cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.u5jcli
title: Anthropogenic Climate Change Likely to Double the Impact of Heat Stress on US Population

description: Globally, heat stress (HS) is nearly certain to increase rapidly over the coming decades, characterized by increased frequency, severity, and spatiotemporal extent of extreme temperatures and humidity. While these characteristics have been investigated independently, a holistic analysis integrating them is potentially more informative. Using observations, climate projections from the CMIP5 model ensemble, and historical and future population estimates, we apply the IPCC risk framework to examine present and projected future potential impact (PI) of summer heat stress for the contiguous United States (CONUS) as a function of non-stationary HS characteristics and population exposure. We find that the PI of short-to-medium duration (1-7-day) HS events is likely to increase more than three-fold across densely populated regions of the U.S. including the Northeast, Southeast Piedmont, Midwest, and parts of the Desert Southwest by late this century (2060-2099) under the highest emissions scenario. The contribution from climate change alone more than doubles the impact in the coastal Pacific Northwest, central California, and the Great Lakes region, implying a substantial increase in HS risk without aggressive mitigation efforts.
DOI: 10.48577/jpl.wscnyj
title: The morpho-kinematical structure and chemical abundances of the complex planetary nebula NGC 1514

description: We present high-resolution, long-slit optical spectra of the planetary nebula NGC1514.The position velocity maps of the [O iii] emission line reveal complex kinematics withmultiple structures: a main inner shell, originally spherical and now distorted by thepresence of some bubbles and an attached outer spherical shell. The two well-defined,mid-infrared rings of NGC1514 are not detected in our high-resolution, long-slit spec-tra, which prevented us from doing a kinematical analysis of them. Based exclusivelyon their morphology, we propose a barrel-like structure to explain the rings.Several ejection processes have been possibly involved in the formation ofthe nebula although this is clearly difficult to establish with the currentdata. The morpho-kinematic analysis is complemented with low-resolution, long-slitspectra with the goal of studying the physical parameters and chemical abundancesof NGC 1514. The nebular spectra reveal a moderate-excitation nebula with weakemission lines of [Ar iii], [Ne iii], and He i. No [Nii] neither other low-excitationemission lines are detected. We found an electron temperature around 14000K inthe gas and an electron density in the range of 2000 and 4000 cm−3.
DOI: 10.48577/jpl.7lqa0f
title: Titan in a Test Tube: Organic Co-Crystals and Implications for Titan Mineralogy

description: In this Account, we highlight recent work in the developing field of mineralogy of Saturn’s moon Titan, focusing on binary co-crystals of small organic molecules. Titan has a massive inventory of organic molecules on its surface that are formed via photochemistry in the atmosphere. Physical processes both in the atmosphere and on the surface can lead to molecules interacting at cryogenic temperatures. Recent work in our labs and others has demonstrated that co-crystals between two or more molecules can form under these conditions. In the organic-rich environment of Titan, such co-crystals are naturally occurring minerals and a critical area of research to understand the physical, chemical, and possibly even biological and prebiotic processes occurring on this alien world.With a future NASA mission, Dragonfly, slated to land on Titan in the next decade, much work is needed to understand organic mineralogy in order to properly interpret the data from this and past Titan missions, such as Cassini-Huygens. By cataloging Titan minerals and their properties, we can begin to connect these behaviors to large-scale surface features observed on Titan (labyrinth terrain, lake evaporites, karst, dunes, etc.), and possible processes leading to their formation (erosion, deposition, etc.). To date, seven co-crystals (aside from clathrates and hydrates) have been experimentally reported to form under Titan-relevant conditions, with an eighth predicted by theoretical modeling. This Account will summarize these mineral co-crystals, and discuss the implications for surface processes on Titan. We will also highlight areas of future work, such as characterization of pure molecular solids and the search for ternary (and more complex) co-crystals. We note that on Titan, organic chemistry dominates, which gives a unique opportunity for chemists to play an even more significant role in planetary science discoveries, and likewise for discoveries motivated by planetary science to inform fundamental organic and physical chemistry research.
DOI: 10.48577/jpl.mer7ur
title: Evaluation of a CONUS-wide ECOSTRESS DisALEXI evapotranspiration product

description: The Atmosphere-Land Exchange Inverse disaggregation (DisALEXI) algorithm is a multi-scale energy balance model that estimates evapotranspiration (ET) using land-surface temperature (LST) as a driving remote sensing input. ECOSTRESS is a thermal radiometer mounted on the International Space Station (ISS), and provides near-daily overpass over sites spread throughout the contiguous United States (CONUS). Using LST products from ECOSTRESS, DisALEXI daily (24hr) ET products have been produced over CONUS with 70m resolution and sub-weekly timesteps. This new product was evaluated at 17 CONUS flux sites over a variety of landcover types, yielding accuracies with R2 = 0.8 and RMSE = 0.81 mm/day, which is comparable to previous DisALEXI validation studies. This work extends DisALEXI spatial coverage, and shows that the algorithm is valid over a larger segment of the contiguous United States. This validation also shows the impact of quality flags, as pixels with high view zenith angles or high aerosol optical depth showed greater deviation from field measurements. As a product demonstration, we show a regional map of fine-scale ET, where the fine-scale variation over wider areas can detect small areas of stress much sooner than products with coarse resolution representing average conditions.
DOI: 10.48577/jpl.nshlw7
title: Wind and Surface Roughness Considerations for Seismic Instrumentation on a Relocatable Lander for Titan

description: The influence of terrain and the atmosphere on seismic measurements to be made by the Dragonfly rotorcraft lander on Saturn’s moon Titan are examined. The need to relocate the vehicle leads to rather different deployment considerations from a fixed lander. Surface texture affects both the steady-state tilt that the instrument must tolerate on deployment, and it affects (via aerodynamic roughness) the wind load on the instrument body, or on a windshield around it: a tolerance of 5-10° and legs of 1-3 cm should eliminate the need for leveling mechanism at most sites. Wind models suggest a characteristic velocity noise of ~1 um/s may be expected on the lander skids on loose ground. The tilt noise caused by ground deformation means the horizontal axes of an instrument deployed between the skids may be at a similar level, so exquisite sensitivity in these axes may not be justified. Wind loads directly on a streamlined seismometer housing, on the tether, and on the lander via the ground all give comparable vertical noise (~10 nm/s) at the instrument, and thus the mechanical complexity of a separate windshield, which would need to be massive to not itself blow away, is not justified.
DOI: 10.48577/jpl.69syxs
title: Warm Cloud Evolution, Precipitation, and Their Weak Linkage in HadGEM3: New Process-Level Diagnostics using A-Train Observations

description: The latest configuration of the Hadley Centre Global Environmental Model version 3 (HadGEM3) contains significant changes in the formulation of warm rain processes and aerosols. We evaluate the impacts of these changes in the simulation of warm rain formation processes using A-Train observations. We introduce a new model evaluation tool, quartile-based Contoured Frequency by Optical Depth Diagrams (CFODDs), in order to fill in some blind spots that conventional CFODDs have. Results indicate that HadGEM3 has weak linkage between the size of particle radius and warm rain formation processes, and switching to the new warm rain microphysics scheme causes more difference in warm rain formation processes than switching to the new aerosol scheme through reducing overly produced drizzle mode in HadGEM3. Finally, we run an experiment in which we perturb the second aerosol indirect effect (AIE) to study the rainfall-aerosol interaction in HadGEM3. Since the large changes in the cloud droplet number concentration (CDNC) appear in the AIE experiment, a large impact in warm rain diagnostics is expected. However, regions with large fractional changes in CDNC show a muted change in precipitation, arguably because large- scale constraints act to reduce the impact of such a big change in CDNC. The adjustment in cloud liquid water path to the AIE perturbation produces a large negative shortwave forcing in the midlatitudes.
DOI: 10.48577/jpl.7eqezn
title: Designing Trajectories Resilient to Missed Thrust Events Using Expected Thrust Fraction

description: With the adoption of efficient low-thrust propulsion methods, the probabil- ity of a missed thrust event occurring has become a significant concern for short and long-duration missions. If the missed thrust event occurs during a critical portion of the trajectory, the mission can be compromised. Therefore, it is essential to develop trajectories that are resilient to missed thrust events. This paper investigates the use of expected thrust fraction, which embeds the stochastic nature of missed thrust events into a deterministic optimal control problem. The technique is applied to a sample Mars-to-Earth trajectory. The performance of trajectories designed using expected thrust fraction is compared with traditionally designed trajectories and trajectories with a forced terminal coast. Thus, the changes in resiliency to missed thrust events are quantified. In this investigation, trajectories designed using ex- pected thrust fraction arrive with a median lateness which is approximately half that of traditionally designed trajectories for a negligible change in de- livered mass. Expected thrust fraction can help astrodynamicists mitigate risks posed by the use of low-thrust propulsion.
DOI: 10.48577/jpl.ap7d51
title: The carbon cycle of southeast Australia during 2 2019–2020: Drought, fires and subsequent recovery

description: 2019 was the hottest and driest year on record for southeast Australia leading to bushfires of unprecedented extent between November 2019 and January 2020. In this study, we utilize space-based measurements of trace gases (TROPOspheric Monitoring Instrument XCO, Orbiting Carbon Observatory 2 XCO2) and up-scaled GPP (FluxSat GPP) to quantify the carbon cycle anomalies resulting from drought and fire in southeast Australia during the 2019--2020 growing season. We find that biomass burning emissions released 113-236 TgC of CO2 while drought and fire induced anomalies in net ecosystem exchange reduced growing season carbon uptake by an additional 19-52 TgC of CO2. These carbon losses were concentrated during the spring and early summer, when hot-dry conditions were most severe. A shift to cooler conditions and above average rainfall during February is found to result in a partial recovery and greening in unburned ecosystems. However, fire impacted areas had continued suppressed productivity for the remainder of the growing season. This study showcases the capability of combining observations from multiple satellites to monitor the carbon and ecosystem anomalies resulting from extreme events.
DOI: 10.48577/jpl.ctfle6
title: Machine-learning characterization of tectonic, hydrological and anthropogenic sources of active ground deformation in California

description: Tectonic, hydrological and industrial processes coexist in the dynamic natural environments. However, our knowledge of ground deformation associated with tectonic, hydrological and anthropogenic processes and their interactions has not been systematically linked, although scientific advances have been achieved in every individual geoscience discipline with more extensive and accurate observations and more robust models, which are remarkably complete in California. California represents a natural laboratory that hosts the San Andreas Fault (SAF) System, the Central Valley and other aquifer systems, and areas with extensive human extraction of natural resources. All these processes contribute to multi-scale ground deformation that has been mapped using Copernicus Sentinel-1 twin-Synthetic Aperture Radar (SAR)-satellite constellation from four ascending tracks and five descending tracks during 2014-2018. We consider the secular horizontal surface velocities and strain rates, constrained from GNSS measurements and tectonic models, as proxies for tectonic processes, and seasonal displacement amplitudes from interferometric SAR (InSAR) time series as proxies for hydrological processes. We synergize 23 types of multidisciplinary spatial data sets, including ground deformation, sedimentary basins, precipitation, soil moisture, topography, and hydrocarbon production fields, using a fundamental machine learning algorithm – random forest, and we succeed in predicting 86%-95% of the representative data sets. High-strain rates along the SAF system mainly occur in areas with a low-to-moderate summer vegetation fraction (~0.3), suggesting the correlation of rough/high-relief coastal range morphology and topography with the active faulting, seasonal and orographic rainfall, and vegetation growth, and likely also a disturbing environment in the shallow shear zone may jointly obstruct the vegetation growth. Linear discontinuities in the long-term, seasonal amplitude and phase of surface displacement fields coincide with some fault strands, the boundary zone between the sediment-fill Central Valley and bedrock-dominated Sierra Nevada, and the margins of the inelastically deforming aquifer in the San Joaquin Valley, suggesting the inference of seismogenic structures influencing groundwater flow, contrasting elastic properties, and heterogeneous hydrological units. On the other hand, the role of fluid extraction and injection in influencing tectonic and hydrological processes is not evident in this analysis, given the insufficient spatial resolution of the available remote sensing data and incomplete knowledge of the distribution of energy fields.
DOI: 10.48577/jpl.iycicx
title: Thickness and structure of the Martian crust from InSight seismic data

description: A planet’s crust bears witness to the history of planetary formation and evolution, but for Mars, no absolute measurement of crustal thickness was available. Here, we determine the structure of the crust beneath the InSight landing site on Mars using both marsquake recordings and the ambient wavefield. Analyzing seismic phases that are reflected and converted at subsurface interfaces, we find that the observations are consistent with models with at least two, and possibly three interfaces. If the second interface is the boundary of the crust, the thickness is 20±5 km, while if the third interface is the boundary, the thickness is 39±8 km. Global maps of gravity and topography allow extrapolation of this point measurement to the whole planet, showing that the average thickness of the Martian crust lies between 24 and 72 km. Independent bulk composition and geodynamic constraints show that the thicker model is consistent with the abundances of crustal heat-producing elements observed for the shallow surface, whereas the thinner model requires greater concentration at depth.
DOI: 10.48577/jpl.ueyruu
title: Upper mantle structure of Mars from InSight seismic data

description: For two years the InSight lander has been recording seismic data on Mars that are vital to constrain the structure and thermochemical state of the planet. We2used observations of direct (P and S) and surface-reflected (PP, PPP, SS, and SSS) body wave phases from 8 low-frequency marsquakes to constrain the in- terior structure to 800 km depth. We found a structure compatible with a low-velocity zone associated with a thermal lithosphere much thicker than on Earth that is possibly related to a weak S-wave shadow zone at teleseismic distances. By combining the seismic constraints with geodynamic models, we predict that the crust is 13–20 times more enriched in heat-producing elements than the primitive mantle, greater than suggested by gamma-ray surface map- ping, and has a moderate-to-elevated surface heat flow.
DOI: 10.48577/jpl.0ndwkc
title: MAIA: Opportunities and Challenges Associated with a Small, Cost-Capped Satellite Mission

description: In 2007 an Earth science decadal survey outlined a vision for “a decadalprogram of Earth science research and applications in support of society”and called for “a renewal of the national commitment to a program of Earthobservations from space in which attention to securing practical benefitsfor humankind plays an equal role with the quest to acquire new knowledgeabout Earth” (NRC 2007, p. 1). The report considered that “the societalbenefits accruing through improved human health should be fundamentalto defining the research and applications goals of the Earth science agenda,including the need for an intellectual framework that directs bridgingresearch between the Earth system framework and the public-health responseand decision-maker community” (NRC 2007, p. 155).
DOI: 10.48577/jpl.a989f3
title: Next Frontier in Planetary Geological Reconnaissance: Low-Latency Telepresence

description: The most compelling questions about the possibility of life on other planetary bodies will likely be answered only once the human mind can fully engage with the explored alien surface. Current interplanetary science operation models are primarily based on the paradigm of using robotic off- Earth assets for exploration. Conducting field geology research on other planetary bodies requires experts to use data collected from advanced technologies to substitute for their on-site presence to overcome the latency and bandwidth constraints. To overcome these constraints, astronauts will need to be placed either directly on the surface (e.g., “boots on the ground”) or robotic systems will need to be deployed and directed by humans from Earth with massive time delays. In the next major stage of planetary reconnaissance, as presented here, deployment of teleoperated robotic assets with humans sufficiently proximal to the exploration targets (referred to here as “Low- Latency Telepresence (LLT)”) will greatly enhance scientific return. Humans in orbit can be present electronically/digitally at multiple sites on a planetary surface, and that presence can be sterile, alleviating planetary protection concerns. Crewed astronauts using LLT, in partnership with robotic agents on the surface, will provide scientists the means to explore, for example, the mountains and vast canyon systems on Mars and the submarine environment of Jupiter’s moon Europa. Consequently, because LLT does not require humans to be physically present at the exploration site, it is potentially advantageous in terms of schedule and cost, reduces human and planetary risks, while increasing the quantity and quality of the science data that can be returned.
DOI: 10.48577/jpl.szbzsm
title: Probing Polarization and the Role of Magnetic Fields in Cloud Destruction in the Keyhole Nebula

description: We present polarimetric observations of the Keyhole Nebula in the Carina Nebula Complex carried out using the Stratospheric Observatory for Infrared Astronomy. The Keyhole Nebula located to the west of $\eta$ Carinae is believed to be disturbed by the stellar winds from the star. We observed the Keyhole Nebula at 89 $\mu$m wavelength with the HAWC+ instrument. The observations cover the entire Keyhole Nebula spanning 8$'$ by 5$'$ with central position RA = 10:44:43 and Dec = -59:38:04. The typical uncertainty of polarization measurement is less than 0.5\% in the region with intensity above 5,500 MJy sr$^{-1}$. The polarization has a mean of 2.4\% with a standard deviation of 1.6\% in the region above this intensity, similar to values in other high--mass star--forming regions. The magnetic field orientation in the bar--shaped structure is similar to the large--scale magnetic field orientation. On the other hand, the magnetic field direction in the loop is not aligned with the large--scale magnetic fields but has tight alignment with the loop itself. Analysis of the magnetic field angles and the gas turbulence suggests that the field strength is $\sim$70 $\mu$G in the loop. A simple comparison of the magnetic field tension to the ram pressure of $\eta$ Carinae's stellar wind suggests that the magnetic fields in the Keyhole Nebula are not strong enough to maintain the current structure against the impact of the stellar wind, and that the role of the magnetic field in resisiting stellar feedback in the Keyhole Nebula is limited.
DOI: 10.48577/jpl.6fm72n
title: Sensitivity of Multi-frequency Polarimetric SAR Data to Post-Fire Permafrost Changes and Recovery Processes in Arctic Tundra

description: Abstract— We used full polarimetric L-band and P-band synthetic aperture radar (SAR) data collected from the recent NASA Arctic Boreal Vulnerability Experiment (ABoVE) airborne campaign and Sentinel-1 C-band dual-polarization data to understand the sensitivity of radar backscatter intensity and phase to fire-induced changes in the surface and subsurface soil processes in Arctic tundra underlain by permafrost. The 2007 Anaktuvuk River fire on the Alaska North Slope was used as a case study. At ~10-year post-fire, we observed strong increases (&gt; ~3-4 dB) in the low frequency radar backscatter in severely burned areas during the thaw season, in contrast to limited (&lt; ~0.5 dB) C-band backscatter differences (VV, VH) between burned and unburned areas. However, C-band winter backscatter is generally higher (&gt;1 dB) in burned areas than adjacent unburned areas. Polarimetric decomposition analysis indicated a general trend towards more random surface scattering, and strong increases in double-bounce and volume scattering power at both P- and L-band in the burned areas. The ice-rich yedoma region shows largest backscatter increases in burned areas, and the highest correlation with burn severity and microtopography changes. The above backscatter changes are attributed to increasing surface roughness and microtopography due to ice wedge degradation and thermokarst development, and increasing subsurface scattering due to an overall drier and deeper active layer in burned areas. Among all frequencies, P-band shows consistently larger contrast in backscatter power and phase between burned and unburned areas, which makes it potentially more useful to study fire-permafrost interactions in the Arctic over decadal time scales.
DOI: 10.48577/jpl.hluvio
title: The cooling of light rains in a warming world

description: Recent changes to how clouds are represented in global models, especially over the Southern Ocean, resulted in increased climate warming. Research now demonstrates that correcting rain processes in a model can improve cloud representation but leads to a greatly enhanced negative feedback that offsets documented increases in model climate sensitivity.