cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.nbfbv0
title: Stability of DSS-25 Ka-band Station Delay during the Juno Prime Mission

description: One of the goals of the Juno mission is to precisely measure the gravitational field of Jupiter. This is accomplished by measuring the Doppler shift of the X-band and Ka-band carrier signals during closest approach periods. Calibration of the station phase delay is crucial to the determination of the spacecraft trajectory and gravitational field as well as their associated uncertainties. The extreme dynamics experienced by the Juno spacecraft make the radiometric measurements sensitive to small errors in the calibration. In 2018, the station delay was measured along the three signal paths used by Juno: X-up/X-down, X-up/Ka-down, and Ka-up/Ka-down. Although the X-band paths were measured consistently with previous estimates, the estimated delay was found to be unexpectedly larger on the Ka-band uplink path. In this work, we estimate the Ka-up/Ka-down round-trip system phase delay using the uplink sweep to the spacecraft. The uplink sweep provides sensitivity to the station delay and allows it to be measured from the carrier frequency observables on a regular basis without the need for specialized ground tests. The Ka-up/Ka-down delay was found to be consistent at 179 microseconds from orbit insertion in July 2016 until the Block 6 Exciter was installed in November 2020, when the delay decreased to 157 microseconds. This change was attributable to the removal of approximately 4.2 km of cable on the Ka-band uplink path during the Block 6 Exciter upgrade.
DOI: 10.48577/jpl.pyvmyt
title: Seasonal Forecasting of Western US Precipitation: Interpretable Machine Learning Trained on Large Climate Model Simulations

description: A barrier to utilizing machine learning in seasonal forecasting applications is the limited sample size of observational data for model training. To circumvent this issue, we explore the feasibility of training various machine learning approaches on a large climate model ensemble, providing a long training set with physically consistent model realizations. After training on thousands of seasons of climate model simulations, the machine learning models are tested for producing seasonal forecasts across the historical observational period (1980-2020). For forecasting large-scale spatial patterns of precipitation across the Western United States, the machine learning-based models are capable of competing with or outperforming existing dynamical models from the North American Multi Model Ensemble. We further show that this approach need not be considered a ‘black box’ by utilizing machine learning interpretability methods to identify the relevant physical processes that lead to prediction skill.
DOI: 10.48577/jpl.la35j1
title: Extreme Surface Winds During Landfalling Atmospheric Rivers: The Modulating Role of Near-Surface Stability

description: 28 Atmospheric rivers (ARs) are long and narrow regions of strong horizontal water vapor29 transport. Upon landfall, ARs are typically associated with heavy precipitation and strong surface30 winds. A quantitative understanding of the atmospheric conditions that favor extreme surface31 winds during ARs has implications for anticipating and managing various impacts associated with32 these potentially hazardous events. Here, a global AR database (1999–2014) with relevant33 information from MERRA-2 reanalysis, QuikSCAT and AIRS satellite observations are used to34 better understand and quantify the role of near-surface static stability in modulating surface35 winds during landfalling ARs. The temperature difference between the surface and 1 km MSL (DT;36 used here as a proxy for near-surface static stability), and integrated water vapor transport (IVT)37 are analyzed to quantify their relationships to surface winds using bivariate linear regression. In38 four regions where AR landfalls are common, the MERRA-2-based results indicate that IVT39 accounts for 22-38% of the variance in surface wind speed. Combining DT with IVT increases the40 explained variance to 36-52%. Substitution of QuikSCAT surface winds and AIRS DT in place of41 the MERRA-2 data largely preserves this relationship (e.g., 44% compared to 52% explained42 variance for USA West Coast). Use of an alternate static stability measure–the bulk Richardson43 number–yields a similar explained variance (47%). Lastly, AR cases within the top and bottom44 25% of near-surface static stability indicate that extreme surface winds (gale or higher) are more45 likely to occur in unstable conditions (5.3%/14.7% during weak/strong IVT) than in stable46 conditions (0.58%/6.15%).
DOI: 10.48577/jpl.vaeai5
title: CCSDS Implementation, Concept, and Architecture of the Psyche Mission's End-to-End Information System

description: The Psyche Mission is a mission to the asteroid (16) Psyche, featuring three science instruments and gravity science. (16) Psyche, located in the asteroid belt between Mars and Jupiter, will be the first potential metal world—instead of rock or ice—visited by the National Aeronautics and Space Administration (NASA). This Jet Propulsion Laboratory (JPL) managed mission will explore Psyche for 21 months after an earliest launch date of August 2022 and a 3.5-year cruise. In this paper, the End-to-End Information System’s (EEIS) concept, architecture, and the Consultative Committee for Space Data Systems (CCSDS) standards implementation of Psyche are studied and analyzed for fulfilment of mission requirements and for satisfaction of operational constraints. The EEIS is a virtual system comprised of distributed data system functions through the subsystems. The system is defined by how the flight, mission, and launch systems work together to enable Psyche’s data flows (uplink, downlink, spacecraft, and ground), as well as validate, account for, process, distribute, and store Psyche’s data. This data includes spacecraft commands, spacecraft health, and instrument science data. EEIS Engineers are specifically responsible for the concept formulation of the information system, its design architecture, as well as the implementation of the CCSDS standards in the flight to ground interface from a high-level project system engineering perspective. This includes evaluating the mission’s operational constraints and requirements as well as inherited mission infrastructure. Criteria for evaluating mission information include the quantity, quality, latency, and continuity (QQCL) of the data. In this paper, the Psyche EEIS will be evaluated in relation to these four criteria. Thus, this paper focuses on the following: the driving EEIS requirements based on program, project, science, and operability requirements; the views and analysis of the EEIS conceptual design; the CCSDS standards implementation; and the EEIS layered architecture comprised of its data flows, flight assets, mission operations system (MOS), ground/science data systems, and multi-mission services. The possible advantages and limitations of the Psyche EEIS architecture and suggestions for future space missions are also discussed.
DOI: 10.48577/jpl.rvb2oi
title: Estimating Mean Surface Backscatter from GPM Surface Backscatter Observations

description: The radar on the Global Precipitation Measurement (GPM) mission observes precipitation at 13.4 GHz (Ku-band) and 35.6 GHz (Ka-band) and also receives echoes from the earth’s surface. These surface measurements are important to GPM for estimating the path-integrated attenuation in precipitation. For land, a measurement of the surface in rain is compared with prior measurements of the same location under non-raining conditions. These prior measurements are stored in a database; in doing so, there is a trade between space and time resolution and number of samples. One of the goals of this paper is to investigate variation of surface backscatter in both time and space to understand how to best construct the database. The author finds that due to inhomogeneity of backscatter in time, increased time averaging can increase measurement standard deviation. This is similar to the effect of spatial averaging noted by Meneghini and Jones (2011). Spaceborne precipitation radar has also been used previously for monitoring of surface water and vegetation. A second goal of this paper is to further investigate this application, using GPM dual-frequency backscatter to perform a global classification.
DOI: 10.48577/jpl.yvjpgg
title: Comment on “Non-Interacting Coronal Mass Ejections and Solar Energetic Particles Near the Quadrature Configuration of Solar Terrestrial Relations Observatory”

description: Aims. The expression for the shock Mach number used by Ravishankar and Michalek (2020) is incorrect. We wish to provide themwith a correct expression so they can redo their analyses.Methods. CME shocks are fast magnetosonic shocks and not intermediate Alfvén shocks. We give the steps for calculating the shocknormal, shock velocity and thus, the shock Mach number.We also mention that the shock properties, such as being quasiperpendicularor quasiparallel, is another important parameter for shock acceleration of energetic particles.Results. We have corrected the errors existing in the Astronomy and Astrophysics literature concerning the mathematical expressionfor the Mach number for a CME shock. Hopefully future authors of A&A papers will use the now correct expression for the Machnumber.Conclusions. The correct shock Mach number expression have been given to Ravishankar and Michalek. It is hopeful that they willredo their calculations (including using other shock properties) to see if their 2020 conclusions still hold true or not.
DOI: 10.48577/jpl.1dfg0l
title: 3D-Printed Shaped and Material-Optimized Lenses for Next-Generation Spaceborne Wind Scatterometer Weather Radars

description: Current spaceborne wind scatterometers have shown failure due to mechanical wear from moving parts used to conically scan a directive beam. In order to eliminate therisk of mechanical rotation failure, an antenna design with no moving parts that achieves the conical beam sweep is desirable. In this paper, a lightweight, 3D-printed, inhomogeneous lens antenna is presented as an all-electronic alternative. The lensantenna is designed using curved-ray geometrical optics coupled to particle swarm optimization to determine the optimum lens surface shapes and material inhomogeneity while obtaining a design with minimum volume and therefore mass. An 18 cm lens is designed using this approach. Instructions on how to 3Dprintthe inhomogeneous lens is given using a unit cell design which permits additive manufacturing using Fused Deposition Modelling (FDM) techniques. The lens is measured for far-field pattern performance at various locations along the ring-shapedfocus of the azimuthally symmetric lens. The measurements agree well with predictions obtained by full-wave simulations. Since the radiation pattern, its conical sweep, and the antenna far-field performance compare well to the current mechanically driven counterparts, these all-electronic alternatives are expected toprolong the lifetime of future spaceborne wind scatterometers.
DOI: 10.48577/jpl.hgaivp
title: Assessing Global Present-day Surface Mass Transport and Glacial Isostatic 􀍴􀀃 Adjustment from Inversion of Geodetic Observations

description: Long-term monitoring of global mass transport within the Earth system􀍵􀍲􀀃 improves our ability to mitigate natural hazards and better understand their relations to􀍵􀍳􀀃 climate change. Satellite gravity is widely used to monitor surface mass variations for its􀍵􀍴􀀃 unprecedented spatial and temporal coverage. However, the gravity data contain signals􀍵􀍵􀀃 from visco-elastic deformation in response to past ice sheet melting, preventing us from􀍵􀍶􀀃 extracting signals of present-day surface mass trend (PDMT) directly. Here we present a􀍵􀍷􀀃 global inversion scheme that separates PDMT and visco-elastic glacial isostatic adjustment􀍵􀍸􀀃 (GIA) signatures by combining satellite gravimetry with satellite altimetry and ground􀍵􀍹􀀃 observations. Our inversion provides global dual data coverage that enables a robust􀍵􀍺􀀃 separation of PDMT and GIA spherical harmonic coefficients. It has the advantage to􀍵􀍻􀀃 provide estimates of the Earth’s long wavelength deformation signatures and their􀍶􀍲􀀃 uncertainties. Our GIA result, along with its uncertainty estimates, can be used in future􀍶􀍳􀀃 GRACE processing to better assess the impact of GIA to surface mass change. Our GIA􀍶􀍴􀀃 estimates includes rapid GIA uplift in the Southeast Alaska and the Amundsen Sea􀍶􀍵􀀃 Embayment, due to the visco-elastic response to recent glacial unloading. We estimate the􀍶􀍶􀀃 average surface mass change rate from 2002-2010 to be -203±3 GT·a-1 in Greenland, -􀍶􀍷􀀃 126±18 GT·a-1 in Antarctica and -62±5 GT·a-1 in Alaska. The GIA low degree spherical􀍶􀍸􀀃 harmonic coefficients are sensitive to rheological properties in Earth’s deep interior. Our􀍵􀀃􀀃􀍶􀍹􀀃 low-degree GIA estimates include geocenter motion and J̇2 which provide unique􀍶􀍺􀀃 constraints to understand Earth’s lower mantle and ice history.􀍶􀍻􀀃 􀀃
DOI: 10.48577/jpl.wpx3jm
title: Spaceborne differential absorption radar water vapor retrieval capabilities in tropical and subtropical boundary layer cloud regimes

description: Differential absorption radar (DAR) near the 183 GHz water vapor absorption line is an emerging measurement techniquefor humidity profiling inside of clouds and precipitation with high vertical resolution, as well as for measuring integratedwater vapor (IWV) in clear air regions. For radar transmit frequencies on the water line flank away from the highly attenuatingline center, the DAR system becomes most sensitive to water vapor in the planetary boundary layer (PBL), which is a region ofthe 5 atmosphere that is poorly resolved in the vertical by existing spaceborne humidity and temperature profiling instruments.In this work, we present a high-fidelity, end-to-end simulation framework for notional spaceborne DAR instruments that featurerealistically achievable radar performance metrics, and apply this simulator to assess DAR’s PBL humidity observationcapabilities. Both the assumed instrument parameters and radar retrieval algorithm leverage recent technology and algorithmdevelopment for an existing airborne DAR instrument. To showcase the capabilities of DAR for humidity observations in a variety of relevant PBL settings, we implement the instrument simulator in the context of large eddy simulations (LES) of 5different cloud regimes throughout the trade-wind subtropical-to-tropical cloud transition. Three distinct DAR humidity observationsare investigated: IWV between the top of the atmosphere and the first detected cloud bin or Earth’s surface; in-cloud water vapor profiles with 200 meter vertical resolution; and IWV between the last detected cloud bin and the Earth’s surface,which can provide a precise measurement of the sub-cloud humidity. We provide a thorough assessment of the systematic and random errors for all 3 measurement products for each LES case, and analyze the humidity precision scaling with along-trackmeasurement integration. While retrieval performance depends greatly on the specific cloud regime, we find generally that fora radar with cross-track scanning capability, in-cloud profiles with 200 m vertical resolution and 10-20% uncertainty can beretrieved for horizontal integration distances of 100-200 km. Furthermore, column IWV can be retrieved with 10% uncertaintyfor 10-20 km of horizontal integration. Finally, we provide some example science applications of the simulated DAR observations, including estimating near-surface relative humidity using the cloud-to-surface column IWV, and inferring in-cloudtemperature profiles from the DAR water vapor profiles by assuming a fully saturated environment.
DOI: 10.48577/jpl.fsnctz
title: Effects of COVID-19 lockdowns on fine particulate matter concentrations

description: Interventions during the COVID-19 pandemic provide an unprecedented opportunity to examine the effects of human activity on air quality. The effects on fine particulate matter (PM2.5) are of interest, as PM2.5 is the leading environmental determinant of health. We map global PM2.5 concentrations with a focus on China, Europe, and North America using a combination of satellite data, simulation, and ground observations for January-April 2020. We examine PM2.5 concentrations during the lockdown periods in 2020 compared to the same periods in 2018-2019. We find changes in population-weighted mean PM2.5 concentrations during the lockdowns of -11 to -17 µg/m3 across China, -2 to +1 µg/m3 across Europe, and 0 to -2 µg/m3 across North America. We explain these changes through a combination of meteorology and emission reductions, mostly due to transportation. This work demonstrates regional differences in the sensitivity of PM2.5 to emission sources.
DOI: 10.48577/jpl.k7wzse
title: Midwest U.S. croplands determine model divergence in North American carbon fluxes

description: Large uncertainties in North American terrestrial carbon fluxes hinder regional climate 26 projections. Terrestrial biosphere models (TBMs), the essential tools for understanding 27 continental-scale carbon cycle, diverge on whether temperate forests or croplands 28 dominate carbon uptake in North America. Evidence from novel photosynthetic proxies, 29 such as those based on chlorophyll fluorescence, has cast doubt on the “weak cropland, 30 strong forest” carbon uptake patterns simulated by most TBMs. However, no systematic 31 evaluation of TBMs has yet been attempted to pin down space-time patterns that are 32 most consistent with regional CO2 observational constraints. Here, we leverage 33 atmospheric CO2 observations and satellite-observed photosynthetic proxies to understand 34 emergent space-time patterns in North American carbon fluxes from a large suite of 35 TBMs and data-driven models. To do so, we evaluate how well the atmospheric signals 36 resulting from carbon flux estimates reproduce the space-time variability in atmospheric 37 CO2, as is observed by a network of continuous-monitoring towers over North America. 38 Models with gross or net carbon fluxes that are consistent with the observed CO2 39 variability share a salient feature of growing-season carbon uptake in Midwest U.S. 40 croplands. Conversely, the remaining models place most growing-season uptake in boreal 41 or temperate forests. Differences in model explanatory power depend mainly on the 42 simulated annual cycles of cropland uptake—especially the timing of peak uptake—rather 43 than the distribution of annual mean fluxes across biomes. Our results suggest that 44 improved model representation of cropland phenology is crucial to robust, policy-relevant 45 estimation of North American carbon exchange.
DOI: 10.48577/jpl.3sqlhr
title: Nowcasting Earthquakes: Imaging the Earthquake Cycle in California with Machine Learning

description: The earthquake cycle of stress accumulation and release is associated with the elastic rebound hypothesis proposed by H.F. Reid following the M7.9 San Francisco earthquake of 1906. However, observing details of the actual values of time- and space-dependent tectonic stress is not possible at the present time. In two previous papers, we have proposed methods to image the earthquake cycle in California by means of proxy variables. These variables are based on correlations in patterns of small earthquakes that occur nearly continuously in time. The purpose of the present paper is to compare these two methods by evaluating their information content using decision thresholds and Receiver Operating Characteristic methods together with Shannon information entropy. Using seismic data from 1950 to present in California, we find that both methods provide nearly equivalent information on the rise and fall of earthquake correlations associated with major earthquakes in the region. We conclude that the resulting timeseries can be viewed as proxies for the cycle of stressaccumulation and release associated with major tectonic activity.
DOI: 10.48577/jpl.c2weya
title: SISTER: Starshade Imaging Simulation Toolkit for Exoplanet Reconnaissance

description: SISTER (Starshade Imaging Simulation Toolkit for Exoplanet Reconnaissance, http://sister.caltech.eduii is a versatile tool designed to provide accurate models of the images of exoplanet systems when observed with a starshade positioned to block the light from the host star. SISTER allows one to control a set of observational parameters including: (1) the Starshade design, position, orientation, and glint properties; (2) the telescope and optical system pupil, aberrations, bandpass, and throughput including a detector model; (3) the exoplanetary system, including stellar distance and spectral type, parallax and proper motion, planet size, reflection properties, orbital parameters, and exozodiacal dust; and (4) background objects. Additionally there is a substantial library of built-in plotting software added, but the simulations may be stored on disk and be plotted with any other software. This paper describes SISTER’s algorithms, its operational modules, and describes how it can be used to generate starshade optical simulations with a high degree of fidelity. We include some imaging examples.
DOI: 10.48577/jpl.xp1iay
title: Diagenesis revealed by fine-scale features at Vera Rubin ridge, Gale crater, Mars

description: Fine-scale (submillimeter to centimeter) depositional and diagenetic features encountered during the Curiosity rover’s traverse in Gale crater provide a means to understand the geologic history of Vera Rubin ridge (VRR). VRR is a topographically high feature on the lower north slope of Aeolis Mons, a 5-km-high stratified mound within Gale crater. We use high spatial resolution images from the Mars Hand Lens Imager (MAHLI) as well as grain sizes estimated with the Gini index Mean Score technique that uses ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) chemical data to constrain the post-depositional history of the strata exposed on this ridge. MAHLI images were used to examine the color, grain size, and style of lamination of the host rocks, as well as to explore the occurrence of nodules, diagenetic crystals, pits, and a variety of dark gray iron-rich features. This survey revealed abundant and widespread diagenetic features within the rocks exposed on VRR and demonstrated that rock targets estimated to be coarser generally contain more diagenetic features than those estimated to have finer grains, which indicate that grain size may have influenced the degree and type of diagenesis. A subset of rocks within VRR are gray in color and exhibit the highest proportion of diagenetic features. We suggest that these targets experienced a different diagenetic history than the other rocks on VRR and hypothesize that redistribution and recrystallization of iron within specific intervals may have resulted in both the gray color and the abundance of dark gray, iron-rich diagenetic features.