cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.rnhn7b
title: Statistically Steady State Large-Eddy Simulations Forced by an Idealized GCM: 1. Forcing Framework and Simulation Characteristics

description: Using large-eddy simulations (LES) systematically has the potential to inform parameterizations of subgrid-scale (SGS) processes in general circulation models (GCMs), such as turbulence, convection, and clouds. Here we show how LES can be run to simulate grid columns of GCMs to generate LES across a cross-section of dynamical regimes. The LES setup approximately replicates the thermodynamic and water budgets in GCM grid columns. Resolved horizontal and vertical transports of heat and water and large-scale pressure gradients from the GCM are prescribed as forcing in the LES. The LES are forced with prescribed surface temperatures, but atmospheric temperature and moisture are free to adjust, reducing the imprinting of GCM fields on the LES. In both the GCM and LES, radiative transfer is treated in a unified but idealized manner (semi-gray atmosphere without water vapor feedback or cloud radiative effects). We show that the LES in this setup reaches statistically steady states without nudging to thermodynamic GCM profiles. The steady states provide training data for developing GCM parameterizations. The same LES setup also provides a good basis for studying the cloud response to global warming.
DOI: 10.48577/jpl.zraq5i
title: Improved GNSS-R Ocean Surface Altimetry with CYGNSS in the Seas of Indonesia

description: Abstract—Ocean surface altimetry with GNSS Reflectometry (GNSS-R) has the potential to improve the observation and retrieval of mesoscale ocean current flows by increasing the spatial density of ocean surface observations. The leading challenges in current GNSS-R altimetry investigations include precise delay re-tracking, correction of ionospheric effects, and spacecraft receiver positioning. Here, we present improved methods to account for these challenges. A reflection-model based approach is presented for delay re-tracking that uses simulated delay-Doppler maps (DDMs) to retrieve the specular delay from measured DDMs. Global ionosphere maps are used to estimate the group delay effect along the direct and reflection paths. Precise orbit determination techniques are used to improve estimates of the receiving spacecraft position and reduce systematic inter-satellite biases. We analyze altimetric height retrievals from two cases, strongly coherent or diffuse reflections. We study the residual systematic error signals with a focus on understanding the errors identified above. The strong coherent observations have narrow, symmetric delay waveforms and provide higher than average signal-to-noise ratio. The DDMs of diffuse observations, originate from relatively rough ocean surfaces, and have the characteristic horse-shoe shape. Only measurements from the ocean and seas surrounding Indonesia are considered as this area provides a significant number of strongly coherent reflections. More than 50; 000 single point observations and week-long averaged results are presented to quantify the noise and systematic characteristics of the retrieved surface heights.
DOI: 10.48577/jpl.22oied
title: Impacts of Degradation on Water, Energy, and Carbon Cycling of the Amazon Tropical Forests

description: Selective logging, fragmentation, and understory fires directly degrade forest structure and composition. Their regional impacts on carbon, water, and energy cycles are com-parable to deforestation. However, studies addressing the effects of forest degradation on ecosystem functions are scarce. Here, we integrate field observations and high-resolution remote sensing from airborne lidar to provide realistic initial conditions to the Ecosystem Demography Model (ED2.2) and investigate the impact of disturbances from for-est degradation on gross primary production (GPP), evapotranspiration (ET), and sensible heat flux (H). We used forest demography information retrieved from airborne lidar samples (13,500 ha) and calibrated with 817 inventory plots (0.25 ha) across precipitation and degradation gradients in the Amazon as initial conditions to ED-2.2 model and simulated fluxes for five regions in Eastern Amazonia. Our results show that the magnitude and seasonality of fluxes were modulated by changes in forest structure caused by degradation. During the dry season and under typical conditions, severely degraded forests experienced water-stress with declines in ET (up to 34%) and GPP (up to 35%),and increases of H (up to 43%) and daily mean ground temperatures (up to 6.5°C) relative to intact forests. In contrast, the relative impact of forest degradation on energy,water, and carbon cycles markedly diminishes under extreme, multi-year droughts, as a consequence of severe stress experienced by intact forests. Our results highlight that the water and energy cycles in the Amazon are not only driven by climate and deforestation, but also the past disturbance and changes of forest structure from degradation, suggesting a much broader influence of human land use activities on the tropical ecosystems.
DOI: 10.48577/jpl.anbtcs
title: Europa’s surface water ice crystallinity: Discrepancy between observations and thermophysical and particle flux modeling

description: Physical processing of Europan surface water ice by thermal relaxation, charged particle bombardment, and possible cryovolcanic activity can alter the percentage of the crystalline form of water ice compared to that of the amorphous form of water ice (the ‘‘crystallinity’’) on Europa’s surface. The timescales over which amorphous water ice is thermally transformed to crystalline water ice at Europan surface temperatures (80–130 K) suggests that the water ice there should be primarily in the crystalline form, however, surface bombardment by charged particles induced by Jupiter’s magnetic field, and vapor deposition of water ice from Europan plumes, can produce amorphous water ice surface deposits on short timescales. The purpose of this investigation is to determine whether the Europan surface water ice crystallinity derived from groundbased spectroscopic measurements is in agreement with the crystallinity expected based upon temperature and radiation modeling. Using a 1D thermophysical model of Europa’s surface, we calculate an integrated full-disk crystallinity of Europa’s leading hemisphere by incorporating the thermal relaxation of amorphous to crystalline water ice and the degradation of crystalline to amorphous water ice by irradiation. Concurrently, we derive the full-disk crystallinity of Europa’s leading hemisphere using a comparison of near-infrared ground-based spectral observations from Grundy et al. (1999), Busarev et al. (2018), and the Apache Point Observatory in Sunspot, NM, with laboratory spectra from Mastrapa et al. (2008) and the Ice Spectroscopy Lab at the Jet Propulsion Laboratory. We calculate a modeled crystallinity significantly higher than crystallinities derived from groundbased observations and laboratory spectra. This discrepancy may be a result of geophysical processes, such as by vapor-deposited plume material, or it may arise from assumptions and uncertainties in the crystallinity calculations.
DOI: 10.48577/jpl.ivdavw
title: Contrasting regional carbon cycle responses to seasonal climate anomalies across the east-west divide of temperate North America

description: Interannual variations in climate modulate the gross primary productivity (GPP) and net ecosystem exchange (NEE) of ecosystems across North America. However, on the scale of 100s–1000s km, interannual variations in these fluxes are poorly understood. Here, we examine the dominant modes of variability in GPP and NEE and their relationship to environmental drives using two state-of-the-science flux products: NEE constrained by surface-based and space-based atmospheric CO2 measurements over 2010–2015 and up-scaled GPP from FluxSat over 2001–2017. We find that, despite a more active carbon cycle in eastern North America, the arid western half of North America provides a larger contribution to IAV in GPP (104% of east) and NEE (127% of east) during the growing season (April-September). This occurs because flux anomalies in western North America are temporally coherent across the growing season leading to an amplification of GPP and NEE. Increased productivity and carbon sequestration in western North America is closely associated with cooler and wetter than average conditions. In contrast, IAV in eastern North America is dominated by seasonal compensation effects, wherein positive anomalies during April–June are compensated for by negative anomalies during July–September. These seasonal compensation effects are most closely linked to temperature, with a phase shift of the seasonal cycle to earlier in the year for warmer years. Terrestrial biosphere models in the MsTMIP ensemble partially capture these differences in IAV between eastern and western North America. However, the models underestimate the sensitivity of flux anomalies in western North America to variations in soil temperature and moisture by 25–100%. The results of this study suggest that ecosystems in western North America may be more sensitive to warming and increasing aridity than models predict, suggesting that reductions in growing season productivity and carbon sequestration under climate change may be larger than predicted by models.
DOI: 10.48577/jpl.tmfigl
title: Magnetic Induction Responses of Jupiter's Ocean Moons Including Effects from Adiabatic Convection

description: Prior analyses of oceanic magnetic induction within Jupiter's large icy moons have as sumed uniform electrical conductivity. However, the phase and amplitude responses of the induced fields will be ininfluenced by the natural depth-dependence of the electrical conductivity. Here, we examine the amplitudes and phase delays for magnetic diffusionin modeled oceans of Europa, Ganymede, and Callisto. For spherically symmetric configurations, we consider thermodynamically consistent interior structures that include realistic electrical conductivity along the oceans' adiabatic temperature profiles. Con-ductances depend strongly on salinity, especially in the large moons. The induction responses of the adiabatic profiles differ from those of oceans with uniform conductivity set to values at the ice{ocean interface, or to the mean values of the adiabatic profile, by more than 10% for some signals. We also consider motionally induced magnetic fields generated by convective fluid motions within the oceans, which might optimistically be used to infer ocean flows or, pessimistically, act to bias the ocean conductivity inversions. Our upper-bound scaling estimates suggest this eect may be important at Europa and Ganymede, with a negligible contribution at Callisto. Based on end-member ocean compositions, we quantify the magnetic induction signals that might be used to infer the oxidation state of Europa's ocean and to investigate stable liquids under high-pressure ices in Ganymede and Callisto. Fully exploring this parameter space for the sake of planned missions requires thermodynamic and electrical conductivity measurements in fluids at low temperature and to high salinity and pressure as well as modeling of motional induction responses.
DOI: 10.48577/jpl.hyvnnv
title: Correction to “The solar and interplanetary causes of superstorms (minimum Dst ≤ -250 nT) during the space age” by Meng et al. (2019)

description: There is a misstatement in the abstract of Meng et al. (2019). There were not compound events involving two ICMEs causing superstorms with Dst ≤ -250 nT detected in the study. There were however two compound events involving magnetic clouds followed by sheath fields causing superstorms. We show the event on April 11-13, 1981 storm main phase as an example.
DOI: 10.48577/jpl.rnqtam
title: Progenitor, Precursor and Evolution of the Dusty Remnant of the Stellar Merger M31-LRN-2015

description: M31-LRN-2015 is a luminous red nova (LRN) and a likely stellar merger discovered in the Andromeda Galaxy in 2015. We present new optical to mid-infrared photometry and optical spectroscopy for this event. We show that the object experienced a ~3mag brightening as compared to its archival progenitor level. We suggest that the complex precursor emission, which started at ~2 years before the nova event, may be explained by the binary undergoing Roche-lobe overerflow. The dynamical mass loss from the outer Lagrange point L2 would create an optically thick outflow, powering the observed brightening of the system. We find two putative periods in different phases of the precursor lightcurve of 16+/-0.3 and 28.1+/-1.4 days. Although the progenitor spectral energy distribution shows no pre-existing warm dust in system, our late-time follow-up proves that the remnant forms an optically thick dust shell at 2-4 months after the outburst peak. The optical depth of the shell increases after 1.5 years, suggesting the existence of shocks that enhance the dust formation process. We propose that the merger remnant is likely an inflated giant obscured by a cooling shell of gas, ejected by the onset of the common envelope phase.
DOI: 10.48577/jpl.7r3nhk
title: GRACE-based mass conservation as a validation target for basin-scale evapotranspiration in the contiguous United States

description: Here, we evaluate basin-scale evapotranspiration (ET) estimates for eleven major river basins in the contiguous United States against a water balance approach with Gravity Recovery and Climate Experiment (GRACE) satellite observations. The relatively precise measurements of large-scale changes in water mass from GRACE are used to estimate the storage rate term in the terrestrial water budget and consequently provide anestimate, with propagated uncertainty, of basin-aggregated ET from mass conservation.We apply GRACE-based ET to two modeling systems (NLDAS-2, GLDAS-2.1) comprised of five land surface models and three remote sensing-based products (MOD16, PT-JPL, FLUXCOM) for 2003 to 2014. Both the land surface model-based and remote sensing based ET are persistently lower than GRACE-based ET in all eleven basins tested. W also find that interannual variability is greater for GRACE-ET than the model and remote sensing products, and this is attributed to precipitation variability.
DOI: 10.48577/jpl.mu8kya
title: Analysis of Scattering Characteristics from Inland Bodies of Water Observed by CYGNSS

description: Measurements made by spaceborne Global Navigation Satellite System Reflectometry (GNSS-R) instruments6 have shown strong reflected power over inland waters that has been attributed to coherent scattering coming from the7 first Fresnel zone. Previous work in the field has shown the ability of GNSS-R to observe the global surface water8 distribution by generating dynamic maps of wetlands and other inundated areas. These maps can be generated by9 leveraging the large difference in received power of the GNSS signals as they reflect from water surfaces compared10 to land. In this paper, we utilize a full-forward scattering model approach to evaluate the accuracy of these maps. The11 CYGNSS End-to-End Simulator (E2ES) was extended to include the contributions from coherent surface scattering in12 heterogeneous regions where the area around the specular point contains both water and land in complex geometries.13 The simulator is then used to analyze the accuracy of a current approach to estimate the surface water content14 in the first Fresnel zone from a single measurement, called a fractional water in footprint approach. We find that15 contributions to the total received power by the scattering from outside the first Fresnel zone as well as CYGNSS16 instrument effects impact the accuracy of this approach. Furthermore, the measured signal from calibration scattering17 targets is compared to the results of simulation to validate the scattering model. The work shows that the variability18 of the peak reflected power over inland bodies of water due to the scene heterogeneities should be accounted for in19 designing retrieval algorithms to map wetland extent.
DOI: 10.48577/jpl.gtynu2
title: Exep: A realistic Determination of Observational Completeness Usingthe Starshade

description: The Starshade is a rising tool to be used in exoplanetary imaging to look for Earth-like planets. Positioned between the telescope and the star, the Starshade blocks the starlight from the telescope’s mirrors. Previous studies have estimated the Earth-like exoplanet yields of future missions using average models of astrophysical parameters. This project aimed to produce a more precise completeness estimate using the Starshade Imaging Simulation Toolkit for Exoplanet Reconnaissance (SISTER), a software that produces predicted images of what will be observed through the telescope. To utilize SISTER, we have devised an algorithm that distributes synthetic Earth-like planets around target stars. The user may input various astrophysical parameters, including planet radius, atmosphere, eccentricity, and inclination. From these simulated images, we compute a regression fit against the Point Spread Function of each planet at each position. Ultimately, we obtain a count of detectable planets over the number of distributed planets, also known as completeness. This algorithm, for the first time, derives a realistic estimation of observational completeness from simulated images, much akin to what an astronomer would do from an observation. This algorithm will be useful for future JPL starshade mission planning, to calculate the probability of a successful mission.
DOI: 10.48577/jpl.hwyrxk
title: Evaluation of UV Aerosol Retrievals from an Ozone Lidar

description: Aerosol retrieval using ozone lidars in the ultraviolet (UV) band is challenging but necessary for correcting aerosol interference in ozone retrieval and for studying the ozone-aerosol correlations. This study describes the aerosol retrieval algorithm for an ozone lidar, quantifies the retrieval error budget, and intercompares the aerosol retrieval products at 299 nm with those at 532 nm from a high spectral resolution lidar (HSRL). After cloud-contaminated data are filtered out, the aerosol backscatter or extinction coefficients at a 30-m and 10-min resolution retrieved by the ozone lidar are highly correlated with the HSRL products, with a coefficient of 0.95 suggesting that the ozone lidar can reliably measure aerosol structures with high spatio-temporal resolution when the signal-to-noise ratio is sufficient. The actual uncertainties of the aerosol retrieval from the ozone lidar generally agree with our theoretical analysis. The backscatter color ratio (backscatter-related exponent of wavelength dependence) linking the coincident data measured by the two instruments at 299 and 532 nm is 1.34±0.11 while the Ångström (extinction-related) exponent is 1.49±0.16.
DOI: 10.48577/jpl.kbmdrr
title: An updated tropospheric chemistry reanalysis and emission estimates, TCR-2, for 2005-2018

description: This study presents the results from the Tropospheric Chemistry Reanalysis version 2 (TCR-2) for the period 2005- 2018 at 1.1◦ horizontal resolution obtained from the assimilation of multiple updated satellite measurements of ozone, CO, NO2, HNO3, and SO2 from the OMI, SCIAMACHY, GOME-2, TES, MLS, and MOPITT satellite instruments. The reanalysis 5 calculation was conducted using a global chemical transport model MIROC-CHASER and an ensemble Kalman filter technique that optimizes both chemical concentrations of various species and emissions of several precursors, which was efficient for the correction of the entire tropospheric profile of various species and its year-to-year variations. Comparisons against independent aircraft, satellite, and ozonesonde observations demonstrate the quality of the reanalysis fields for numerous key species on regional and global scales, as well as for seasonal, yearly, and decadal scales, from the surface to the lower strato10 sphere. The multi-constituent data assimilation brought the model vertical profiles and inter-hemispheric gradient of OH closer to observational estimates, which was important in improving the description of the oxidation capacity of the atmosphere and thus vertical profiles of various species. The evaluation results demonstrate the capability of the chemical reanalysis to improve understanding of the processes controlling variations in atmospheric composition, including long-term changes in near-surface air quality and emissions. The estimated emissions can be employed for the elucidation of detailed distributions of the anthro15 pogenic and biomass-burning emissions of co-emitted species (NOx, CO, SO2) in all major regions, as well as their seasonal, and decadal variabilities. The datasets are available at: https://doi.org/10.25966/9qgv-fe81 (Miyazaki et al., 2019a).
DOI: 10.48577/jpl.9a7hxx
title: Seasonal and Annual Changes of The Regional Tropical Belt in GPS-RO Measurements and Reanalysis Datasets

description: No abstract available.
DOI: 10.48577/jpl.dyhpvz
title: Pseudoline parameters to represent n-butane (n-C4H10) cross-sections measured in the 7-15 m region for the Titan atmosphere

description: We measured temperature-dependent cross-sections of n-butane (CH3-CH2-CH2-CH3) in the mid-infrared (7-15 m) region in support of remote sensing for the Titan’s atmosphere. For this, 28 pure and N2-mixture spectra were obtained at 180–298 K using a high-resolution Fourier transform spectrometer (Bruker IFS 125 HR) at the Jet Propulsion Laboratory. The spectral resolutions were selected to be between 0.0039 and 0.06 cm-1, depending on the sample pressures. The observed spectra were fit simultaneously to generate one single set of pseudolines, which include line intensities and lower state energies at individual pseudoline positions. The observed spectra could be reproduced by the pseudolines to within 4 % through line-by-line radiative transfer calculations. The integrated intensities at 296 K were measured to be 5.06(28), 7.18(27), 0.91(4), and 49.01(20)×10-19 cm-1/(molec.cm-2) in the 660-860, 860-1060, 1060-1200, and 1200-1538 cm-1 regions, respectively, by summing up the pseudoline intensity parameters. These results are observed to be significantly lower than that of the PNNL (Pacific Northwest National Laboratory) cross-sections obtained at a low resolution at N2-backup pressure of 1 atm. The pseudolines are electronically compiled in the HITRAN database format, which can be readily integrated with existing radiative transfer calculations. The measured cross-sections represented by the pseudolines could provide critical laboratory input in search of elusive species that might be captured in the Cassini/CIRS spectral observations.
DOI: 10.48577/jpl.ebqzab
title: SI-Traceability of the Atmospheric Infrared Sounder Version 5 Level 1B Radiances

description: The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. The AIRS was designed to measure atmospheric temperature and water vapor profiles and has demonstrated exceptional radiometric and spectral accuracy and stability in-orbit. The International System of Units (SI)-traceability of the derived radiances is achieved by transferring the calibration from a Large Area Blackbody (LABB), and Space View Source (SVS), to the On-Board Calibrator (OBC) blackbody during preflight testing and frequent on-board calibration. The AIRS also provides a full aperture space view every scan for offset calibration. AIRS nonlinearity and polarization calibration coefficients are based on pre-flight testing and have been among the highest uncertainty sources in the calibration. Recent methods using on-board data has improved our understanding of the magnitude and uncertainty of these terms. An estimate of the system radiometric accuracy (defined as the uncertainty relative to SI-traceable standards), is made based for the Version 5 AIRS L1B radiance product. SI-traceability and quantification of the radiometric uncertainty is critical to reducing biases in reanalysis products and radiative transfer models that use AIRS data, as well as establishing the suitability of AIRS as a benchmark for radiances established in the early 2000’s.