Mechanisms of Global Climate Change at Millennial Time Scales

Geophysical Monograph Series......Page 1
Geophysical Monograph Series......Page 2
Mechanisms of Global Climate Change at Millennial Time Scales......Page 3
CONTENTS......Page 5
PREFACE......Page 7
REVIEWERS......Page 8
Some aspects of ocean heat transport by the shallow,intermediate and deep overturning circulations......Page 9
1. INTRODUCTION......Page 10
2.1. Winter Mixed Layer Depth......Page 11
2.2. Upper Ocean- Subtropical Gyres......Page 12
2.3. Intermediate Water Formation......Page 14
3. HEAT TRANSPORTS AND WATER MASSES......Page 15
3.1. Heuristic Structure of the Overturning Heat Transport......Page 16
3.2. Direct Estimates of Heat Transport in the Northern Hemisphere......Page 20
REFERENCES......Page 28
2. BACKGROUND......Page 31
3. DEPTH / AGE MODELS......Page 32
4.1. Some Statistical Issues......Page 34
5. COMPARISON OF METHODS......Page 35
5.1. Empirical Experiments......Page 36
7. COMMENTS AND CONCLUSIONS......Page 38
REFERENCES......Page 39
1. INTRODUCTION......Page 42
2. SOURCES OF DATA AND METHODS......Page 43
3. CHRONOLOGIES......Page 44
4.1. Tracing The 1-2 Kyr Climate Cycle To 80 Ka......Page 46
4.2. Strength And Consistency Of The Petrologic Signal......Page 48
4.4. A Caveat On Evidence From Other Marine Proxies......Page 50
4.5. Heinrich Events, Precursors And The 1-2 Kyr Cycle......Page 55
4.6 . Dansgaard/Oeschger Events And The 1-2 Kyr Cycle......Page 58
5. SUMMARY AND CONCLUSIONS......Page 60
REFERENCES......Page 62
1. INTRODUCTION......Page 66
2. STRATEGY......Page 67
3. METHODS......Page 68
4.1. Deep Water Variability - Ceara Rise......Page 70
4.2. Therrnocline and Intermediate Water Variability- Bahamas......Page 73
4.3. North Atlantic Surface and Intermediate Waters......Page 75
5. DISCUSSION AND IMPLICATIONS......Page 76
5.1. Ventilation of the Upper Water Column andMixing with Southern Ocean Water......Page 77
5.2. Oscillations in Temperature or Sea water O in the Thermocline......Page 78
5.3. Isopycnal Mixing and Cooling of the Tropics......Page 80
6. SUMMARY......Page 81
REFERENCES......Page 82
Temporal Variability of the Surface and Deep Waters of the North W es tAtlantic Ocean at Orbital and Millenial Scales......Page 84
2. MATERIAL, METHODS AND DATA......Page 85
2.1 Planktic foraminifera species distribution......Page 86
2.2 Isotopic studies......Page 88
2.4 AMS14C dating and the time scale of core CH 69-K09......Page 89
3. DISCUSSION......Page 91
3.1.2. Deep water proxy: the benthic foraminifera 13C record......Page 92
3.2.1. The glacial world......Page 95
3.2.2. The Holocene......Page 96
4. CONCLUDING REMARKS......Page 98
REFERENCES......Page 102
Origin of Global Millennial Scale Climate Events: Constraints from the Southern Ocean Deep Sea Sedimentary Record......Page 106
INTRODUCTION......Page 107
METHODS AND MATERIALS......Page 108
Deep Water Records......Page 109
Surface Water Records......Page 111
DISCUSSION......Page 113
REFERENCES......Page 117
INTRODUCTION......Page 120
OBJECTIVE......Page 121
1.2 The low latitude east Pacific, Santa Barbara Basin 0-25 Calka......Page 122
1.3. Tropical central Africa, the equatorial rain forest Domain, Lake Barombi Mbo in SW Cameroon 0-25 Calka......Page 123
2.1. The monsoonal climate, Arabian Sea 20-70 Cal ka......Page 124
2.2 The low latitude east Pacific, Santa Barbara Basin 20-70 Cat ka......Page 126
3.1. Forcing mechanism for globally teleconnected millennial-scale climate oscillations......Page 128
REFERENCES......Page 131
Rapid Climate Oscillationsin the Northeast Pacific During the Last Deglaciation Reflect Northern and Southern Hemisphere Sources......Page 134
2. WHY THE NORTHEAST PACIFIC?......Page 135
3.2. North Pacific Intermediate Water......Page 136
3.4. Intermediate and deep waters......Page 137
4.2. Radiocarbon......Page 138
4.4. Organic Carbon......Page 139
5.2. Time Series of Changing Environments......Page 140
6.2. Mid-Holocene cooling: An abrupt response to orbital forcing?......Page 143
6.3. Variability in the North Pacific oxygen minimum zone: Productivity or intermediate water formation?......Page 144
6.4. Ventilating intermediate waters:A northern source?......Page 145
6.6. Deep-seat emperatures and Antarctic warming......Page 150
7. CONCLUSIONS......Page 151
REFERENCES......Page 152
INTRODUCTION......Page 156
EXPERIMENTAL PROCEDURES AND RESULTS......Page 157
Correlation of Gas and Ice Records......Page 159
Correlation of lnterstadial Events Between Vostok and GISP2......Page 163
Extent of lnterstadial Climate Change......Page 164
CLIMATE PHASING DURING INTERSTADIAL EVENTS AND TERMINATION I......Page 165
CONCLUSIONS......Page 168
REFERENCES......Page 169
Atmospheric Methane and Millennial-Scale Climate Change......Page 172
3. METHODS......Page 173
4.1 General Trends......Page 174
4.2 Rapid Methane Changes During Interstadial Events......Page 175
4.3 Interpolar Methane Gradient, 40-10 ka......Page 176
4.4 Evaluation of the Clathrate Hypothesis......Page 177
4.5 Implications of Millennial-Scale Changes in Methane Mixing Ratio......Page 179
REFERENCES......Page 181
INTRODUCTION......Page 183
Defining Cryohydrological Basins......Page 184
Estimating Runoff from Precipitation......Page 185
Total Runoff......Page 186
Background......Page 187
The Early Stages of Retreat 21 - 15.2 14C ka......Page 190
Establishment of Eastern Great Lakes Flow to the Hudson Valley......Page 191
The Addition of Lake Agassiz Drainage to Outflow to the North Atlantic......Page 193
Reopening of the Eastern Outlets of Lake Agassiz......Page 194
OTHER FRESHWATER FLUXES TO THE NORTH ATLANTIC......Page 195
DISCUSSION AND CONCLUSIONS......Page 196
APPENDIX A. PRECIPITATION, ICE MELT, AND TOTAL RUNOFF VALUES......Page 198
REFERENCES......Page 202
Background......Page 208
Proxies of Alpine Glaciation......Page 209
Proxies of Change in the Hydrologic Balance......Page 210
Owens Lake......Page 211
Comparison of Owens Lake Records With North Atlantic Climate Events......Page 219
Pyramid Lake......Page 220
Mono Lake......Page 221
SUMMARY AND CONCLUSIONS......Page 224
REFERENCES......Page 227
SPATIAL AND TEMPORAL CONTROLS OF VEGETATION CHANGE......Page 231
VEGETATION RESPONSE ONMILANKOVITCH TIME SCALES......Page 233
EVIDENCE FOR MILLENNIAL-SCALE VARIATIONSIN MIS 2 AND 3......Page 234
THE YOUNGER DRYAS IN THE PACIFIC NORTHWEST......Page 239
EVIDENCE OF HOLOCENE VARIABILITY......Page 240
CONCLUSIONS......Page 241
REFERENCES......Page 242
INTRODUCTION......Page 246
Anatomy of Heinrich Events......Page 247
PHYSICAL CONSTRAINTS ONSURFACE-TO-BED COUPLING......Page 251
Ice Shelf Breakup......Page 252
Other Possibilities......Page 253
PROBLEMS OF SEDIMENT ENTRAINMENT ANDRETENTION......Page 254
EVALUTION OF CANDIDATE MECHANISMS......Page 255
A POSSIBLE MECHANISM FOR FASTSURFACE-TO-BED COUPLING......Page 256
MODELING OF SURGING AND TIDEWATERINSTABILITY MECHANISMS......Page 259
CONCLUSIONS......Page 262
REFERENCES......Page 263
1. INTRODUCTION......Page 266
2. MODEL DESCRIPTION......Page 268
3.1. Physical Changes during Abrupt Events......Page 269
3.2. 14C Changes during Abrupt Events......Page 271
3.3. Oceanic PO4 and 13C Changes during Abrupt Events......Page 273
4.1. Physical Changes......Page 276
APPENDIX A: BIOGEOCHEMICAL PROCESSES IN THE EUPHOTIC ZONE......Page 283
APPENDIX C: GAS EXCHANGE......Page 284
REFERENCES......Page 285
1. INTRODUCTION......Page 288
2.1. Mixed Boundary Conditions......Page 290
2.2. Millennial Timescale Variability......Page 291
2.3. The Younger Dryas Event......Page 293
2.4. The Eemian......Page 294
3. THE OCEAN RESPONSE TO HEINRICH EVENT FRESHWATER FORCING......Page 296
4. DISCUSSION......Page 299
REFERENCES......Page 300
INTRODUCTION......Page 304
Holocene Paleothermometry......Page 305
Ice-Isotopic Calibration to Temperature......Page 309
Climatic Variability......Page 310
DISCUSSION......Page 311
REFERENCES......Page 313
1. INTRODUCTION......Page 316
2. EXPERIMENTAL DESIGN......Page 317
3. RESULTS......Page 318
3.1 Global Model......Page 320
3.2 Regional Model......Page 322
4.1 Alpine glaciers and ice caps......Page 325
4.2 Lakes......Page 326
4.4 Coastal upwelling......Page 327
5. DISCUSSION AND CONCLUSIONS......Page 328
REFERENCES......Page 329
1. INTRODUCTION......Page 331
2. ONE-DIMENSIONAL SINGLE-LAYER MODEL......Page 332
3. SINGLE-LAYER MODEL ON A SPHERE......Page 334
4. DISCUSSION......Page 337
5. CONCLUSIONS......Page 338
REFERENCES......Page 339
1. INTRODUCTION......Page 340
2. THE OBSERVED HUMIDITY PATTERN......Page 341
3. CLIMATIC IMPACT OF SUBTROPICAL HUMIDITY......Page 347
3. 1. Radiative cooling and tropical circulations......Page 348
3.2. Influence of water vapor on the radiation budget......Page 353
4. WHAT CONTROLS SUBTROPICAL HUMIDITY?......Page 356
5. DISCUSSION......Page 359
REFERENCES......Page 361
1. INTRODUCTION......Page 363
2.1. Milankoviich Forcing......Page 364
2.2. Low Frequency Variability in the Control run......Page 366
REFERENCES......Page 369
1. INTRODUCTION......Page 372
2. A RECONSIDERATION OF THE ROLE OFTHE NORTH ATLANTIC......Page 374
3. A ROLE FOR THE TROPICAL PACIFIC......Page 375
REFERENCES......Page 381
INTRODUCTION......Page 383
MODES OF NORTH ATLANTIC DEEP WATERFORMATION......Page 384
DANSGAARD-OESCHGER OSCILLATIONS......Page 385
COMPARISON TO ORBITAL TIMESCALES......Page 388
DISCUSSION......Page 389
REFERENCES......Page 390