Publications

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2015
Qiu, B, Rudnick DL, Cerovecki I, Cornuelle BD, Chen S, Schonau MC, McClean JL, Gopalakrishnan G.  2015.  The Pacific North Equatorial Current: New insights from the Origins of the Kuroshio and Mindanao Currents (OKMC) Project. Oceanography. 28:24-33.   10.5670/oceanog.2015.78   AbstractWebsite

Located at the crossroads of the tropical and subtropical circulations, the westward-flowing North Equatorial Current (NEC) and its subsequent bifurcation off the Philippine coast near 13 degrees N serve as important pathways for heat and water mass exchanges between the mid- and low-latitude North Pacific Ocean. Because the western Pacific warm pool, with sea surface temperatures > 28 degrees C, extends poleward of 17 degrees N in the western North Pacific, the bifurcation and transport partitioning of the NEC into the Kuroshio and Mindanao Currents are likely to affect the temporal evolution of the warm pool through lateral advection. In addition to its influence on physical conditions, NEC variability is also important to the regional biological properties and the fisheries along the Philippine coast and in the western Pacific Ocean. This article synthesizes our current understandings of the NEC, especially those garnered through the recent Origins of the Kuroshio and Mindanao Current (OKMC) project.

2011
Song, H, Miller AJ, Cornuelle BD, Di Lorenzo E.  2011.  Changes in upwelling and its water sources in the California Current System driven by different wind forcing. Dynamics of Atmospheres and Oceans. 52:170-191.   10.1016/j.dynatmoce.2011.03.001   AbstractWebsite

In the California Current System (CCS), upwelling is one of the most important features that enrich the coastal ecosystem. It is highly dependent on both wind stress and wind stress curl, because they contribute to the upwelling system through Ekman transport away from the coast and Ekman pumping as a result of the surface divergence, respectively. Various wind stress products are known to contain sharply different patterns of wind stress, and well-resolved wind forcing products have been shown to drive stronger upwelling due to their better-resolved wind stress curl in previous studies. However, sensitivities of upwelling to changes in wind stress patterns, and each of their control to the source waters and paths of the upwelling cells, are not yet well known for the CCS. Here we study these effects using the Regional Ocean Modeling System (ROMS) and its adjoint model under idealized wind stress forcing patterns representing three widely-used products in addition to a constant wind stress field (no curl): the NCEP/NCAR Reanalysis, the QuikSCAT satellite observations, and the Regional Spectral Model (RSM) downscaling. Changes in currents and isopycnal patterns during the upwelling season are first studied in ROMS under the four different wind stress fields. The model simulations show that the locations of the core of the equatorward flow and the gradient of the cross-shore isopycnals are controlled by the wind stress curl field. The core of the equatorward flow is found under negative wind stress curl, and a deeper upwelling cell is found as the gradient from positive and negative wind stress curl increases. Source waters for the upwelling in each of the four wind stress patterns are investigated using the ROMS adjoint model. The simulations follow a passive tracer backward in time and track the source waters for upwelling in two key areas of interest: inshore and offshore of the Point Sur region of California. The upwelling source waters depend strongly on the depth of the upwelling cell and the alongshore current location. We further relate these results to recent studies of the observed trends in upwelling favorable winds and consequent wind stress curl changes in the CCS. (C) 2011 Elsevier B.V. All rights reserved.