Temperature variability plays an important role in estuarine ecosystems but is understudied because it is not typically a primary driver of circulation. Here, temperature variability within the Delaware Estuary system (defined to include the tidal river, estuary, bay, and adjacent shelf) is characterized over tidal to interannual timescales using nearly 20-year records of surface temperature from eight NOAA monitoring sites. The seasonal cycle explains ≥ 93 ^∘ C). A combination of spring-neap, weather-band, and river discharge variations generate ∼ 1-6 ^∘ C fluctuations, and semidiurnal tidal variability is ∼ 1-3 ^∘ C. The along-estuary surface temperature gradient reverses seasonally, with a summertime mid-estuary temperature maximum in most years. Satellite sea-surface temperature data and near-surface temperature data from eight along-estuary seasonal cruises in 2010 and 2011, which provide greater horizontal resolution than the NOAA sites, are used to further evaluate along-system patterns. Despite a significant warming trend on the shelf, long-term trends in water temperature are statistically insignificant within the estuary. There is interannual variability in the characteristics of the seasonal cycle at each site, including annual minimum/maximum surface temperatures (which vary up to ∼ 6 ^∘ C from year to year), the onset of the warming season (+/- 30 days), and the length of the warming season (+/- 40 days), but there are no long-term trends in these characteristics over the 20-year record. This system-wide characterization of surface temperature patterns, variability, and change provides a foundation for future studies of mechanisms controlling temperature variability.

Olympic Coast National Marine Sanctuary (OCNMS) off Washington State was designated by the National Oceanic and Atmospheric Administration (NOAA) in 1994 and is embedded in the northern California Current (NCC) system, which is affected by climate fluctuations such as marine heat waves, El Niño, hypoxia, ocean acidification, and changes in timing of the spring transition to upwelling conditions. There is a need to better understand the climatological conditions in the Sanctuary, especially considering the presence of four Coastal Treaty Tribes with treaty-protected rights to marine resources on the Olympic Coast. Oceanographic moorings at five cross-shelf lines along the Olympic Coast have measured surface and subsurface water properties from 2000 to present. Measurements focus on the summer upwelling season, when hydrographic conditions fluctuate on the time scale of local wind events and remotely-generated coastal trapped waves, and biogeochemical stressors like hypoxia and ocean acidification tend to worsen. Additionally, temperature sensors deployed at the Teahwhit Head site and, in more recent years, at the Makah Bay site in 42 meters water depth remain in the water throughout the year to measure winter temperatures. This article provides a description of the OCNMS mooring program and our efforts to combine 26 years of water temperature, salinity, dissolved oxygen, pressure, and velocity data into quality-controlled time series available via Zenodo at https://doi.org/10.5281/zenodo.19751759.

The NSF Ocean Observatories Initiative (OOI) Coastal Endurance Washington Offshore Profiler Mooring (CE09OSPM) was first deployed in April 2014. The mooring is located on the Washington continental slope about 60 km west of Grays Harbor, WA at 46.8517°N, 124.982°W. This mooring includes a McLane® Moored Profiler (MMP), which carries energy-efficient instruments that simultaneously measure water temperature, conductivity, pressure, and dissolved oxygen, as well as photosynthetically active radiation, chlorophyll-a fluorescence, coloured dissolved organic matter, optical backscatter, and water velocity. Moving at about 25 cm/s, the MMP collects up to eight profiles per day between approximately 35 m and 510 m water depth. This data article describes a data set that consists of 3244 daily averaged temperature, practical salinity, potential density, and dissolved oxygen profiles collected between October 2014 and May 2025 that were processed using a MATLAB® toolbox that was specifically created to process OOI MMP data. The toolbox imports unpacked MMP data files, applies the necessary calibration coefficients and data corrections, including adjusting for thermal-lag, flow, and sensor time constant effects, and produces a final, 0.5-dbar binned data set. From the daily, gridded profiler data, we calculated seasonal cycles for each variable using a least squares fit of the annual, semi-annual, and triannual harmonics. These gridded profiler data, which are vital for advancing our understanding of subsurface oceanographic phenomena — including modulation of the California Undercurrent, water mass and upwelling source water variability, marine heat waves, ocean acidification, and the increasing prevalence and severity of seasonal hypoxia in the Northern California Upwelling System — are available via Zenodo at https://doi.org/10.5281/zenodo.15627742.

Olympic Coast National Marine Sanctuary (OCNMS), which was established in 1994 and covers an area of 8257 km2, is located along Washington State's remote and rugged outer coast towards the northernmost extent of the California Current System (CCS). In this region, summertime equatorward winds drive seasonal upwelling of cold, nutrient rich waters onto the continental shelf. These waters help fuel a highly diverse and productive ecosystem that includes marine mammal and seabird communities as well as commercially and culturally important fisheries. The sanctuary is located within the boundaries of the legally defined Usual and Accustomed (U&A) fishing grounds of four Coastal Treaty Tribes, the Hoh Tribe, Makah Tribe, Quileute Tribe, and the Quinault Indian Nation, which hold treaty fishing rights and co-manage fisheries and other natural resources within the sanctuary through state, federal, and international partnerships and agreements. This data article describes shipboard hydrographic Conductivity-Temperature-Depth (CTD) and dissolved oxygen profile data that were collected within the sanctuary at fourteen locations during mooring deployment, recovery, and maintenance cruises between the months of May and October from 2005–2023. The 792 CTD profiles were acquired using Sea-Bird Scientific 19 SeaCAT or 19plus SeaCAT CTD profilers with associated SBE-43 (Sea-Bird Electronics) or Beckman or YSI-type (Yellow Springs Instruments) dissolved oxygen sensors. The data were processed using Sea-Bird Scientific's SBE Data Processing application. These data are needed for improving our understanding of subsurface oceanographic conditions — including marine heat waves, changes in timing of spring transition to upwelling, seasonal hypoxia, and ocean acidification — in this important but undersampled region, and can be used to help improve the management of marine resources regionally and within the sanctuary. The CTD cast data are available via Zenodo at https://doi.org/10.5281/zenodo.10466124.

We use moored observations in 80 m water depth at the NH-10 site along the historic Newport Hydrographic Line from 1999 to 2021 to calculate water temperature anomalies at the surface, near surface, and bottom. Analysis is focused on the subsurface temporal and spatial characteristics of marine heatwaves (MHWs) during 2014-2016 and 2019-2020 on the continental shelf and slope. Warm anomalies extend throughout the water column in fall/winter 2014-2016 when winds are predominantly downwelling-favorable, while the 2019-2020 period is characterized by shallower summer and fall anomalies on the shelf. Sustained temperature anomalies during the bottom MHW in late 2016 are the largest in the NH-10 time series. Analysis of temporal patterns in wind stress during MHW and non-MHW periods shows the onset of upwelling-favorable winds interrupts warm events. Indices of cumulative upwelling and annual spring transition dates reveal the spring transition was unusually late in 2014, with only five years with later spring transitions since the upwelling index record began in 1967. In 2015 and 2019, in contrast, spring transition is close to the climatological mean of April 15. In 2016 and 2020, anomalous warming is observed when cumulative upwelling decreases after an early spring transition.

The highly biologically productive northern California Current, which includes the Oregon continental shelf, is an archetypal eastern boundary region with summertime upwelling driven by prevailing equatorward winds and wintertime downwelling driven by prevailing poleward winds. Between 1960 and 1990, monitoring programs and process studies conducted off the central Oregon coast advanced the understanding of many oceanographic processes, including coastal trapped waves, seasonal upwelling and downwelling in eastern boundary upwelling systems, and seasonal variability of coastal currents. Starting in 1997, the U.S. Global Ocean Ecosystems Dynamics – Long Term Observational Program (GLOBEC-LTOP) continued those monitoring and process study efforts by conducting routine CTD (Conductivity, Temperature, and Depth) and biological sampling survey cruises along the Newport Hydrographic Line (NHL; 44.652°N, 124.1 – 124.65°W), located west of Newport, Oregon. Additionally, GLOBEC-LTOP maintained a mooring slightly south of the NHL, nominally at 44.64°N, 124.30°W, on the 81-meter isobath. This location is referred to as NH-10, as it is located 10 nautical miles or 18.5 km west of Newport. A mooring was first deployed at NH-10 in August 1997. This subsurface mooring collected water column velocity data using an upward-looking acoustic Doppler current profiler. A second mooring with a surface expression was deployed at NH-10 starting in April 1999. This mooring included velocity, temperature and conductivity measurements throughout the water column as well as meteorological measurements. GLOBEC-LTOP and the Oregon State University (OSU) National Oceanographic Partnership Program (NOPP) provided funding for the NH-10 moorings from August 1997 to December 2004. Since June 2006, the NH-10 site has been occupied by a series of moorings operated and maintained by OSU with funding from the Oregon Coastal Ocean Observing System (OrCOOS), the Northwest Association of Networked Ocean Observing Systems (NANOOS), the Center for Coastal Margin Observation & Prediction (CMOP), and most recently the Ocean Observatories Initiative (OOI). While the objectives of these programs differed, each program contributed to long-term observing efforts with moorings routinely measuring meteorological and physical oceanographic variables. This article provides a brief description of each of the six programs, their associated moorings at NH-10, and our efforts to combine over twenty years of temperature, practical salinity, and velocity data into one coherent, hourly averaged, quality-controlled data set. Additionally, the data set includes best-fit seasonal cycles calculated at a daily temporal resolution for each variable using harmonic analysis with a three-harmonic fit to the observations. The stitched together, hourly NH-10 time series and seasonal cycles are available via Zenodo at https://doi.org/10.5281/zenodo.7582475.

Odontocetes play an important ecological role as apex predators in the northern California Current System (CCS), which is characterized by seasonal rises in primary productivity fueled by wind-driven upwelling of cold nutrient-rich water. This productivity sustains higher trophic-level prey optimal for deep-diving odontocetes including beaked and sperm whales. Due to the cryptic ecology of these whales, there are few systematic studies of their occurrence across seasons in northern CCS waters. The Holistic Assessment of Living marine resources off Oregon (HALO) Project—a collaboration between Oregon State University and Cornell University—addresses this gap via quarterly vessel-based visual surveys and year-round passive acoustic monitoring (PAM). Here, we detect and classify species-specific odontocete acoustic signals using long-term spectral averages, automated click detection, and unsupervised clustering of semi-continuous PAM data from 10/2021 to 12/2022. Site-specific occurrence of beaked and sperm whales is revealed on hourly to seasonal temporal scales at three recording sites along a depth gradient spanning the continental slope (300 and 630 m water depth) and abyssal plain (2860 m). By relating odontocete detections to dynamic oceanographic conditions from nearby profiling moorings, we identify likely drivers of prey availability influencing predator distribution. These results will inform conservation efforts of cryptic odontocetes in the face of rapid environmental change.

Under future climate scenarios, ocean temperatures that are presently extreme and qualify as marine heatwaves (MHW) are forecasted to increase in frequency and intensity, but little is known about the impact of these events on one of the most common paleoproxies, planktonic foraminifera. Planktonic foraminifera are globally ubiquitous, shelled marine protists. Their abundances and geochemistry vary with ocean conditions and fossil specimens are commonly used to reconstruct ancient ocean conditions. Planktonic foraminiferal assemblages are known to vary globally with sea surface temperature, primary productivity, and other hydrographic conditions, but have not been studied in the context of mid-latitude MHWs. For this study, the community composition and abundance of planktonic foraminifera were quantified for 2010-2019 along the Newport Hydrographic Line, a long-term monitoring transect at 44.6°N in the Northern California Current (NCC). Samples were obtained from archived plankton tows spanning 46 to 370 km offshore during annual autumn (August – October) cruises. Two MHWs impacted the region during this timeframe: the first during 2014-2016 and a second, shorter duration MHW in 2019. During the 2014-2016 MHW, warm water subtropical and tropical foraminifera species were more prevalent than the typical polar, subpolar, and transitional species common to this region. Cold water species were abundant again after the first MHW dissipated in late 2016. During the second, shorter-duration MHW in 2019, the assemblage consisted of a warm water assemblage but did not include tropical species. The foraminiferal assemblage variability correlated with changes in temperature and salinity in the upper 100 meters and was not correlated with distance offshore or upwelling. These results suggest that fossil foraminiferal assemblages from deep sea sediment cores may provide insight into the magnitude and frequency of past MHWs.

Outputs of the regional ocean circulation model are analyzed to demonstrate the measurable impact of the El Nino remote oceanic forcing mechanism along the US West Coast during the major heat wave period of 2014-2016. The 2-km horizontal resolution model, based on the Regional Ocean Modeling System (ROMS), was run for the period of 2009-2018. Though the model does not assimilate observations, it performs well by comparison with time series data explaining observed variability on temporal scales from several days to seasonal and interannual. The El Nino-related oceanic anomalies provided by a global state estimate are introduced in the regional model at the southern boundary at 24N. These propagate alongshore with coastally trapped waves (CTWs) and influence the variability off Oregon (41 degrees-46 degrees N). In particular, CTWs are evident in the subsurface along-slope current, v(s), and in the depth of the 26.5 kg m(-3) isopycnal surface over the slope, z(26.5). In summer 2014 and 2015, v(s) anomalies are positive (northward) and z(26.5) anomalies are negative (deeper) along the US West Coast. In addition to the CTW patterns, z(26.5) anomalies also exhibit slow-moving features associated with undercurrent widening, separation, and subsurface eddy variability. Over the Oregon shelf, El Nino conditions contributed to the sharp weakening of the southward alongshore current throughout the water column in July 2014 and 2015, despite the near-average southward, upwelling-favorable winds.

This data set, described in detail in Risien et al. (2022), contains Newport Hydrographic Line station data; gridded, cross-shelf hydrographic sections; and derived monthly climatologies for temperature, practical salinity, potential density, spiciness, and dissolved oxygen. It consists of CSV (Comma Separated Values) files (newport_hydrographic_line_station_data.zip) that contain CTD observations collected at the seven hydrographic stations located 1, 3, 5, 10, 15, 20 and 25 nautical miles west of Newport, Oregon between March 1997 and July 2021. Additionally, the data set contains three NetCDF files that follow CF (Climate and Forecast) metadata conventions: newport_hydrographic_line_gridded_sections.nc contains observations gridded to a 0.01o x 1 dbar longitude - pressure grid to create cross-shelf hydrographic sections for each of the five variables for each cruise. newport_hydrographic_line_gridded_section_climatologies.nc contains climatological hydrographic sections, calculated using harmonic analysis over the 24-year period March 1997 to February 2021 and reported here for the middle of each month, and newport_hydrographic_line_gridded_section_coefficients.nc contains the associated linear regression model coefficients for all five variables. From the regression coefficients, users can construct seasonal cycles at any location in the gridded section with a temporal resolution that best suits their specific needs. Finally, this data set includes example MATLAB and R scripts that show how to read the data files, plot cross-shelf hydrographic sections, and calculate daily and monthly climatologies using the regression coefficients.

The vast spatial extent of the ocean presents a major challenge for monitoring changes in marine biodiversity and connecting those changes to management practices. Remote-sensing offers promise for overcoming this problem in a cost-effective, tractable way, but requires interdisciplinary expertise to identify robust approaches. In this study, we use generalized additive mixed models to evaluate the relationship between an epipelagic fish community in the Northeastern Pacific Ocean and oceanographic predictor variables, quantified in situ as well as via remote-sensing. We demonstrate the utility of using MODIS Rrs555 fields at monthly and interannual timescales to better understand how freshwater input into the Northern California Current region affects higher trophic level biology. These relationships also allow us to identify a gradient in community composition characteristic of warmer, offshore areas and cooler, nearshore areas over the period 2003–2012, and predict community characteristics outside of sampled species data from 2013 to 2015. These spatial maps therefore represent a new, temporally and spatially explicit index of community differences, potentially useful for filling gaps in regional ecosystem status reports and is germane to the broader ecosystem-based fisheries management context.

The filtering properties of the standardized precipitation index (SPI), the Palmer drought severity index (PDSI), and the model calibrated drought index (MCDI) are investigated to determine their relations to past, present, and future precipitation anomalies in regions with a wide diversity of precipitation characteristics. All three indices can be closely approximated by weighted averages of precipitation, but with different weighting. The SPI is well represented by one-sided, uniformly weighted averages; the MCDI is well represented by one-sided, exponentially weighted averages; and the PDSI is well represented by two-sided, exponentially weighted averages with much higher weighting of past and present precipitation than future precipitation. Detailed analyses identify interpretational complications and other undesirable features in the SPI and PDSI. In addition, the PDSI and MCDI are each restricted to single regionally specific "intrinsic'' time scales that can significantly differ between the two indices. Inspired by the strengths of the SPI, PDSI, and MCDI, a hybrid index is developed that consists of exponentially weighted averages of past and present precipitation that are implicit in the PDSI and MCDI. The explicit specification of the exponential weighting allows users to control the time scale of the hybrid index to investigate precipitation variability on any time scale of interest. This advantage over the PDSI and MCDI is analogous to the controllability of the time scale of the SPI, but the exponentially fading memory is more physical than the uniform weighting of past and present precipitation in the SPI.

The hybrid precipitation index developed in Part I of this study is applied to investigate precipitation variability along the west coast of North America during the wet season November–March on monthly-to-interannual time scales. The variability in each of six regions considered in this study is negatively correlated with nearby 500-hPa geopotential height anomalies. Except in Southeast Alaska, these correlation patterns indicate that precipitation variability in each region is predominantly influenced by local atmospheric forcing analogous to the ridging of the westerly flow that has been studied extensively with regard to California drought variability. The first empirical orthogonal function (EOF) accounts for nearly all of the Southeast Alaska precipitation variability, which is controlled by the strength of the onshore flow rather than ridging. In association with this mode of variability, precipitation anomalies of opposite sign account for about 40% of the precipitation variance in Northern California and Oregon on all time scales. On short time scales, the second and third EOFs account primarily for precipitation variability in British Columbia/Washington and California, respectively. With increasing time scale, the third EOF diminishes in importance and the second EOF evolves into a pattern of synchronous precipitation anomalies of the same sign from British Columbia to Northern California. Precipitation variability in Southern California is only modestly related to precipitation elsewhere. With increasing time scale, Southern California precipitation variability becomes increasingly related to precipitation anomalies of opposite sign in Washington.

The ocean knows no political borders. Ocean processes, like summertime wind-driven upwelling, stretch thousands of kilometers along the Northeast Pacific (NEP) coast. This upwelling drives marine ecosystem productivity and is modulated by weather systems and seasonal to interdecadal ocean-atmosphere variability. Major ocean currents in the NEP transport water properties such as heat, fresh water, nutrients, dissolved oxygen, pCO(2), and pH close to the shore. The eastward North Pacific Current bifurcates offshore in the NEP, delivering open-ocean signals south into the California Current and north into the Gulf of Alaska. There is a large and growing number of NEP ocean observing elements operated by government agencies, Native American Tribes, First Nations groups, not-for-profit organizations, and private entities. Observing elements include moored and mobile platforms, shipboard repeat cruises, as well as land-based and estuarine stations. A wide range of multidisciplinary ocean sensors are deployed to track, for example, upwelling, downwelling, ocean productivity, harmful algal blooms, ocean acidification and hypoxia, seismic activity and tsunami wave propagation. Data delivery to shore and observatory controls are done through satellite and cell phone communication, and via seafloor cables. Remote sensing from satellites and land-based coastal radar provide broader spatial coverage, while numerical circulation and biogeochemical modeling complement ocean observing efforts. Models span from the deep ocean into the inland Salish Sea and estuaries. NEP ocean observing systems are used to understand regional processes and, together with numerical models, provide ocean forecasts. By sharing data, experiences and lessons learned, the regional ocean observatory is better than the sum of its parts.

Over the past few decades coastal regions have experienced considerable socio-economic change. Accompanying these socio-economic shifts are unprecedented environmental changes, which include variation in magnitude and frequency of extreme weather events, marine heatwaves, increased ocean acidification, expansion of dead zones, extreme harmful algal blooms, and accelerating sea level rise. To understand these emerging environmental shifts, the past two decades have witnessed increased capacity to monitor changing environmental conditions and predict with greater accuracy such variations and events. These observation and prediction systems produce ever increasing amounts of data. Ongoing efforts to deliver this information using standard data models, metadata, data access protocols, and community accepted data server applications have helped reduce the heterogeneity of these data and improved data distribution. However, delivering critical information to stakeholders in a user-friendly and accessible manner remains a challenge. Beginning in 2009, the Northwest Association of Networked Ocean Observing Systems (NANOOS), the U.S. Integrated Ocean Observing System (IOOS) regional association for the Pacific Northwest, began to address this challenge by developing the NANOOS Visualization System (NVS), a map-based platform that aggregated a multitude of diverse data sets and forecast model fields into one system with the goal of delivering a more seamless, one-stop-shopping experience for users of coastal, ocean and atmospheric data. Here we describe the early vision and development of NVS and how it evolved into a flexible, multi-application platform where customized web applications can be developed to meet the needs of specific stakeholder groups. We focus on three applications (Seacast, Shellfish Growers, and Tsunami Evacuation Zones) that were developed using more formal design processes in close coordination with commercial crab fishermen, shellfish growers, and state and local emergency managers. In addition, we briefly describe the Tuna Fishers application, which evolved out of informal discussions with recreational tuna fishers. In highlighting these applications, we demonstrate the flexibility of NVS to quickly spin up prototype applications using pre-existing NVS framework elements. Working closely with small groups of dedicated stakeholders, we are then able to refine and extend an application before releasing it to the broader audience. Such a capability has enabled NANOOS to truly meet stakeholder needs, while increasing user capacity to understand and better respond to ongoing regional environmental changes.

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 Nino-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.