1,721,187 research outputs found
Unlocking a global ocean mixing dataset: toward standardization of seismic-derived ocean mixing rates
No full textTurbulent mixing is vital for water transformation in the ocean and sustains the global thermohaline circulation. Despite decades of global observations using different platforms, our understanding of ocean turbulence is still limited. More observations are needed to better characterize the spatiotemporal distribution of mixing to reduce uncertainties in climate models. Marine seismic reflection surveys are an untapped data resource for high-resolution ocean turbulence observation. Turbulent mixing can be extracted from seismic data through horizontal internal wave slope spectra. However, to date, a standardized approach to prepare seismic data for this spectral analysis is still lacking, leading to insufficient consideration of the impact of noise on the resulting diffusivities. To address these issues, we perform a full-wavefield synthetic modeling and processing to reveal noise-induced overestimation of diffusivities. We further propose a widely applicable workflow and apply it to three field seismic surveys with increasing noise levels conducted in regions of different turbulence environments: ocean ridges, open ocean interior, and continental slope. The derived diffusivities are bench-marked against direct measurements around the region to show the fidelity of this seismic method. The extended observation records by seismic data across the Kauai Channel and away from the Mid-Atlantic Ridges reveal the importance of topography in modifying the propagation of internal tides and the distribution of turbulent mixing in both near and far fields. Our proposed workflow marks a key advancement toward standardization of seismic-derived ocean mixing rates and holds the potential to unlock massive marine seismic reflection datasets worldwide for ocean mixing characterization.</p
Deep Sea Drilling Program Site 10-95 benthic foraminifera stable isotope, grain size and X-ray fluorescence data across Eocene/Oligocene Boundary, southern Gulf of Mexico
No full textThis dataset contains analysis of Deep Sea Drilling Program Site 95 sediment cores from the southeastern Gulf of Mexico from the late Eocene to the early Oligocene. The data include benthic foraminifera population counts of 300 individuals from each sample where possible; however, most samples did not yield 300 individuals. From these population counts, there are calculated Fisher-α diversity and Shannon Diversity Index values. The data set also includes stable carbon (δ13C) and oxygen (δ18O) isotope data from benthic foraminifera species Nuttallides truempyi, Oridorsalis umbonatus, and Cibicidoides spp. Isotope values are corrected to Cibicidoides spp. according to Katz et al. (2003). The dataset provides corrected and uncorrected values for N. truempyi and O. umbonatus. Stable isotopes were measured on a Gasbench II coupled to a Thermo MAT253 isotope ratio mass spectrometer in the Stable Isotope Laboratory at the University of Texas at Austin and reported VPDB. Additional data are grain size measurements acquired from a laser grain size analyzer (Malvern Mastersizer 3000), and X-Ray Fluorescence (XRF) data acquired on the third-generation XRF scanner at the Gulf Coast Repository at Texas A&M University. XRF data were measured at ~5 cm resolution at 10kv and 30kV and quality controlled by removing data with positive Ar values, which indicate air was measured rather than the sediment core surface
Deep Sea Drilling Program Site 77-540 bulk carbonate stable isotope, grain size, and X-ray fluorescence data across the Eocene/Oligocene Boundary, southern Gulf of Mexico
No full textThis dataset contains analysis of Deep Sea Drilling Program Site 540 sediment cores from the southeastern Gulf of Mexico from the late Eocene to the early Oligocene. The data include bulk carbonate stable carbon (δ13C) and oxygen (δ18O) isotopes values. Stable isotopes were measured on a Gasbench II coupled to a Thermo MAT253 isotope ratio mass spectrometer in the Stable Isotope Laboratory at the University of Texas at Austin and reported VPDB. Additional data are grain size measurements acquired from a laser grain size analyzer (Malvern Mastersizer 3000), and X-Ray Fluorescence (XRF) data acquired on the third-generation XRF scanner at the Gulf Coast Repository at Texas A&M University. XRF data were measured at ~5 cm resolution at 10kv and 30kV and quality controlled by removing data with positive Ar values, which indicate air was measured rather than the sediment core surface
- …
