cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.uihxcu
title: Using Orbitrap mass spectrometry to assess the isotopic compositions of individual compounds in mixtures

description: The isotopic compositions of individual chemical species are routinely used by the geochemical, environmental, forensic, anthropological, chemical, and biomedical communities to elucidate the conditions, sources, and reaction pathways of the molecules in question. Mass spectrometric methods of measuring isotopic compositions of individual compounds generally require that analytes be pure to yield precise, accurate results. Yet most applications examine materials that are mixtures of multiple components. Various methods of chemical purification, e.g., chromatography, are used to isolate analytes from mixtures prior to mass spectrometric analysis. However, these techniques take time and specialized equipment and are not always desirable, feasible, or even possible (e.g., in field- or space-deployable instrumentation). Here we report on the use of Orbitrap-based Fourier-transform mass spectrometry to perform isotope ratio measurements of single species within mixtures delivered to the mass spectrometer without prior chromatographic separation. We demonstrate that instrument biases (attributed here to space charge effects) within the Orbitrap mass analyzer can cause the measured 13C/12C ratio of a molecular ion to spuriously decrease relative to the ratio measured for the same ion in a pure analyte by an amount that is proportional to the proportions of the additional components. We then recommend several strategies by which this effect can be mediated such that accurate isotope ratios can be obtained.
DOI: 10.48577/jpl.zl4key
title: Inter-Comparison of Ionizing Doses from Space Shielding Analyses using MCNP, Geant4, FASTRAD, and NOVICE

description: Several commonly-used space radiation particle transport tools, MCNP, Geant4, FASTRAD, and NOVICE are compared to check consistency of total ionizing dose (TID) estimates for hardware in a harsh-electron Jovian mission environment. Simple geometries with aluminum, tantalum, and a combination of both materials were used to represent typical and high density shields. The forward Monte Carlo (FMC) analyses from MCNP and Geant4 were in a good agreement within run uncertainty. Compared to FMC results, the reverse Monte Carlo (RMC) analysis results from NOVICE and FASTRAD differed by ±20% ~ ±50%, depending on the simple geometrys’ material. The doses from FASTRAD’s ray-tracing methods differed from NOVICE RMC doses by +60% / 10%. TID analyses of complex as-designed geometries from selected flight instruments and electronics boxes were also compared using the NOVICE and FASTRAD tools. The TID results from these complex geometries with aluminum equivalent thickness ranging from 0.1 mil to 3000 mil (3 inches) differed by as much as +200% / 50% between FASTRAD (ray-tracing and RMC) and NOVICE analyses. We conclude that while MCNP and Geant4 FMC analysis results have extensive experimental validation and therefore provide the most accurate TID estimates, RMC analyses are faster to implement and suitable as conservative tools for missions with a sufficient mass margin. We also conclude that ray-tracing analyses can be suitable during the development phase of shield design optimization for its fast runtime capability.
DOI: 10.48577/jpl.5aap3z
title: Capillary Electrophoresis Methods for Monitoring of Silver Biocide in the Water System of Future Human Spaceflight Missions

description: Silver ion is proposed as biocide to treat the water in NASA’s next generation of human space exploration vehicles/habitats. Here, two analytical methods were developed to address the need to monitor silver levels in the water. In addition to silver, other inorganic cations frequently found in the ISS potable water were analyzed.
DOI: 10.48577/jpl.qvpedh
title: Using Machine Learning to Model Uncertainty for Water-Vapor Atmospheric Motion Vectors

description: Abstract. Wind-tracking algorithms produce Atmospheric Motion Vectors (AMVs) by tracking water vapor across spatial-temporal fields. Thorough error characterization (also known as uncertainty quantification) of wind-track algorithms is critical in properly assimilating AMVs into weather forecast models and climate reanalysis datasets. Uncertainty quantification should yield estimates of two key quantities of interest: bias— the systematic difference between a measurement and the true value, and standard error— a measure of variability of the measurement. The current process of specification of the errors as input into inverse modelling are often cursory and commonly consist of a mixture of model fidelity, expert knowledge, and need for expediency. The methods presented in this paper supplement existing approaches to error specification by providing an error-characterization module that is purely data-driven and requires few tuning parameters. This paper proposes an error-characterization method that combines the flexibility of machine learning (random forest) with the robust error estimates of unsupervised parametric clustering (using a Gaussian Mixture Model). Traditional techniques for uncertainty quantification through machine learning have focused on characterizing bias, but often struggle when estimating standard error. In contrast, model-based approaches such as k-means or Gaussian mixture modelling can provide reasonable estimates of both bias and standard error, but they are often limited in complexity due to reliance on linear or Gaussian assumptions. In this paper, methodology is developed and applied to characterize error in tracked-wind using a high-resolution global model simulation, and it is shown to adequately capture the error features of the tracked wind.
DOI: 10.48577/jpl.dd0v9f
title: An Extension of LTL with Rules and its Application to Runtime Veriﬁcation

description: Veriﬁcation (RV) consists of analyzing execution traces using formal techniques, e.g., monitoring executions against Linear Temporal Logic (LTL) properties. Propositional LTL is, however, limited in expressiveness, as ﬁrst shown by Wolper [32]. Several extensions of propositional LTL, which promote the expressive power to that of Büchi automata, have therefore been proposed; however, none of which was, by and large, adopted for RV. We present an extension of propositional LTL with rules that is as expressive as these extensions, for which preforming RV follows a simple adaptation of classical algorithms. Furthermore, in many practical cases, there is a need in RV to monitor events that carry data, and for which the propositional temporal logic is not sufﬁcient. This problem has been addressed by numerous authors, and in previous work we provided an algorithm for ﬁrst-order LTL that uses BDDs to represent relations over data elements. We show deﬁciencies in expressiveness also of ﬁrst-order LTL and suggest an extension of ﬁrst-order LTL with rules to address these limitations. We show how to adapt the RV algorithm to allow this extension. We describe how the D EJAV U RV tool is modiﬁed to encapsulate the extended algorithm and provide experimental results.
DOI: 10.48577/jpl.udhi9i
title: A SOFIA Survey of [C II] IN THE GALAXY M51 II. [C II] AND CO KINEMATICS ACROSS SPIRAL ARMS

description: We present the first complete, velocity–resolved [C II ] 158μm image of the M51 grand-design spiral galaxy, observed with the upGREAT instrument on SOFIA. [C II ] is an important tracer of various phases of the inter-stellar medium, including ionized gas, neutral atomic, and diffuse molecular regions. We combine the [C II ] datawith H I , CO, 24μm dust continuum, FUV, and near–infrared (NIR) K–band observations to study the evolution of the ISM across M51’s spiral arms in both position–position, and position–velocity space. Our data show velocity discontinuities in H I , 12 CO, and [C II ] at the locations of stellar arms (traced by K–band data) with a clear offset in position–velocity space between upstream molecular gas (traced by 12 CO) and downstream star formation (traced by [C II ]). We compare the observed position–velocity maps across spiral arms with synthetic observations from numerical simulations of galaxies with both dynamical and quasi–stationary steady spiralarms that predict both tangential and radial velocities at the location of spiral arms. We find that our observations, based on the observed velocity discontinuities and associated offset between CO and [C II ], are consistent with the presence of shocks in spiral arms in the inner parts of M51 and in the arm connecting the companiongalaxy, M51b, in the outer parts of M51.
DOI: 10.48577/jpl.2eoxy2
title: Additive Manufacturing of Structural Shells for Venus Surface Probes

description: The authors designed, built, and tested a lightweight metallic doubly curved structural shell using Ti-6Al-4V and Additive Manufacturing (AM) techniques. A 1 m diameter structural shell capable of surviving a Venus surface environment was designed and assessed via analytical methods and Finite Element Modeling (FEM). A small number of subscale test articles (200 mm diameter) were produced using Laser Powder Bed Fusion (LPBF). A full sphere was successfully tested under Venus-like pressures and temperatures at a Hot Isostatic Press (HIP) facility. Model correlation was performed on hemispherical shells using an ambient temperature isostatic pressure test chamber, and the results were compared with non-linear FEA and classical buckling models.
DOI: 10.48577/jpl.adswxa
title: Absorption Coefficient (ABSCO) Tables for the Orbiting Carbon Observatories: Version 5.1

description: The accuracy of atmospheric trace gas retrievals depends directly on the accuracy of the molecular absorption model used within the retrieval algorithm. For remote sensing of well-mixed gases, such as carbon dioxide (CO$_2$), where the atmospheric variability is small compared to the background, the quality of the molecular absorption model is key. Recent updates to oxygen (O$_2$) absorption coefficients (ABSCO) for the 0.76 $\mu$m A-band and the water vapor (H$_2$O) continuum model within the 1.6 $\mu$m and 2.06 $\mu$m CO$_2$ bands used within the Orbiting Carbon Observatory (OCO-2 and OCO-3) algorithm are described here. Updates in the O$_2$ A-band involve the inclusion of new laboratory measurements within multispectrum fits to improve relative consistency between O$_2$ line shapes and collision-induced absorption (CIA). The H$_2$O continuum model has been updated to MT$\_$CKD v3.2, which has benefited from information from a range of laboratory studies relative to the model utilized in the previous ABSCO version. Impacts of these spectroscopy updates have been evaluated against ground-based atmospheric spectra from the Total Carbon Column Observing Network (TCCON) and within the framework of the OCO-2 algorithm, using OCO-2 soundings covering a range of atmospheric and surface conditions. The updated absorption coefficients (ABSCO version 5.1) are found to offer improved fitting residuals and reduced biases in retrieved surface pressure relative to the previous version (ABSCO v5.0) used within B8 and B9 of the OCO-2 retrieval algorithm and have been adopted for the OCO B10 Level 2 algorithm.
DOI: 10.48577/jpl.3t9ef7
title: Direct Numerical Simulation of the Moist Stably Stratified Surface Layer: Turbulence and Fog Formation

description: We investigate the effects of condensation and liquid water loading on the stably stratified surface layer, with an eye towards understanding the influence of turbulent mixing on fog formation. Direct numerical simulations (DNS) of dry and moist open channel flows are conducted in which a constant cooling rate is applied at the ground to mimic longwave radiative cooling. Depending on the cooling rate, it can lead to either turbulent (weakly stable) or laminar (very stable) flows. Compared to the completely dry case, the condensation of liquid water in the moist case enables slightly higher cooling rates to be achieved before leading to turbulence collapse. In the very stable cases, runaway cooling leads to the substantial condensation of liquid water close to the ground and fog (visibility less than 1 km) results over much of the domain. In the weakly stable cases, turbulent mixing narrowly yields visibilities of 1 km close to the ground over a similar time period. However, despite the idealised nature of the system, the present results suggest that turbulence impedes, although will not necessarily inhibit, fog formation. A possible mechanism for fog formation within turbulent flows is identified, wherein regions of increased liquid water content form within the low-speed streaks of the near-wall cycle. These streaks are energised in the moist cases due to reduced dissipation of turbulent kinetic energy compared to the dry case, although in both cases the streaks are less energetic and persistent than in neutrally stratified flow.
DOI: 10.48577/jpl.d6tm8a
title: The potential of space-based sea surface salinity on monitoring the Hudson Bay Freshwater cycle

description: Hudson Bay (HB) is the largest semi-inland sea in Northern Hemisphere, connecting with the Arctic Ocean through the Foxe Basin and the northern Atlantic Ocean through the Hudson Strait. HB is covered by ice and snow in winter, which completely melt in summer. For about six months each year, satellite remote sensing of sea surface salinity (SSS) is possible over open water. SSS links freshwater contributions from river discharge, sea ice melt/freeze, and surface precipitation/evaporation. Given the strategic importance of HB, SSS has great potential in monitoring the HB freshwater cycle and studying its relationship with climate changes. However, SSS retrieved in polar regions (poleward of 50) from currently operational spacebased L-band microwave instruments has large uncertainty (&gt; 1 psu) mainly due to sensitivity degradation in cold water (&lt; 5C) and sea ice contamination. This study analyzes SSS from NASA Soil Moisture Active and Passive (SMAP) and ESA SMOS missions in the context of HB freshwater contents. We found that the main source of the year-to-year SSS variability is sea ice melting, in particular, the onset time and places of ice melt in the first couple of months of open water season. The freshwater contribution from surface forcing P-E is smaller in magnitude comparing with sea ice contribution, but lasts on longer time scale through the whole open water season. River discharge is comparable with P-E in magnitude but peaks before ice melt. The spatial and temporal variations of freshwater contents largely exceed the remote sensed SSS uncertainty. This fact justifies the use of remote sensed SSS for monitoring the HB freshwater cycle.
DOI: 10.48577/jpl.d9jxmc
title: Applying tipping point theory to remote sensing science to improve early warning drought signals for food security

description: Famines have long been associated with drought. With the severity of droughts growing in association with climate change, there is increasing pressure to do a better job predicting famines and delivering international aid to avert human suffering and civil instability. We examine recent advances in remote sensing technology, focusing on the latency, historical availability and spatial and temporal scales of the data these satellites provide. Because of their global coverage, seven variables derived from satellite observations emerge as especially pertinent to drought and famine: precipitation (TRMM/GPM), groundwater (GRACE/GRACE-FO), snow (MODIS), soil moisture (SMOS, SMAP, Sentinel-1), evapotranspiration (MODIS, ECOSTRESS), vegetation health (Landsat, AVHRR, MODIS, SPOT) and chlorophyll fluorescence (OCO-2). We discuss tipping point theory as a possible framework for taking advantage of long time series of these satellite data where they exist in order to enhance the effectiveness of existing famine early warning systems.
DOI: 10.48577/jpl.rmxvzy
title: Empirical rovibrational energy levels of ammonia up to 7500 cm-1

description: The most recent version of the MARVEL (Measured Active RotationalVibrational Energy Levels) protocol and code is used to update and extend the list of accurately known empirical rovibrational energy levels of 14NH3 falling in the range of 0 − 7500 cm−1 . Compared to an earlier similar study covering all the measured transitions of 14NH3 (Al-Derzi et al., J. Quant. Spectrosc. Rad. Transfer 161 (2015) 117–130), the present investigation is limited to transitions with an upper energy level below 7500 cm−1 , considers 27 new sources of transitions data, corrects several older assignments, and utilizes an improved validation procedure based partially on high-quality first-principles rovibrational energies. This study yields 4936 uniquely labelled empirical rovibrational energy levels, the set is complete up to 2413 cm−1 . We confirm the overall high accuracy of the most recent “spectroscopic” (fitted) 14NH3 potential energy surface, C2018, up to 7500 cm−1 . Investigation of energy values resulting from previous effective Hamiltonian (EH) fits forms an important part of this study. It is established that previous EH fits, using high expansion orders in the Hamiltonian, are inaccurate for certain high rotational excitations for all vibrational parent states considered. Employing the ground vibrational state as a test case, it is shown that the origin of the problem is that the observed 14NH3 spectroscopic Preprint submitted to Elsevier March 6, 2020 network used for the EH fit contains floating components. A much improved EH fit is presented whereby the floating components are connected to the principal components of the spectroscopic network by carefully selected first-principles “bridges”. It is recommended that for all molecules the experimental set of transitions employed for an EH fit should be checked for floating components and extra care is exercised if they existed, as in these cases the adequate reproduction of the transitions does not automatically mean that the energies derived from the EH parameters are correct, as well. The connectivity problem of measured spectroscopic networks becomes more and more pronounced as the order of the Hamiltonian is increased. Keywords: ammonia (14NH3), rovibrational transitions, rovibrational energy levels, MARVEL, database, spectroscopic networks, effective
DOI: 10.48577/jpl.7hbcoi
title: Quadrupole Ion Trap Mass Spectrometer for Ice Giant Atmospheres Exploration

description: To date, a variety of dierent types of mass spectrometers have been utilized on missionsto study the composition of atmospheres of solar system bodies, including Venus, Mars,Jupiter, Titan, the moon, and several comets. With the increasing interest in future smallprobe missions, mass spectrometers need to become even more versatile, lightweight, compact,and sensitive.For in situ exploration of ice giant atmospheres, the highest priority composition measurementsare helium and the other noble gases, noble gas isotopes, including 3He/4He, andother key isotopes like D/H. Other important but lower priority composition measurementsinclude abundances of volatiles C, N, S, and P; isotopes 13C/12C, 15N/14N, 18O/17O/16O;and disequilibrium species PH3, CO, AsH3, GeH4, and SiH4. Required measurement accuraciesare largely dened by the accuracies achieved by the Galileo (Jupiter) probe NeutralMass Spectrometer and Helium Abundance Detectors, and current measurement accuraciesof solar abundances [1].An inherent challenge of planetary entry probe mass spectrometers is the introduction ofmaterial to be sampled (gas, solid, or liquid) into the instrument interior, which operates ata vacuum level. Atmospheric entry probe mass spectrometers typically require a speciallydesigned sample inlet system, which ideally provides highly choked, nearly constant mass-ow intake over a large range of ambient pressures. An ice giant descent probe would haveto operate for 1-2 hours over a range of atmospheric pressures, possibly covering 2 or moreorders of magnitude, from the tropopause near 100 mbar to at least 10 bars, in an atmosphericlayer of depth beneath the tropopause of about 120 km at Neptune and about 150 km atUranus.The Jet Propulsion Laboratory's Quadrupole Ion Trap Mass Spectrometer (QITMS) [2] isbeing developed to achieve all of these requirements. A compact, wireless instrument with amass of only 7.5 kg, and a volume of 7 liters (7U), the JPL QITMS is currently the smallestight mass spectrometer available for possible use on planetary descent probes as well assmall bodies, including comet landers and surface sample return missions. The QITMS iscapable of making measurements of all required constituents in the mass range of 1 - 600atomic mass units (u) at a typical speed of 50 mass spectra per second, with a sensitivityof up to 1013 counts/mbar/sec and mass resolution of m=m = 18000 at m/q=401. The QITMS features a novel MEMS-based inlet system driven by a piezoelectric actuator thatcontinuously regulates gas ow at inlet pressures of up to 100 bar.In this paper, we present an overview of the QITMS capabilities, including instrument designand characteristics of the inlet system, as well as the most recent results from laboratorymeasurements in dierent modes of operation, especially suitable for ice giant atmospheresexploration.
DOI: 10.48577/jpl.cjt48h
title: Remote sensing of angular scattering effect of aerosols in a North American megacity

description: The angle-dependent scattering effect of aerosols in the atmosphere not only influences climate through radiative forcing effects but also impacts trace gas remote sensing by modifying the path of radiation through the atmosphere. The aerosol phase function, which characterizes the angular signature of scattering, has been continuously monitored from ground-based and space-borne observations. However, the range of scattering angles these instruments can sample is very limited. Here, we report multi-year measurements from a mountain-top remote sensing instrument: the California Laboratory for Atmospheric Remote Sensing Fourier Transform Spectrometer (CLARS-FTS), which overlooks the Los Angeles megacity. The observational geometries of CLARS-FTS provide a wide range of scattering angles, from about 20° (forward) to about 140° (backward), which is larger than the range provided by any existing aerosol remote sensing instrument. We then quantify the aerosol angular scattering effect using the O2 ratio, which is the ratio of retrieved O2 Slant Column Density (SCD) to geometric O2 SCD. The O2 ratio quantifies the light path modification due to aerosol scattering, with a value of 1 representing an aerosol-free scenario. The lower the O2 ratio value than 1, the stronger the aerosol loading. CLARS-FTS measurements are highly sensitive to the angular scattering effect of aerosols in the Los Angeles (LA) urban atmosphere, due to the long light path going through the boundary layer and the wide range of observational angles. The differences in aerosol scattering between different surface reflection points targeted by CLARS-FTS can be explained by differences in their angular scattering geometries. The correlation between measurements at different targets can be used to quantify the strength of the angular dependence of the aerosol phase function. Applying the correlation technique to CLARS-FTS measurements, we find that, from 2011 to 2018, there is no significant trend in the aerosol phase function in the LA megacity. Overall, this study provides a practical observing strategy for quantifying the angular dependence of aerosol scattering in urban atmospheres that could potentially contribute towards improved greenhouse gas remote sensing in megacities.