An inverse box model of the Scotia Sea balances the Antarctic Circumpolar Current (ACC) heat, salt, mass and biogeochemical transports up to the 28.00 kg m-3 isoneutral. We construct hydrographic and biogeochemical vertical sections enclosing the Scotia Sea using several datasets up to 2018, and constrain the reference velocity at 1000 m with the Argo floats drift. The results reveal 136.7 ± 1.0 Sv entering through the Drake Passage and 137.9 ± 1.0 Sv exiting through the northern passages (113.6 Sv via the North Scotia Ridge and 24.3 Sv through the Georgia Passage), dominated by the deep circumpolar waters. Salt is near-conservative because of scarce water exchange with the atmosphere, with a freshwater flux gain of only 0.06 Sv, but heat is influenced by the intense ocean-atmosphere energy exchange, with a net loss of 0.065 PW. The combination of physical and biogeochemical processes leads to a total net production  of nitrate and dissolved inorganic carbon (DIC), and a net consumption of alkalinity and dissolved oxygen (DO). Further, we observe a subsurface poleward transfer of water mass and associated properties across the Polar Front, which sustains overall remineralization and DO outgassing in the mode and intermediate waters of the southern sector. The carbon budget is internally dominated by DIC production at 0.16 ± 0.03 Pg C yr-1, accumulating at 0.12 ± 0.03 Pg C yr-1; however, the air-sea exchange is closely balanced despite additional anthropogenic DIC inputs, suggesting that DIC outgasses at faster rates.  

Ultra-low velocity zones (ULVZs) above the core-mantle boundary (CMB) are seismically-observed structures that may be related to the liquid outer-core. As ”thin patches” of dramatically low seismic-wave velocity, they are occasionally found in/near simply low seismic-wave-velocity regions or alternatively in/near simply high velocity regions, right at/above the CMB. The causes of their morphology and geodynamics remain unclear, and simulation of high-density melts diverge from observations. We introduce two-dimensional time-dependent Stokes two-phase flow (with melt migration) numerical models to investigate the evolution of high melt-fraction regions affected by CMB-mantle tangential flows, amidst a hot mantle-plume upwelling and an optional neighboring cold downwelling. We find that (a) the participation of cold sources with temperature differences between ~4000 K at the plume-base central regions to <~3900 K at the plume-cooling flanks, separated by horizontal distances of approximately 100 {plus minus}50 km are necessary for dense melts (fractional mass-density difference >+1-2%, <+10%) to attain total-mass quasi-stability, (b) an enhanced tangential-horizontal flow in reverse circulation within the broad plume base (with speeds >1-3 times the lowermost-mantle characteristic flow speeds); are necessary for high aspect-ratio-morphology melt-lenses to be compatible with seismic observations. Stresses exerted on variable CMB topography may arise from lateral motion of localized outer-core rigidity-zone structures. The CMB-mantle tangential flow and/or outer-core interacting with CMB-topography may help generate mega-ULVZs, particularly if they appear along the edges of large low-shear-wave-velocity provinces (LLSVPs) or in/near high-seismic-velocity ”cold” zones. A strong link exists between ULVZ morphology-evolution and the kinematic-thermodynamic heterogeneous environment in-around the CMB.

The increased frequency of wildland fires (wildfires) poses a severe threat to the environment and human health, especially particulate matter (PM2.5) produced during wildfire events. Its effects and interactive effects with other factors on life expectancy are still poorly understood. The objective of this study is to examine the impact of wildfire smoke PM2.5, greenspace and terrain ruggedness as well as their interactive effects on the life expectancy at birth in the United States. The estimate of life expectancy in census tracts in the contiguous United States (US) during 2010 -2015 period was obtained from the US Centers for Disease Control and Prevention (CDC) using a small area estimation method. The number of smoke days, the concentration of smoke PM2.5, the percentage of forest and terrain ruggedness index were also obtained for each census tract during 2010-2011. The relationship between life expectancy and these environmental factors was examined with several models, including linear regression, multi-level regression, geographical weighted regression. The study found: (1) Life expectancy was significantly associated with the concentration of smoke PM2.5, the number of smoke days, and green space metrics. Specifically, our analysis revealed that for each 1 µg/m³ increase in smoke PM2.5 levels, life expectancy decreased by 1.2 years. Additionally, for every extra smoke day, life expectancy fell by 0.02 years. Conversely, a 1% increase in coverage of forest types—deciduous forest, mixed forest, or shrubland—resulted in an increase in life expectancy of 0.006, 0.009, 0.03, and 0.01 years, respectively. (2) The concentration of smoke PM2.5 has a consistent negative effect on life expectancy. (3) Greenspace measured by the percentage of forest might have a negative effect on life expectancy when it interacted with smoke PM2.5. (4) Terrain ruggedness has no significant effect on life expectancy. To sum up, our study suggests that smoke PM2.5 not only has a negative effect on life expectancy itself but also influences the beneficial impact of green space on life expectancy, may turning the interactive effects detrimental. The study provides new insights on the health effects of smoke PM2.5, which have implications in urban planning and public health policies.

We investigated the diversity of saprotrophic fungi in mixed tree communities of Douglas-fir and Bishop Pine compared to mono-dominant stands of both species. Soil cores were collected from three sites of each type, for a total of nine samples. By using DNA sequencing, we hypothesize that mixed communities exhibit higher saprotrophic fungal biodiversity due to the heterogeneity of mixed-tree plant litter. Our predictions should show that there are statistically significant differences between the three forest types, with mixed stands showing the greatest saprotrophic fungal diversity. This work highlights the ecological significance of forest management wit h i n heterogeneous plant communities. Research on these topics is especially important in regards to carbon sequestration as saprotrophic fungi play a major role in decomposition, which can alter carbon sequestration rates.

Space-based coronagraphs have allowed for improving the methodology for detecting CMEs and predicting interplanetary shock waves and geomagnetic storms. However, studies show not all solar sources of CMEs can be identified. The reasons for this are, first of all, the notable variability of the event parameters. This is especially characteristic of the so-called Stealth CMEs. Such events only have weak signatures in the low corona.Coronal mass ejections go through several phases each of which may have observational features in the X-ray and radio ranges. A series of weak bursts in the soft X-ray range (SXR) characterizes the initiation phase. It is followed by a rapid acceleration phase with maximum ejection speeding up. This shortest phase, as a rule, falls at the X-ray flare’s peak and is accompanied by radio bursts of different types. In this work, we present preliminary results of an analysis of the signatures of a few Stealth-like CMEs in X-ray and radio ranges and data on solar energetic particles within the acceleration phase of the coronal ejection. For the analysis, we use data from the STIX spectrometer for imaging X-rays, RPW radio and plasma wave instrument, and EPD energetic particles detector suite of the Solar Orbiter mission.We show that gradual and prolonged SXR bursts can accompany the formation and development of Stealth-like CMEs in the solar corona. Bursts in the SXR range during the initiation phase are often accompanied by type III radio bursts. The acceleration phase of the coronal cloud is accompanied by type II radio bursts and acceleration of solar energetic particles. These signatures are caused by overcoming critical stability points in the magnetic field configuration, intensive ascent of the flux rope in the corona and the formation of a shock wave at its front.This work is supported by the “Long-term program of support of the Ukrainian research teams at the Polish Academy of Sciences carried out in collaboration with the U.S. National Academy of Sciences with the financial support of external partners”.

The study of icy moons is of great importance to furthering our understanding of the origins of life in the solar system due to their high liquid water content. While missions like JUICE aim to study these bodies through an observational lens, there has yet to be a mission that probes the subsurface of one of these icy moons. This study details our novel mission plan to explore the Saturnian moon Enceladus. This icy world houses a large subsurface ocean filled with important elements for life, alongside potential catalysts for life to form, such as thermal vents. This mission relies on three main components, an orbiter, a lander, and a drill. We detail the designs for every part of the mission and test a simulated thruster system used for landing as well as the water sampling mechanism of the drill. Our testing of the water sampler highlighted the importance of placing the water sampling mechanism above as few mechanical components as possible to prevent the drill from being unable to resurface, and proved that our sampling design is able to collect water efficiently. Similarly, by using drone propellers to simulate thrust from a descent stage and imitate the lack of an atmosphere, we were able to test the lander concept to gain insight on the thrust required to decelerate the lander and negate horizontal velocity for optimal landing on a surface of unknown material composition. We will analyze the water found in the subsurface region of the planet to gauge the habitability of Enceladus and the potential for finding prebiotic lifeforms on the natural satellite. Our mission aims to further study Enceladus and understand more about icy moons through analysis of surface particles and subsurface ocean water. Our mission will help provide key insights into remote sensing, orbiting, landing, and drilling technologies that will be pivotal to exploring other distant icy moons such as Europa or Titan.

A document by Shenyue Jia. Click on the document to view its contents.

The planktonic copepod, Calanus finmarchicus, typically dominates the zooplankton biomass in deep waters of the Gulf of Maine. The sources and processes controlling the population dynamics of C. finmarchicus in the Gulf of Maine, particularly on the coastal shelves and ledges along the Maine coast, where lipid-rich copepodid stages of C. finmarchicus serve as a primary source of nutrition for planktivorous fish such as herring and mackerel, are not well understood. Knowledge of coastal C. finmarchicus abundance and distribution patterns is particularly important for evaluation of risks associated with right whale foraging in the vicinity of high nearshore densities of fixed fishing gear. Here we document the seasonal patterns and summer distribution of C. finmarchicus copepodid stage abundance in Maine coastal waters of the Gulf of Maine, based on three plankton surveys conducted in July or August in three successive years and concomitant time series of plankton collections at two mid-coast stations. C. finmarchicus copepodid stages CV-CVI, the most energy-rich prey for planktivores, were most abundant in spring (April-May), and again from mid-July through September at the coastal time series station. Abundances of these stages in mid summer (Jul-Aug) were significantly higher, by a factor of 2-47 for stage CV-CVI at offshore coastal stations > 100m depth than shallower nearshore coastal stages. Very few older stage C. finmarchicus were observed in the Damariscotta Estuary at any time of year. Our observations are most consistent with the hypothesis that local coastal production originating upstream from Jordan Basin or the Eastern Maine Coastal Current is the first-order source of C. finmarchicus in the coastal ocean. Abundance of later copepodid stages that develop from this coastal production is diminished in summer by planktivorous predation and possibly by offshore, cross-shelf drift of stage CV entering dormancy. Estimated concentrations of late, lipid-rich copepodid stages based on profiles with a Laser Optical Plankton counter were not sufficiently high to attract right whale foraging behavior inshore of the 100 m isobath; dense layers generally occurred at stations deeper than 150 m.

This study presents and quantitatively analyzes a new dataset detailing areas affected by ballistic projectiles generated by major explosions and paroxysms at Stromboli. The dataset includes a total of 67 events over ≈150 years, based on an extensive review of historical, observational, and monitoring data. By quantifying distances, directions, and areas affected by ballistic fallout, we provide the necessary data, together with their uncertainty, to produce probabilistic maps of ballistic hazard as presented in a companion study. Our main findings include: (1) 23%-37% of major explosions do not exceed 500 m in their maximum ballistic distance, while 17%-42% of paroxysms remain under 1,500 m; however, 12%-14% of major explosions can exceed 1,000 m, and 29% of paroxysms extend over 2,000 m; (2) sector-based analysis of ballistic distance distribution produces probabilities up to three times lower compared to those based on the maximum distances; (3) directional analysis of ballistic dispersal shows a predominant direction towards the East half-plane (87%) for major explosions and towards the North half-plane (64%) for paroxysms; (4) the average affected area was 6.9e+04 m² for major explosions and 3.6e+05 m² for paroxysms with a mean amplitude of ≈90 degrees for both categories. Notably, major explosions and paroxysms show a continuous distribution of maximum ballistic distance and area affected, suggesting the absence of a net separation between these two categories with respect to this phenomenon. Results highlight the limited influence of uncertainty in reconstructing the dispersal areas and stress the importance of volcanological monitoring of Stromboli’s explosive phenomena

Radio frequency interference (RFI), particularly human-made RFI such as FM radio, presents a unique challenge to radio astronomy experiments at low frequencies (10 to 200 MHz) such as those for 21cm cosmology and searches for exoplanet auroral emission. Current experiments aim to avoid RFI by building instruments in remote locations. However, as usage patterns change with time and radio bands become more crowded, new sites and mitigation strategies are needed. Here we report efforts toward a survey of the most isolated places on Earth, reflected in measures of human activity, including vessels, transmitter databases, and human censuses. Astronomers have also begun to consider experiments on the radio quiet lunar far side. This work bridges the development of Earth-based and lunar projects for radio astronomy. Over several locations on the planet, the RFI experienced by a space-based instrument, either in low-Earth orbit or on a high-altitude balloon, could be low enough to merit use for a full-fledged 21-cm experiment or as a staging ground for future lunar work. As a precursor to scientific use, we aim to make measurements of the low-frequency radio spectrum in low-Earth orbit. The Radio Background Experiment (RBE) is a compact radio spectrometer built using elements of the EDGES ground-based global 21cm experiment. A prototype of RBE was deployed from the International Space Station as a guest payload on the DORA cubesat in October 2024. The spacecraft re-entered rapidly due to strong solar activity but managed to acquire data indicating healthy functioning of the spectrometer components.

Effective assessment of potential climate impacts requires the ability to rapidly predict the time-varying response of climate variables. This prediction must be able to consider different combinations of forcing agents at high resolution. Full-scale ESMs are too computationally intensive to run large scenario ensembles due to their long lead times and high costs. Faster approaches such as intermediate complexity modeling and pattern scaling are limited by low resolution and invariant response patterns, respectively. We propose a generalizable framework for emulating climate variables to overcome these issues, representing the climate system through spatially resolved impulse response functions. We derive impulse response functions by directly deconvolving effective radiative forcing (ERF) and near-surface air temperature time series. This enables rapid emulation of new scenarios through convolution and derivation of other impulse response functions from any forcing to its response. We present results from an application to near-surface air temperature based on CMIP6 data. We evaluate emulator performance across 5 CMIP6 experiments including the SSPs, demonstrating accurate emulation of global mean and spatially resolved temperature change with respect to CMIP6 ensemble outputs. Global mean relative error in emulated temperature averages 1.49% in mid-century and 1.25% by end-of-century. These errors are likely driven by state-dependent climate feedbacks, such as the non-linear effects of Arctic sea ice melt. We additionally show an illustrative example of our emulator for policy evaluation and impact analysis, emulating spatially resolved temperature change for a 1000 member scenario ensemble in less than a second.

A document by Abdelhamid Ads. Click on the document to view its contents.

A document by Matthew Pudig. Click on the document to view its contents.

A document by Md Shadman Sakib. Click on the document to view its contents.

Based on over 8 years of moored observation data near the Xisha Islands in the South China Sea (SCS), this study investigated the seasonal variability and vertical distribution of near-inertial waves (NIWs) and internal tides (ITs). It also investigated the impact of mesoscale cyclonic eddies on the downward propagation of NIWs, as well as the mechanism of nonlinear interactions between NIWs and ITs following typhoons. Both NIWs and ITs exhibited significant seasonal variations. Near-inertial kinetic energy (NIKE) was stronger in autumn and winter, while internal tide energy peaked in both summer and winter. Over the entire observation period, ITs were primarily dominated by low modes. In contrast to internal tides, which are dominated by low modes, NIWs exhibit high-mode structures under the influence of negative vorticity. During periods of positive vorticity, the modal structures of NIWs show significant variability. In addition, the study found that cold eddies can also facilitate the downward transfer of near-inertial energy. Taking the autumn of 2011 as an example, under the influence of positive vorticity, NIKE was transmitted downward to the maximum observed depth of 543m, contributing to deep-ocean mixing. The study also revealed that typhoon-induced NIWs, characterized by strong vertical shear, played a dominant role in the nonlinear interactions between NIWs and ITs, leading to the enhancement of nonlinear coupled waves.

Enhanced Weathering (EW) of silicate rocks is viewed an essential methodology for scaling carbon dioxide removal (CDR) to reach goals of negative global CO2 emissions. EW has an equally important potential for improving agricultural soil, increasing crop yields, and reducing traditional fertilizer use and associated waste. Of all potential silicate raw materials for EW basaltic (mafic) rocks have perhaps the greatest potential, even though the total amount of CDR per unit is less than pure minerals like olivine. Basaltic rocks are widespread compared to other lithologies, are proven to benefit degraded agricultural soils, have significant CDR potential, and minimal negative environmental impacts including heavy metals. Systematic approaches to select basaltic raw material for agricultural and CDR benefits include petrographic and XRD analyses of minerals, XRF and ICP-MS analyses of major and trace elements and grainsize analysis of primary milled material or byproduct material from other aggregate uses. Analysis of commercially available “basalt” shows a wide range in relative quality in terms of primary mineralogy, chemical composition, degree of alteration and metamorphism, achievable grain size, proximity to low carbon transportation and application sites, climate, soil type, and other economic factors. Some products advertised as basalt are dark colored felsic rocks (andesite, dacite) or metamorphosed mafic rocks all of which have lower potential for CDR. These factors limit potential sources of basalt to a small percentage of quarry locations. Mafic, basaltic rocks have SiO2 contents between 45 and 52 percent and vary widely in percentages of mineral phenocrysts– e.g. olivine may range from 0 to >5%, which are also factors in selection of raw material. From an agricultural perspective, analyses of water extractable and Mehlich-3 nutrients reveal values less than the totals of primary unweathered basaltic material; these values increase with degree of EW. Widespread adoption of EW methods for improving soil health will require local and regional crop specific trials and realistic guidelines for application rates and grain sizes that are practical and economic for producers. Characterizing raw material is paramount to instilling confidence in CDR potential and benefits for crops and soil health.

Abrupt reconfiguration (reconnection) of solar magentic fields is leading to active phenomena (flares and CMEs) which are efficient particle accelerators. These particles populations contain around 30% of total released magnetic energy. In the standard model of a solar flare particles (mainly electrons) transport energy to the chromosphere where they experience Coulomb collisions with ambient plasma leading to emission of bremsstrahlung (non-thermal radiation) and heating (thermal radiation). Other part of particles may escape the Sun and propagate in the interplanetary space where they can be investigated in situ. The multi-messenger analyses of energetic particles were proven to give extremely interesting results. On of the best examples is the existence of third radiation belt in the Earth magnetosphere which was supported by in situ (STEP-F) and remote (SphinX) instruments onboard CORONAS-Photon satellite. Recently, in February 2020, Solar Orbiter has been launched carrying onboard ten scientific instruments. Among them Spectrometer/Telescope for Imaging X-rays (STIX) and Energetic Particle Detector (EPD) are instruments that allow to observe energetic particles accelerated in the solar corona. STIX is measuring X-rays in the energy range 4-150 keV, in 32 energy channels, which gives opportunity for investigation of non-thermal part of a solar flare spectrum. From spectral analysis of STIX data we can obtain properties of non-thermal particle beams and compare them to remote data from ground based radio observatories (Ondrejov observatory). The comparison gives reach information about particles propagating down to the chromosphere (X-rays) and up to the solar corona and, eventually, interplanetary space (radio). Particles propagating in the interplanetary space may reach EPD onboard Solar Orbiter allowing for linking their properites observed in the acceleration site and after traveling large distance. The reacheness of data allows to investigate non-thermal particles (electrons in this case) properties from several points of view. Here we present few case studies of very interesting events that allow to look from a new perspective to flare-related particles acceleration and propagation problems.

In this work, we explore embodied data interaction with the empirical space weather datasets in a mixed reality (MR) environment using extended reality (XR) technologies. Three empirical variables related to the study of solar storms over an 18-year period are shown: SYM-H index data, sunspot number, and ground-based total electron content from the northwest sector of the continental United States. We aim to showcase correlations among these data variables in a novel MR environment and use audio and visual analytics to explore using the XR capabilities to detect correlations. We provide sonification (the use of non-speech audio to convey information) and visual analytics techniques in an MR tool deployed on an MR headset. A human research study involving 54 participants tested the usability and efficacy of the newly developed MR tool on users with no space-science expertise or prior knowledge of the datasets. The results show that even with minimal knowledge of space weather and limited experience with MR environments, the participants were able to identify correlations and begin to understand the scientific context of space weather phenomena. At the CEDAR 2023 conference, we broadened the demographics of the study by studying the responses of space-weather experts in order to more rigorously quantify and assess the potential impact of XR technologies on educational and analysis tools and techniques. Forty-two space science experts gave their feedback about the usability and the potential of this emerging technology as a scientific education and analysis methodology. At the NASA 4th Eddy Cross-Disciplinary Symposium in 2023, we gained a global perspective and feedback from the heliophysics community around the world. At AGU 2024, we intend to present the results collected from space weather experts worldwide, discuss the next steps, and highlight the strengths and challenges of this novel approach to data analysis.