Applied Ocean Physics and Engineering (AOP&E)
Permanent URI for this collection
The Department is a major center for research in fluid mechanics, coastal processes, ocean mixing, acoustics, air-sea interaction, deep submergence, ocean systems and moorings, remote sensing, robotics, certain biological processes, image processing, signal processing and estimation, control theory, and the dynamics of ocean cables.
Browse
Recent Submissions
1 - 20 of 1524
-
ArticleDistributed acoustic sensing for future planetary applications: Initial results from the San Francisco Volcanic Field, a lunar analogue(American Geophysical Union, 2024-11-27)Seismic imaging is one of the most powerful tools available for constraining the internal structure and composition of planetary bodies as well as enabling our understanding planetary evolution, geology, and distribution of natural resources. However, traditional seismic instrumentation can be heavy and voluminous, expensive, and/or difficult to rapidly deploy in large numbers. Distributed acoustic sensing (DAS) provides a promising new alternative given the ease of deployment, light weight and simplicity of fiber optic cables. However, the feasibility and best operational practices for using DAS for planetary exploration are not well-known. We examine the use of DAS with surface deployed fiber for planetary near-surface seismic exploration at two lunar geophysical analogue sites in San Francisco Volcanic Field. We compare DAS recordings to 3-component seismometer recordings and geophone shot recordings and determine empirical response functions for the DAS system with respect to the 3-component recordings. Shot sections of DAS and traditional seismic equipment compare well visually, with similar moveout of identifiable phases. DAS records first arrivals in good agreement with seismometers making them suitable for refraction work. Multichannel analysis of surface waves is performed on DAS records to estimate shallow shear velocities. The DAS has high spectral coherence with the horizontal components of ∼0.7 in the frequency band of the seismic shot energy. The empirical response functions are stable with amplitudes of ∼1.0–3.0 × 10−10 m per strain. Finally, the phase response is linear but not flat or zero. Our experiment demonstrates that there is potential for surface deployed DAS in planetary landscapes.
-
ArticlePermafrost thaw subsidence, sea-level rise, and erosion are transforming Alaska's Arctic coastal zone.(National Academy of Sciences, 2024-12-10)Arctic shorelines are vulnerable to climate change impacts as sea level rises, permafrost thaws, storms intensify, and sea ice thins. Seventy-five years of aerial and satellite observations have established coastal erosion as an increasing Arctic hazard. However, other hazards at play—for instance, the cumulative impact that sea-level rise and permafrost thaw subsidence will have on permafrost shorelines—have received less attention, preventing assessments of these processes’ impacts compared to and combined with coastal erosion. Alaska’s Arctic Coastal Plain (ACP) is ideal for such assessments because of the high-density observations of topography, coastal retreat rates, and permafrost characteristics, and importance to Indigenous communities and oilfield infrastructure. Here, we produce 21st-century projections of Arctic shoreline position that include erosion, permafrost subsidence, and sea-level rise. Focusing on the ACP, we merge 5 m topography, satellite-derived coastal lake depth estimates, and empirical assessments of land subsidence due to permafrost thaw with projections of coastal erosion and sea-level rise for medium and high emissions scenarios from the Intergovernmental Panel on Climate Change’s AR6 Report. We find that by 2100, erosion and inundation will together transform the ACP, leading to 6-8x more land loss than coastal erosion alone and disturbing 8-11x more organic carbon. Without mitigating measures, by 2100, coastal change could damage 40 to 65% of infrastructure in present-day ACP coastal villages and 10 to 20% of oilfield infrastructure. Our findings highlight the risks that compounding climate hazards pose to coastal communities and underscore the need for adaptive planning for Arctic coastlines in the 21st century.
-
ArticleThe two-decade evolution of Antarctica's Hektoria Glacier and Its 2022 rapid retreat from satellite observations(American Geophysical Union, 2024-11-28)Beginning in March 2022, the Antarctic Peninsula's Hektoria Glacier experienced an unprecedented retreat of ∼23 km over 1.5 years, one of the fastest observed glacier retreats on record. Improving constraints on the drivers of such extreme events is key to understanding glacier change around the continent and future sea-level rise. We use satellite remote sensing and reanalysis data to characterize changes in Hektoria, a former Larsen B Ice Shelf tributary, over the last ∼20 years and document a period of retreat from 2002 to 2011, and readvancement from 2011 to 2022. We find that the long-term ice front and velocity response (2002–2022) correlated more strongly with changes in modeled ocean temperatures compared to surface air temperatures. However, the acute loss of buttressing support following fast ice collapse paired with a near-contemporaneous extreme atmospheric river in the region likely catalyzed the unprecedented 2022–2023 retreat.
-
ArticleBias‐corrected high‐resolution vertical nitrate profiles from the CTD rosette‐mounted submersible ultraviolet nitrate analyzer(Association for the Sciences of Limnology and Oceanography (ASLO), 2024-11-05)Measurements by the submersible ultraviolet nitrate analyzer (SUNA) can be used to derive high-resolution in situ nitrate concentration with reliable accuracy and precision. Here we report our operational practices for SUNA deployment (including pre-cruise instrument preparation and in-cruise instrument maintenance) and detailed post-cruise nitrate quality control procedures for SUNA integrated onto the CTD rosette. This work is based on experiences and findings from over 500 individual SUNA casts collected from 24 cruises (of which 14 cruises have been quality controlled so far) over the past 5 yr. After applying previously published spectral corrections for temperature, salinity, and pressure effects, we found residual biases in SUNA nitrate estimates compared to independently measured discrete samples. We further develop and assess a new two-step procedure to remove remaining biases: (1) a general temperature-dependent adjustment at low-nitrate concentrations; and (2) a cruise-specific full-range bias correction. Our final quality-controlled SUNA nitrate data achieve an accuracy of 0.34–0.78 μM, with a precision of 0.08–0.21 μM, at a vertical resolution of 1 m. Additional comparisons between the nitrate and density data confirm the high quality of the quality-controlled SUNA data. Although applying spectral correction algorithms increases the accuracy and precision of the instrument-output nitrate concentration, we emphasize that additional constraints of SUNA measurements against other independent sources (e.g., bottle data, temperature, and density) are irreplaceable to ensure the accuracy of final nitrate data.
-
DatasetVoltage scans from a prototype hollow core fiber isotope ratio laser spectrometer(Woods Hole Oceanographic Institution, 2025-11-18)This dataset consiststs of 900 one-second-long voltage acquisitions across 2000 detector channels from a prototype hollow core fiber isotope ratio laser spectrometer developed and operated at the Woods Hole Oceanographic Institution’s David Center for Ocean Innovation. Each acquisition covers a spectral range of ~2290.55 to 2299.15 cm-1. The operational conditions are 10 torr of pure CO2 in a 1m-long hollow core fiber with an inner diameter of 200 µm at 20ºC. The laser was scanned across this spectral range at 50kHz and each one-second acquisition is the average of 50000 individual spectral scans within that one second.
-
ArticleThe probabilistic dependence of ship-induced waves is preserved spatially and temporally in the Savannah River (USA)(Nature Research, 2024-11-15)The rapid changes in the shipping fleet during the last decades has increased the ship-induced loads and, thus, their impact on infrastructures, margin protections and ecosystems. Primary waves have been pointed out as the cause of those impacts, with heights that can exceed 2 m and periods around 2 minutes. Consequently, extensive literature can be found on their estimation mainly from a deterministic perspective with methods based on datasets limited to one location, making difficult their generalization. These studies propose either computationally expensive numerical models or empirical equations which often underestimate the extreme primary waves, hindering their use for design purposes. Moreover, a framework to allow the design of infrastructure under ship-wave attack based on probabilistic concepts such as return periods is still missing. In this study, a probabilistic model based on bivariate copulas is proposed to model the joint distribution of the primary wave height, the peak of the total energy flux, the ship length, the ship width, the relative velocity of the ship and the blockage factor. This model, a vine-copula, is developed and validated for four different deployments along the Savannah river (USA), with different locations and times. To do so, the model is quantified using part of the data in one deployment and validated using the rest of the data from this deployment and data of the other three. The vine-copula is validated from both a predictive performance point of view and with respect to the statistical properties. We prove that the probabilistic dependence of the data is preserved spatially and temporally in the Savannah river.
-
ArticleDrone-based infrared thermography to measure the intranasal temperature of baleen whales(Taylor and Francis Group, 2024-10-23)Traditional methods for quantifying the internal temperature of marine mammals require handling live animals, which is not practical for free-swimming baleen whales. Developing a less invasive, more repeatable method would significantly improve our understanding of whale health and thermal physiology. Infrared thermography (IRT) devices compatible with remotely piloted aircraft systems (RPAS) have facilitated qualitative assessments of heat signatures from marine mammals at sea, but absolute temperatures derived using this approach are rare. The goal of this study was to develop a precise empirical method for estimating intranasal temperatures of baleen whales using RPAS-based IRT. We conducted controlled field experiments and flights over North Atlantic right whales (Eubalaena glacialis, NARWs) to develop and test the methodology. Two approaches were evaluated to estimate intranasal temperatures from IRT sensor intensities: a three-point empirical line regression calibrated per flight using known-temperature objects and a generalized linear model incorporating environmental variables. Controlled field experiments demonstrated that the former approach had a median bias of −0.6°C (interquartile range: 1.5ºC), while the latter approach had unexplained negative proportional bias with increasing true temperature of the target object. After accounting for bias, the former approach yielded an average intranasal temperature of 26.9 ± 1.7°C for 21 unique NARWs. The anatomy of the mysticete upper respiratory tract and physiological heat conservation strategies may explain why estimates were low compared to internal temperatures measured from baleen whales using other techniques (30–39ºC). Variability within whales was less than ± 2°C, supporting the use of these methods to monitor the health of individuals over time. However, variability among whales was greater (up to 7ºC). Improvements in our understanding of whale physiology and respiratory mechanics and advancements in RPAS-based IRT calibrations could make this technology more reliable for assessing individual body temperatures and monitoring populations in the future.
-
ArticleThe abundance and localization of environmental microplastics in gastrointestinal tract and muscle of Atlantic killifish (Fundulus heteroclitus): a pilot study(SpringerOpen, 2024-11-01)Microplastics (MPs) have been found in a diverse range of organisms across trophic levels. While a majority of the information on organismal exposure to plastics in the environment comes from gastrointestinal (GI) data, the prevalence of MP particles in other tissues is not well understood. Additionally, many studies have not been able to detect the smallest, most prevalent, MPs (1 µm – 5 mm) that are the most likely to distribute to tissues in the body. To address these knowledge gaps, MPs in the GI tract and muscle of Atlantic killifish (Fundulus heteroclitus) collected from two sites (Falmouth and Bourne) on Buzzards Bay, Cape Cod, MA were quantified down to 2 µm in size. Eight fish from Falmouth and 10 fish Bourne site were analyzed. Fourier-transform infrared spectroscopy and Raman spectroscopy were used to identify all particles. The mean concentrations of MPs in the GI tract and muscle from fish collected from Falmouth was 85.5 ± 70.2 and 11 ± 12.5 particles per gram wet weight, respectively. Fish collected from Bourne site had mean particle concentrations of 12.2 ± 18.1 and 1.69 ± 5.36 particles per gram wet weight. Of the 2,008 particles analyzed in various fish tissue samples, only 3.4% (69 particles) were identified as plastic; polymers included nylon, polyethylene, polypropylene, and polyurethane. MPs detected in the GI tract samples also tended to be more diverse in both size and polymer type than those found in the muscle. We found that MPs < 50 µm, which are often not analyzed in the literature, were the most common in both the GI tract and muscle samples. There was not a significant correlation between the MP content in the muscle compared to the GI tract, indicating that GI tract MP abundance cannot be used to predict non-GI tract tissue MP content; however, MP abundance in muscle correlated with fish total length, suggesting potential bioaccumulation of these small MPs.
-
ArticleMechanisms regulating coccolithophore dynamics in the Great Calcite Belt in the Southern Ocean in the Community Earth System Model(American Geophysical Union, 2024-11-01)The Great Calcite Belt (GCB) is a region of elevated particulate inorganic carbon (PIC) generated by coccolithophore growth that spans the subantarctic Southern Ocean. The GCB is thought to play an important role in the global carbon cycle. Coccolithophores, however, are sensitive to multiple climate-related environmental factors. To understand these controls on Southern Ocean coccolithophores comprising the GCB, we explore its major bottom-up and top-down processes using the Community Earth System Model (CESM). We find that coccolithophore biomass accumulates where both macronutrients and iron are available at concentrations greater than ∼50% of their half-saturation constants, and temperature is more limiting than both light and nutrients. Coccolithophore biomass is decoupled from growth rates due to top-down control. At higher temperatures and lower latitudes, microzooplankton grazing outpaces coccolithophore growth. This occurs because the temperature dependence of grazing is parameterized with an exponential (Q10) function, whereas coccolithophore growth is parameterized with a power function; these temperature curves diverge at higher temperatures. While the extent of the GCB is primarily controlled by temperature, its magnitude is most strongly controlled by environmental factors affecting iron concentrations. Our results suggest that (a) the temperature relationships for both coccolithophore growth and its loss terms are critical for resolving a GCB in CESM, and (b) the spatial extent of Southern Ocean coccolithophores may be sensitive to continued increases in sea surface temperatures.
-
ArticleAn underwater methane sensor based on laser spectroscopy in a hollow core optical fiber(American Chemical Society, 2024-11-10)Existing sensors for measuring dissolved methane in situ suffer from excessively slow response times or large size and complexity. The technology reported here realizes improvements by utilizing a hollow core optical fiber (HFC) as the detection cell in an underwater infrared laser spectrometer. The sensor operates by using a polymer membrane inlet to continuously extract dissolved gas from water. Once inside the sensor, the gas passes through an HCF, within which tunable diode laser spectroscopy is used to quantify methane. The use of an HCF for the optical cell enables advantages of sensitivity, selectivity, compactness, response time, and ease of integration. A submersible prototype has been developed, characterized in the laboratory, and tested in the ocean to a depth of 2000 m. Initial laboratory environmental testing showed a pCH4 detection range up to 10,000 μatm, an uncertainty of 5.6 μatm or ±1.4% (whichever is greater) and a response time of 4.6 min over a range of controlled operating conditions. Operation at sea demonstrated its utility in generating dissolved methane maps, targeted point sampling, and water column profiling.
-
ArticleField observations of surfzone vorticity(American Geophysical Union, 2024-10-28)In the surfzone, breaking-wave generated eddies and vortices transport material along the coast and offshore to the continental shelf, providing a pathway from land to the ocean. Here, surfzone vorticity is investigated with unique field observations obtained during a wide range of wave and bathymetric conditions on an Atlantic Ocean beach. Small spatial-scale [O(10 m)] vorticity estimated with a 5 m diameter ring of 14 current meters deployed in ∼2 m water depth increased as the directional spread of the wave field increased. Large spatial-scale [O(100 m)] vorticity calculated from remote sensing estimates of currents across the surfzone along 200 m of the shoreline increased as alongshore bathymetric variability (channels, bars, bumps, holes) increased. For all bathymetric conditions, large-scale vorticity in the inner surfzone was more energetic than in the outer surfzone.
-
ArticleEffects of temperature and light on early sporophyte development of Saccharina japonica and S. latissima (Phaeophyta)(Wiley, 2024-10-24)Saccharina japonica is common aquaculture species in Asia, whereas S. latissima is cultivated in North America and Europe. This study aims to select superior strains using breeding techniques for high-temperature tolerance and faster development at the early sporophytic stage. Qualitative experiments were conducted to observe the reproduction and early development of sporophytes under different temperatures (5, 10, 15, and 20°C) and light conditions (5 and 40-μmol photons m−2 s−1) for 20 days after male and female gametophytes were crossed. Two female (F05 and F15, S. japonica; FB and FO, S. latissima) and male (M06 and M14, S. japonica; MB and MO, S. latissima) gametophyte strains in each species were used. No inter-specific crosses were made. Four possible intraspecific crosses were cultured. Regardless of the species, the development of sporophytes was observed earlier at 10°C than all other temperatures (5, 15, and 20°C). No sporophytes were observed at 20°C during the experiment. The crosses of F15xM14 (S. japonica) and FBxMB (S. latissima) showed higher thermal tolerance and rapid development of sporophytes than other crosses. These results suggest that optimal reproduction and early development of sporophytes can vary from species to species of the same genus and even between strains of the same species.
-
ArticleObservations of trash in the deep tropical Atlantic and Caribbean Sea(Elsevier, 2024-10-30)Evidence of anthropogenic impacts on deep-ocean systems is frequently observed, even upon the first explorations of these remote environments. One of these impacts comes from marine debris, trash that is dumped or transported into the deep ocean. Understanding the abundance and distribution of marine debris is critical to identifying holistic changes and feedbacks that influence the health and sustainability of ocean ecosystems. Here, we document widespread plastic, metal, and glass debris in deep waters of the tropical Atlantic and Caribbean Sea, observed by remotely operated and human occupied submersibles. Trash was observed from depths 250 to >6000 m. A total of 139 pieces of debris were found, including a ladder, clothing, cans, cutlery, single-use sauce packages, and a parachute. These findings further illustrate the extent of debris pollution in deep waters and the need to understand the impact of debris pollution on sustainability in Earth's largest habitat.
-
ArticleSubsurface superoxide spans the Baltic Sea(American Geophysical Union, 2024-10-06)Superoxide is a reactive oxygen species that is influential in the redox chemistry of a wide range of biological processes and environmental cycles. Using a novel in situ sensor we report the first water column profiles of superoxide in the Baltic Sea, at concentrations higher than previously observed in other oceans. Our data revealed consistent peaks of superoxide (2.0–15.1 nM) in dark waters just below the mixed layer. The oxic waters, low metal concentrations, and lack of sunlight imply that the peak is likely of biological origin. Several profiles displayed a concomitant dip in dissolved oxygen mirroring this superoxide peak, strongly suggesting a link between the two features. The magnitude and distribution of superoxide observed warrants re-evaluation of the most relevant sources and controls of superoxide in seawater. Locally, these high concentrations of superoxide may create environments conducive to reactions with trace metals and organic matter and present an overlooked sink of oxygen in the Baltic Sea.
-
ArticleContrasting nitrogen dynamics across the Mid-Atlantic Bight shelfbreak front: Insights from nitrate dual isotopes and nitrifier gene abundance(Association for the Sciences of Limnology and Oceanography, 2024-10-01)Observations and model studies suggest that front dynamics can enhance phytoplankton productivity. This study tested whether frontal systems also increase the abundance of nitrifying microbes and nitrogen recycling during repeat sampling transects across the Mid-Atlantic Bight shelfbreak in July 2019. We measured ammonium concentrations, nitrate dual isotopes (δ15N, δ18O), and ammonia monooxygenase subunit A (amoA) genes of ammonia-oxidizing archaea (AOA) and bacteria (AOB). In subsurface shelf waters, ammonium concentrations exceeded 2 μmol L−1, due to a temporary imbalance in regeneration from sinking particles and subsequent nitrification. The inverse correlation between nitrate δ15N values and ammonium concentrations confirmed nitrate was partially or entirely from local nitrification on the shelf. In contrast, the shelfbreak frontal zone and slope sea subsurface waters had much lower ammonium concentrations (0.1–0.2 μmol L−1) due to tight coupling between ammonium regeneration and nitrification. The deviation of nitrate δ15N and δ18O from algal uptake-driven 1 : 1 ratio suggests concurrent nitrification in the euphotic zone. The shelfbreak front acted as an ecological boundary where AOA and AOB amoA gene numbers were partitioned, with AOAs abounding in slope waters and AOBs in shelf waters, likely due to ammonium availability. At certain slope stations, deep-water nutrient inputs via isopycnal lifting induced by Gulf Stream intrusions caused unexpectedly high phytoplankton biomass, which doubled nitrifier abundance and potentially stimulated both ammonium regeneration and nitrification. These findings demonstrate distinct distributions of nitrifying microbes along the salinity gradient from shelf to slope and highlight the significant influence of coastal ocean-western boundary current interactions on nitrogen biogeochemistry.
-
ArticleIt takes a village: the sea of technical, administrative, and other support colleagues who enable ocean science(Oceanography Society, 2024-08-20)Scientific discoveries and progress are often attributed to a single scientist or to a small team of scientists. Increasingly, we also recognize the important contributions of students, postdocs, and early career researchers. But there is a “village” of people behind the scenes in each institution, in each agency, in each ship and shipyard that allows ocean science to function. This large part of our community makes oceanographic research dynamic and achievable. Yet, many of these people are often not well recognized. How can we best acknowledge the tireless and often invisible workers who make scientists look good?
-
ArticleMisaligned wind-waves behind atmospheric cold fronts(American Geophysical Union, 2024-08-24)Atmospheric fronts embedded in extratropical cyclones are high-impact weather phenomena, contributing significantly to mid-latitude winter precipitation. The three vital characteristics of the atmospheric fronts, high wind speeds, abrupt change in wind direction, and rapid translation, force the induced surface waves to be misaligned with winds exclusively behind the cold fronts. The effects of the misaligned waves under atmospheric cold fronts on air-sea fluxes remain undocumented. Using the multi-year in situ near-surface observations and direct covariance flux measurements from the Pioneer Array off the coast of New England, we find that the majority of the passing cold fronts generate misaligned waves behind the cold front. Once generated, the waves remain misaligned, on average, for about 8 hr. The parameterized effect of misaligned waves in a fully coupled model significantly increases the roughness length (185%), drag coefficient (19%), and air-sea momentum flux (11%). The increased surface drag reduces the wind speeds in the surface layer. The upward turbulent heat flux is weakly decreased by the misaligned waves because of the decrease in temperature and humidity scaling parameters being greater than the increase in friction velocity. The misaligned wave effect is not accurately represented in a commonly used wave-based bulk flux algorithm. Yet, considering this effect in the current formulation improves the overall accuracy of parameterized momentum flux estimates. The results imply that better representing a directional wind-wave coupling in the bulk formula of the numerical models may help improve the air-sea interaction simulations under the passing atmospheric fronts in the mid-latitudes.
-
ArticleA deep-sea isopod that consumes Sargassum sinking from the ocean's surface(The Royal Society, 2024-09-11)Most deep-ocean life relies on organic carbon from the surface ocean. While settling primary production rapidly attenuates in the water column, pulses of organic material can be quickly transported to depth in the form of food falls. One example of fresh material that can reach great depths across the tropical Atlantic Ocean and Caribbean Sea is the pelagic macroalgae Sargassum. However, little is known about the deep-ocean organisms able to use this food source. Here, we encountered the isopod Bathyopsurus nybelini at depths 5002–6288 m in the Puerto Rico Trench and Mid-Cayman Spreading Center using the Deep Submergence Vehicle Alvin. In most of the 32 observations, the isopods carried fronds of Sargassum. Through an integrative suite of morphological, DNA sequencing, and microbiological approaches, we show that this species is adapted to feed on Sargassum by using a specialized swimming stroke, having serrated and grinding mouthparts, and containing a gut microbiome that provides a dietary contribution through the degradation of macroalgal polysaccharides and fixing nitrogen. The isopod’s physiological, morphological, and ecological adaptations demonstrate that vertical deposition of Sargassum is a direct trophic link between the surface and deep ocean and that some deep-sea organisms are poised to use this material.
-
ArticleInteracting influences of diurnal tides, winds, and river discharge on a large coastal plume(American Geophysical Union, 2024-09-03)The dispersal of large river plumes in the coastal ocean depends on multiple factors, and in some cases, can be categorized into distinct dynamical regimes: a tidally dominated near-field, a rotational mid-field, and a coastal current far-field. In this study, observations and modeling are used to evaluate the factors controlling the variability in the buoyant plume from Mobile Bay. Rather than distinct dynamical regimes, the Mobile Bay plume depends on forcings that act at overlapping temporal and spatial scales: diurnal tides, river discharge events, and winds. Satellite synthetic aperture radar images along with shipboard in-situ sampling and marine radar are used to observe plume fronts in spring 2021. Hydrodynamic model simulations are compared with observations and used to characterize a large coastal plume at consistent tidal phase across a range of forcing conditions. The along-shore position of the plume depends primarily on advection by wind-driven surface currents. The cross-shore extent and plume area depend primarily on the tidal amplitude and river discharge, and secondarily on northerly (seaward) winds. Along-shore winds influence the buoyancy anomaly by altering salinity in the estuary and offshore. Upwelling winds increase the buoyancy anomaly and advect previous plumes away from the mouth. Downwelling winds reduce the buoyancy anomaly by trapping previous plumes near the coast and directing freshwater discharge toward a secondary outlet. Thus, the combined, overlapping influences of the tide, wind, and discharge dominate the variability in freshwater delivery to the shelf at time scales of days and distances of tens of km.
-
ArticleAcoustic scattering by smooth and rough elastic cylinders insonified by directional sonars: Bistatic experiments(Acoustical Society of America, 2024-10-02)Bistatic laboratory measurements are presented for acoustic scattering from both smooth and rough elastic cylinders insonified by directional spherical waves. A scattering model, accounting for incident directional spherical waves while assuming negligible end effects, was derived in a previous article [Mursaline, Stanton, Lavery, and Fischell, J. Acoust. Soc. Am. 154, 307–322 (2023)] but only evaluated for monostatic scattering by smooth cylinders. The evaluation is extended here to bistatic geometries for both smooth and rough cylinders. The effect of axi-symmetric Gaussian roughness (axi-symmetric random variations in cylinder radius) on the cylinder on overall scattering levels and resonances is investigated. Particular emphasis is given to the influence of roughness on the excitation of axially propagating guided wave resonances associated with oblique incident angles. Bistatic laboratory observations presented herein further substantiate the effects on scattering due to the properties of the incident field from practical sonars, such as spherical spreading, as observed in the above-mentioned article. For smooth cylinders, axially propagating guided wave resonances are seen to become more prominent during bistatic in-plane scattering compared to bistatic orthogonal-plane scattering and previously published monostatic data. For rough cylinders, both overall scattering levels and resonances are found to be diminished compared to the smooth case.