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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Dynamic Testbed Demonstration of WFIRST Coronagraph Low Order Wavefront Sensing and Control (LOWFS/C)

To maintain the required performance of WFIRST Coronagraph in a realistic space environment, a Low Order Wavefront Sensing and Control (LOWFS/C) subsystem is necessary. The LOWFS/C uses a Zernike wavefront sensor (ZWFS) with the phase shifting disk combined with the starlight rejecting occulting mask. For wavefront error corrections, WFIRST LOWFS/C uses a fast steering mirror (FSM) for line-of-sight (LoS) correction, a focusing mirror for focus drift correction, and one of the two deformable mirrors (DM) for other low order wavefront error (WFE) correction. As a part of technology development and demonstration for WFIRST Coronagraph, a dedicated Occulting Mask Coronagraph (OMC) testbed has been built and commissioned. With its configuration similar to the WFIRST flight coronagraph instrument the OMC testbed consists of two coronagraph modes, Shaped Pupil Coronagraph (SPC) and Hybrid Lyot Coronagraph (HLC), a low order wavefront sensor (LOWFS), and an optical telescope assembly (OTA) simulator which can generate realistic LoS drift and jitter as well as low order wavefront error that would be induced by the WFIRST telescope’s vibration and thermal changes. In this paper, we will introduce the concept of WFIRST LOWFS/C, describe the OMC testbed, and present the testbed results of LOWFS sensor performance. We will also present our recent results from the dynamic coronagraph tests in which we have demonstrated of using LOWFS/C to maintain the coronagraph contrast with the presence of WFIRST-like line-of-sight and low order wavefront disturbances.

Zhou, Hanying↗
NASA NTRS2018

WFIRST Low Order Wavefront Sensing and Control Testbed Performance under Flight Like Photon Flux

To maintain the required performance for the WFIRST Coronagraph Instrument (CGI) in a realistic space environment, a Low Order Wavefront Sensing and Control (LOWFS/C) subsystem is necessary. The WFIRST CGI LOWFS/C subsystem would use the Zernike wavefront sensor, which has the phase-shifting disk combined with the coronagraph’s focal plane mask, to sense the low-order wavefront drift and line-of-sight (LoS) error using the rejected starlight. The dynamic tests on JPL’s on the Occulting Mask Coronagraph (OMC) Testbed have demonstrated that LOWFS/C can maintain coronagraph contrast to better than 10-8 in presence of WFIRST-like line of sight and low order wavefront disturbances in both Shaped Pupil Coronagraph (SPC) and Hybrid Lyot Coronagraph (HLC) modes. However, the previous dynamic tests have been done using a bright source with photon flux equivalent to stellar magnitude of Mv = -3.5. The LOWFS/C technology development continues on the OMC testbed especially in evaluating and improving the LOWFS/C performance under the realistic photon flux that is equivalent to WFIRST Coronagraph target stars. Our recent testbed tests have demonstrated that the LOWFS/C can work cohesively with the stellar light suppression wavefront control, which brings broad band coronagraph contrast from 1x10-6 to 6x10-9, while LOWF/C is simultaneously suppressing the WFIRST like LoS and low order wavefront drift disturbances on a source that photon flux is equivalent to a Mv = 2 star. This demonstration mimics the CGI initial dark hole establish process on a bright reference star. We also demonstrated on the testbed that LOWFS/C can maintain the coronagraph contrast by suppressing the WFIRST like line-of-sight disturbances on a fainter Mv = 5 star. This mimics scenario of CGI science target observations. In this paper we will present the recent testbed results on LOWFS/C LoS loops and low order wavefront error correction loop performance on the flight like photon flux.

Truong, Tuan↗
NASA NTRS2018

Hybrid Lyot Coronagraph for WFIRST: High Contrast Testbed Demonstration in Flight-like Low Flux Environment

In order to validate required operation of the proposed Wide-Field InfraRed Survey Telescope (WFIRST) coronagraph instrument, we have built a testbed in Jet Propulsion Laboratory (JPL), which is analogous to the baseline WFIRST coronagraph instrument architecture. Since its birth in 2016, this testbed, named as Occulting Mask Coronagraph (OMC) testbed, has demonstrated several crucial technological milestones: Broadband high contrast demonstration in both Hybrid Lyot Coronagraph (HLC) and Shape Pupil Coronagraph (SPC) modes while the Low Order Wavefront Sensing and Control (LOWFS/C) subsystem senses and corrects the dynamic flight-like wavefront disturbances. In this paper, we present up-to-date progress of HLC mode demonstration in the OMC testbed. While injecting the flight-like low photon flux starlight with expected Line of Sight (LoS) and Wavefront Error (WFE) perturbation to the OMC testbed, we demonstrate generating high contrast dark hole images. We first study the expected photon flux in actual flight environment, and estimate detection noise and estimation accuracy of the complex electric field if the wavefront sensing algorithm is used based on the pair-wise difference imaging. Then, we introduce our improved scheme to mitigate this photon-starved flight-like low flux environment. As a result, we generate a dark hole that meets the WFIRST raw contrast requirements using the 2nd magnitude star light. We establish the key ideas, describe test setups, and demonstrate test results with data analysis.

Wilson, Daniel↗
NASA NTRS2020

Prediction and Evaluation of the Image of the WFIRST Coronagraph Pupil at the Shaped-Pupil Mask

To create a high contrast field of view with a shaped pupil coronagraph (SPC), the telescope pupil is imaged onto the shaped pupil mask, the shaped pupil mask is designed and fabricated through a design optimization based on a given pupil wavefront, and deformable mirrors (DM) in the coronagraph are modulated according to a nonlinear optimization procedure. Both the mask design optimization and the DM optimization require accurate knowledge of the image of the pupil at the shaped pupil plane for the calculation of Jacobians, and the evaluation of alignment tolerances. The shaped pupil coronagraphs demonstrated in the high contrast imaging testbed (HCIT) at JPL has heretofore assumed perfect imaging of the pupil onto the shaped pupil mask. Similarly, the design and performance modeling of the WFIRST CGI instrument makes the same assumption. In this paper we estimate and compare the image of the pupil mask at the shaped pupil plane in the case of the coronagraph testbed, and the image of the telescope pupil at the shaped pupil plane for the WFIRST CGI instrument. The estimated pupil images include field curvature and aberrations resulting from the layout of the parabolic mirror imaging system, which is optimized for the source image, not the image of the pupil. We also show the results of direct measurement of the image of the pupil mask at the shaped pupil plane in the coronagraph testbed.

Crowther, Blake↗
NASA NTRSDate not supplied

On-board Limb-based Shape Modeling for Small Body Navigation

Missions to small bodies within our solar system are becoming more frequent. Generally, shape models of the target body are required to perform proximity operations as demonstrated by the OSIRIS-REx, Hayabusa2, and Rosetta missions. However, these missions required image downlinking to create high-resolution models on the ground. In some missions, especially small-sats, there may be data downlink data constraints, resulting in the inability to provide the large number of images needed for high-resolution shape models. A solution to this is the ability to generate shape models on-board during the approach to the target or initial proximity surveying. Current work implements a limb-based shape model routine that is able to be executed on a Raspberry Pi 1, which is similar to the processing capability to the flight computer on OSIRIS-REx, and that does not require low phase angle geometries. Initial shape model results generated from Bennu approach (Nov 2-3, 2018) show that the limb-based shape model agrees well with a 75-cm SPC shape model generated after Preliminary Survey; Results are: min difference -7.047m, max difference 17.347m, mean 1.122m, and RMS 3.219m. Further scenarios are presented herein.

Limb-based↗
DOE OSTI2025

ECAR-8446 Rev 0 MARVEL BPVC Section III Division 5 HBB Fatigue Acceptance Tests

The objective of this analysis is to evaluate the fatigue and creep behavior of 316 SS materials used in the Primary Coolant System (PCS) and Guard Vessel System (GVS) for the first two years of MARVEL reactor operation. The analysis follows the requirements set forth in ASME BPVC Section III, Division 5, HBB-2800, which mandates a fatigue test if operational conditions exceed allowable thresholds. By determining whether the materials meet the HBB-T-1324(a) and HBB-T-1324(b) criteria, this evaluation establishes whether a fatigue test is necessary, as well as the maximum allowable operational hours and temperatures before fatigue testing would be required. The deliverables of this analysis include calculations validating compliance with fatigue acceptance criteria, determination of maximum operational limits for the two-year period, and identification of conditions under which a fatigue test would be necessary. This ensures that the PCS and GVS can operate safely without premature material degradation and align with the design life requirements outlined in SPC-70731. Additionally, this evaluation provides conservative estimates for Service Level B occurrences and their impact on allowable Service Level A hours and temperatures, offering guidance for future operational assessments and potential life extensions beyond the initial two-year period.

21 - SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLAN↗
DOE OSTI2026

Progress and innovations in the TCV tokamak research programme

Research on the Tokamak à Configuration Variable addresses a wide range of key questions relevant to ITER and future fusion power plants. Over the past two years, highly productive experimental campaigns have led to major advances across several areas: the ITER baseline scenario; pedestal properties in low-collisionality, peeling-limited conditions; and the development of high- β N , non-inductive regimes. Alternative high-confinement scenarios have likewise received significant attention, with remarkable progress in quasi-continuous exhaust operation, X-point radiator plasmas, and negative triangularity configurations. Substantial achievements were also made in the mitigation or benign termination of runaway electron beams, in elucidating fast-ion loss mechanisms, and in improving exhaust behaviour in both conventional and alternative divertor geometries. These experimental results have been strongly supported by advances in modelling and their direct application to the experiment, ranging from gyrokinetic simulations of core and pedestal turbulence to fluid-based studies of scrape-off layer and divertor physics in diverse geometries. Plasma control has taken on an increasingly important role, with model-based and data-driven approaches now closely intertwined with physics studies. This article provides a overview of these recent activities, together with a brief outlook on forthcoming upgrades and next steps.

EPFL↗
DOE OSTI2026

Results from the last DD and DT JET campaigns in the framework of the EUROfusion Tokamak Exploitation Work Package activity

JET, the only tokamak capable of operating with deuterium–tritium (D–T) fuel (since TFTR was shutdown in 1999), has provided essential experimental data to support ITER and DEMO design and operation. Within the EUROfusion Tokamak Exploitation Work Package, JET completed its final campaigns (2022–2023), culminating in the third D–T campaign (DTE3). These experiments addressed key challenges in plasma scenarios, exhaust control, and tritium management under reactor-relevant conditions. Significant progress was achieved in demonstrating ITER-like integrated scenarios with impurity seeding, achieving partial divertor detachment and high confinement ($H_{98}(y,2)$ ≈ 0.85) at 3 MA in D–T plasmas. Advanced exhaust regimes such as quasi-continuous exhaust (QCE) and X-point radiator (XPR) were successfully achieved first in D–D and then extended to D–T operation, confirming their relevance for mixed isotope operation. Operational milestones included a new world record of 69 MJ fusion energy in tritium-rich hybrid plasmas and long-pulse H-mode operation up to 60 s, contributing with unique data to the CICLOP database. Physics studies focused on peeling-limited pedestals in support of ITER and improved understanding of edge stability and impurity screening in metallic environments. Extensive usage of the shattered pellet injector (SPI) on JET provided critical information for the design of the ITER disruption mitigation system (DMS). Real-time control systems for D/T ratio control and plasma exhaust were deployed and demonstrated in D–D and D–T, while energetic particle physics investigations unfolded the role of fast ions in turbulence suppression mechanisms. Comprehensive tritium retention studies using gas balance method, post-mortem analysis, and ITER-relevant laser induced desorption spectroscopy (LIDS) diagnostics provided essential input for tritium accountancy strategies. These results are validating the ITER operational concepts, inform DEMO design, and deliver critical experience in nuclear operation and scenario integration.

disruptions↗
DOE OSTI2024

Constructing nested coordinates inside strongly shaped toroids using an action principle

A new approach for constructing polar-like boundary-conforming coordinates inside a toroid with strongly shaped cross-sections is presented. A coordinate mapping is obtained through a variational approach, which involves identifying extremal points of a proposed action in the mapping space from [0,2π] 2 ×[0,1] to a toroidal domain in $\mathbb{R}$ 3 . This approach employs an action built on the squared Jacobian and radial length. Extensive testing is conducted on general toroidal boundaries using a global Fourier–Zernike basis via action minimisation. The results demonstrate successful coordinate construction capable of accurately describing strongly shaped toroidal domains. The coordinate construction is successfully applied to the computation of three-dimensional magnetohydrodynamic equilibria in the GVEC code where the use of traditional coordinate construction by interpolation from the boundary failed.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Overview of the ASDEX Upgrade results

After a 26-month vent ASDEX Upgrade (AUG) went back in operation with a newly designed upper W-divertor suitable for alternative divertor configurations (featuring in-vessel coils and cryo-pump). Parameter scans and an extensive set of measurements were obtained and their interpretation is ongoing. Prompted by the ITER wall change, dedicated experiments on non-boronized plasma startup were contrasted to that employing asymmetric and more symmetric boronizations. The asymmetric boronization proved to be as beneficial as the more symmetric one, which is in contrast to previous model calculations assuming perfect sticking of boron (measurements suggest sticking ≈ 0.3). In the startup phase also the impurity influxes at the outboard limiters were investigated contrasting the unboronized case featuring cold edges (low- Z radiation) to the boronized case, in which the lifetime of the boron layers could be estimated. Pedestal stability investigations revealed that the quasi-continuous exhaust (QCE) regime is obtained when ballooning modes are active in the vicinity of the separatrix and the global peeling-ballooning stability is high enough. Thus, at high enough shaping and high gas flux both can be achieved and QCE is a consequence. The closely related enhanced D-alpha (EDA) mode is not clearly distinguishable from QCE, e.g. the quasi-coherent mode characteristic for EDA also shows up in QCE. In QCE the impurity transport is behaving benign as could be measured for Ne with a novel analysis method making use of a comprehensive set of CXRS measurements. For high radiative fractions the regime of the X-point radiator (XPR) is accessible at AUG and the understanding of its access conditions and behaviour is further developed. Due to the localized radiative cooling at the X-point the XPR can be well diagnosed and thus controlled. For negative triangularity shapes, further experiments at increased shaping resulted in strongly heated L-mode plasmas avoiding ELMs. Two integrated modelling approaches towards ITER suggested that core W-accumulation will be no issue for ITER and that the fusion yield in ITER may be Q = 12 (i.e. ITPA20-IL scaling is too pessimistic). Further, investigations of the ITER ramp-down in AUG provide insights into maintaining position control. Various aspects of shattered pellet injection were investigated in AUG and one of the results show that with increasing Ne fraction the radiation during the current quench increases and the current decay becomes faster.

ASDEX Upgrade↗
DOE OSTI2026

Multimachine analysis of intermittent fluctuations in the scrape-off layer of magnetically confined fusion plasmas

Far scrape-off layer fluctuations, also known as blobs/filaments, are compared for the first time across six tokamaks: Alcator C-Mod, DIII-D, TCV, KSTAR, MAST, and MAST-U, under the context of stochastic modeling in Ohmic and low confinement mode scenarios. In this model, which well describes these fluctuations, measurements from Langmuir probes are modeled as a superposition of uncorrelated, two-sided exponential temporal pulses. The key parameters of this model are the mean waiting times between consecutive pulses, the pulse duration times and the mean of the pulse amplitudes. The study examines the influence of line-averaged density, plasma current, magnetic field and aspect ratio. The mean amplitudes and pulse waiting times increase with the line-averaged density across devices, while the pulse duration times remain constant. Whereas the variation in waiting times is gradual across the density scan, the mean amplitudes increase abruptly as the density profile broadens and flattens for Alcator C-Mod. The blob waiting times decrease with increasing plasma current and the toroidal magnetic field, while they increase with aspect ratio for conventional tokamaks. The duration times follow the same trends as the waiting times in these parameters but vary more slowly, resulting in the trends in the waiting times dominating the intermittency level of the fluctuations.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Specific conductivity and salinity of the Parker River, PIE LTER, Plum Island Sound MA, August-November 2022

This dataset contains specific conductivity and calculated salinity data of Parker River water at a tidal brackish wetland dominated by Typha angustifolia at the upper estuary of the Plum Island Sound in Newbury, Massachusetts (MA) within the Plum Island Ecosystems Long Term Ecological Research site (PIE LTER). Measurements were taken to evaluate temporal changes in surface water salinity in high frequency to characterize boundary conditions of soil and plant responses to changes in salinity. A PVC pipe was installed in a low elevation spot in the creek bank so that the bottom of the pipe sat on the sediment surface allowing flushing with water during flooding. Raw measurements were collected using an Onset HOBO U24-002 Saltwater Conductivity/Salinity data logger. The specific conductance and salinity measurements were corrected and calculated respectively using Onset’s HOBOware software and reference specific conductivity measurements taken in tandem with the first and last points recorded by the HOBO sensor. These reference measurements were taken using a HACH HQ14D Portable Conductivity Meter. Because of the installation design, only data one hour before and after high tide are used. Metadata files Typha_ctd_salinity_dd.csv and Typha_ctd_salinity_flmd.csv contain detailed information on data variables, sampling and QA/QC methods, and site location.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Upland tidal brackish marsh specific conductivity and salinity measurements, PIE LTER, Plum Island Sound, MA, 2023

This dataset includes raw and corrected specific conductivity, temperature, and calculated salinity measurements collected at 10 cm depth in a Typha angustifolia-dominated tidal brackish wetland at the upper estuary of Plum Island Sound in Newbury, Massachusetts (MA) within the Plum Island Ecosystems Long Term Ecological Research (PIE LTER) site. Measurements were taken to evaluate temporal variation in porewater salinity (a proxy for porewater sulfate concentration) in high frequency to assess soil and plant responses to changes in salinity. Measurements were collected using an Onset HOBO U24-002 Saltwater Conductivity/Salinity data logger deployed in a well. Specific conductivity was corrected using non-linear temperature compensation, and salinity was calculated using the Practical Salinity Scale 1978 via Onset's HOBOware software. Reference conductivity measurements to correct for sensor drift were taken at the start and end of each deployment using a HACH HQ14D Portable Conductivity Meter. Data were then filtered in MATLAB to remove values logged while the sensor was out of the well or during post-deployment equilibration. Detailed metadata, including variable descriptions, sampling methods, QA/QC procedures, and site information, are provided in the files: Typha_ctd_salinity_dd.csv and Typha_MI_ctd_salinity_2023_flmd.csv.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Upland tidal brackish marsh specific conductivity and salinity measurements, PIE LTER, Plum Island Sound, MA, May-December 2022

This dataset includes raw and corrected specific conductivity, temperature, and calculated salinity measurements collected at 10 cm depth in a Typha angustifolia-dominated tidal brackish wetland at the upper estuary of Plum Island Sound in Newbury, Massachusetts (MA) within the Plum Island Ecosystems Long Term Ecological Research (PIE LTER) site. Measurements were taken to evaluate temporal variation in porewater salinity (a proxy for porewater sulfate concentration) in high frequency to assess soil and plant responses to changes in salinity. Measurements were collected using an Onset HOBO U24-002 Saltwater Conductivity/Salinity data logger deployed in a well. Specific conductivity was corrected using non-linear temperature compensation, and salinity was calculated using the Practical Salinity Scale 1978 via Onset's HOBOware software. Reference conductivity measurements to correct for sensor drift were taken at the start and end of each deployment using a HACH HQ14D Portable Conductivity Meter. Data were then filtered in MATLAB to remove values logged while the sensor was out of the well or during post-deployment equilibration. Detailed metadata, including variable descriptions, sampling methods, QA/QC procedures, and site information, are provided in the files: Typha_ctd_salinity_dd.csv and Typha_MI_ctd_salinity_2023_flmd.csv.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Specific conductivity and salinity of the Parker River, PIE LTER, Plum Island Sound MA, March-November 2023

This dataset contains specific conductivity and calculated salinity data of Parker River water at a tidal brackish wetland dominated by Typha angustifolia at the upper estuary of the Plum Island Sound in Newbury, Massachusetts (MA) within the Plum Island Ecosystems Long Term Ecological Research site (PIE LTER). Measurements were taken to evaluate temporal changes in surface water salinity in high frequency to characterize boundary conditions of soil and plant responses to changes in salinity. A PVC pipe was installed in a low elevation spot in the creek bank so that the bottom of the pipe sat on the sediment surface allowing flushing with water during flooding. Raw measurements were collected using an Onset HOBO U24-002 Saltwater Conductivity/Salinity data logger. The specific conductance and salinity measurements were corrected and calculated respectively using Onset’s HOBOware software and reference specific conductivity measurements taken in tandem with the first and last points recorded by the HOBO sensor. These reference measurements were taken using a HACH HQ14D Portable Conductivity Meter. Because of the installation design, only data one hour before and after high tide are used. Metadata files Typha_ctd_salinity_dd.csv and Typha_ctd_salinity_flmd.csv contain detailed information on data variables, sampling and QA/QC methods, and site location.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Global gyro-kinetic ion temperature gradient and trapped electron mode turbulence modelling in X -point geometry in negative and positive triangularity

Comparative modelling of ion temperature gradient (ITG)/trapped electron mode (TEM) turbulence in negative (NT) and positive (PT) triangularity plasma shapes was done using the nonlinear global full-f gyrokinetic particle code JOREK-GK in the realistic X-point tokamak geometry including the Scrape Off Layer (SOL) for TCV and DIII-D parameters. A comparison of JOREK-GK code with the gyrokinetic codes GS2 and GENE was done using NT/PT triangularity TCV L-modes parameters showing good agreement between codes in linear growth rates and clear beneficial effect of NT as compared to PT. Global non-linear modelling of the ITG/TEM saturated turbulence for realistic DIII-D NT pulses was done and compared with numerically constructed PT equilibrium with the same plasma profiles. Existence of longer correlation length of density fluctuations in PT compared to NT was demonstrated. Stronger and more sheared zonal flows are generated via Reynolds stress in NT compared to PT. These factors are stabilizing for TEM/ITG turbulence in NT and lead to smaller heat fluxes and heat conductivities in NT compared to PT configuration. Weak dependence of plasma confinement on collisionality and plasma rotation was found in modelling of DIII-D NT shots similar to the experiment. The confinement scaling with normalized ion gyro-radius ρ* was estimated both for NT and PT. Bohm-like scaling was obtained in both configurations, however with better confinement for NT compared to PT which could be favourable factor for reactor size machines.

ITG↗
DOE OSTI2026

First Demonstration of Resonant Pitch-Angle Scattering of Relativistic Electrons by Externally Launched Helicon Waves

Helicon waves (a.k.a whistler waves) satisfying the normal wave-particle cyclotron resonance are observed to limit the growth and maximum energy of relativistic electrons (REs) in low-density Ohmic DIII-D tokamak plasmas. Following the application of helicon waves, pitch-angle scattering of high-energy REs causes an increase in both synchrotron and electron-cyclotron emissions. The hard x-ray emission, a proxy for the RE population, ceases to grow. Energy-resolved hard x-ray measurements also show a striking decrease in the number of high-energy REs (above the resonance at approximately 8MeV) to below the noise floor and an increase in low-energy (∼ 4 MeV) REs. This occurs despite the toroidal electric field remaining high enough to drive exponential RE growth in the absence of helicon waves. Furthermore, these results open new directions for limiting the maximum energy of RE populations in laboratory and fusion plasmas.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Yakima River Basin Temporal Study: Sensor and Sample Data from Wenas Creek following the Evans Canyon Fire in Washington, USA

The Evans Canyon Fire occurred in Washington in August 2020 and burned 76,000 acres of the semi-arid shrub-steppe landscape at low to moderate severities. This fire burned across the Wenas Creek watershed, allowing for a sampling design that included a portion of the stream within the burned area and a reference site upstream of the burn. Monthly data was collected at an unburned (W10) and burned (W20) site from November 2020 to August 2022 for in situ hydrological and water chemistry sensor data, handheld sensor water chemistry data, general environmental context photos, and field metadata. This dataset is comprised of one folder with field photos and one main data folder containing (1) sensor and sample field protocols; (2) file-level metadata (flmd); (3) data dictionary (dd); (4) international geo-sample number (IGSN) mapping file; (5) field metadata; (6) readme; (7) methods codes; (8) dissolved organic carbon (DOC; measured as non-purgeable organic carbon; NPOC); (9) total nitrogen (TN); (10) total suspended solids (TSS); (11) sensor data (specific conductance, pH, total dissolved solids, temperature, pressure, dissolved oxygen, and turbidity) averages; and (12) sensor installation methods. All files are .csv, .jpg, .jpeg, or .pdf.

54 ENVIRONMENTAL SCIENCES↗