Publications by David Marshall


A sea change in our view of overturning in the subpolar North Atlantic.

Science (New York, N.Y.) 363 (2019) 516-521

MS Lozier, F Li, S Bacon, F Bahr, AS Bower, SA Cunningham, MF de Jong, L de Steur, B deYoung, J Fischer, SF Gary, BJW Greenan, NP Holliday, A Houk, L Houpert, ME Inall, WE Johns, HL Johnson, C Johnson, J Karstensen, G Koman, IA Le Bras, X Lin, N Mackay, DP Marshall, H Mercier, M Oltmanns, RS Pickart, AL Ramsey, D Rayner, F Straneo, V Thierry, DJ Torres, RG Williams, C Wilson, J Yang, I Yashayaev, J Zhao

To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st century, the Overturning in the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins is largely responsible for overturning and its variability in the subpolar basin.


AMOC sensitivity to surface buoyancy fluxes: the role of air-sea feedback mechanisms

Climate Dynamics (2019)

Y Kostov, HL Johnson, DP Marshall

© 2019, The Author(s). We interrogate the sensitivity of the Atlantic Meridional Overturning Circulation (AMOC) to surface heat and freshwater fluxes over the Subpolar Gyre in an ocean general circulation model and its adjoint. Surface heat loss out of the Subpolar Gyre in the winter strengthens the AMOC at a lead time of approximately 6 months. However, the same surface heat flux anomaly in the summer leads to a delayed AMOC weakening that emerges at a lag of 8 months. Under a summer surface cooling perturbation, the AMOC progressively weakens up to a lag of approximately 80 months, and then the negative overturning anomaly persists for years. Compared with the sensitivity to surface heat fluxes, seasonality in the AMOC sensitivity to surface freshwater fluxes is less pronounced, and there is no sign reversal between the response to summer and winter perturbations. We explain the mechanisms behind the large seasonal differences in the AMOC sensitivity to surface heat fluxes and highlight the role of evaporation. Heat flux anomalies over the Subpolar Gyre trigger changes in the rate of evaporation and hence affect the salinity of the mixed layer. Surface cooling gives rise to freshening in the following months, whereas warming leads to salinification. Persistent buoyancy changes due to salinity responses counteract the impact of heat fluxes to a varying extent depending on the seasonal mixed layer depth. On the other hand, air-sea feedback mechanisms exert a positive feedback on the AMOC response to surface freshwater flux perturbations both in the summer and in the winter months.


A geometric interpretation of Southern Ocean eddy form stress

Journal of Physical Oceanography American Meteorological Society (2019)

M Poulsen, M Jochum, D MARSHALL, J Maddison, R Nuterman


Eddy-mixing entropy and its maximization in forced-dissipative geostrophic turbulence

JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT (2018) ARTN 073206

TW David, L Zanna, DP Marshall


Implementation of a Geometrically Informed and Energetically Constrained Mesoscale Eddy Parameterization in an Ocean Circulation Model

JOURNAL OF PHYSICAL OCEANOGRAPHY 48 (2018) 2363-2382

J Mak, JR Maddison, DP Marshall, DR Munday


Impacts of Atmospheric Reanalysis Uncertainty on Atlantic Overturning Estimates at 25°N

Journal of Climate American Meteorological Society 31 (2018) 8719-8744

HR Pillar, HL Johnson, DP Marshall, P Heimbach, S Takao


Atlantic-Pacific Asymmetry in Deep Water Formation

ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES, VOL 46 46 (2018) 327-352

D Ferreira, P Cessi, HK Coxall, A de Boer, HA Dijkstra, SS Drijfhout, T Eldevik, N Harnik, JF McManus, DP Marshall, J Nilsson, F Roquet, T Schneider, RC Wills


Implications of Eddy Cancellation for Nutrient Distribution Within Subtropical Gyres

JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 123 (2018) 6720-6735

EW Doddridge, DP Marshall


Relative strength of the Antarctic Circumpolar Current and Atlantic Meridional Overturning Circulation

TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY 69 (2017) ARTN 1338884

DP Marshall, HL Johnson


OVERTURNING IN THE SUBPOLAR NORTH ATLANTIC PROGRAM A New International Ocean Observing System

BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 98 (2017) 737-752

MS Lozier, S Bacon, AS Bower, SA Cunningham, MF de Jong, L de Steur, B deYoung, J Fischer, SF Gary, BJW Greenan, P Heimbach, NP Holliday, L Houpert, ME Inall, WE Johns, HL Johnson, J Karstensen, F Li, X Lin, N Mackay, DP Marshall, H Mercier, PG Myers, RS Pickart, HR Pillar, F Straneo, V Thierry, RA Weller, RG Williams, C Wilson, J Yang, J Zhao, JD Zika


Eddy saturation and frictional control of the Antarctic Circumpolar Current

GEOPHYSICAL RESEARCH LETTERS 44 (2017) 286-292

DP Marshall, MHP Ambaum, JR Maddison, DR Munday, L Novak


The impact of Southern Ocean residual upwelling on atmospheric CO2 on centennial and millennial timescales

CLIMATE DYNAMICS 48 (2017) 1611-1631

JM Lauderdale, RG Williams, DR Munday, DP Marshall


Emergent eddy saturation from an energy constrained eddy parameterisation

OCEAN MODELLING 112 (2017) 125-138

J Mak, DP Marshall, JR Maddison, SD Bachman


The statistical nature of turbulent barotropic ocean jets

OCEAN MODELLING 113 (2017) 34-49

TW David, DP Marshall, L Zanna


Evaluation of a scalar eddy transport coefficient based on geometric constraints

OCEAN MODELLING 109 (2017) 44-54

SD Bachman, DP Marshall, JR Maddison, J Mak


Characterizing the chaotic nature of ocean ventilation

JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 122 (2017) 7577-7594

GA MacGilchrist, DP Marshall, HL Johnson, C Lique, M Thomas


Submesoscale Instabilities in Mesoscale Eddies

JOURNAL OF PHYSICAL OCEANOGRAPHY 47 (2017) 3061-3085

L Brannigan, DP Marshall, ACN Garabato, AJG Nurser, J Kaiser


A Model of the Ocean Overturning Circulation with Two Closed Basins and a Reentrant Channel

JOURNAL OF PHYSICAL OCEANOGRAPHY 47 (2017) 2887-2906

R Ferrari, L-P Nadeau, DP Marshall, LC Allison, HL Johnson


Gill's model of the Antarctic Circumpolar Current, revisited: The role of latitudinal variations in wind stress

OCEAN MODELLING 97 (2016) 37-51

DP Marshall, DR Munday, LC Allison, RJ Hay, HL Johnson


Seasonality of submesoscale flows in the ocean surface boundary layer

GEOPHYSICAL RESEARCH LETTERS 43 (2016) 2118-2126

CE Buckingham, ACN Garabato, AF Thompson, L Brannigan, A Lazar, DP Marshall, AJG Nurser, G Damerell, KJ Heywood, SE Belcher

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