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Kathie Kelly

Senior Principal Oceanographer

Professor, Oceanography

Email

kkelly@apl.washington.edu

Phone

206-543-9810

Research Interests

Large-Scale Ocean Circulation, Atmosphere-Ocean Coupling, Climate Change

Biosketch

Dr. Kelly's primary scientific interest is in the application of large data sets, particularly from satellite sensors, to problems of climate, atmosphere-ocean interaction and ocean circulation. She works in collaboration with numerical modelers and scientists who make in situ measurements to better understand the ocean and to improve the quality of the satellite data. She has been a member of the science teams for the NASA scatterometer (NSCAT) and the TOPEX/POSEIDON altimeter and has served on NASA science advisory committees.

She advises graduate students and teaches classes on combining data and models in physical oceanography, which is a hands-on introduction to principal component methods, inverse theory, and data assimilation. Dr. Kelly joined the Laboratory in 1996.

Education

B.S. Engineering Math/Statistics, University of California, Berkeley, 1977

Ph.D. Oceanography, Scripps Institution of Oceanography, 1983

Publications

2000-present and while at APL-UW

Impact of slowdown of Atlantic overturning circulation on heat and freshwater transports

Kelly, K.A., K. Drushka, L. Thompson, D. Le Bars, and E.L. McDonagh, "Impact of slowdown of Atlantic overturning circulation on heat and freshwater transports," Geophys. Res. Lett., 43, 7625-7631, doi:10.1002/2016GL069789, 2016.

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28 Jul 2016

Recent measurements of the strength of the Atlantic overturning circulation at 26°N show a 1 year drop and partial recovery amid a gradual weakening. To examine the extent and impact of the slowdown on basin wide heat and freshwater transports for 2004–2012, a box model that assimilates hydrographic and satellite observations is used to estimate heat transport and freshwater convergence as residuals of the heat and freshwater budgets. Using an independent transport estimate, convergences are converted to transports, which show a high level of spatial coherence. The similarity between Atlantic heat transport and the Agulhas Leakage suggests that it is the source of the surface heat transport anomalies. The freshwater budget in the North Atlantic is dominated by a decrease in freshwater flux. The increasing salinity during the slowdown supports modeling studies that show that heat, not freshwater, drives trends in the overturning circulation in a warming climate.

The role of heating, winds, and topography on sea level changes in the North Atlantic

Zhang, J., K.A. Kelly, and L. Thompson, "The role of heating, winds, and topography on sea level changes in the North Atlantic," J. Geophys. Res., 121, 2887-2900, doi:10.1002/2015JC011492, 2016.

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1 May 2016

Seasonal and interannual-to-decadal variations of large-scale altimetric sea surface height (SSH) owing to surface heating and wind forcing in the presence of topography are investigated using simplified models. The dominant forcing mechanisms are time scale dependent. On the seasonal time scale, locally forced thermosteric height explains most of the SSH variance north of 18°N. First-mode linear long baroclinic Rossby waves forced by changes in the winds and eastern boundary conditions explain most of the variance between 10°N and 15–N and are also important east of Greenland. On interannual-to-decadal time scales, local thermosteric height remains important at several locations in the middle and high latitudes. A topographic Sverdrup response explains interannual-to-decadal SSH between 53°N and 63°N east of Greenland. Farther south, the linear Rossby wave model explains SSH variations on interannual-to-decadal time scales between 30°N and 50°N from mid-basin to the eastern boundary. Propagation of the eastern boundary condition into the interior dominates the interannual-to-decadal SSH signals south of 30°N. The effect from NAO-related heat flux on SSH is small, but forcing the topographic Sverdrup models with NAO-regressed winds gives slightly better agreement with the observed SSH in the subpolar gyre on interannual-to-decadal time scales than using the full winds.

The coherence and impact of meridional heat transport anomalies in the Atlantic Ocean inferred from observations

Kelly, K.A., L. Thompson, and J. Lyman, "The coherence and impact of meridional heat transport anomalies in the Atlantic Ocean inferred from observations," J. Clim., 27, 1469-1487, doi:10.1175/JCLI-D-12-00131.1, 2014.

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2 Feb 2014

Observations of thermosteric sea level (TSL) from hydrographic data, equivalent water thickness (EWT) from the Gravity Recovery and Climate Experiment (GRACE), and altimetric sea surface height (SSH) are used to infer meridional heat transport (MHT) anomalies for the Atlantic Ocean. An "unknown control" version of a Kalman filter in each of eight regions extracts smooth estimates of heat transport convergence (HTC) from discrepancies between the response to monthly surface heat and freshwater fluxes and observed mass and heat content. Two models are used: model A using only the heat budget for 1993–2010 and model B using both heat and mass budgets for 2003–10. Based on the small contributions of mass to SSH, model A is rerun using SSH in place of TSL to improve temporal resolution and data consistency. Estimates of MHT are derived by summing the HTC from north to south assuming either negligible anomalies at 67°N or setting MHT to observed values near 40°N. Both methods show that MHT is highly coherent between 35°S and 40°N. The former method gives a large drop in coherence north of 40°N while the latter method gives a less dramatic drop. Estimated anomalies in MHT comparable to or larger than that recently observed at the Rapid Climate Change and Meridional Overturning Circulation and Heatflux Array (RAPID/MOCHA) line at 26.5°N have occurred multiple times in this 18-yr period. Positive anomalies in coherent MHT correspond to increased heat loss in the North Atlantic subtropical gyre demonstrating the feedback of oceanic heat transport anomalies on air–sea fluxes. A correlation of MHT with the Antarctic Oscillation suggests a southern source for the coherent MHT anomalies.

More Publications

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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