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Water Volume Transport Necessary to Remove This Heat Is at Least

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Water Volume Transport Necessary to Remove This Heat Is at Least AN ABSTRACT OF THE THESIS OF Boyd Ellertson Olson for the Ph. D. (Name) (Degree) in Oceanography presented on August 2,1967 (Major) (Date) Title: On the Abyssal Temperatures of the World Oceans Redacted for Privacy Abstract approved: June G. Pattullo In comparison with solar radiation, the energy ofgeothermal heat flowing through the sea bottom is extremely small; nevertheles;, this energy is not insignificant in the circulation of the bottom water. Calculations indicate that in the deep basins of the South Atlantic the water volume transport necessary to remove this heat is atleast one-tenth of the total northward flow of Antarctic Bottom Water. Plots of mean values of near bottom salinity and oxygen versus mean potential temperatures help to trace the movement of the bottom water. Geothermal and adiabatic warming associated with downslope flow combine to produce a deep temperature (in situ) minimum in portions of most of the deep basins of the world.Adiabatic or near adiabatic temperature gradients have been measured near the bottom in many of these basins.Evidence of superadiabatic gradients from temperature measurements made with reversing thermometersis inconclusive; however, careful measurements with closely spaced thermometers suggest that such gradients do exist over vertical dis- tances of a few hundred meters in some of the deepest basins. Decreasing potential density with depth, as found in some of the Atlantic Basins in association with sharp temperature and salinity gradients, is not necessarily an indication of unstable equilibrium. This is demonstrated by the results of stability calculations in the manner prescribed by Hesselberg and Sverdrup(1915). On the Abyssal Temperatures of the World Oceans by Boyd Ellertson Olson A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy June 1968 APPROVED: Redacted for Privacy 'rofessor of Oceanography In Charge of Major Redacted for Privacy Crm7tepartmentof Oceanography Redacted for Privacy Dean of Graduate School Date thesis is presentedAugust 2, 1967 Typed by Marcia Ten Eyck for Boyd Ellertson Olson ACKNOWLEDGMENTS Chronologically, my first expression of appreciation should be to Dr. Wayne V. Burt, Chairman of the Department of Oceanography, who provided the opportunity for my return to school after a lapse of many years.I am indebted to him for his realistic appraisal of course requirements and his assistance in developing my doctoral program. For hours of stimulating discussions and written suggestions on my dissertation, I am indebted to my two major professors, Dr. Peter K. Weyl, now Professor of Oceanography at State University of New York at Stony Brook, and Dr. June G. Pattullo.To these and the other members of my Committee--Dr. Norman H. Anderson, Dr. Byron L. Newton, Captain John F. Tatom and Dr. Robert L. Smith--I extend my sincere appreciation. Arranging in absentia for typing, printing and proofreadingwas a formidable obstacle until Dan Panshin offered to undertake this for me,I am deeply grateful for his generous assistance in making these arrangements and in resolving the innumerable small problems that arose. To the many others who offered assistance and encouragement-- faculty members, fellow students, friends, my understanding wife and tolerant children--I am also grateful. TABLE OF CONTENTS Page L INTRODUCTION 1 IL DISTRIBUTION OF TEMPERATURE, SALINITY, POTENTIAL DENSITY AND OXYGEN IN THE DEEP OCEAN BASINS 12 Atlantic-Indian Basin 12 South Indian Basin 17 Southeast Pacific Basin 22 Argentine Basin 24 Brazil Basin 28 North American and Contiguous Basins 36 Sierra Leone Basin 41 Canary and Iberian Basins 42 Guinea and Angola Basin 49 Cape, Agulhas and Natal Basins 53 Crozet Basin 59 Madagascar-Mascarene Basins 61 Somali Basin 66 Mid-Indian Basin 67 Wharton Basin 73 South Australian Basin 77 Tasman Basin 79 Southwest Pacific Basin 83 Central Pacific Basin 817 Northeast Pacific Basin 91 Northwest Pacific and Mariana Basins 98 Philippine Basin 101 Ill. DISCUSSION AND CONCLUSION 108 IV. BIBLIOGRAPHY 126 V. APPENDICES 130 LIST OF FIGURES Figure Page 1 Comparison of scale used for temperatureprofiles in this study with conventional scale. 11 2 Deep temperature (in situ) and salinityprofiles, Atlantic-Indian Basin. 14 3 Deep sigma-Q and oxygen profiles,Atlantic-Indian Basin. 16 4 Deep temperature (in situ) and salinityprofiles from small basins within the Scotia Sea. 18 5 Deep temperature (in situ) and salinityprofiles, South Indian Basin. 20 6 Deep sigma-Q and oxygen profiles,South Indian Basin.21 7 Deep temperature (in situ) and salinityprofiles, Southeast Pacific Basin. 25 8 Deep sigma-Q and oxygen profiles,Southeast Pacific Basin. 26 9 Deep temperature (in situ) and salinity piofiles, Argentine Basin. 29 10 Deep sigma-0 and oxygen profiles,Argentine Basin. 30 11 Deep temperature (in situ) and salinityprofiles, Brazil Basin. 33 12 Deep sigma-.0 and oxygen profiles, BrazilBasin. 35 13 Deep temperature (in situ) and salinityprofiles, North American Basin. 38 14 Deep sigma-Q and oxygen profiles,North American Basin. 40 15 Deep temperature (in situ) and salinityprofiles, Sierra Leone Basin. 43 LIST OF FIGURES Continued Figure Page 16 Deep sigma-.0 and oxygen profiles, Sierra Leone Basin. 44 17 Deep temperature (in situ) and salinity profiles, Canary and Iberian Basin. 47 18 Deep sigma-Q and oxygen profiles, Canary and Iberian Basin. 48 19 Deep temperature (in situ) and salinity profiles, Guinea and Angola Basin. 52 20 Deep sigma-0 and oxygen profiles, Guinea and Angola Basin. 54 21 Deep temperature (in situ) and salinity profiles, Cape. Agulhas and Natal Basin. 56 22 Deep sigma-Q and oxygen profiles, Cape, Agulhas, and Natal Basins. 57 23 Deep temperature (in situ) and salinity profiles, Crozet Basin. 60 24 Deep sigma-0 and oxygen profiles, Crozet Basin. 62 25 Deep temperature (in situ) and salinity profiles, Madagascar-Mascarene Basin. 64 26 Deep sigma.0 and oxygen profiles, Madagascar- Mascarene Basin. 65 27 Deep temperature (in situ) and salinity profiles, Somali Basin. 68 28 Deep sigma.-0 and oxygen profiles, Somali Basin. 69 29 Deep temperature (in situ) and salinity profiles, Mid-Indian Basin. 71 30 Deep sigma-0 and oxygen profiles, Mid-Indian Basin. 72 LIST OF FIGURES Continued Figure Page 31 Deep temperature (in situ) and salinity profiles, Wharton Basin. 75 32 Deep sigma-Q and oxygen profiles, Wharton Basin. 76 33 Deep temperature (in situ) and salinity profiles, South Australian Basin. 78 34 Deep sigma-.Q and oxygen profiles, South Australian Basin. 80 35 Deep temperature (in situ) and salinity profiles, Tasman Basin. 82 36 Deep sigma-Q and oxygen profiles, Tasman Basin. 84 37 Deep temperature (in situ) and salinity profiles, Southwest Pacific Basin. 86 38 Deep sigma -Q and oxygen profiles, Southwest Pacific Basin. 88 39 Deep temperature (in situ) and salinity profiles, Central Pacific Basin. 90 40 Deep sigma-Q and oxygen profiles, Central Pacific Basin. 92 41 Deep temperature (in situ) and salinity profiles, Northeast Pacific Basin. 95 42 Deep sigma-0 profiles, Northeast Pacific Basin. 96 43 Mean profiles of deep temperature (in situ), salinity and sigma-Q from 13 repeated casts, Northeast Pacific Basin. 97 44 Mean profiles of deep temperature and salinity, Northwest Pacific Basin. 100 45 Mean profiles of deep sigma-Q, Northwest Pacific Basin. 102 LIST OF FIGURES Continued Figure Page 46 Deep oxygen profiles, Northwest Pacific Basin. 103 47 Deep temperature (in situ) and salinity profiles, Philippine Basin. 105 48 Deep sigma-0 and oxygen profiles, Philippine Basin. 107 49 Adiabatic processes. 111 50 Potential temperature gradient vs. depth. 114 51 Potential temperature vs. salinity, major deep ocean basins. 119 52 Dissolved oxygen vs. potential temperature, major deep ocean basins. 120 LIST OF TABLES Table Page 1 Temperature and Salinity Increases Between CRAWFORD Stations 1335 and 251. 49 2 Stability Function, F, for the Near-Bottom Water in the Major Basins of the World Oceans. 116 3 Stability Function, F, at Various Depths in the Brazil Basin. 118 4 Minimum Transport Required to Remove Geo- thermal Heat by Advection. 124 LIST OF PLATES Plate Page I Major Deep Basins of the World Oceans. 145 II Temperature (In Situ) Distribution at the Deep Temperature Minimum. 146 III Areas in Which the Deep Temperature Minimum and Adiabatic Lapse Rates Have Been Observed. 147 IV Bottom Potential Temperature Distribution in the Major Deep Ocean Basins. 148 V Salinity Near the Bottom in the Major Deep Ocean Basins. 149 VI Sigma-O [1000 x (potential density-1)11Near the Bottom in the Major Deep Ocean Basins. 150 VII Dissolved Oxygen Content (ml/l) Near the Bottom in the Major Deep Ocean Basins. 151 ON THE ABYSSAL TEMPERATURES OF THE WORLD OCEANS I.INTRODUCTION The object of this study is to examine deep oceanographic station data for evidences of terrestrial heating and to explore how this heat affects the abyssal circulation.The inadequacy of information on ocean bottom depths, the inaccuracy of temperature and salinity measurement and the complexity of processes largely limit this examination to qualitative considerations.Because the density, hence the stability, of a water column is determined by the vertical distribution of temperature and salinity, these properties will be considered in some detail.In addition, dissolved oxygen content will be examined superficially for indications of the relative length of residence of the water in the different basins. In the process, charts (Plates
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