Science

Summary

Understanding and predicting the Earth's climate system, particularly climate variability and possible human-induced climate change, presents one of the most difficult and urgent challenges in science. Climate scientists worldwide have responded to that challenge over the past decade by creating a wide variety of ever more sophisticated climate models that are beginning to show considerable ability to replicate many aspects of the climate system. At the same time, to fully understand climate change, one also has to look to past climates. For this purpose five eminent scholars who span the disciplines of modeling and observation, including elements of past, present and future climate studies came together at this Les Houches school. They presented a systematic development of each of their respective subjects which provided a comprehensive overview of this vast and complex subject. These core lectures were supplemented by a set of shorter lectures and of seminars.

Table of Contents

Organizers	ix
Lecturers	xi
Seminar Speakers	xiii
Participants	xv
Preface (French)	xxi
Preface (English)	xxv
MAIN COURSES
The Observed Climate of the 20th Century	1	(138)
E.M. Rasmusson
M. Chelliah
C.F. Ropelewski
Climatology: From statistics to science	5	(13)
The evolution of climate science	5	(3)
Characteristics and limitations of the instrumental data bases	8	(7)
Interannual to interdecadal variability	15	(2)
Modern climate diagnostics	17	(1)
The atmospheric general circulation	18	(17)
From Hadley to the mid-20th century: Theory underconstrained by observations	20	(4)
Post-World War II: Resolving the controversies	24	(1)
Quantifying the balance requirements	25	(1)
Angular momentum balance	25	(2)
Atmospheric energy cycle	27	(2)
Planetary heat balance	29	(3)
Hydrologic cycle	32	(3)
The annual cycle	35	(26)
Basic controls	43	(9)
Focus on the tropics	52	(4)
A monsoon system perspective	56	(1)
Focus on the extratropics	57	(4)
Interannual variability	61	(38)
Atmospheric teleconnections	62	(5)
The ENSO phenomenon: Early investigations	67	(4)
ENSO cycle time series	71	(1)
ENSO warm episode evolution	72	(16)
ENSO global response	88	(1)
Tropical anomalies	88	(10)
Extratropical anomalies	98	(1)
Decadal/interdecadal variability	99	(40)
Focus on the tropical oceans	102	(1)
Pacific sector	102	(2)
Atlantic sector	104	(1)
Focus on the extratropics	105	(1)
Northern Hemisphere wintertime temperatures: relationship to the SO and the NAO	105	(6)
North Atlantic and North Pacific	111	(8)
Continental precipitation variability	119	(1)
Sahel rainfall	120	(6)
North American drought	126	(1)
Indian rainfall	127	(1)
Concluding remarks	128	(1)
References	129	(10)
Numerical Modelling of the Earth's Climate	139	(98)
L. Bengtsson
A strategic approach to climate modelling	143	(8)
Introduction	143	(1)
Dynamics of climate	144	(1)
Phillips' experiment	145	(1)
The key scientific issues in 1955	146	(1)
Climate modelling for different time-scales	147	(4)
Climate modelling	151	(15)
Introduction	151	(2)
The climate model as a mathematical system	153	(3)
Overall design of an atmospheric climate model	156	(2)
Numerical solution	158	(2)
Physical parameterization	160	(2)
Climate model performance	162	(4)
An atmospheric model for climate simulation and prediction studies	166	(29)
Introduction	166	(1)
Horizontal diffusion	167	(1)
Surface fluxes and vertical diffusion	168	(4)
Land surface processes	172	(1)
Gravity wave drag	172	(2)
Cumulus convection	174	(1)
Adjustment closure	174	(2)
Stratiform clouds	176	(2)
Radiation	178	(1)
Longwave radiation	178	(3)
Shortwave radiation	181	(4)
Shortwave cloud optical properties	185	(1)
Longwave cloud optical properties	186	(1)
Effective radii of cloud droplets and ice crystals	187	(1)
Surface albedo	188	(1)
Solar zenith angle	188	(1)
Model validation	188	(1)
Radiation and clouds	189	(2)
The hydrological cycle	191	(1)
The large scale extra-tropical circulation	192	(3)
Climate response to greenhouse gas forcing	195	(14)
Introduction	195	(3)
Climate feedback processes	198	(2)
The Wonderland climate model	200	(3)
Forcing experiments with the Wonderland model	203	(1)
Response to 2 x CO2 and 2% solar forcing	204	(1)
Response to the horizontal and vertical distribution of the forcing	205	(2)
Forcing experiments with more realistic climate models	207	(2)
Climate change prediction	209	(28)
Introduction	209	(3)
Mechanisms behind climate change	212	(1)
How can climate change?	212	(1)
Changes in the solar radiation	212	(1)
Changes in the greenhouse gases	213	(1)
Changes in atmospheric aerosols	214	(1)
Internal, natural variations	215	(2)
Coupled models	217	(4)
Coupled model experiments	221	(1)
Transient greenhouse gas experiment	222	(1)
Changes in the energy cycle	223	(2)
The hydrological cycle	225	(2)
Temperature changes	227	(3)
References	230	(7)
Ocean Modelling and the Role of the Ocean in the Climate System	237	(78)
P. Delecluse
G. Madec
Physical properties of the ocean	241	(8)
General structure	241	(1)
Why does the ocean move?	241	(1)
Radiative forcing	241	(2)
Momentum flux	243	(1)
Turbulent fluxes	244	(2)
Freshwater flux	246	(1)
Mean vertical structure	247	(1)
Seasonal cycle of the mixed layer	247	(1)
Midlatitude thermocline ventilation	247	(1)
Equatorial thermocline	247	(1)
Deep convection and sea ice	248	(1)
Turbulence of the ocean	249	(1)
Equations of motion	249	(6)
The physical equations	249	(1)
Basic assumptions (refer to Pedlosky, 1987)	249	(1)
The Primitive Equations	250	(1)
The boundary conditions	251	(1)
Horizontal pressure gradient formulation	252	(1)
Pressure formulation	252	(1)
Diagnosing the surface pressure gradient	253	(1)
Boundary conditions	254	(1)
Modelling approach	255	(22)
System of coordinates	255	(1)
Model equations	256	(2)
Vertical system of coordinates	258	(1)
Meridian convergence at the pole	259	(1)
Discretization in space	260	(1)
Arrangement of variables for the C grid	260	(1)
Discrete operators	261	(1)
Conservation properties for the dynamics	262	(3)
Conservation properties for the thermodynamics	265	(1)
Discretization in time	265	(1)
Robust diagnostic modelling	266	(1)
Acceleration of convergence	267	(2)
Surface boundary conditions	269	(1)
Subgrid scale parameterisations	270	(1)
Vertical mixing	270	(3)
Convection	273	(2)
Lateral mixing	275	(2)
The global coupled system	277	(11)
Ocean-only models	277	(1)
Space or time?	277	(1)
Oceanic observations	278	(1)
Atmospheric forcing	278	(1)
Sensitivity to parameterisation	278	(3)
Coupled models	281	(1)
General description of the problem	281	(2)
Illustration of drift	283	(1)
Flux correction	283	(2)
Sensitivity	285	(3)
The equatorial coupled system	288	(20)
Oceanic equatorial waves	289	(1)
Vertical eigenvectors	290	(1)
Meridional normal modes	291	(2)
Inertia-gravity and Rossby waves	293	(2)
Mixed Rossby--gravity wave	295	(1)
Equatorial Kelvin wave	295	(1)
Equatorial waves and El Nino	296	(1)
Response of forced simulations	297	(1)
Coupled models	298	(3)
Prediction	301	(3)
Some new features to study El Nino	304	(1)
Meridional coupling	304	(1)
Barrier layer and freshwater flux	305	(3)
Conclusion	308	(7)
References	309	(6)
Past Climatic Changes	315	(62)
J.-C. Duplessy
Paleoclimatic and Paleoceanographic tools	319	(18)
Introduction	319	(1)
Transfer functions	320	(1)
The Imbrie and Kipp (I&K) technique	320	(2)
The Modern Analog Technique (MAT)	322	(1)
Improving or validating transfer functions	322	(4)
Stable isotope ratio variations	326	(1)
Oxygen isotope fractionation during the water cycle	327	(2)
Oxygen isotope fractionation during carbonate precipitation	329	(3)
Isotope fractionation during the carbon cycle	332	(2)
Dating	334	(1)
Radiocarbon	334	(2)
Uranium series disequilibria	336	(1)
Longer time scales	336	(1)
The climatic record of the Plio-Pleistocene and the evidence for the Astronomical Theory of paleoclimates	337	(14)
Historcal introduction	337	(2)
The Astronomical Theory of glaciations	339	(3)
Extension of the climatic record over the last 6 million years	342	(4)
The last climatic cycle	346	(2)
The last glacial maximum	348	(2)
The last climatic optimum	350	(1)
Rapid variations within the climate system	351	(26)
Introduction	351	(1)
Evidence of rapid climatic change during the deglaciation	352	(1)
Evidence of rapid climatic change during the glaciation	353	(4)
Mechanisms of rapid climatic change under glacial conditions	357	(2)
A case for the Younger Dryas	359	(3)
Evidence of rapid climatic change during the Eemian	362	(1)
Evidence of rapid climatic change during the Holocene	363	(4)
Modeling of abrupt climatic changes and implications for future climates	367	(2)
References	369	(8)
Paleomyths I Have Known	377	(72)
T.J. Crowley
Introduction	381	(1)
General features of past climate change	381	(4)
Some significant misconceptions about past climate change	385	(2)
Discussion of the ``paleo-paradigms''	387	(23)
``There is growing evidence that the tropics were about 5°C colder during the last glacial maximum''	387	(8)
``North Atlantic deep water variations cause global temperature change''	395	(3)
``Global warmth during the early Holocene and Last Interglacial was greater than present''	398	(5)
``Deep water formation occurred in the subtropics during ice-free periods''	403	(3)
``There is no evidence that low frequency variations in solar irradiance have occurred''	406	(4)
Application to the problem of decadal--centennial scale variability	410	(10)
Nature of observed changes	410	(4)
Evaluating the relative contribution of different mechanisms to decadal--centennial climate change	414	(2)
Variations of North Atlantic deep water	416	(1)
Additional sources of oceanic variability	417	(1)
Concluding remarks on natural variability: A challenge to modelers	418	(2)
Concluding remarks	420	(11)
References	422	(9)
SPECIALIZED COURSES
Climate Variability of a Coupled Ocean--Atmosphere--Land Surface Model: Implication for the Detection of Global Warming	431	(2)
S. Manabe
R.J. Stouffer
Introduction	433	(1)
Numerical experiment	433	(3)
Local variability	436	(6)
Global variability	442	(3)
Transient model response	445	(1)
Concluding remarks	446	(3)
References	447	(2)
Variability of the Oceanic Thermohaline Circulation	449	(78)
W.R. Holland
A. Capotondi
Introduction	453	(1)
Experiments with a sector ocean driven by stochastic forcing	454	(32)
The model	457	(3)
Surface stochastic forcing	460	(4)
Thermal boundary conditions	464	(3)
The stochastically forced experiments	467	(1)
Strong restoring cases	468	(4)
Weak SST constraint	472	(8)
Sensitivity to the spatial pattern	480	(1)
Thermal stochastic forcing	481	(1)
Effects of nonlinearities in the equation of state	482	(3)
Discussion and conclusions for sector ocean model results	485	(1)
Experiments with a regional North Atlantic ocean model driven by stochastic forcing	486	(6)
A numerical experiment with the NCAR climate system model	492	(30)
The ocean model and data sets used in the analyses	494	(1)
Thermohaline circulation variability: year 30--year 299	495	(10)
Period 1 (year 110--189)	505	(7)
Period 2 (year 200--299)	512	(9)
Discussion of CSM/North Atlantic results	521	(1)
Discussion and conclusions	522	(5)
References	523	(4)
Modeling Extreme Climates of the Past 20,000 Years with General Circulation Models	527	(40)
S. Joussaume
Introduction	531	(2)
Methodology	533	(4)
Simulating past climates	533	(3)
Model--data comparisons	536	(1)
The last glacial maximum	537	(12)
PMIP experiments of the last glacial maximum	538	(6)
Model--data comparisons	544	(4)
Additional feedbacks	548	(1)
Mid-Holocene climate	549	(10)
PMIP simulations of the mid-Holocene	550	(2)
Model--model comparisons	552	(1)
Model--data comparisons	553	(2)
Additional feedbacks	555	(4)
Conclusions	559	(8)
References	560	(7)
Seminars by Participants	567