Shin, D. W., G. A. Baigorria, Y.-K. Lim, S. Cocke, T. E. LaRow, J. J. O'Brien, and J. W. Jones. (2009). Assessing Crop Yield Simulations with Various Seasonal Climate Data.
Science and Technology Infusion Climate Bulletin, .
Smith, S. R., Alory, G., Andersson, A., Asher, W., Baker, A., Berry, D. I., et al. (2019). Ship-Based Contributions to Global Ocean, Weather, and Climate Observing Systems.
Front. Mar. Sci., 6, 434.
Abstract: The role ships play in atmospheric, oceanic, and biogeochemical observations is described with a focus on measurements made near the ocean surface. Ships include merchant and research vessels; cruise liners and ferries; fishing vessels; coast guard, military, and other government-operated ships; yachts; and a growing fleet of automated surface vessels. The present capabilities of ships to measure essential climate/ocean variables and the requirements from a broad community to address operational, commercial, and scientific needs are described. The authors provide a vision to expand observations needed from ships to understand and forecast the exchanges across the ocean–atmosphere interface. The vision addresses (1) recruiting vessels to improve both spatial and temporal sampling, (2) conducting multivariate sampling on ships, (3) raising technology readiness levels of automated shipboard sensors and ship-to-shore data communications, (4) advancing quality evaluation of observations, and (5) developing a unified data management approach for observations and metadata that meet the needs of a diverse user community. Recommendations are made focusing on integrating private and autonomous vessels into the observing system, investing in sensor and communications technology development, developing an integrated data management structure that includes all types of ships, and moving toward a quality evaluation process that will result in a subset of ships being defined as mobile reference ships that will support climate studies. We envision a future where commercial, research, and privately owned vessels are making multivariate observations using a combination of automated and human-observed measurements. All data and metadata will be documented, tracked, evaluated, distributed, and archived to benefit users of marine data. This vision looks at ships as a holistic network, not a set of disparate commercial, research, and/or third-party activities working in isolation, to bring these communities together for the mutual benefit of all.
Smith, S. R., Briggs, K., Bourassa, M. A., Elya, J., & Paver, C. R. (2018). Shipboard automated meteorological and oceanographic system data archive: 2005-2017.
Geosci Data J, 5(2), 73–86.
Abstract: Since 2005, the Shipboard Automated Meteorological and Oceanographic System (SAMOS) initiative has been collecting, quality-evaluating, distributing, and archiving underway navigational, meteorological, and oceanographic observations from research vessels. Herein we describe the procedures for acquiring ship and instrumental metadata and the one-minute interval observations from 44 research vessels that have contributed to the SAMOS initiative from 2005 to 2017. The overall data processing workflow and quality control procedures are documented along with data file formats and version control procedures. The SAMOS data are disseminated to the user community via web, FTP, and Thematic Real-time Environmental Distributed Data Services from both the Marine Data Center at the Florida State University and the National Centers for Environmental Information, which serves as the long-term archive for the SAMOS initiative. They have been used to address topics ranging from air-sea interaction studies, the calibration, evaluation, and development of satellite observational products, the evaluation of numerical atmospheric and ocean models, and the development of new tools and techniques for geospatial data analysis in the informatics community. Maps provide users the geospatial coverage within the SAMOS dataset, with a focus on the Essential Climate/Ocean Variables, and recommendations are made regarding which versions of the dataset should be accessed by different user communities.
Smith, S. R., Lopez, N., & Bourassa, M. A. (2016). SAMOS air-sea fluxes: 2005-2014.
Geosci. Data J., 3(1), 9–19.
Stukel, M. R., Aluwihare, L. I., Barbeau, K. A., Chekalyuk, A. M., Goericke, R., Miller, A. J., et al. (2017). Mesoscale ocean fronts enhance carbon export due to gravitational sinking and subduction.
Proc Natl Acad Sci U S A, 114(6), 1252–1257.
Abstract: Enhanced vertical carbon transport (gravitational sinking and subduction) at mesoscale ocean fronts may explain the demonstrated imbalance of new production and sinking particle export in coastal upwelling ecosystems. Based on flux assessments from 238U:234Th disequilibrium and sediment traps, we found 2 to 3 times higher rates of gravitational particle export near a deep-water front (305 mg Cm-2d-1) compared with adjacent water or to mean (nonfrontal) regional conditions. Elevated particle flux at the front was mechanistically linked to Fe-stressed diatoms and high mesozooplankton fecal pellet production. Using a data assimilative regional ocean model fit to measured conditions, we estimate that an additional approximately 225 mg Cm-2d-1 was exported as subduction of particle-rich water at the front, highlighting a transport mechanism that is not captured by sediment traps and is poorly quantified by most models and in situ measurements. Mesoscale fronts may be responsible for over a quarter of total organic carbon sequestration in the California Current and other coastal upwelling ecosystems.
Stukel, M. R., Biard, T., Krause, J. W., & Ohman, M. D. (2018). Large Phaeodaria in the twilight zone: Their role in the carbon cycle.
Association for the Sciences of Limnology and Oceanography, .
Abstract: Advances in in situ imaging allow enumeration of abundant populations of large Rhizarians that compose a substantial proportion of total mesozooplankton biovolume. Using a quasi-Lagrangian sampling scheme, we quantified the abundance, vertical distributions, and sinking‐related mortality of Aulosphaeridae, an abundant family of Phaeodaria in the California Current Ecosystem. Inter‐cruise variability was high, with average concentrations at the depth of maximum abundance ranging from < 10 to > 300 cells m−3, with seasonal and interannual variability associated with temperature‐preferences and regional shoaling of the 10°C isotherm. Vertical profiles showed that these organisms were consistently most abundant at 100�150 m depth. Average turnover times with respect to sinking were 4.7�10.9 d, equating to minimum in situ population growth rates of ~ 0.1�0.2 d−1. Using simultaneous measurements of sinking organic carbon, we find that these organisms could only meet their carbon demand if their carbon : volume ratio were ~ 1 μg C mm−3. This value is substantially lower than previously used in global estimates of rhizarian biomass, but is reasonable for organisms that use large siliceous tests to inflate their cross‐sectional area without a concomitant increase in biomass. We found that Aulosphaeridae alone can intercept > 20% of sinking particles produced in the euphotic zone before these particles reach a depth of 300 m. Our results suggest that the local (and likely global) carbon biomass of Aulosphaeridae, and probably the large Rhizaria overall, needs to be revised downwards, but that these organisms nevertheless play a major role in carbon flux attenuation in the twilight zone.
Stukel, M. R., Ohman, M. D., Kelly, T. B., & Biard, T. (2019). The Roles of Suspension-Feeding and Flux-Feeding Zooplankton as Gatekeepers of Particle Flux Into the Mesopelagic Ocean in the Northeast Pacific.
Front. Mar. Sci., 6.
Abstract: Zooplankton are important consumers of sinking particles in the ocean's twilight zone. However, the impact of different taxa depends on their feeding mode. In contrast to typical suspension-feeding zooplankton, flux-feeding taxa preferentially consume rapidly sinking particles that would otherwise penetrate into the deep ocean. To quantify the potential impact of two flux-feeding zooplankton taxa [Aulosphaeridae (Rhizaria), and Limacina helicina (euthecosome pteropod)] and the total suspension-feeding zooplankton community, we measured depth-stratified abundances of these organisms during six cruises in the California Current Ecosystem. Using allometric-scaling relationships, we computed the percentage of carbon flux intercepted by flux feeders and suspension feeders. These estimates were compared to direct measurements of carbon flux attenuation (CFA) made using drifting sediment traps and U-238-Th-234 disequilibrium. We found that CFA in the shallow twilight zone typically ranged from 500 to 1000 m mol organic C flux remineralized per 10-m vertical depth bin. This equated to approximately 6-10% of carbon flux remineralized/10 m. The two flux-feeding taxa considered in this study could account for a substantial proportion of this flux near the base of the euphotic zone. The mean flux attenuation attributable to Aulosphaeridae was 0.69%/10 m (median = 0.21%/10 m, interquartile range = 0.04-0.81%) at their depth of maximum abundance (similar to 100 m), which would equate to similar to 10% of total flux attenuation in this depth range. The maximum flux attenuation attributable to Aulosphaeridae reached 4.2%/10 m when these protists were most abundant. L. helicina, meanwhile, could intercept 0.45-1.6% of carbon flux/10 m, which was slightly greater (on average) than the Aulosphaeridae. In contrast, suspension-feeding zooplankton in the mesopelagic (including copepods, euphausiids, appendicularians, and ostracods) had combined clearance rates of 2-81 L m(-3) day(-1) (mean of 19.6 L m(-3) day(-1)). This implies a substantial impact on slowly sinking particles, but a negligible impact on the presumably rapidly sinking fecal pellets that comprised the majority of the material collected in sediment traps. Our results highlight the need for a greater research focus on the many taxa that potentially act as flux feeders in the oceanic twilight zone.
Villas Bôas, A. B., Ardhuin, F., Ayet, A., Bourassa, M. A., Brandt, P., Chapron, B., et al. (2019). Integrated Observations of Global Surface Winds, Currents, and Waves: Requirements and Challenges for the Next Decade.
Front. Mar. Sci., 6.
Abstract: Ocean surface winds, currents, and waves play a crucial role in exchanges of momentum, energy, heat, freshwater, gases, and other tracers between the ocean, atmosphere, and ice. Despite surface waves being strongly coupled to the upper ocean circulation and the overlying atmosphere, efforts to improve ocean, atmospheric, and wave observations and models have evolved somewhat independently. From an observational point of view, community efforts to bridge this gap have led to proposals for satellite Doppler oceanography mission concepts, which could provide unprecedented measurements of absolute surface velocity and directional wave spectrum at global scales. This paper reviews the present state of observations of surface winds, currents, and waves, and it outlines observational gaps that limit our current understanding of coupled processes that happen at the air-sea-ice interface. A significant challenge for the coming decade of wind, current, and wave observations will come in combining and interpreting measurements from (a) wave-buoys and high-frequency radars in coastal regions, (b) surface drifters and wave-enabled drifters in the open-ocean, marginal ice zones, and wave-current interaction �hot-spots,� and (c) simultaneous measurements of absolute surface currents, ocean surface wind vector, and directional wave spectrum from Doppler satellite sensors.
Wang, S., Kranz, S. A., Kelly, T. B., Song, H., Stukel, M. R., & Cassar, N. (2020). Lagrangian Studies of Net Community Production: The Effect of Diel and Multiday Nonsteady State Factors and Vertical Fluxes on O
2/Ar in a Dynamic Upwelling Region. J. Geophys. Res. Biogeosci., 125(6), e2019JG005569.
Abstract: The ratio of dissolved oxygen to argon in seawater is frequently employed to estimate rates of net community production (NCP) in the oceanic mixed layer. The in situ O2/Ar‐based method accounts for many physical factors that influence oxygen concentrations, permitting isolation of the biological oxygen signal produced by the balance of photosynthesis and respiration. However, this technique traditionally relies upon several assumptions when calculating the mixed‐layer O2/Ar budget, most notably the absence of vertical fluxes of O2/Ar and the principle that the air‐sea gas exchange of biological oxygen closely approximates net productivity rates. Employing a Lagrangian study design and leveraging data outputs from a regional physical oceanographic model, we conducted in situ measurements of O2/Ar in the California Current Ecosystem in spring 2016 and summer 2017 to evaluate these assumptions within a �worst‐case� field environment. Quantifying vertical fluxes, incorporating nonsteady state changes in O2/Ar, and comparing NCP estimates evaluated over several day versus longer timescales, we find differences in NCP metrics calculated over different time intervals to be considerable, also observing significant potential effects from vertical fluxes, particularly advection. Additionally, we observe strong diel variability in O2/Ar and NCP rates at multiple stations. Our results reemphasize the importance of accounting for vertical fluxes when interpreting O2/Ar‐derived NCP data and the potentially large effect of nonsteady state conditions on NCP evaluated over shorter timescales. In addition, diel cycles in surface O2/Ar can also bias interpretation of NCP data based on local productivity and the time of day when measurements were made.
Weihs, R., & Bourassa, M. A. (2012). A comparison of modeled diurnally varying sea surface temperatures to geostationary satellite data. In
IEEE International Symposium on Geoscience and Remote Sensing IGARSS (pp. 5764–5766).