Journals
2025 EN
AkhavanTafti M. · Soni S. L. · Higgins C.
+5 more
Abstract The Sun Radio Interferometer Space Experiment (SunRISE) Ground Radio Lab (GRL) is a Science, Technology, Engineering, Arts, and Mathematics (STEAM) project, sponsored by NASA's SunRISE mission and organized by the University of Michigan College of Engineering. The project aims to engage and train the next generations of scholars. To achieve this, the project deployed antennas to 18 high schools nationwide to observe solar radio bursts (SRB). SRBs are defined as low‐frequency radio emissions emanated by accelerated electrons associated with extreme solar activity, including solar flares and coronal mass ejections (CMEs). Type II SRBs were found to predominantly correspond to coronal shocks caused by CMEs, highlighting particle acceleration events in the solar atmosphere and interplanetary space. These bursts can act as early warning signs of upcoming solar disturbances which can lead to geomagnetic storms. The type II bursts were then investigated to estimate the corresponding shock and Alfvén speeds: 277 < v shock < 1,480 km/s and 194 < v A < 947 km/s at heliocentric distances of around 1–2 solar radii, respectively. The Alfvén Mach number was further found to be 1.2 < M A < 2, while the measured magnetic field strength followed a single power law of B ( r ) = 0.3 r −2 , where r represents the heliocentric distance. Our results were found to agree with previous studies. Through SunRISE GRL, an ever‐expanding catalog of SRBs is being collected by high school students nationwide, curated by a team of solar physics experts, and made publicly available to the scientific community to make progress toward the SunRISE mission's objectives.
Journals
2025 EN
Caprarelli Graziella · Baratoux David · Bulusu Subrahmanyam
+12 more
Abstract The journal Earth and Space Science ( ESS ) was founded in 2014 to offer the scientific community a new platform for the dissemination of key new data, observations, methods, instruments, and models, presented within the context of their application. Thus, the aim of the journal was (and is) to highlight the complexity and importance of experimental design, methodology, data acquisition and processing, intertwined with data interpretation. Such approach is consistent with the mission of most AGU journals, but the distinctive element for ESS is its focus on the concept of the useful impact of publication, progressively replacing that on conventional publication metrics. In this context, the journal has been, since its inception, the preferred home for studies stemming from both global and local geoscience research. This special collection contains 16 papers published in ESS , selected by the Editorial Board to highlight the aims, scope and path of evolution and growth of the journal since it inaugural issue, in 2014.
American Geophysical Union
Journals
2025 EN
Carr James L. · Chong Heesung · Liu Xiong
+12 more
Abstract The NASA Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is hosted on a geostationary commercial communications satellite. TEMPO is an imaging spectrometer with primary mission to measure trace‐gas concentrations from the observed spectra of reflected sunlight over the Continental United States and parts of Canada, Mexico, and the Caribbean. TEMPO produces an ultraviolet (UV, 293–494 nm) and a visible (538–741 nm) spectrum for each spatial pixel. TEMPO saw first light in August 2023. At night, TEMPO can observe city lights, gas flaring, maritime lights from fishing and offshore oil platforms, clouds and snow in the moonlight, lightning, aurorae, and nightglow without interfering with its primary daytime air quality/chemistry mission. This paper describes the capabilities of TEMPO to make nighttime observations and surveys of some early results. Repetitive coverage of North America enables production of clearest‐sky composites that are similar to VIIRS Day‐Night Band (DNB) “Black Marble” products. Spectra of urban areas contain spectral signatures of artificial lighting of various types that allow the radiance from each class of lighting to be estimated. Moonlight imaging of clouds provides a useful capability for discriminating clouds and fog. Lightning illuminating cloud tops from below is seen with distinct spectral features. Gas flares, associated with oil production, are observed and flare temperatures can be estimated from their spectra. Known auroral and nightglow spectral lines of atomic oxygen and molecular nitrogen are seen in the UV and visible spectra. The sodium d‐layer is also observed.
Journals
2025 EN
Reddy S. A. · Pi X. · Forsyth C.
+2 more
Abstract Vertical plasma drift, v z , plays a key role in the dynamics, morphology, and space weather effects of the equatorial and low latitude ionosphere. Modeling the drift has been an on‐going effort for climatology‐based prediction. To address daily prediction, the Vertical drIfts : Predicting Equatorial ionospheRic dynamics (VIPER) model has been developed. VIPER is a machine learning model that is trained on total electron content (TEC) data to predict low‐latitude vertical plasma drift observed by the C/NOFS mission across the period 2009–2015. The uniqueness of VIPER is that it uses TEC data for the prediction, and the data is globally and readily available. A Gaussian fitting routine is developed to strengthen the link between TEC and v z . VIPER is a multi‐layer perceptron framework with Monte Carlo (MC) uncertainty estimation capabilities. It has a mean absolute error of 8.3 m/s, an R of 0.89/1, and a skill of 0.78/1, all of which are strong scores. The model is capped at quiet and unsettled activity levels (Kp < 3). MC analysis reveals that predictions should be interpreted as distributions and the uncertainty can vary with distributions of TEC data and regions of prediction even if the predicted value is the same. VIPER offers longitudinally global coverage and uncertainty estimation capabilities. It could also be expanded to handle storm‐time conditions with additional work.
Journals
2025 EN
Das Pritam · Hossain Faisal
Abstract The Surface Water and Ocean Topography (SWOT) satellite, launched in December 2022, represents a significant advancement in the remote sensing of global water bodies, providing simultaneous measurements of Water Surface Elevation (WSE) and extent in all‐weather conditions. This study evaluates SWOT's capability to estimate reservoir storage dynamics in comparison to pre‐SWOT methods. SWOT demonstrates high accuracy in measuring WSE, achieving a median R 2 close to 1 and root mean square errors nearly an order of magnitude lower compared to earlier non‐SWOT approaches. SWOT offers substantial improvement over single‐sensor and multi‐sensor methods, due to spatial averaging of distributed elevation measurements, which was further validated by similar measurements of the ICESat‐2 satellite. The key limiting factor in estimating storage from elevation measuring sensors was found to be the accuracy of Area‐Elevation‐Volume curve. Furthermore, preliminary applications of machine learning to integrate SWOT with non‐SWOT data sets show promise, although constrained by limited data availability of SWOT as of late 2024.
Journals
2025 EN
HosseiniArani Alireza · Schilling Manuel · Tennstedt Benjamin
+7 more
Abstract Cold atom interferometry based quantum accelerometers (Q‐ACCs) are very promising for future satellite gravity missions thanks to their strength in providing long‐term stable and precise measurements of non‐gravitational accelerations. However, their limitations due to the low measurement rate and the existence of ambiguities in the raw sensor measurements call for hybridization of the Q‐ACC with a classical one (e.g., electrostatic) with higher bandwidth. While previous hybridization studies have so far considered simple noise models for the Q‐ACC and neglected the impact of satellite rotation on the phase shift of the accelerometer, we perform here a more advanced hybridization simulation by implementing a comprehensive noise model for the satellite‐based Q‐ACCs and considering the full impact of rotation, gravity gradient, and self‐gravity on the instrument. We perform simulation studies for scenarios with different assumptions about quantum and classical sensors and satellite missions. The performance benefits of the hybrid solutions, taking the synergy of both classical and Q‐ACCs into account, will be quantified. We found that implementing a hybrid accelerometer onboard a future gravity mission improves the gravity solution by one to two orders in lower and higher degrees. In particular, the produced global gravity field maps show a drastic reduction in the instrumental contribution to the striping effect after introducing measurements from the hybrid accelerometers.
American Geophysical Union
Journals
2025 EN
Lehmann N. · Kienast M. · Normandeau C.
+4 more
Abstract The Northwest Atlantic continental shelf is a highly productive marine region with major uncertainties regarding the supply mechanisms of nutrients fueling productivity. This study uses nitrate isotopes (δ 15 N NO3 and δ 18 O NO3 ) from the Atlantic Zone Monitoring Program 2020 fall mission and an Optimum Multiparameter Analysis to evaluate on‐shelf nutrient transport versus biological supply pathways across three transects from the Laurentian Channel to the central Scotian Shelf. Surface waters showed an imprint of remineralized production, with partial nitrification creating an isotopically light (δ 15 N NO3 ≥2.7‰) surface lens extending from Cabot Strait across the coastal Scotian Shelf. A concurrent enrichment in δ 15 N NO3 and δ 18 O NO3 (<8.5‰, <7.4‰) alongside decreasing nitrate concentrations further indicated phytoplankton assimilation over the deep central shelf (overlying Emerald Basin), a process not observed across Cabot Strait or coastal shelf stations. Subsurface nutrients in Cabot Strait are highly regenerated (<43%), with increased bottom water δ 15 N NO3 signaling sedimentary denitrification in the deep Laurentian Channel. Conversely, subsurface nutrients on the Scotian Shelf were predominantly preformed (<86%), sustained by Cold Intermediate Water from the Gulf of St. Lawrence and warm North Atlantic Central Water (NACW) from offshore. Derived water mass contributions and a distinct isotopically light subsurface layer offshore (δ 15 N NO3 of >4.2‰)−characteristic of N 2 fixation in shallow NACW−indicate a stronger NACW imprint on the central Scotian Shelf compared to the Laurentian Channel and eastern shelf. Our results confirm the importance of slope water advection in supplying subsurface nutrients to the shelf while highlighting the seasonal imprint of recycled production on near‐shore surface waters during fall.
Journals
2025 EN
Bickel V. T. · Daubar I. J. · Zenhäusern G.
+9 more
Abstract The InSight lander represents a unique opportunity to correlate seismic data with impact events identified in orbital images, enabling the characterization of the physical properties of the martian crust and mantle. Here, we present the first comprehensive catalog of impacts that occurred during the InSight mission within a 50° radius around the lander. We use a machine learning‐enabled approach to identify 123 date‐constrained impacts with diameters between ∼1 and 22.5 m. We estimate an impact rate of 2.7 × 10 −6 /km 2 /year for >3.9 m effective diameter, which is ∼1.6–∼2.5 times higher than previously derived for Mars. We identify 49 seismic events with one or several potential impact match(es) including a 21.5 m crater located near Cerberus Fossae. Our catalog will enable a more accurate characterization of the propagation of seismic body waves at intermediate distances to InSight (5–50°), with major implications for estimates of other seismic event distances.
American Geophysical Union
Journals
2025 EN
Wang Fei · Bausch Hannah J. · Gardner Laura L.
+6 more
Abstract The Martian mantle is considered to have a higher Fe/Mg ratio than the Earth's mantle. Ringwoodite, γ‐(Mg,Fe) 2 SiO 4 , is likely the dominant polymorph of olivine in the core‐mantle boundary (CMB) region of Mars. We synthesized anhydrous iron‐rich ringwoodite with molar Mg/(Mg + Fe) = 0.44 and determined its thermal equation of state up to 35 GPa and 750 K by synchrotron X‐ray diffraction. Using a third order Birch‐Murnaghan equation of state, we obtain K T 0 = 182 (3) GPa, K′ = 4.6 (2), and α 0 = 3.18 (6) × 10 −5 K −1 . Using these results and an updated mineralogical model with an iron‐rich composition of Mg/(Mg + Fe) = 0.75 for the Martian mantle, we estimate ∼1900 K for the temperature of the D1000 seismic discontinuity inside Mars. The resulting adiabat predicts a warm aerotherm, which could explain the presence of partial melt at the CMB of Mars recently detected with seismic data from the 2019 InSight mission.
American Geophysical Union
Journals
2025 EN
Charalambous Constantinos · Pike W. Thomas · Fernando Benjamin
+12 more
Abstract To date, eight meteoroid impacts have been identified in the seismic record of NASA's InSight mission on Mars, occurring either within 300 km or beyond 3,500 km. We report the association of a high‐frequency marsquake, S0794a, with a new 21.5‐m‐diameter impact crater discovered at an intermediate distance of 1,640 km in the tectonically active Cerberus‐Fossae graben system. This impact enables the direct comparison between surface and subsurface sources, as well as providing the first data point in the critical gap between previous impacts, both in distance and crater size. Additionally, the location of this event necessitates a reassessment of assumed seismic raypaths that were thought to propagate along a slow crustal waveguide. We find that the raypaths instead penetrate and travel through the faster mantle, implying numerous identified marsquake epicenters should be relocated up to two times farther from InSight, with implications for seismically derived impact rates and regional seismicity.
American Geophysical Union