There is large uncertainty in the future sea level change at regional scales under anthropogenic global warming. This study uses a novel design of ocean-only general circulation model (OGCM) experiments to investigate the ocean’s response to surface buoyancy and momentum flux perturbations, as part of the Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP), and compares with results from coupled, atmosphere-ocean GCM (AOGCM) experiments. Much of the inter-model spread is driven by the response to surface heat flux perturbations. In a multi-model ensemble of OGCMs forced with identical surface heat flux perturbations, regional sea level and ocean heat content changes demonstrate considerable disagreement, especially in the North Atlantic. Spread in both residual mean advection and diapycnal diffusion changes contribute to much of the multi-model disagreement over regional heat content change. Residual mean advection changes are related to the large spread in simulated Atlantic meridional overturning circulation (AMOC) weakening (20-50%). We find approximately 10% more AMOC weakening in response to surface heat flux perturbations in AOGCMs relative to OGCMs with consistent ocean models. This enhanced AMOC weakening is driven by an atmosphere-ocean feedback which amplifies the surface heat flux perturbation. In the North Pacific, there is little agreement amongst the ensemble over which processes lead to ocean warming, with varying contributions from residual mean advection and diapycnal diffusion. For the Pacific basin, the atmosphere-ocean feedback reduces sea surface temperature (SST) warming by 0.5°C. In the Southern Ocean, the atmosphere-ocean feedback is not generally important for buoyancy and momentum flux perturbations.

The interannual variability of the annual maximum ice cover (AMIC) of the Great Lakes is generally dominated by a dipole pattern over mid-latitude North America and Western Alaska via a ridge-trough system. We discovered a significant breakpoint in the winter of 1997/98 after which AMIC increased its interannual variability and negatively correlated with sea ice coverage over the Bering and Chukchi Seas in the preceding Novermber and Decemeber. The first covarying mode of the 500hPa geopotential height and surface air temperature indicated that the dipole pattern shifted northward to the northern Rocky Mountains after the breakpoint. Correlati The correlations with AMIC of the other well-known teleconnection patterns such as the El Niño–Southern Oscillation on AMIC became insignificant after the brekpoint and were replaced by that from the Eastern Pacific Oscillaiton, which likely controlled the interannual variabilities of AMIC and sea ice cover the Bering and Chukchi Seas.

The growth of the world’s population living in urban areas has led to change from natural to highly dense and impermeable landscapes. Moreover, the intensity and frequency increase of extreme events resulting from climate change (e.g. inundations, heat waves) produce a degradation of urban systems resilience capacity. The integration of nature-based solutions NbS in urban spaces has been widely accepted, like a sustainable strategy that allows to tackle these urban challenges while building resilience and improving well-being and health. NbS are inspired by the nature, favouring natural processes in the cities like water infiltration or evapotranspiration (ET). Thanks to the latest, the vegetation shadow and wind dynamics favours air temperature reduction during heatwave events or mitigation of Urban Heat Island (UHI) phenomenon. Consequently, the distribution of urban green spaces might impact heat fluxes dynamics, by reducing temperature and its perception. They may also reduce virus spreads and also the sensitivity factors to them. Following a spatial approach, this study aims to analyse the green space distribution across different scales in the agglomeration located in the east of Paris (France) and various scenarios of its development. To achieve this goal, the spatial simulation model “Fractalopolis” is used. This allows to generate fractal urban forms using an iterative downscaling scheme (IFS: Iterative Function System) applied to existing large scale patterns of green areas. This work enables to analyse i) the access of population to the nearest green area and the fractal dimension of public urban green spaces; and ii) the impact of temperature reduction of different land-use scenarios by coupling a multifractal analysis of ET scaling behaviour measured at the local scale.

We present evidence of volcano-tectonic interactions at Sabancaya volcano that we relate to episodic magma injection and high regional fluid pore pressures. We present a surface deformation time series at Sabancaya including observations from ERS-1/2, Envisat, Sentinel-1, COSMO-SkyMed, and TerraSAR-X that spans June 1992 - February 2019. These data show deep seated inflation northwest of Sabancaya from 1992-1997 and 2013-2019, as well as creep and rupture on multiple faults. Afterslip on the Mojopampa fault following a 2013 Mw 5.9 earthquake is anomalously long-lived, continuing for at least six years. The best fit fault plane for the afterslip is right-lateral motion on an EW striking fault at 1 km depth. We also model surface deformation from two 2017 earthquakes (Mw 4.4 and Mw 5.2) on unnamed faults, for which the best fit models are NW striking normal faults at 1-2 km depth. Our best fit model for a magmatic inflation source (13 km depth, volume change of 0.04 to 0.05 km^3 yr^-1), induces positive Coulomb static stress changes on these modeled fault planes. Comparing these deformation results with evidence from satellite thermal and degassing data, field observations, and seismic records, we interpret strong pre-eruptive seismicity at Sabancaya as a consequence of magmatic intrusions destabilizing tectonic faults critically stressed by regionally high fluid pressures. High fluid pressure likely also promotes fault creep driven by static stress transfer from the inflation source. We speculate that strong seismicity near volcanoes will be most likely with high pore fluid pressures and significant, offset magmatic inflation.

We study quasi-periodic VLF emissions observed simultaneously by Van Allen Probes spacecraft and Kannuslehto and Lovozero ground-based stations on 25 December 2015. Both Van Allen Probes A and B detected quasi-periodic emissions, probably originated from a common source, and observed on the ground. In order to locate possible regions of wave generation, we analyze wave normal angles with respect to the geomagnetic field, Poynting flux direction, and cyclotron instability growth rate calculated by using the measured phase space density of energetic electrons. We demonstrate that even parallel wave propagation and proper (downward) Poynting flux direction are not sufficient for claiming observations to be in the source region. Agreement between the growth rate and emission bands was obtained for a restricted part of Van Allen Probe A trajectory corresponding to localized enhancement of plasma density with scale of 700~km. We employ spacecraft density data to build a model plasma profile and to calculate ray trajectories from the point of wave detection in space to the ionosphere, and examine the possibility of their exit to the ground. For the considered event, the wave could exit to the ground in the geomagnetic flux tube with enhanced plasma density, that ensured ducted propagation. The region of wave exit was confirmed by the analysis of wave propagation direction at the ground detection point.

Recent space missions have identified organics, chlorinated and non-chlorinated, on Mars. Understanding the origin, current state and reactivity of this carbonaceous material is critical to efforts to detect organic signatures of possible past life on Mars. Environmental effects such as UV radiation, pressure, diagenesis, aqueous activity and presence of perchlorates have been previously been assessed using analog experiments. To this list, Fox, et al. adds and quantifies the effect of galactic cosmic rays and solar winds on organic material on the surface and in the near sub-surface of Mars. Their work, using laboratory analog materials and radiation, shows that the same organic acids, formic and oxalic acid, are produced after exposure equivalent to that over Martian history at depths of less than 5 cm, independent of mineral matrix or starting organic materials. These experiments suggest that planned sub-surface exploration using the drill on the Rosalind Franklin Rover (ExoMars) will sample organic material which has not been altered by cosmic rays, although it may have been exposed to other environmental factors such as water or salts.

The 2014 Iquique seismic crisis (Chile), culminating with a Mw 8.1 earthquake, April 1st, highlights a complex unlocking of the North Chile subduction interface which has been considered as a seismic gap since 1877. During the year preceding this event, at least three seismic clusters were observed: in July 2013 and January and March 2014. These clusters possibly indicate aseismic slip transients accompanying the progressive destabilization of the plate contact. Recent studies have proposed large-scale slab deformation as a potential trigger for the megathrust earthquake; However, no evidence of gradual unlocking of the interface or transient deformation has yet been found in the seismic rate. To address this question, we develop a dense earthquake catalog during the fifteen months preceding the mainshock from the continuous waveform dataset recorded by the Integrated Plate Boundary Observatory Chile (IPOC) and Iquique Local Network (ILN) networks. After declustering the seismicity, a space-time analysis highlights a large-scale acceleration of the seismicity along the interface while it decelerates at intermediate-depths. We then demonstrate the existence of a seismic quiescence down-dip of the mainshock rupture before the July 2013 cluster. We propose that this seismic quiescence is related to fluid circulation and/or aseismic motion along upper-plate crustal fault(s).

Under a high-end emission scenario to the year 2300, climate warming drives a drastic slowdown in the ocean’s meridional overturning circulation, with a cessation of Antarctic Bottom Water (AABW) production and North Atlantic Deep Water (NADW) formation reduced to 5 Sv. In conjunction with regionally enhanced biological production and upper-ocean nutrient trapping in the Southern Ocean, this deep circulation slowdown drives long-term sequestration of nutrients and dissolved inorganic carbon in the deep ocean, but also greatly reduces the ocean’s capacity to take up heat and anthropogenic CO from the atmosphere, prolonging peak warmth climate conditions. Surface nutrients (N, P, and Si) are steadily depleted driving down biological productivity and weakening the biological pump, which transfers carbon to the ocean interior. Ocean dissolved oxygen concentrations steadily decline, with the potential for anoxia eventually developing in some regions. This Community Earth System Model (CESM) simulation did not include active ice sheet dynamics, but the strong climate warming simulated would lead to large freshwater discharge from the Antarctic and Greenland ice sheets. This would further stratify the polar regions, potentially leading to complete shutdown of the meridional overturning circulation. The impacts of this would be catastrophic as the hothouse Earth climate conditions could be extended for thousands of years, with widespread ocean anoxia developing, driving a mass extinction event.

New Caledonia’s Ni deposits account for ~ 8.2% of the world’s production of mined nickel, with a major smelting facility located in the country’s capital city of Nouméa (population 100,000). There are emerging concerns relating to contamination of human and natural ecosystems from dust and soil contamination from mineral processing emissions, which started the late 19th century. There is widespread reuse of Ni smelter slag in the city for multiple uses (e.g. building aggregate, erosion control, added to soil and surface as ‘gravel’) in the city, which contains up to 2% Cr. This study provides the first integrated environmental analysis of the impact of the smelter and associated anthropogenic trace element contamination of Noumea’s natural and human environments. To assess the impacts from smelting, hundreds of trace element data points were collected across Nouméa in a variety of matrices. These include natural rocks and deep soils, top soils, deposited dusts, residential garden soils, indoor vacuum dusts, honey bees and honey produced within the city’s urban environment. Rocks, soils and exterior and interior vacuum dusts were analysed for their trace element concentrations using X-ray fluorescence at < 100 locations within a 3 km radius of Nouméa’s Ni smelter. Samples of bees (live and dead), honey, soil and deposited dust were collected at 15 beehive locations across the Noumea area to ascertain if and what contaminants are being remobilized in dust, contaminating both food and ecological systems. Natural/background values were assessed using two bee hive locations, distant from the smelter, along with analysis of rocks and sub-surface soils from the main geological strata present in the city. Preliminary environmental data show that anthropogenic contaminants Cr, Ni, Pb and S exceed natural values by up to 8, 2.5, 10 and 15 times in different matrices. Analysis shows that CrVI is present in the slag and surface dusts (x̅ total Cr in deposited dust = 450 µg/m2) and that more than 60% of Ni dust loadings are > 1000 µg/m2 (x̅ Ni in dust = 2,400 µg/m2). The presentation will detail trace element concentrations in live and dead bees and corresponding honey samples and evaluate the data against corresponding levels measured in the adjoining environment to assess the remobilization and recycling of anthropogenic contaminants.

A significant stress drop characterizes sometimes earthquakes induced by injection or extraction of fluids in rocks. Moreover, long-term fluid operations in underground reservoirs can impact a seismogenic reaction of the rocks per a unit volume of the involved fluid. The seismogenic index is a quantitative characteristic of such a reaction. We derive a relationship between the seismogenic index and the stress drop. We propose a simple and rather general phenomenological model of the stress drop of induced events in various faulting regimes. Our results suggest that high stress drops of some earthquakes induced by long-term underground fluid operations may be controlled by drops of cohesion of more cohesive faults getting seismically activated due to gradually increasing with time differential stresses. On the one hand, this effect can result in an increase of seismogenic index with production time. On the other hand, a production-caused depleting of the pore pressure can also cause a systematic increase of the stress drop. This provides an additional contribution to the growth of seismogenic index with production time at such reservoirs.

The Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC) is a multidisciplinary data repository created as a result of the Deepwater Horizon oil spill. Essentially “building a ship while sailing”, GRIIDC developed a repository while researchers were collecting vital post-spill data during a time when data sharing was not a widely accepted practice. Priorities for the data repository during those early years focused on ingesting data and metadata quickly, while working with researchers who had never shared data before. Almost ten years later, GRIIDC has come a long way – improving data curation, training researchers, and developing software that greatly simplified the submission process. While the ease of submission will always be a priority, GRIIDC has shifted the focus of software development and data curation to implement FAIR data principles, which ensure that data are findable, accessible, interoperable, and reusable. The data package review process has improved by increasing the number of subject matter experts who ensure that files are not corrupt, are in non-proprietary formats, contain complete datasets, and are well-documented with ISO-19115-2 metadata. Datasets are assigned a digital object identifier (DOI) and can be searched using GRIIDC’s data discovery tool. GRIIDC is a DataONE member node and is listed in the Registry of Research Data Repositories (re3data), which increases findability and accessibility of data. Datasets have landing pages which display the DOI, links to associated publications, number of downloads, and a suggested citation. Although the GRIIDC data management system currently supports several FAIR data principles, there is always room for improvement. Potential future tasks include adding vocabularies, improving provenance records, and adding additional attributes to metadata. Challenges to accomplishing these goals include funding, limited resources, and program priorities. Despite these challenges, GRIIDC will always continue to evolve to improve the needs of users as well as support the FAIR data movement. Life may not always be fair, but data should be.

Three new equilibrium Mid-Pliocene (MP) simulations are implemented with the Community Climate System Model version 4 (CCSM4), Community Earth System Model version 1.2 (CESM1.2), and 2 (CESM2). All simulations are carried out with the same boundary and forcing conditions following the protocol of Pliocene Model Intercomparison Project Phase 2. These simulations reveal amplified MP climate change relative to preindustrial going from CCSM4 to CESM2, seen in global mean and polar amplification of surface warming, sea ice reduction in both Arctic and Antarctic, and weakened Hadley circulation. The enhanced global mean warming arises from both enhanced Earth System Sensitivity (ESS) and Equilibrium Climate Sensitivity (ECS) to CO forcing. ESS is amplified by up to 70% in CCSM4, and up to 100% in CESM1.2 and CESM2 relative to ECSs of respective models. Simulations also agree on the strengthened Atlantic Meridional Overturning Circulation, but disagree on several other climate metrics. Compared to preindustrial, CCSM4 features small increase in both low and high cloud cover and no change in the mean climate state of the equatorial Pacific. Whereas, both CESM1.2 and 2 show reduction of cloud cover at all heights, and an anomalous El Niño-like state of the equatorial Pacific. The performances of MP simulations are assessed with a new compilation of paleo-observations of sea surface temperature (SST). CESM1.2 and 2 show better skills than CCSM4 in simulating MP global mean warming and amplified SST warming in the northern middle and high latitudes, supporting the amplified ESS compared to the CCSM4.

Lakes emit globally significant amounts of carbon dioxide (CO) to the atmosphere, but quantifying these rates for individual lakes is extremely challenging. The exchange of CO across the air-water interface is driven by physical, chemical, and biological processes in both the lake and the atmosphere that vary at multiple spatial and temporal scales. None of the methods we use to estimate CO flux fully capture this heterogeneous process. Here, we compared concurrent CO flux estimates from a single lake based on commonly used methods. These include floating chambers (FC), eddy covariance (EC), and two concentration gradient based methods labelled fixed (F-CO₂) and spatial (S-CO₂). At the end of summer, cumulative carbon fluxes were similar between EC, F-CO₂ and S-CO₂ methods (-4, -4 and -9.5 gC), while methods diverged in directionality of fluxes during the fall turnover period (-50, 43 and 38 gC). Collectively these results highlight the discrepancies among methods and the need to acknowledge the uncertainty when using any of them to approximate this heterogeneous process.

The Delaware Basin in Texas, one of the largest oil and gas production sites in the US, has been impacted by widespread seismicity in recent years. The M5.0 earthquake that occurred in March 2020 near the town of Mentone is one of the largest induced earthquakes recorded in this region. Characterizing the source parameters and triggering mechanism of this major event is imperative to assess and mitigate future hazard risk. A former study showed that this event may be attributed to the deep injection nearby. Interestingly, the earthquake is located in proximity to shallow injection wells with much larger total injection volume. In this study, we investigate the role of these shallow injection wells in the triggering of the M5.0 event despite their farther distance from the mainshock. We perform source-parameter inversion and earthquake relocation to determine the precise orientation of the south-facing normal fault plane where the mainshock occurred, followed by fully coupled poroelastic stress modeling of the change of Coulomb Failure Stress (ΔCFS) on the fitted fault plane caused by shallow injection in the region. Results show that shallow wells caused up to 20 kPa of ΔCFS near the mainshock location, dominated by positive poroelastic stress change. Such perturbation surpasses the general triggering threshold of faults that are well aligned with the local stress field and suggests the nonnegligible role of these shallow wells in the triggering of the mainshock. We also discuss the complex effect of poroelastic stress perturbation in the subsurface and highlight the importance of detailed geomechanical evaluation of the reservoir when developing relevant operational and safety policies.

We employ in this work the first airglow dataset registered at the Remote Optical Facility (ROF) in Culebra, Puerto Rico, during the descending phase of the solar cycle #24. From November 4, 2015, to September 26, 2019, observations were carried out during 633 nights at ROF using a small all-sky imager, while events were identified in 225 of 499 nights classified as clear. A quantitative analysis of these and their dependency by geophysical parameters (solar and geomagnetic activities) are the main focus of this study. We introduce an original statistical methodology that examines the unique features of the dataset and minimizes the cross-contamination of individual modulators onto one another, avoiding bias in the results. Our findings include a primary peak of occurrence in the December solstice and a secondary peak in the June solstice. We observed a remarkable correlation in the occurrence rate of the with the geomagnetic activity. A notable modulation of the occurrence rate with the solar activity is also found, which includes periods of correlation and anti-correlation depending on the season. This modulation has an annual component that is ~33% and ~83% stronger than the semi-annual and terannual components, respectively. We discuss these findings based on the behavior of the thermospheric neutral winds derived from 30 years of Fabry-Perot interferometer observations. Our results, which are valid for low to moderate solar activity, point out circumstances that might explain differences in previous climatological studies of nighttime

Globally-significant quantities of carbon (C), nitrogen (N), and phosphorus (P) enter freshwater reservoirs each year. These inputs can be buried in sediments, respired, taken up by organisms, emitted to the atmosphere, or exported downstream. While much is known about reservoir-scale biogeochemical processing, less is known about spatial and temporal variability of biogeochemistry within a reservoir along the continuum from inflowing streams to the dam. To address this gap, we examined longitudinal variability in surface water biogeochemistry (C, N, and P) in two small reservoirs throughout a thermally-stratified season. We sampled total and dissolved fractions of C, N, and P, and chlorophyll-a from each reservoir’s major inflows to the dam. We found that time was generally a more important driver of heterogeneity in biogeochemical concentrations than space. However, dissolved nutrient and organic carbon concentrations had high site-to-site variability within both reservoirs, potentially as a result of shifting biological activity or environmental conditions. When considering spatially explicit processing, we found that certain locations within the reservoir, most often the stream-reservoir interface, acted as ‘hotspots’ of change in biogeochemical concentrations. Our study suggests that spatially explicit metrics of biogeochemical processing could help constrain the role of reservoirs in C, N, and P cycles in the landscape. Ultimately, our results highlight that biogeochemical heterogeneity in small reservoirs is driven more by seasonality than longitudinal spatial gradients, and that some sites within reservoirs play critically important roles in whole-ecosystem biogeochemical processing.

The Demonstration and Science Experiments (DSX) mission operated in medium Earth orbit from 25 June 2019 until 31 May 2021. During this time it conducted experiments that actively injected very low frequency waves into the inner magnetosphere to study wave generation, wave propagation, and wave-particle interactions. Experiment planning used cold plasma ray tracing to predict conjunctions for space-to-space transmissions, and the same technique supports post-mission analysis of both monostatic and bistatic signal receptions. Modifications for warm plasma may also be required for extremely oblique waves. In addition, evaluations of amplitude thresholds for triggered emissions provide bounds on DSX signal amplitudes useful for constraining the antenna performance. This report describes both of these analytical tools in the context of mission planning and data analysis. Ongoing analysis using these techniques will be reported in future publications.

• Poor estimates of the sinking speed of marine aggregates stem primarily high variance in aggregate excess density. • Self-similarity of aggregation facilitates efficiently modelling of aggregate size and excess density, and hence sinking speed. • This provides a mechanistic description of how planktonic communities impact the size and density-resolved export flux of organic matter.