Michael Spall

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Watermass transformation in marginal seas

Waters formed at high latitudes have distinct water mass characteristics that can be traced throughout the worlds oceans. This water mass transformation and transport is a fundamental component of the oceanic thermohaline circulation and plays an important role in the global climate system. I am interested in several aspects of how these waters are formed, where they sink, and how they are transported away from their formation regions. I am also interested in how the thermohaline circulation interacts with the wind-driven circulation, both at mid-latitudes and at high latitudes.

I have found that the dominant component of the downwelling limb of the thermohaline circulation takes place very close to lateral boundaries and steep topography. I have been using analytic models, simple scaling ideas, and general circulation modelling studies to understand and quantify the amplitude of boundary sinking and demonstrate its importance relative to large-scale interior downwelling and eddy-driven downwelling in a subpolar gyre.

This work has been generously supported through grants from the National Science Foundation and the Office of Naval Research.


Recent manuscripts on these subjects - click on PDF icon or author name to download

Spall, M. A., 2007 Circulation and water mass transformation in a model of the Chukchi Sea. J. Geophys. Res. ., 112, C05025,doi:10.1029/2005JC002264

Spall, M. A., 2012:Influences of precipitation on water mass transformation and deep convection. J. Phys. Oceanogr, in press.
Vage, K., R. S. Pickart, M. A. Spall, H. Valdimarsson, S. Jonsson, D. J. Torres, S. Osterhus, T. Eldevik, 2011: Formation of Denmark Strait overflow water via boundary currents and transformation in the central Iceland Sea, Nature Geosciences,DOI:10.1030/NGEO1234
Spall, M. A., 2011:On the role of eddies and surface forcing in the heat transport and overturning circulation in marginals seas. J. Climate, 24, 4844-4858.
Spall, M. A., 2010: Dynamics of downwelling in an eddy-resolving convective basin. J. Phys. Oceanogr., 40,2341-2347
Spall, M. A., 2010: Non-local topographic influences on deep convection: An idealized model for the Nordic Seas. Ocean Modell., 32, 72-85, doi:10.1016/j.ocemod.2009.10.009
Spall, M. A., 2008: Buoyancy-forced downwelling in boundary currents. J. Phys. Oceanogr., 38, 2704-2721
Spall, M. A., 2008: Low-frequency interaction between horizontal and overturning gyres in the ocean Geophys. Res. Lett., 35, L18614, doi:10.1029/2008GL035206
  Spall, M. A., 2008: Buoyancy-forced downwelling in boundary currents. J. Phys. Oceanogr., in press.
Pickart, R. S. and M. A. Spall, 2007. Impact of Labrador Sea convection on the North Atlantic meridional overturning circulation. J. Phys. Oceanogr. 37, 2207-2227.
Pedlosky, J. and M. A. Spall, 2005. Boundary intensification of vertical velocity in a beta-plane basin. J. Phys. Oceanogr. 35, 2487-2500.
Spall, M. A., 2005. Buoyancy-forced circulations in shallow marginal seas. J. Mar. Res. 63, 729-752.
Spall, M. A., 2004. Boundary currents and water mass transformation in marginal seas. Journal of Physical Oceanography 34, 1197-1213.
Katsman, C. A., M. A. Spall, R. S. Pickart, 2003. Boundary current eddies and their role in the restratification of the Labrador Sea. submitted to: Journal of Physical Oceanography.
  Pickart, R. S., M. A. Spall, M. H. Ribergaard, G. W. K. Moore, and R. F. Milliff, 2003. Convection east of Greenland: Atmospheric forcing and oceanic response. Nature, 424,152-156
Spall, Michael A., R. S. Pickart, 2003. Wind-driven recirculations and exchange in the Labrador and Irminger Seas. Journal of Physical Oceanography, 33,1829-1845
Spall, Michael A., 2003. On the thermohaline circulation in flat bottom marginal seas. Journal of Marine Research, 61, 1-25
Spall, Michael A., 2002. Wind- and buoyancy-forced upper ocean circulation in two-strait marginal seas with application to the Japan / East Sea. Journal of Geophysical Research, 107(C1), 6.1-6.12.
Spall, Michael A., R. S. Pickart, 2001. Where does dense water sink? A subpolar gyre example. Journal of Physical Oceanography, 31(3), 810-825.
Joyce, Terrence M., Clara Deser and Michael A. Spall, 2000. On the relation between decadal variability of Subtropical Mode Water and the North Atlantic Oscillation. Journal of Climate, 13(14), 2550-2569.
Spall, Michael A., 1999. A simple model of the large scale circulation of Mediterranean water and Labrador Sea water. Deep Sea Research II, 46, 181-204.
Spall, Michael A., and James F. Price, 1998. Mesoscale variability in Denmark Strait: the PV outflow hypothesis. Journal of Physical Oceanography, 28(8), 1598-1623.
Pickart, Robert S., Michael A. Spall and J. R. N. Lazier, 1997. Mid-depth ventilation in the western boundary current system of the subpolar gyre. Deep-Sea Research, 44(6), 1025-1054.
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