Significant changes are found in the modeled phase partitioning of Arctic mixed-phase clouds in the U.S. Department of Energy (DOE) Energy Exascale Earth System Model (E3SM) Atmosphere Model version 1 (EAMv1) compared to its predecessor, the Community Atmosphere Model version 5 (CAM5). In this study, we aim to understand how the changes in modeled mixed-phase cloud properties are attributed to the updates made in the EAMv1 physical parameterizations. Impacts of the Classical Nucleation Theory (CNT) ice nucleation scheme, the Cloud Layer Unified By Binormals (CLUBB) parameterization, and updated Morrison and Gettelman microphysical scheme (MG2) are examined. Sensitivity experiments using the short-term hindcast approach are performed to isolate the impact of these new features on simulated mixed-phase clouds. Results are compared to the DOE’s Atmospheric Radiation Measurement (ARM) Mixed-Phase Arctic Cloud Experiment (M-PACE) observations. We find that mixed-phase clouds simulated in EAMv1 are overly dominated by supercooled liquid and cloud ice water is substantially underestimated. The individual change of physical parameterizations is found to decrease cloud ice water mass mixing ratio in EAMv1 simulated single-layer mixed-phase clouds. A budget analysis of detailed cloud microphysical processes suggests that the lack of ice particles that participate in the mass growth processes strongly inhibits the mass mixing ratio of cloud ice. The insufficient heterogeneous ice nucleation at temperatures warmer than -15C in CNT and the negligible ice processes in CLUBB are primarily responsible for the significant underestimation of cloud ice water content in the Arctic single-layer mixed-phase clouds.

Observational networks enhance real-time situational awareness for emergency and water resource management during extreme weather events. We present examples of how a diverse, multi-tiered observational network in California provided insights into hydrometeorological processes and impacts during a three-day atmospheric river storm centered on 14 February 2019. This network, which has been developed over the past two decades, aims to improve understanding and mitigation of effects from extreme storms influencing water resources and natural hazards. We combine atmospheric reanalysis output and additional observations to show how the network allows for: 1) the validation of record cool season precipitable water observations over southern California, 2) the identification of phenomena that produce natural hazards and present difficulties for short-term weather forecast models, such as extreme precipitation amounts and snow level variability, 3) the use of soil moisture data to improve hydrologic model forecast skill in northern California’s Russian River basin, and 4) the combination of meteorological data with seismic observations to “observe” a large avalanche on Mount Shasta. This case study highlights the value of investments in diverse observational assets and the importance of continued support and synthesis of diverse observations to characterize climatological context and advance understanding of processes modulating extreme weather.

Recent advances in imaging techniques and related modeling have made it possible to study micron and sub-micron scales in unprecedented detail. Currently, performing direct simulations at a representative scale has proven computationally prohibitive, hence, the ability to simulate flow cannot keep up with the size of images available (e.g. x-ray micro-tomography or large area scanning electron microscopy). To overcome this issue, we propose to train a neural network architecture to understand relationships between pore-scale morphology and the simulation outputs. With this, we improve our portability and prediction time. Convolutional neural networks are attractive for this task because they support flexible input size, they are able to capture local interactions, and they can find places that present similar patterns. Generally, deeper networks have better prediction performance, but they are very difficult to train due to the vanishing gradient problem. Also, information from different scales is commonly lost along the network.

Infrared spectra of evolved stars have a rise in signal between the 7.0 μm and 8.0 μm wavelengths; the antisymmetric Si−O stretches of small silicon oxide clusters fall in this range and have large intensities. Hence, this quantum chemical analysis provides data for such molecules that may be of significance for astrochemical classification and could play a role in the formation or degradation of mineral nanocrystals from or into their constituent atoms. Both explicitly computed anharmonic fundamental vibrational frequencies and those determined from scaled harmonic frequencies agree well with known experimental data, and spectroscopic constants are provided herein such that astronomical rotational spectral characterization may also be possible for the C2v SiO3 and Si2O3 molecules.

Inland waters, such as lakes, reservoirs and rivers, are important sources of greenhouse gases to the atmosphere. A key parameter that regulates the gas exchange between water and the atmosphere is the gas transfer velocity, which itself is controlled by near-surface turbulence in the water. While in lakes and reservoirs, near-surface turbulence is mainly driven by atmospheric forcing, in shallow rivers and streams it is generated by flow-induced bottom friction. Large rivers represent a transition between these two cases. Near-surface turbulence has rarely been observed in rivers and the drivers of turbulence have not been quantified. We obtained continuous measurements of flow velocity and fluctuations from which we quantified turbulence, as the rate of dissipation of turbulent kinetic energy ($\varepsilon$) over the ice-free season in a large regulated river in Northern Finland. Atmospheric forcing was observed simultaneously. Measured values of $\varepsilon$ were well predicted from bulk parameters, including mean flow velocity, wind speed, surface heat flux and a one-dimensional numerical turbulence model. Values ranged from $\sim 10^{-9}$ m$^2$ s$^{-3}$ to $10^{-5}$ m$^2$ s$^{-3}$. Atmospheric forcing and river flow contributed to near-surface turbulence a similar fraction of the time, with variability in near-surface dissipation rate occurring at diel time scales, when the flow velocity was strongly affected by downstream dam operation. By combining scaling relations for boundary-layer turbulence at the river bed and at the air-water interface, we derived a simple model for estimating the relative contributions of wind speed and bottom friction in rivers as a function of flow depth.

Elements with variable valence state (i.e. redox-sensitive) often show contrasting mineral/melt partition coefficients as a function of oxygen fugacity (fO2) in magmatic systems. This is because trace-element incorporation into crystal lattices depends on the charge, size, and crystal-field stabilization energy of atoms, all of which differ greatly between oxidized and reduced species of the same element. This has two critical implications: (1) petrologic/ geochemical modelling of partitioning behavior of redox-sensitive trace-elements in magmatic systems requires some knowledge of their oxidation state, and (2) the oxidation state of magmatic systems may be inferred from partitioning relations of redox-sensitive trace elements preserved in mineral and melt phases of rapidly cooled magmas. The advantage of this oxybarometric approach is that mineral/melt partitioning relations are not sensitive to late stage degassing, charge-transfer on quenching, or surficial alteration. In this chapter we discuss the theoretical treatment of experimental mineral/melt partitioning data of redox-sensitive trace elements, and review aspects concerning the partitioning behavior of well-known redox-sensitive elements, including transition metals (Ti, V, Cr, Fe), rare earth elements (Ce, Eu), U, and siderophile elements (Mo, W, Re, and platinum group elements) under planetary magmatic fO2 conditions.

We provide a method to estimate how to determine the amount of carbon to remove to affect the cumulative emitted anthropogenic carbon dioxide for Carbon Dioxide Removal (CDR) targets when climate modeling is unavailable. Additionally, comparing the growth in anthropogenic carbon dioxide emissions to the late-Holocene atmospheric carbon dioxide concentration for historical context and present hypothetical emissions declines for climate restoration. We explore the recent historical context of cumulative anthropogenic carbon dioxide emissions and how it has induced increases to each of the natural sinks: the oceans, atmosphere, and land. The magnitude of cumulative emissions is obscured when only considering yearly emissions change. A possible baseline CO2 concentration of 280.9 ± 0.9 ppm for pre-human change stretching from 600 BCE to 1750 CE was found and could be explored separately. We show multiple speculative emission declines to zero cumulative CO2 emissions to reach complete climate restoration. For groups seeking climate restoration, which completes in less than half a human lifespan, a pair of emission declines are presented, which complete in twenty years. The declines bound a possibility horizon of complete climate restoration ending with 2100 targets. There is a tradeoff between how fast the climate can be restored compared to how long humans can continue to emit carbon dioxide from the use of fossil fuels and land use change. We conclude with hypothesized climate reversibility through hypothesized emissions declines.

Groundwater discharge to headwater streams and concomitant terrestrial dissolved inorganic carbon (DIC) export play a significant role in headwater stream CO2 evasion. However, previous studies rarely examined diffuse groundwater discharge and its impact on headwater stream CO2 evasion, thereby lacking the understanding of the role of diffuse groundwater discharge in terrestrial DIC export and stream CO2 evasion. This study quantified diffuse groundwater discharge along a 43 km semiarid headwater stream by combining hydraulic, isotopic (radon-222) and chemical (electrical conductivity) approaches, and estimated the reach-level CO2 budgets of the stream. Reach-scale water and mass balance modeling yielded highly variable diffuse groundwater discharge rates (n = 16, range: 1.08-7.80 m2/d, mean ± 1 sd: 4.57 ± 1.81 m2/d). Groundwater was supersaturated with CO2 at all sites, with strongly variable CO2 partial pressure (pCO2) and DIC concentrations at 1,223-27,349 μatm and 30-119 mg/L, respectively. Diffuse groundwater discharge dominated terrestrial DIC export to the stream (12-111 g C m-2 d-1, normalized to water surface area). A portion of groundwater dissolved CO2 transported to the stream was emitted to the atmosphere with evasion rates varying at 0.62-3.18 g C m-2 d-1. However, most dissolved CO2 was transformed into HCO3- through carbonate buffering because of the regulation of carbonate equilibrium. Overall, the stream CO2 evasion was driven by carbon transfer but limited by carbon supply. This study provides a bottom-up perspective to understand terrestrial DIC export and stream CO2 evasion in arid and semiarid areas.

We evaluate the longitudinal variation in meridional shifts of the tropical rainband in response to natural and anthropogenic forcings using a large suite of coupled climate model simulations. We find that the energetic framework of the zonal mean Hadley cell is generally not useful for characterizing shifts of the rainband at regional scales, regardless of the characteristics of the forcing. Forcings with large hemispheric asymmetry such as extratropical volcanic forcing and meltwater forcing give rise to robust zonal mean shifts of the rainband, however the direction and magnitude of the shift varies strongly as a function of longitude. Even the Pacific rainband doesn't shift uniformly under any forcing considered. Forcings with weak hemispheric asymmetry such as CO and mid-Holocene forcing give rise to zonal mean shifts that are small or absent, but the rainband does shift regionally in coherent ways across models that may have important dynamical consequences.

The Earth’s Arctic ice cover has diminished rapidly. NOAA reported last December that 95% of the most-reflective multi-year ice has disappeared over the past 40 years. The effects of this lost reflectivity in the Arctic is to increase the net energy influx to the Arctic accelerating heating locally and worldwide, as well as affecting the jet stream, all leading to increasing climate-related impacts on populations and ecosystems worldwide. When considering any interventions to attempt to restore global ecosystems, the safety and reversibility of these interventions must be considered a key metric. As an example, the focus of our work is to restore a natural ecosystem (reflective multi-year ice in the Arctic) that was there until very recently. Our focus is on using a safe material, hollow glass microspheres, made of components (primarily silica) that are ubiquitous in the Earth’s ecosystem, and that are not in a respirable range, and that do not have a tendency to take up oil-based or other toxic pollutants. We will detail these and further safety considerations in such approaches in our presentation.

Tourmaline is a common mineral in Sn-W mineralizations. It is commonly strongly zoned, both optically and chemically, and may host a range of trace elements. High levels of Sn have been observed in tourmaline throughout the world, whereas W is typically very low, even in mineralized areas. Tourmaline from subeconomic cassiterite mineralizations and hydrothermally altered granite from the Land’s End granite, SW England, was analyzed by EPMA in order to identify Sn-rich zones. LA-ICP-MS is typically the go-to instrument for trace element analyses, but spatial resolution is strongly compromised compared to EPMA. The behavior of Sn in tourmaline varies from patchy to concentric zoning between different samples, and the highest recorded value was 2.48 wt% SnO2 in a patchily zoned rim. A high resolution WDS map of the area did not show any major Sn spikes, and TiO2, a common minor element in cassiterite, is low in the Sn-rich regions. Also, cassiterite in these samples are commonly light brown in plane polarized light, and the Sn-rich zones can be related to dark green zones. This indicates that the high Sn-values are not due to cassiterite inclusions, and may be structurally bound in tourmaline, most likely substituting into the Y-site. The highest Sn-values (>0.4 wt% SnO2) are coupled with a substantial substitution of Fe for Al in the Z-site, and the structural formula calculation indicate that some Fe is present as Fe3+ in the analyses with over ca. 20 wt% FeO. Trends between Sn and other elements are erratic, except for a weak positive correlation with Sr. The Sn-content in tourmaline combined with the inferred Fe3+ and the observed cassiterite in the samples may indicate that oxidation of the ore fluid caused cassiterite precipitation.

Vegetation patterns often affected by the soil pH, soil compaction and human mediated disturbance. Several studies have explored how pH, compaction and human disturbance have altered the ecosystem patterns, functioning and services. These studies about semi-arid drylands, explain how lifeforms and productivity resulting from soil acidity, hardness and human disturbance in arid-land. To further enhance the understanding of this correlation, we have surveyed five different eco-system within Yookamurra Sanctuary (Murray lands of South Australia), which is protecting over 5000 hectares of epidemic vegetation and wildlife species. Data has been collected by random sampling method with 150 quadrate samples for soil pH, soil compaction, litter depth, disturbance (Animal or Human) and lifeforms within Yookamurra region. Results suggest that the impacts of pH and compaction are varying across five different ecosystems. Moreover, vehicle disturbance has greater consequences at Roadside ecosystem. These findings amend our understanding of the interaction of soil characteristics with the vegetation patterns, especially in semi-arid region, such as Yookamurra wildlife sanctuary.

Quantitatively estimating magnetotail flapping motion is critical to understanding and characterizing the dynamics of flapping behaviors. Such an estimation could be achieved in principle by the multipoint analysis of spacecraft tetrahedron, e.g. Cluster or MMS mission, but, owing to the inability of single-point measurement to separate the spatial-temporal variation of magnetic field, would be inadequate for a spacecraft. Since single-point missions dominate explorations of planetary magnetotail, we have developed a single-point method based on the magnetic field measurement that quantitatively estimates the parameters of flapping motion, including spatial amplitude, wavelength, and propagation velocity. A comparison with the application of multi-point analysis of Cluster demonstrates that our method can be reasonably be applied to infer the average parameters over a flapping period. Thus, this method could be applied widely to the “big dataset” accumulated by single-point spacecraft missions in order to study magnetotail flapping dynamics.

Although there are several attempts to compare the age distributions on travertines with episodes of surrounding volcanism, the correlation between the precipitation record of carbonate veins and the fractural pattern around a volcanic conduit has not yet been examined. In this study, we investigate the geochronological, geochemical and isotopic characteristics of two travertine deposits (Balkaya and Sarıhıdır) surrounded by many eruption centers in the central Anatolia with ample paleoeruption records. High-resolution carbonate precipitation records revealed by U-series dating are well correlated with the compiled dataset on Acıgöl caldera and Erciyes stratovolcano eruptions with regard to fractural positioning to the volcanic centers. Syn-eruptive carbonate precipitation is thought to occur because of sudden flux of CO-rich fluid along the extensional fracture systems aligned tangential to the related volcanic conduit and, therefore, may be an alternative technique for the reconstruction of paleoeruptions. δO and δC values of the travertine sites are within the range of meteogene fluids and δO values show a similar trend to climate proxies preserved in different depositional environments throughout the world. It is likely due to that studied carbonates were precipitated under similar fluid conditions which are represented by high rate of dilatation followed by the meteoric water influx into the extensional fracture systems.

Artificial carbon dioxide removal (CDR) from the atmosphere has been proposed as a measure for mitigating climate change and restoring the climate system to a target state after exceedance (“overshoot”). This research investigates to what extent overshoot and subsequent recovery of a given cumulative CO2 emissions level by CDR leaves a legacy in the marine environment using an Earth system model. We use RCP2.6 and its extension to year 2300 as the reference scenario and design a set of cumulative emissions and temperature overshoot scenarios based on other RCPs. Our results suggest that the overshoot and subsequent return to a reference cumulative emissions level would leave substantial impacts on the marine environment. Although the changes in sea surface temperature, pH and dissolved oxygen are largely reversible, global mean values and spatial patterns of these variables differ significantly from those in the reference scenario when the reference cumulative emissions are attained.

The Adler Planetarium’s Teen Programs engages hundreds of young people in authentic STEM experiences each year. Several of our programs focus on artificial light at night (ALAN), a critical environmental, health, ecological and astronomical issue. Our work in ALAN Community Advocacy and Education began in 2015 through Youth Organization for Lights Out (YOLO), a bilingual program in English and Spanish based in Chicago’s predominantly Mexican and Mexican-American Little Village neighborhood. YOLO program participants use tools to collect and analyze light pollution data, attend field trips to local and state dark sky sites, facilitate telescope viewing at the Adler and in their community, and develop prototype solutions and action plans to increase awareness of light pollution’s local effects in Chicago. Programs focused on Instrumentation and Research grew out of the Adler’s educational high-altitude ballooning program, Far Horizons. In 2018, Far Horizons astronomers and engineers began developing Mission NITELite (Night Imaging of Terrestrial Environments), a high altitude balloon-based light pollution mapping mission along with undergraduate interns. To complement NITELite, Far Horizons designed GONet (Ground Observing Network), a low-cost all-sky imaging system to measure sky quality at night as part of its Stratonauts teen program. In 2019, high school students helped design, test, and build 50 GONet units as a potential new standard for worldwide ALAN monitoring. In 2020, Adler teen interns are working with the Cook County Forest Preserves to quantify regional sky quality with GONets in support of an application for an Urban Night Sky Place designation from the International Dark-Sky Association. Reflecting the collaborative nature of science, teens in the Instrumentation and Research programs partner closely with peers in the Community Advocacy and Education programs, learning from one another’s perspective while undertaking joint projects.

We quantify sliding stability and rupture styles for a horizontal interface between an elastic layer and stiffer elastic half-space with a free surface on top and rate-and-state friction on the interface. This geometry includes shallowly dipping subduction zones, landslides, and ice streams. Specific motivation comes from quasi-periodic slow slip events on the Whillans Ice Plain in West Antarctica. We quantify the influence of layer thickness on sliding stability, specifically whether steady loading of the system produces steady sliding or sequences of stick-slip events. We do this using both linear stability analysis and nonlinear earthquake sequence simulations. We restrict our attention to the 2D antiplane shear problem, but anticipate that our findings generalize to the more complex 2D in-plane and 3D problems. Steady sliding with velocity-weakening rate-and-state friction is linearly unstable to Fourier mode perturbations having wavelengths greater than a critical wavelength (λ_c). We quantify the dependence of λ_c on the rate-and-state friction parameters, elastic properties, loading, and the layer thickness (Η). We find that λ_c is proportional to sqrt(Η) for small Η and independent of Η for large Η. The linear stability analysis provides insight into nonlinear earthquake sequence dynamics of a nominally velocity-strengthening interface containing a velocity-weakening region of width W. Sequence simulations reveal a transition from steady sliding at small W to stick-slip events when W exceeds a critical width (W_cr), with W_cr proportional to sqrt(H) for small H. Overall this study demonstrates that the reduced stiffness of thin layers promotes instability, with implications for sliding dynamics in thin layer geometries.

Solar flare and magnetotail observations show simultaneous acceleration of ions and electrons into power-law energy distributions extending to high energy. This suggests a common reconnection acceleration process but the underlying physics is not well understood.During magnetic reconnection, energetic particles undergo a universal Fermi acceleration process involving the curvature drift of particles. However, the efficiency of this mechanism is limited by the trapping of energetic particles within flux ropes. Using 3D fully kinetic simulations, we demonstrate that the flux-rope kink instability leads to field-line chaos in weak-guide-field regimes where the Fermi mechanism is most efficient, thus allowing particles to transport out of flux ropes and undergo further acceleration. As a consequence, both ions and electrons form clear power-laws which contain a significant fraction of the released energy. The low-energy bounds, which control the nonthermal energy contents, are determined by the injection physics, while the high-energy cutoffs are limited only by the system size. These results have strong relevance to observations of nonthermal particle acceleration in both the solar corona and magnetotail.