cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.vuvh5w
title: Smart Power Supply Calibration System

description: Abstract- This paper details the development of an automated procedure to conduct calibrations of power supplies at Jet Propulsion Laboratory, California Institute of Technology (JPL). The fundamentals of power supply calibrations is given, and discussion on the method by which this custom software handles that calibration. Additionally, this technique provides real time uncertainty quantification of the calibrations. This automated system has demonstrated a time savings over existing automated techniques in use today.
DOI: 10.48577/jpl.rkbuw8
title: FluxSat: Measuring the ocean-atmosphere turbulent exchange of heat and moisture from space

description: Abstract: Recent results using wind and sea surface temperature data from satellites and high 16 resolution coupled models suggest that mesoscale ocean-atmosphere interactions affect the 17 locations and evolution of storms and seasonal precipitation over continental regions such as the 18 western US and Europe. The processes responsible for this coupling are difficult to verify due to the 19 paucity of accurate air-sea turbulent heat and moisture flux data. These fluxes are currently derived 20 by combining satellite measurements that are not coincident and that have differing and relatively 21 low spatial resolutions, introducing sampling errors that are largest in regions with high spatial and 22 temporal variability. Observational errors related to sensor design also contribute to increased 23 uncertainty. Leveraging recent advances in sensor technology, here we describe a satellite mission 24 concept, FluxSat, that aims to simultaneously measure all variables necessary for accurate 25 estimation of the ocean-atmosphere turbulent heat and moisture fluxes and capture the effect of 26 oceanic mesoscale forcing. FluxSat will improve the accuracy of the fluxes at spatial scales critical to 27 understanding the coupled ocean-atmosphere boundary layer system, providing measurements 28 needed to improve weather forecasts and climate model simulations. The improved spatial 29 resolution will also enable the estimation of fluxes closer to coasts, thereby facilitating studies of 30 near-coastal physical and ecosystem processes as well as supporting interdisciplinary research
DOI: 10.48577/jpl.ztam0b
title: Improving the representation of subtropical boundary layer clouds in the NASA GEOS model with the Eddy-Di usivity/Mass-Flux parameterization

description: A systematic underestimation of subtropical planetary boundary layer (PBL) stratocumulusclouds by the GEOS model has been signicantly improved by a new Eddy-Diusivity/Mass-Flux (EDMF) parameterization. The EDMF parameterization representsthe subgrid-scale transport in the dry and moist parts of the PBL in a unied mannerand it combines an adjusted eddy-diusivity PBL scheme from GEOS with a stochasticmulti-plume mass-ux model. The new EDMF version of the GEOS model is rst comparedagainst the CONTROL version in a single-column model (SCM) framework for twobenchmark cases representing subtropical stratocumulus and shallow cumulus clouds, andvalidated against large eddy simulations. Global simulations are performed and comparedagainst observations and reanalysis data. The results show that the EDMF version of theGEOS model produces more realistic subtropical PBL clouds. Noteworthy, the EDMF improvementsrst detected in the SCM framework translate into similar improvements of theglobal GEOS model.
DOI: 10.48577/jpl.gpgver
title: Properties and Behavior of the Acetonitrile-Acetylene Co-Crystal under Titan Surface Conditions

description: Titan, the largest satellite of Saturn, possesses a complex photochemical cycle producing a broad inventory of organic molecules in its thick atmosphere and on its surface. Two of the most common molecules in this inventory include acetylene (C2H2) and acetonitrile (CH3CN). We have previously demonstrated that certain organic molecules (such as benzene and ethane) readily form co-crystals under Titan-relevant conditions. We report here Raman spectroscopic and X-ray diffraction evidence for a co-crystal between acetonitrile and acetylene at Titan surface conditions. This molecular mineral could be relatively abundant on Titan, in particular in the large fluvially-dissected plateaux of labyrinth terrains and possibly the undifferentiated plains, which are believed to be the end-stage product of the labyrinth terrains. Co-crystals might provide a mechanism for storing energy-rich molecules such as acetylene, permitting sequestration and transport to the subsurface where these deposits could be accessed by putative life.
DOI: 10.48577/jpl.qb1ies
title: Sea surface salinity as a proxy for Arctic Ocean freshwater changes

description: The changing Arctic freshwater content and distribution have significant implications for ocean circulation, climate, and water and biogeochemical cycles. The paucity of in-situ salinity measurements in the Arctic Ocean has limited our ability to study Arctic-Ocean freshwater variability. Although satellite-derived sea surface height (SSH) and ocean bottom pressure (OBP) have been used together to infer depth-integrated freshwater content changes, these measurements are limited in sampling and resolution. Motivated by the recent development of sea surface salinity (SSS) remote sensing, we explore the use of SSS as a proxy for Arctic freshwater changes. As a first step, here we conduct a proof-of-concept study by analyzing the output of an ocean-ice state estimation product. We find that SSS variations are coherent with those of SSH-minus-OBP across the Arctic basin (with R ~ -0.8) except for in the center of the Beaufort Gyre and the region affected by the subpolar North Atlantic inflow. On Arctic shelves, the linear regression coefficient between SSS and SSH-minus-OBP is -0.3 pss/cm or larger in magnitude. The results suggest that SSS is a good proxy for Arctic freshwater changes, and satellite SSH-minus-OBP can be used to evaluate satellite SSS quality.
DOI: 10.48577/jpl.wmigur
title: Goldstone Apple Valley Radio Telescope Monitoring Flux Density of Jupiter’s Synchrotron Radiation during the Juno Mission

description: AbstractGoldstone Apple Valley Radio Telescope (GAVRT) is a science education partnership among NASA, the Jet Propulsion Laboratory (JPL), and the Lewis Center for Educational Research (LCER), offering unique opportunities for K -12 students and their teachers. As part of a long-term Jupiter synchrotron radiation (JSR) flux density monitoring program, LCER has been carrying out Jupiter observations with some student participation. In this paper we present the results of processed data sets observed between March 6, 2015 and April 6 2018. The data are divided into 5 epochs, grouped by time and by Jupiter’s ephemeris parameters as observed from Earth. We derive JSR beaming curves at different epochs and Earth declinations. We present a comparison of the observed beaming curves with those derived from most recent models for the radiation belts. Our results show an increasing trend of the JSR flux density which seem consistent with the models for the magnetospheric solar wind interactions
DOI: 10.48577/jpl.uj7wgq
title: Determinant Role of Aerosols from Industrial Sources in Hurricane Harvey’s Catastrophe

description: The destructive power of tropical cyclones is driven by latent heat released from water 36 condensation and is inevitably linked to the abundance of aerosols as cloud condensation nuclei. 37 However, the aerosol effects are unaccounted for in most operational hurricane forecast models. 38 We combined multi-source measurements and cloud-resolving model simulations to show 39 fundamentally altered cloud microphysical and thermodynamic processes by anthropogenic 40 aerosols during Hurricane Harvey. Our observations reveal intense lightning and precipitation in 41 the proximity of Houston industrial areas, and these hotspots exhibit a striking geographic 42 similarity to a decadal climatological maximum of lightning flash density in the south-central U.S. 43 Our ensemble cloud-resolving simulations of Hurricane Harvey indicate that anthropogenic 44 aerosols can increase precipitation and lightning by a factor of 2 in the Houston urban area, 45 unraveling the key factor in regulating flooding during this weather extreme.
DOI: 10.48577/jpl.xrsbjb
title: Understanding hypervelocity sampling of biosignatures in space missions

description: The atomic scale fragmentation processes involved in molecules undergoing hyper- velocity impacts (HVI; defined as &gt; 3km=s) are challenging to investigate and still not well understood. This is especially relevant for solar system robotic missions sampling atmospheres and plumes at hypervelocities. Light gas guns, magnetic particle accelerators, or laser field shock experiments are used on earth in an attempt to replicate space conditions during HVI events. Experimental measurements on the HVI effects on small molecular weight neutral organics are extremely difficult, both in terms of accelerating uncharged species and in isolating the multiple transition states on extremely rapid time scales (&lt; 1ps). First-principles based simulations are of high value in modeling the non-adiabatic, non-equilibrium phenomena involved, so as to extend the range of physical parameters and species of interest beyond what is possible with experiments. We report on high fidelity simulations of the fragmentation of small organic biosignature molecules over the range v = 1–12km=s, using a first-principles based approach. We demonstrate that the fragmentation fraction is a sensitive function of velocity, impact angle, molecular structure, impact surface material, and the presence or absence of surrounding ice-shells, and generate interpretable fragmentation pathways and spectra for velocity values above the fragmentation thresholds. We demonstrate how organic molecules encased in ice grains, as would likely be the case for those in 'ocean worlds', preserve these molecules at even higher velocities. Our results place ideal spacecraft encounter velocities between 3-5km/s for bare amino and fatty acids and within 4-6 km/s for the same species encased in ice grains, which is consistent with recent experiments exploring HVI effects using impact-induced ionization and analysis via mass spectrometry.1 The predicted results match the major amino acid fragments observed in lab spectra, and the onset of organic fragmentation in ice grains at &gt; 5km/s from the analysis of Enceladus organics in Cassini Data.2 We show that HVI energy is dissipated by ice casings via thermal velocity resistance from the impact shock wave, and that there is a limit defined by the tensile forces caused by water molecules during the expansion phase at which ultimately all organic contents will fragment, independent of the number of ice shells. These results contribute to our understanding of molecular fragmentation under HVI, and allow us to bracket instrument design and future mission parameters.
DOI: 10.48577/jpl.3n8sow
title: The Aerosol Characterization from Polarimeter and Lidar (ACEPOL) airborne field campaign

description: In the fall of 2017, an airborne field campaign was conducted from the NASA Armstrong Flight Research Center in Palmdale, California to advance the remote sensing of aerosols and clouds with Multi-angle Polarimeters (MAP) and Lidars. The Aerosol Characterization from Polarimeter and Lidar (ACEPOL) campaign was jointly sponsored by NASA and the Netherlands Institute for Space Research (SRON). Six instruments were deployed on the ER-2 high altitude aircraft. Four were MAPs: the Airborne Hyper Angular Rainbow Polarimeter (AirHARP), the Airborne Multiangle SpectroPolarimetric Imager (AirMSPI), the Airborne Spectrometer for Planetary EXploration (SPEX Airborne) and the Research Scanning Polarimeter (RSP). The remainder were Lidars, including the Cloud Physics Lidar (CPL) and the High Spectral Resolution Lidar 2 (HSRL-2). The southern California base of ACEPOL enabled observation of a wide variety of scene types, including urban, desert, forest, coastal ocean and agricultural areas, with clear, cloudy, polluted and pristine atmospheric conditions. Flights were performed in coordination with satellite overpasses and ground based observations, including the Groundbased Multiangle SpectroPolarimetric Imager (GroundMSPI), sun photometers, and a surface reflectance spectrometer. ACEPOL is a resource for remote sensing communities as they prepare for the next generation of spaceborne 40 MAP and lidar missions. Data are appropriate for algorithm development and testing, instrument intercomparison, and investigations of active and passive instrument data fusion. They are freely available to the public, at 10.5067/SUBORBITAL/ACEPOL2017/DATA001 (ACEPOL Science Team, 2017). This paper describes ACEPOL for potential data users, and also provides an outline of requirements for future field missions with similar objectives.
DOI: 10.48577/jpl.rmjwmh
title: Microconical silicon mid-IR concentrators: Spectral, angular and polarization response

description: Abstract: It is widely discussed in the literature that a problem of reduction of thermal noise of mid-wave and long-wave infrared (MWIR and LWIR) cameras and focal plane arrays (FPAs) can be solved by using light-concentrating structures. The idea is to reduce the area and, consequently, the thermal noise of photodetectors still providing good collection of photons on photodetector mesas that can help to increase the operating temperature of FPAs. It is shown that this approach can be realized using microconical Si light concentrators with (111) oriented sidewalls, which can be mass-produced by anisotropic wet etching of Si (100) wafers. The design is performed by numerical modeling in a mesoscale regime when the microcones are sufficiently large (several MWIR wavelengths) to resonantly trap photons, but still too small to apply geometrical optics or other simplified approaches. Three methods of integration Si microcone arrays with the focal plane arrays (FPAs) are proposed and studied: (i) Inverted microcones fabricated in a Si slab which can be heterogeneously integrated with the front illuminated FPA photodetectors made from high quantum efficiency materials to provide resonant power enhancement factors (PEF) up to 10 with angle-of-view (AOV) up to 10°; (ii) Inverted microcones which can be monolithically integrated with metal-Si Schottky barrier photodetectors to provide resonant PEFs up to 25 and AOVs up to 30° for both polarizations of incident plane waves; and iii) Regular microcones which can be monolithically integrated with near-surface photodetectors to provide a non-resonant power concentration on compact photodetectors with large AOVs. It is demonstrated that inverted microcones allow realizing multispectral imaging with ~100 nm bands and large AOVs for both polarizations. In contrast, the regular microcones operate similar to single-pass optical components (such as dielectric microspheres) producing sharply focused photonic nanojets.
DOI: 10.48577/jpl.glcjbx
title: Characterizing landing site safety on Venus using Venera panoramas and Magellan radar properties

description: This study explores an approach for identifying and characterizing sites on Venus where a future lander mission could attain a high probability of safe landing through a synthesis of Venera surface panoramas, Magellan radar properties, and existing global geological maps of the Venus surface. Surface panoramas from the Venera 9 and Venera 13 landers were used to define rock size distributions and to calculate the probability of a hazardous rock encounter for a reference Venus lander design at these specific landing sites. This surface analysis formed the basis and rationale for the development of a set of global filters seeking to identify “safe” 150-km-diameter landing ellipses with Magellan radiophysical properties including root mean square slope, radar backscatter coefficient, and emissivity values similar to the most benign regional plains unit (rp2) mapped by Ivanov and Head [2011] within the Venera 13 landing site. Using this method, 178 unique ellipses for which &gt;95% of pixels exhibited rms slope and radar backscatter coefficient values similar to the Venera 13 rp2 unit were identified across the Venus surface. Of these ellipses, 36 also contained &gt;95% of pixels with similar emissivity values as the Venera 13 rp2 unit. “Safe” ellipses identified by this method were predominantly composed of regional plains, shield plains, and smooth plains as defined in the Venus global geologic map of Ivanov and Head [2011]. Although the method developed in this study for identifying and characterizing safe landing sites on Venus requires several assumptions regarding the correlation of orbiter radar data to surface properties relevant to lander safety, this approach provides a best effort starting point integrating available data for the systematic, relatively objective, and automatic identification of safe landing sites on Venus.
DOI: 10.48577/jpl.b9ydfw
title: The NANOGrav 12.5-year Data Set: Wideband Timing of 47 Millisecond Pulsars

description: We present a new analysis of the profile data from the 47 millisecond pulsars comprising the 12.5-year data set of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), which is presented in a parallel paper (Alam et al. submitted to ApJS; NG12.5). Our reprocessing is performed using “wideband” timing methods, which use frequency-dependent template profiles, simultaneous time-of-arrival (TOA) and dispersion measure (DM) measurements from broadband observations, and novel analysis techniques. In particular, the wideband DM measurements are used to constrain the DM portion of the timing model. We compare the ensemble timing results to NG12.5 by examining the timing residuals, timing models, and noise model components. There is a remarkable level of agreement across all metrics considered. Our best-timed pulsars produce encouragingly similar results to those from NG12.5. In certain cases, such as high-DM pulsars with profile broadening, or sources that are weak and scintillating, wideband timing techniques prove to be beneficial, leading to more precise timing model parameters by 10 −15%. The high-precision multi-band measurements in several pulsars indicate frequency-dependent DMs. The TOA volume is reduced by a factor of 33, which may ultimately facilitate computational speed-ups for complex pulsar timing array analyses. This first wideband pulsar timing data set is a stepping stone, and its consistent results with NG12.5 assure us that such data sets are appropriate for gravitational wave analyses.
DOI: 10.48577/jpl.52nbfq
title: Evidence for a Diagenetic Origin of Vera Rubin Ridge, Gale Crater, Mars: Summary and Synthesis of Curiosity’s Exploration Campaign

description: This paper provides an overview of the Curiosity rover’s exploration at Vera Rubin ridge and summarizes the science results. Vera Rubin ridge (VRR) is a distinct geomorphic feature on lower Aeolis Mons (informally known as Mt. Sharp) that was identified in orbital data based on its distinct texture, topographic expression, and association with a hematite spectral signature. Curiosity conducted extensive remote sensing observations, acquired data on dozens of contact science targets, and drilled three rock samples from the ridge, as well as one rock sample immediately below the ridge. Strata comprising VRR were deposited in a predominantly lacustrine setting and are part of the Murray formation. The rocks within the ridge are chemically in family with underlying Murray formation strata. Red hematite is dispersed throughout much of the VRR bedrock, and this is the source of the CRISM orbital detection. Gray hematite is also present in isolated, gray-colored patches concentrated towards the upper elevations of VRR, and the gray patches contain small, dark Fe-rich nodules. We that propose VRR formed when diagenetic event(s) preferentially hardened rocks, which were subsequently eroded into a ridge by wind-erosion. This process also led to enhanced crystallization and/or cementation that deepened the ferric-related spectral absorptions on the ridge that are readily distinguishable from orbit. Results add to existing evidence of protracted aqueous environments at Gale crater and give new insight into how diagenesis shaped Mars’ rock record.
DOI: 10.48577/jpl.ejeepy
title: The NANOGrav 12.5-year Data Set: Observations and Narrowband Timing of 47 Millisecond Pulsars

description: We present time-of-arrival measurements and timing models of 47 millisecond pulsars (MSPs) ob- served from 2004 to 2017 at the Arecibo Observatory and the Green Bank Telescope by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). The observing cadence was three to four weeks for most pulsars over most of this time span, with weekly observations of six sources. These data were collected for use in low-frequency gravitational wave searches and for other astrophysical purposes. We detail our observational methods and present a set of time-of-arrival (TOA) measurements, based on \narrowband" analysis, in which many TOAs are calculated within narrow radio-frequency bands for data collected simultaneously across a wide bandwidth. A separate set of \wideband" TOAs will be presented in a companion paper. We detail a number of methodological changes compared to our previous work which yield a cleaner and more uniformly processed data set. Our timing models include several new astrometric and binary pulsar measurements, including previously unpublished values for the parallaxes of PSRs J1832􀀀0836 and J2322+2057, the secular derivatives of the projected semi-major orbital axes of PSRs J0613􀀀0200 and J2229+2643, and the rst detection of the Shapiro delay in PSR J2145􀀀0750. We report detectable levels of red noise in the time series for fourteen pulsars. As a check on timing model reliability, we investigate the stability of astrometric parameters across data sets of dierent lengths. We report ux density measurements for all pulsars observed. Searches for stochastic and continuous gravitational waves using these data will be subjects of forthcoming publications.
DOI: 10.48577/jpl.vpe4bm
title: Initial Results and Diurnal Variations Measured by a new Microwave Stratospheric ClO Instrument at Mauna Kea

description: We present the first year of ClO and O3 measurements from a new 278 GHz Chlorine monOxide Experiment (ChlOE) microwave instrument on Mauna Kea. We make use of comparisons with the Aura Microwave Limb Sounder (MLS) O3 measurements to recalibrate the ground‐based instrument and find that the recalibrated ground‐based O3 retrievals remain stable relative to MLS throughout the year. The MLS measurements provide daily daytime (~1330 local solar time) and nighttime (~0200 local solar time) ClO retrievals, and we find that the monthly ChlOE ClO retrievals show mixing ratios slightly smaller than those from MLS in the vicinity of Mauna Kea, with daytime values near the peak ~6–8% lower at 30–45 km for the average of the 12 months in this study. The nighttime monthly ClO values are almost all within ±0.03 ppbv over most of this altitude range, with very little overall bias. We have also made detailed hourly diurnal O3 comparisons with a multiyear analysis of previous retrievals from the much stronger 110 GHz O3 emission line being measured by our instrument at Mauna Loa and find that the hour‐to‐hour differences are within ±2% at 40 km, which indicates that the overall calibration of the ChlOE instrument is stable relative to time of day. We show hourly diurnal variations of ClO and compare these to 2010 measurements from the Submillimeter‐Wave Limb‐Emission Sounder and to a model.