ISBN: 3540636625
TITLE: Beyond El Nino
AUTHOR: Navarra, Antonio (Ed.)
TOC:

List of Contributors xvii
1 Interdecadal Variability at Northern High Latitudes 1
LAWRENCE A. MYSAK
1.1 Introduction 1
1.2 A feedback loop for interdecadal climate variability in the Arctic 8
1.3 Evidence for a Great Ice and Salinity Anomaly (GISA) event in the late 1980s 9
1.4 Possible sources for the precipitation and runoff anomalies in the Mackenzie basin: An attempt to verify the cyclogenesis-related links in the feedback loop 13
1.5 Models of the "Great Salinity Anomaly" (GSA) and other interdecadal variability in the Arctic and northern North Atlantic 18
1.5.1 Simulations of the GSA 18
1.5.2 Models of coupled ice-ocean interdecadal oscillations 22
1.5.3 Interdecadal variability in ocean GCMs 23
1.5.4 The 50-year oscillation in the North Atlantic THC 23
2 Sea Surface Temperature Variability in the North Atlantic: Monthly to Decadal Time Scales 25
CLAUDE FRANKIGNOUL
2.1 Introduction 25
2.2 Short-term variability 27
2.3 Decadal variability 34
2.3.1 Observations 34
2.3.2 Coupled ocean-atmosphere models 39
2.3.3 Thermocline response to stochastic wind stress forcing 44
2.3.4 Ocean-atmosphere feedback 46
2.4 Conclusions 47
3 Recent Decadal SST Variability in the Northwestern Pacific and Associated Atmospheric Anomalies 49
HISASHI NAKAMURA AND TOSHIO YAMAGATA
3.1 Introduction 49
3.2 Data 51
3.3 Characteristics of SST Variability over the NW Pacific 54
3.4 Dominant Decadal Variability in Winter 55
3.4.1 Spatial Structure 55
3.4.2 Time Evolution 59
3.4.3 Comparison with ENSO-Scale Variability 63
3.5 Dominant Decadal Variability in Summer 65
3.6 Discussion 70
4 Large Scale Modes of Ocean Surface Temperature Since the Late Nineteenth Century 73
C.K. FOLLAND, D.E. PARKER, A.W. COLMAN, R. WASHINGTON
4.1 Introduction 73
4.2 Data 74
4.3 Low Frequency Variability in Marine Surface Temperatures 75
4.3.1 Global and Regional Time Series of SST and NMAT Anomalies 75
4.3.2 Power spectra 75
4.3.3 Spatial patterns of near bidecadal ocean surface temperature variability 81
4.3.4 Synthesis of variability: Empirical Orthogonal Function (EOF) analysis 83
4.3.5 Extended EOF analysis of LF SST 90
4.3.6 Stability of the all seasons EOF analyses 92
4.4 Relationships between marine surface temperatures and tropic-wide rainfall on multi decadal time-scales 93
4.5 Low Frequency relationships between marine surface temperatures and southern African rainfall 96
4.6 Discussion and conclusions 99
4.7 Appendix: Enhancement Of EOF Time Series For Missing Data 100
5 The Indian Summer Monsoon and its Variability 103
JULIA SLINGO
5.1 Introduction 103
5.2 Mean behavior of the Indian Summer Monsoon 105
5.3 Interannual to decadal variability and its relationship with El Nio 106
5.4 Understanding the factors that influence monsoon interannual variability 109
5.5 Subseasonal behaviour and its relevance to interannual variability 113
5.6 Potential Predictability of the Indian Summer Monsoon 116
6 Climate Variability in Northern Africa: Understanding Droughts in the Sahel and the Mahgreb 119
M. NEIL WARD, PETER J. LAMB, DIANE H. PORTIS, MOSTAFA EL HAMILY, RACHID SEBBARI
6.1 Introduction 119
6.2 Discussion of Data and Methods 121
6.3 The Boreal summer season July-September: The Sahelian rainy season 122
6.4 Transition seasons in tropical North Africa 128
6.5 Sub-tropical Northwestern Africa 132
6.6 Discussion 138
6.7 Appendix - Examples of Filtering Procedures 140
7 SST-Forced Experiments and Climate Variability 141
ANTONIO NAVARRA
7.1 Introduction 141
7.2 Ensembles of Simulations 145
7.2.1 The need for ensembles 145
7.2.2 Reproducibility 150
7.2.3 Manifolds 152
7.3 Evaluation of performance: skill and reproducibility 153
7.3.1 Information and ensemble 153
7.4 Skill and Reproducibility for 1961-1994 154
7.5 Longer time scales 159
8 Impact of Ensemble Size on the Assessment of Model Climate Signal 163
Z.X. LI
8.1 Introduction 163
8.2 Model and climate signal 163
8.3 Impact of ensemble size 165
8.4 Conclusion 168
9 Interannual and Decadal Variability in the Tropical Pacific 171
SIMON F. B. TETT, MICHAEL K. DAVEY AND SARAH INESON
9.1 Introduction 171
9.2 Data sources 172
9.3 Model Description 173
9.4 Climatology and Interannual Variability 175
9.4.1 Climatology 175
9.4.2 Inter-annual variance 178
9.4.3 Timeseries Analysis 182
9.4.4 SST and VAT propagation characteristics 186
9.4.5 Zonal windstress relationships to SST 189
9.5 Decadal variability in ENS0 191
9.6 Summary and Conclusions 192
10 The Decadal Variability of the Pacific with the MRI Coupled Models 197
SEIJI YUKIMOTO
10.1 Introduction 197
10.2 Models 197
10.3 Spatial structure of the decadal variability 198
10.4 Temporal structure of the decadal variability 203
10.5 Two distinct decadal modes in the AOGCM 204
10.6 Discussion about the inherent mechanism 211
11 Dynamics of Interdecadal Variability in Coupled Ocean-Atmosphere Models 213
MOJIB LATIF
11.1 Introduction 213
11.2 Interdecadal variability originating in the tropics 215
11.2.1 The Tropical Pacific 215
11.2.2 The Tropical Atlantic 217
11.3 Tropics-Midlatitudes Interactions 222
11.4 Midlatitude Decadal Variability Involving the Wind-driven Gyres 224
11.4.1 The North Pacific Gyre Mode 226
11.4.2 The North Atlantic Gyre Mode 229
11.4.3 Relative Roles of Stochastic and Deterministic Processes 235
11.5 Midlatitude lnterdecadal Variability Involving the Thermohaline Circulation 236
11.6 Predictability at Decadal Time Scales 243
11.7 Discussion 249
12 Simulations of the Variability of the Tropical Atlantic 251
M.J. ORTIZ BEVIA, W. CABOS NARVAEZ, J.M. OBERHUBER
12.1 Introduction 251
12.2 Simulation of the seasonal variability 254
12.3 The simulation El of the interannual variability 256
12.4 Sensitivity experiments: simulations S1, S2 and E2 258
12.5 The tropical Atlantic variability in a coupled general circulation model 261
12.6 Statistical Comparison of the simulated interannual variability 261
12.6.1 The simulations E1 and E2 263
12.6.2 Simulations S1 and S2 265
12.6.3 The coupled ECHAM4/OPYC run 266
12.6.4 Comparison of statistical relationships among variables 266
12.7 Discussion 270
13 North-Atlantic Decadal Climate Variability in a Coupled Atmosphere/Ocean/Sea-Ice Model of Moderate Complexity 275
R.J. HAARSMA, F.M. SELTEM. J.D. OPSTEFGH. Q. LIU AND A. KATTENBERG
13.1 Introduction 275
13.2 Description of the model 277
13.2.1 Atmospheric model 277
13.2.2 Ocean model 280
13.2.3 Sea-ice model 282
13.2.4 The coupled model 282
13.3 Climate of the atmosphere model 282
13.4 Climate of the ocean model 285
13.5 Climatology and variability of the coupled model 288
13.6 Decadal variability of the North-Atlantic 291
13.7 Conclusions 297
14 A Theory For Interdecadal Climate Fluctuations 301
D. GU AND S.C.H. PHILANDER
14.1 Introduction 301
14.2 The influence of the extra-tropical winds 302
14.3 A simple model of interdecadal variability 305
15 Decadal Variability of the Thermohaline Ocean Circulation 309
STEFAN RAMSTORF
15.1 The thermohaline circulation as component of the climate system 309
15.2 Evidence for decadal variability of the thermohaline circulation 311
15.3 Physics of the thermohaline circulation 313
15.4 Basic variability mechanisms 318
15.4.1 Hasselmann's mechanism 318
15.4.2 Internal variability modes of the ocean 319
15.4.3 Forced variability 320
15.4.4 Coupled modes 321
15.5 Models with realistic geography 322
15.6 Idealized models 328
15.7 Conclusions 330
References 333
Abbreviations 368
Subject Index 371
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