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Barry Ma

Senior Oceanographer





Department Affiliation

Ocean Physics


B.S., ROC Naval Academy, Kaohsiung, Taiwan, 1988

M.S. Physical Oceanography, US Naval Postgraduate School, 1998

Ph.D. Oceanography, University of Washington, 2004


2000-present and while at APL-UW

LC–DRI Field Experiment and Data Calibration Report

Ma, B., E. D'Asaro, T. Sanford, J. Thomson, "LC–DRI Field Experiment and Data Calibration Report," Technical Report, APL-UW TR 2002, Applied Physics Laboratory, University of Washington, Seattle, March 2020.

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10 Mar 2020

The goal of the Waves, Langmuir Cells and the Upper Ocean Boundary Layer Departmental Research Initiative (LC–DRI) is to explore the upper ocean physics necessary to advance our understanding of the fluxes into and across the ocean mixed layer, including surface waves and wave breaking, Langmuir cells, and wave–current interaction. A set of comprehensive observational data was collected during the LC–DRI field experiment from various platforms including autonomous floats, drifter, buoys, and shipboard observations. The field campaign was conducted on the coast of Southern California 21 March – 5 April 2017. The fieldwork, including the event log and instrument deployment, is described in Part I. The inter-calibration between observed CTD data from EM-APEX and MLF floats, SWIFT drifters and R/V Sproul are described in Part II. For the MLF vs. EM-APEX calibration, the average salinity of MLF #82 and #83 top and bottom sensors is used as a reference. The calculated salinity offset for EM-APEX #6667, #6672, and #6678 is ~ 0.004 psu, for EM-APEX #6671 and #6674 is ~0.001 psu, and for EM-APEX #6675 is ~–0.001 psu. For seven SWIFT drifters at 0.2, 0.5, and 1.2 m, the calculated temperature offset varies from –0.1 to 0.1°C and the salinity offset varies from –0.003 to 0.2 psu. The salinity data from SWIFT #16 and #17 at 0.2 m exhibited large offsets, which suggest data bias. The comparison of wave energy measurements between SWIFT drifters and a Datawell Waverider buoy moored at CDIP station 299 are described in Part III. Excluding the periods when the mean separation distance was greater than 30 km (periods 3−1, 3, 5, 6, 8, 12), the root-mean-square error (RMSE) of significant wave height (Hs) is 0.25 ± 0.08 m, the RMSE of integrated wave energy is 0.057 ± 0.029 m2, and the average percent error of Hs is ~13%. In general, given the temporal, spatial, and spectral differences in the sampling strategy of SWIFTdrifters and the CDIP buoy, the comparison suggests no significant bias in either dataset.

Downstream evolution of the Kuroshio's time-varying transport and velocity structure

Andres, M., V. Mensah, S. Jan, M.-H. Chang, Y.-J. Yang, C.M. Lee, B. Ma, and T.B. Sanford, "Downstream evolution of the Kuroshio's time-varying transport and velocity structure," J. Geophys. Res., 122, 3519-3542, doi:10.1002/2016JC012519, 2017.

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1 May 2017

Observations from two companion field programs—Origins of the Kuroshio and Mindanao Current (OKMC) and Observations of Kuroshio Transport Variability (OKTV)—are used here to examine the Kuroshio's temporal and spatial evolution. Kuroshio strength and velocity structure were measured between June 2012 and November 2014 with pressure-sensor equipped inverted echo sounders (PIESs) and upward-looking acoustic Doppler current profilers (ADCPs) deployed across the current northeast of Luzon, Philippines, and east of Taiwan with an 8 month overlap in the two arrays' deployment periods. The time-mean net (i.e., integrated from the surface to the bottom) absolute transport increases downstream from 7.3 Sv (±4.4 Sv standard error) northeast of Luzon to 13.7 Sv (±3.6 Sv) east of Taiwan. The observed downstream increase is consistent with the return flow predicted by the simple Sverdrup relation and the mean wind stress curl field over the North Pacific (despite the complicated bathymetry and gaps along the North Pacific western boundary). Northeast of Luzon, the Kuroshio—bounded by the 0 m s–1 isotach—is shallower than 750 dbar, while east of Taiwan areas of positive flow reach to the seafloor (3000 m). Both arrays indicate a deep counterflow beneath the poleward-flowing Kuroshio (–10.3 ± 2.3 Sv by Luzon and –12.5 ± 1.2 Sv east of Taiwan). Time-varying transports and velocities indicate the strong influence at both sections of westward propagating eddies from the ocean interior. Topography associated with the ridges east of Taiwan also influences the mean and time-varying velocity structure there.

Ekman circulation in the Arctic Ocean: Beyond the Beaufort Gyre

Ma, B., M. Steele, and C.M. Lee, "Ekman circulation in the Arctic Ocean: Beyond the Beaufort Gyre," J. Geophys. Res., 122, 3358-3374, doi:10.1002/2016JC012624, 2017.

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1 Apr 2017

Data derived from satellite-based observations, with buoy-based observations and assimilations, are used to calculate ocean Ekman layer transport and evaluate long-term trends in the Arctic Ocean over the period 1979–2014. The 36 year mean of upwelling (downwelling) is 3.7 ± 2.0 (–4.0 ± 2.2) Sv for the entire Arctic Basin, with ~0.3 Sv net downwelling contributed mostly by the Canadian region. With regard to long-term trends, the annual mean upwelling (downwelling) over the entire Arctic Basin is increasing at a linear rate of 0.92 (–0.98) Sv/decade. The Canada/Alaska coasts and Beaufort and Laptev Seas are regions of greatest Ekman transport intensification. The central Arctic Ocean and Lincoln Sea also have an increasing trend in transport. The Canadian and Eurasian regions each account for about half the total vertical Ekman variations in the Arctic Basin.

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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