@article {RN75,
	title = {Why Gliders Appreciate Good Company: Glider Assimilation in the Oregon-Washington Coastal Ocean 4DVAR System With and Without Surface Observations},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {124},
	number = {1},
	year = {2019},
	pages = {750-772},
	type = {Journal Article},
	abstract = {Gliders are low-power autonomous underwater vehicles used to obtain oceanic measurements in vertical sections. Assimilation of glider temperature and salinity into coastal ocean circulation models holds the potential to improve the ocean subsurface structure estimate. In this study, the impact of assimilation of glider observations is studied using a four-dimensional variational (4DVAR) data assimilation and forecast system set offshore of Oregon and Washington on the U.S. West Coast. Four test cases are compared: (1) no assimilation, (2) assimilation of glider temperature and salinity data alone, (3) assimilation of the glider data in combination with the surface observations including satellite sea surface temperature, sea surface height, and high-frequency radar surface velocities, and (4) assimilation of the surface data alone. It is found that the assimilation of glider observations alone creates unphysical eddies in the vicinity of the glider transect. As a consequence, the forecast errors in the surface velocity and temperature increase compared to the case without data assimilation. Assimilation of surface and subsurface observations in combination prevents these features from forming and reduces the errors in the forecasts for the subsurface fields compared to the other three experiments. These improvements persisted in 21-day forecasts run after the last data assimilation cycle.

},
	issn = {2169-9275},
	doi = {10.1029/2018JC014230},
	url = {https://doi.org/10.1029/2018JC014230},
	author = {Pasmans, I. and Kurapov, A. L. and Barth, J. A. and Ignatov, A. and Kosro, P. M. and Shearman, R. K.}
}
@article {RN34,
	title = {Warm Blobs, Low-Oxygen Events, and an Eclipse THE OCEAN OBSERVATORIES INITIATIVE ENDURANCE ARRAY CAPTURES THEM ALL},
	journal = {Oceanography},
	volume = {31},
	number = {1},
	year = {2018},
	pages = {90-97},
	type = {Journal Article},
	abstract = {The Ocean Observatories Initiative (OOI) Endurance Array in the Northeast Pacific off the coasts of Oregon and Washington is designed to measure changes in the ocean on timescales from hours to decades. The Endurance Array is located halfway between the pole and the equator in one of the major coastal upwelling systems on our planet, the California Current System. This area is forced locally by winds, waves, tides, and freshwater inputs from rivers and, more broadly, by large-scale ocean-atmosphere phenomena from both the south, for example, the El Ni{\~n}o-Southern Oscillation, and the north, for example, changes originating in the subarctic Gulf of Alaska. The Endurance Array spans the continental shelf and slope and hosts a variety of platforms and sensors for measuring physical-biogeochemical oceanographic processes. After briefly introducing the unique OOI platforms and range of sensors that make up the Endurance Array, we describe three phenomena with durations spanning hours to years. These include an ocean response to the total eclipse of the Sun on August 21, 2017, the devastating effects of a low-oxygen event off central Oregon, and the appearance of an anomalously warm upper-ocean feature off the Pacific Northwest in recent years.},
	issn = {1042-8275},
	doi = {10.5670/oceanog.2018.114},
	url = {<Go to ISI>://WOS:000427367300014},
	author = {Barth, J. A. and Fram, J. P. and Dever, E. P. and Risien, C. M. and Wingard, C. E. and Collier, R. W. and Kearney, T. D.}
}
@article {RN35,
	title = {Intraseasonal Cross-Shelf Variability of Hypoxia along the Newport, Oregon, Hydrographic Line},
	journal = {Journal of Physical Oceanography},
	volume = {46},
	number = {7},
	year = {2016},
	pages = {2219-2238},
	type = {Journal Article},
	abstract = {Observations of hypoxia, dissolved oxygen (DO) concentrations < 1.4 ml L-1, off the central Oregon coast vary in duration and spatial extent throughout each upwelling season. Underwater glider measurements along the Newport hydrographic line (NH-Line) reveal cross-shelf DO gradients at a horizontal resolution nearly 30 times greater than previous ship-based station sampling. Two prevalent hypoxic locations are identified along the NH-Line, as is a midshelf region with less severe hypoxia north of Stonewall Bank. Intraseasonal cross-shelf variability is investigated with 10 sequential glider lines and a midshelf mooring time series during the 2011 upwelling season. The cross-sectional area of hypoxia observed in the glider lines ranges from 0 to 1.41 km2. The vertical extent of hypoxia in the water column agrees well with the bottom mixed layer height. Midshelf mooring water velocities show that cross-shelf advection cannot account for the increase in outer-shelf hypoxia observed in the glider sequence. This change is attributed to an along-shelf DO gradient of -0.72 ml L-1 over 2.58 km or 0.28 ml L-1 km-1. In early July of the 2011 upwelling season, near-bottom cross-shelf currents reverse direction as an onshore flow at 30-m depth is observed. This shoaling of the return flow depth throughout the season, as the equatorward coastal jet moves offshore, results in a more retentive near-bottom environment more vulnerable to hypoxia. Slope Burger numbers calculated across the season do not reconcile this return flow depth change, providing evidence that simplified two-dimensional upwelling model assumptions do not hold in this location.},
	keywords = {Circulation/Dynamics, Coastal flows, Upwelling/downwelling},
	issn = {0022-3670},
	doi = {10.1175/Jpo-D-15-0119.1},
	author = {Adams, K. A. and Barth, J. A. and Shearman, R. K.}
}
@article {RN52,
	title = {Anomalous Near-Surface Low-Salinity Pulses off the Central Oregon Coast},
	journal = {Sci Rep},
	volume = {5},
	year = {2015},
	pages = {17145},
	type = {Journal Article},
	abstract = {From mid-May to August 2011, extreme runoff in the Columbia River ranged from 14,000 to over 17,000 m(3)/s, more than two standard deviations above the mean for this period. The extreme runoff was the direct result of both melting of anomalously high snowpack and rainfall associated with the 2010-2011 La Ni{\~n}a. The effects of this increased freshwater discharge were observed off Newport, Oregon, 180 km south of the Columbia River mouth. Salinity values as low as 22, nine standard deviations below the climatological value for this period, were registered at the mid-shelf. Using a network of ocean observing sensors and platforms, it was possible to capture the onshore advection of the Columbia River plume from the mid-shelf, 20 km offshore, to the coast and eventually into Yaquina Bay (Newport) during a sustained wind reversal event. Increased freshwater delivery can influence coastal ocean ecosystems and delivery of offshore, river-influenced water may influence estuarine biogeochemistry.},
	issn = {2045-2322 (Electronic) 2045-2322 (Linking)},
	doi = {10.1038/srep17145},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/26607750},
	author = {Mazzini, P. L. and Risien, C. M. and Barth, J. A. and Pierce, S. D. and Erofeev, A. and Dever, E. P. and Kosro, P. M. and Levine, M. D. and Shearman, R. K. and Vardaro, M. F.}
}
