In this study, we examine the accuracy of global geospace simulations by analyzing the relationship between the solar wind and its propagation parameters and the errors in auroral electrojet index AU and AL, ring current index SYM-H and the cross-polar cap potential (CPCP) in simulations. We show that generally the error distributions are wider for higher level of solar wind driving. Our results also show that the observing solar wind monitor distance from the Sun-Earth line and the phase front normal angle produce only minor effects on the error distributions, however, for oblique angles (<0.4) of the phase front normal there are noticable effects on the error distributions. Furthermore, we show that the results hold true also when using two magnetometer station recordings, one at subauroral and the other at auroral latitudes, which speak to the similarity of the error sources in local and global activity measures. These results are important elements in assessing the accuracy of the timing and magnitude of space weather events recorded on ground.

In this work, we focus on plasma discharges produced between two electrodes with a high potential difference, resulting in the ionization of the neutral particles supporting a current in the gaseous medium. At low currents and low temperatures, this process can create luminescent emissions: the glow and corona discharges. The parallel plate geometry used in Townsend’s (1900) theory lets us develop a theoretical formalism, with explicit solutions for the critical voltage effectively reproducing experimental Paschen curves. However, most discharge processes occur in non-parallel plate geometries, such as discharges between grains or ice particles in multiphase flows. Here, we propose a generalization of the classic parallel plate configurations to concentric spherical and coaxial cylindrical geometries in Earth, Mars, Titan, and Venus atmospheres. In a spherical case, a small radius effectively represents a sharp tip rod, while larger, centimeter-scale radii represent blunted tips. Similarly, in a cylindrical case, a small radius corresponds to a thin wire. We solve continuity equations in the gap and estimate a critical radius and minimum breakdown voltage that allows ionization of neutral gas and formation of a glow discharge. We show that glow coronæ form more easily in Mars’s low-pressure, CO2-rich atmosphere than in Earth’s high-pressure atmosphere. Addition- ally, we present breakdown criteria for Titan and Venus. We further demonstrate that critical voltage minima occur at 0.5 cm·Torr for all three investigated geometries, suggesting easier initiation around millimeter-size particles in dust and water clouds and could be readily extended to examine other multiphase flows with inertial particles.

Fires and droughts are important drivers of disturbance in Mediterranean forests. Despite this, there is a gap of knowledge of the effect of climate change and particularly the interaction of longer periods of drought with other disturbance processes in remnants of native forests. As the frequency of these events is expected to increase in the future, it is important for forest managers to understand recovery patterns and the response of vegetation to these interactions. The objective of this work is to quantify the effects of the interaction of drought and fires in the recovery of Mediterranean-type forests at a local scale in South America using field data, satellite images, and trend analysis. These forests have experienced significant reductions in their extension and fragmentation, and in recent years have been subjected to the longest drought since there are records and that occurred between 2010 and 2020. Using a time series of Landsat satellite images (1986-2020) and the fire registry of the National Forestry Corporation (CONAF) we evaluate the relationship between the Normalized Difference Vegetation Index (NDVI) and other vegetation indices with characteristics measured in the field to evaluate the recovery after a fire event. We quantify the temporal trends of the NDVI to discover the location, direction, and timing of the change. In addition, we evaluate the interaction of climate, soil, and topography by forest type. We observe that the NDVI recovery slope is less steep in burned areas in the periods after 2015, exacerbating in topographic conditions of northern exposure (of the southern hemisphere). Even for the time period analyzed, some areas were reported where recovery levels still do not show a significant positive trend. We also observed a difference in the recovery of areas that experienced high severity fires versus low or intermediate severity fires in a period of drought, the recovery of areas exposed to a high severity fire takes twice as long to recover. These results indicate that the vegetation recovery processes can be negatively affected by the drought that occurs before, during, and after fires. Our analysis identifies spatially explicit patterns of short- and medium-term trends in these “new” regimes of prolonged droughts and fires, providing insight into forecast warmer and drier weather conditions so that our results can serve as a general framework for the resource management of these highly stressed areas, which can be applied to similar Mediterranean ecosystems.

The relativistic (~500 keV–2 MeV) and ultra-relativistic (~> 2 MeV) electron three-belt structure can originate from the partial depletion of the preexisting outer belt and replenishment of the new belt without direct electron injections. These processes may be related to radial diffusion caused by ULF (Ultra-Low Frequency) waves and local acceleration by VLF (Very-Low Frequency) waves. In this study, we reported a three-belt event with several hundred keV electrons based on Arase observation. The partial depletion of the outer belt and subsequent formation of a new belt due to source and seed electron (~30–500 keV) injection may be the primary mechanisms responsible for the three-belt structure. This discovery showed that the three-belt structure might not be limited to relativistic and ultra-relativistic electrons. Our study provided evidence for the existence of the source and seed electron three-belt structure, which could help improve our understanding of the radiation belt configuration.

Ertel’s potential vorticity (PV) is an important quantity in atmospheric dynamics that succinctly encompasses the principles of mass, momentum, and energy conservation and is applicable to all scales of motion. In this paper, we describe the implementation of a PV diagnostics package into the atmospheric component of the Model for Prediction Across Scales (MPAS), a fully compressible nonhydrostatic global model that enables regional mesh refinement to convection-permitting resolutions and is highly suited for studies on multiscale process interactions and forecast error-growth dynamics. The version of the PV diagnostics package emphasized herein will be included in an upcoming MPAS release and significantly improves upon an original version that was introduced in MPAS v5.0. Specifically, this revised version enables the calculation of the full Eulerian PV budget at each time step Δt (i.e., the instantaneous budget) and the accumulation of PV tendencies throughout the model integration (i.e., the accumulated budget). Through the formulation of the discretized PV budget equation and global simulations conducted on a 15–3-km variable-resolution mesh, we demonstrate that the instantaneous PV budget closes down to machine roundoff in both single- and double-precisions. Further, we find that the PV budget computed using accumulated PV tendencies leads to a small source of residual that arises due to the inherent nonlinearity of PV, which leads to leads to mathematical inconsistencies between the discretized equation for calculating the PV budget over any arbitrary period longer than Δt and that which results from accumulating the PV tendencies themselves over successive time steps.

Using the data from Van Allen Probe A and B, we investigate rapid enhancements of relativistic electrons in the Earth’s outer radiation belt caused by the intense substorms (AEmax > ~ 900 nT) for 29 events from January 2013 to April 2015. These intense substorms may occur during the storm main phase or recovery phase. Based on the different substorm evolution characteristics, the intense substorms are divided into isolated substorm activities and continuous substorm activities. In this study, we set a criterion for rapid enhancements when the electron phase space densities (PSDs) for μ = 1096, 2290, and 3311 MeV/G increased by more than 2 times in 9 hours. In the time interval of 9 hours, the local acceleration of chorus waves is the dominant process for accelerating the seed populations (100s keV) up to MeV energies. Our statistical results show that enhanced chorus waves and seed electrons during the intense substorms are observed in the outer radiation belt. Continuous substorm activities can more rapidly (< 9 h) and efficiently accelerate relativistic electrons in the outer radiation belt than isolated substorm activity. During the intense substorms, MeV electron injections could contribute to rapid enhancements of relativistic electrons in the outer radiation belt. Our statistical study suggests that the intense substorms during geomagnetic storms have a significant effect on the rapid variations of relativistic electron dynamics.

The amount of aerosol is a key parameter modulating the cloud microphysics and its subsequent long-term impact on climate through Twomey (cloud albedo) effect and Albrecht (lifetime) effect. As the relative dispersion (ε; standard deviation divided by mean) of the cloud droplet size distribution is an important factor in controlling the droplet collision rate and precipitation, along with its relevance in cloud modeling, it would be valuable to study the influence of aerosol concentration (Na) on ε. The impact on ε from Na can be observed from two aspects: intra-cloud and inter-cloud correlation. The intra-cloud correlation may reveal the cloud microphysical processes that are affected by the local variability of aerosol concentration, whereas inter-cloud correlation sheds light onto how different background aerosol concentration affects the macrophysics of clouds under different meteorological settings. Past studies that investigated from these two aspects have shown inconsistent correlation between Na and ε. Hence, the objective of this study is to identify whether and how the Na affects ε, observed from these two aspects. In this study, to ensure statistical significance, we choose five in-situ campaign data sets that were collected in vastly different places around the world: VOCALS (Chilean west coast), MASE (California), POST (California, sampling emphasized near the cloud top), GoMACCS (Texas, emphasized on highly polluted areas), and ORACLES (Central African west coast). Surprisingly, we observe that both intra-cloud and inter-cloud Na-ε correlations are largely nonexistent, whether within individual campaigns or across campaigns. We also found that the intra-cloud correlation is instead pronounced only between cloud droplet concentration (Nd) and relative dispersion, suggesting that the cloud microphysics related to Nd and ε is not strongly influenced by Na but by other cloud processes. This strong (negative) correlation could also help models better predicting relative dispersion from droplet concentration to construct a more close-to-reality droplet size distribution.

Regional cycles of agricultural land expansion and abandonment have been common throughout history in many countries of the world. Following the cessation of agricultural practice, landscapes undergo the spontaneous process of ecological succession resulting in significant above and belowground changes over time. As agricultural lands are often severely depleted of soil carbon, they represent one of the land types with the highest potential to act as carbon sinks through the process of soil carbon sequestration. While best management practices for increasing soil carbon stocks through sustainable agriculture are understandably a key focus point in climate change research today, the lasting effect of the abandonment of agriculture on soil organic carbon has received relatively less attention. However, significant amounts of farmland have been abandoned across the globe in both developed and developing countries, especially over the last several decades. To better understand the ability of old agricultural lands to act as carbon sinks through time, this study compiles field and published data to perform a comprehensive meta-analysis on the impacts of this land use change on soil organic carbon dynamics. Using a chronosequence approach, three study sites in Catalonia, Spain, each with four fields representing different stages of ecological succession post-abandonment spanning roughly 60 years, were sampled at soil depths of 10, 20, and 30 cm. To determine soil carbon stocks at each site, bulk density samples were also collected. Samples were analyzed for organic carbon, nitrogen and pH. Additionally, published chrononsequence and paired-plot data from abandoned agricultural lands throughout the Mediterranean region were also compiled into a database to perform multiple regression analysis. Our findings are not only meant to test the hypothesis that abandoned fields can act as carbon sinks over time, but to also determine the rate of soil carbon stock increase and projected vulnerability in relation to a variety of environmental and land management variables, thereby highlighting the climate change mitigation value of an as of yet understudied global land use change.

The Arctic climate changes at a faster rate than the rest of the globe. Boundary-layer clouds may play an important role to this change. At temperatures below 0°C, mixed-phase clouds exist and their phase and longevity is influenced by the abundance of ice crystals, which in turn is a function of aerosols serving as ice nucleating particles (INPs). Previous in-situ studies suggested a local source of INPs due to biological activity over open ocean. Here we investigate ice crystal concentrations in clouds below 2km at a large scale, by exploiting a newly-developed dataset - DARDAR-Nice - retrieved from active satellite remote sensing. The dataset spans from 2006-2016. Contrary to previous expectation, we find that at a given latitude and temperature, there are more ice crystals over sea ice than over open ocean. This enhancement is particularly found in clouds south of 70°N, but also at temperatures between 0 and -10°C.

Brine systems in Europa’s ice shell have been hypothesized as potential habitats that could be more accessible than the sub-ice ocean. We model the distribution of sub-millimeter-scale brine pockets in Europa’s ice shell. Through examination of three habitability metrics (water activity, ionic strength, salinity), we determine that brine pockets are likely not geochemically prohibitive to life as we know it for the chloride and sulfate-dominated ocean compositions considered here. Brine volume fraction is introduced as a novel habitability metric to serve as a proxy for nutrient transport and recycling—because of its role in governing permeability—and used to define regions where nutrient-open, nutrient-closed, and relict habitats are stable. Whereas nutrient-closed habitats could exist wherever brine is stable, nutrient-open habitats are confined to meter-scale regions near the ice-ocean interface where freezing is occurring. This classification scheme can help guide future life-detection missions to ocean worlds.

Despite many studies on seafloor hydrothermal systems conducted to date, the generation mechanism of seafloor massive sulfide (SMS) deposits is not yet fully understood. To elucidate this mechanism, this study clarifies the three-dimensional regional temperature distribution and fluid flow of a seafloor hydrothermal system of the Iheya North, middle Okinawa Trough. Lateral flow and boiling of hydrothermal fluids below the seafloor were the main features found by the simulation, leading to an interpretation of two-layered SMS deposit generation as follows. Hydrothermal fluids discharging from black smokers first formed the upper SMS deposits on the seafloor. Caprocks formed below the seafloor, and the above-mentioned occurrences were then induced under the caprocks. In the present system, vapor-rich hydrothermal fluids poor in metals are discharged from the vents as white smokers, whereas liquid-dominated hydrothermal fluids rich in metals flow laterally below the caprocks, forming lower SMS deposits tens of meters below the seafloor.

Climate change and nitrogen (N) pollution are altering biogeochemical and ecohydrological processes in dryland watersheds, increasing N export, and threatening water quality. While simulation models are useful for projecting how N export will change in the future, most models ignore biogeochemical “hotspots” that develop in drylands as moist microsites become hydrologically disconnected from plant roots when soils dry out. These hotspots enable N to accumulate over dry periods and rapidly flush to streams when soils wet up. To better project future N export, we developed a framework for representing hotspots using the ecohydrological model RHESSys. We then conducted a series of virtual experiments to understand how uncertainties in model structure and parameters influence N export. Modeled export was sensitive to the abundance of hotspots in a watershed, increasing linearly and then reaching an asymptote with increasing hotspot abundance. Peak streamflow N was also sensitive to a soil moisture threshold at which subsurface flow from hotspots reestablished, allowing N to be transferred to streams; it increased and then decreased with an increasing threshold value. Finally, N export was generally higher when water diffused out of hotspots slowly. In a case study, we found that when hotspots were modeled explicitly, peak streamflow nitrate export increased by 29%, enabling us to better capture the timing and magnitude of N losses observed in the field. This modeling framework can improve projections of N export in watersheds where hotspots play an increasingly important role in water quality.

The Atlantic Hurricane season and the European Windstorm season are found to be co-related in a seasonal forecast model. The probability of extremes occurring in both seasons is compared to the probability of extremes in each season being independent of one another. An above average Atlantic hurricane season is followed by an above average European windstorm season less often than if they were independent, consistent across three intensity measures. The El Niño Southern Oscillation is found to be in the positive (negative) phase when Hurricane activity is suppressed (enhanced) and European windstorm activity is enhanced (suppressed). A clear extra-tropical response in the seasonal forecast model to El Niño/La Niña provides a probable pathway for the observed co-relation between the extreme event seasons. This result has important predictability implications for both the actuarial and seasonal forecasting communities.

The hazard of wildfires in Chile is latent, especially in densely populated urban centers that are embedded in a Wildland-Urban Interface (WUI). As an example of that is Concepción which is the second most populated conurbation in Chile. This kind of hazard is strengthened by development models that end up conflicting as is the case of the Chilean Forest Model (MFC) and the Urban Development Model (MDU). Both models are based on liberalized economic principles and spatial growth that have been contributed to the construction of wildfire risk scenarios. In this work, the complexity of the wildfire hazard in the Metropolitan Area of Concepción is addressed. LANDSAT-8 and ASTER satellite images are used to evaluate the danger of wildfires. The anthropic factors (soil cover, road network, controlled burning points, camping), and natural factors (topography, flammability, insolation, altitude) that influence the hazard are analyzed. To corroborate the detected hazard zones and WUI according to satellite data, the foci of fires provided by the forestry management government agency (CONAF) are also spatialized. Finally, the main structural agents that can contribute to wildfire hazard in the area are discussed, specifically: the closeness between land cover associated with monocultives and the areas resulting from urban expansion; and the economic incentives given by the government that have increased the area of the plantations and the housing area.

In our current system, research assessment and reward are weighted heavily towards scientific inputs and outputs, and research impact is measured in funding dollars awarded and research articles produced. The value of science, however, extends well beyond contributions to the research activity itself. ‘Project Redefining Recognition’ is a cross-society initiative which seeks to develop a shared future vision and clear set of actions across the Earth, Space, and Environmental Sciences to expand research assessment to explicitly include, recognize, and reward actions that advance open science, broad communication and public engagement.This presentation will look closely at the ways in which Society partners participating in ‘Project Redefining Recognition’ are supporting their communities in sharing and applying their science, and the challenges and opportunities in our current system to recognize and reward those efforts.

TEC maps show the intensification and spread of the 11 May 2024 extreme auroral event across the continental US over a 20-minute interval. All sky camera imagery indicates that the TEC enhancement closely matches the westward and equatorward expansion of strong red aurora. Coincident with auroral breakup, individual receiver/satellite data sets show sharp bursts of greatly elevated TEC 50 TECu above background.

This article is a commentary about the state of Integrated, Coordinated, Open, and Networked (ICON) principles (Goldman et al., 2021) in Space Physics and Aeronomy and a discussion on several scopes and limitations to implementing them. The commentary focuses on the basic introduction and brief literature survey (Section 1); possibilities of implementation of ICON in Space Physics and Aeronomy (Section 2) and limitations or challenges in this field with possible solutions using ICON principles (Section 3). The Space Physics and Aeronomy section of the American Geophysical Union (AGU) comprises the interactions between solar wind, Interplanetary Magnetic Field (IMF) and different planetary magnetospheres and ionospheres. The section also deals with solar physics, mechanisms behind existence of solar magnetic fields, and evaluations of high and low speed solar winds. This field is a collection of different interdisciplinary subtopics, making this an excellent example of integrated research. Similar and transparent methodologies are adopted to solve problems all over the world which shows a coordinated approach of research. Freely available data from different space agencies and universities are also great assets for this domain which supports open research. The scopes of possible networked research with mutual benefits are also highlighted. Examples of ICON-based international collaborations and support mechanisms towards young scientists are elaborated which are helpful to mitigate limitations in this domain.

Environmental spatial planning of urban coastal regions is critical for sustainable development and designing of coastal resilience in developing countries. The process of environmental spatial planning in coastal regions involves classification of areas into different categories by retaining the synergy between environmental conservation and urban development. Existing coastal regulations for classification of coastal regions in India are based on the subjective approaches. In this study, a quantitative approach is developed by coupling geospatial science and multicriteria decision making in which we prioritized the different physical coastal features quantitatively based on the environmental sensitivity of particular physical coastal feature for the integrated natural coastal ecosystem. Afterwards, these quantitative ranking values of coastal features are combined with linear weighting schemes to derive distinct categories of urban coastal regions spatially, where each category embodies the unique environmental sensitivity. A final map indicating the environmental sensitivity of different coastal regions is prepared. Uncertainty analysis for different weighting schemes was performed to assess the robustness of the developed approach. Finally, we carried out a comparative assessment of the prevailing method of coastal area classification being used by planning authorities and the application of this quantitative approach along the coast of Mumbai, India. Results of comparison clearly demonstrate the effectiveness of the quantitative approach for environmental spatial planning in urban coastal regions. Essentially, the method is found useful for highlighting the locations which need special consideration by planning authorities for the application of inclusive coastal management measures. Furthermore, this approach is modular and scalable, which will facilitate the environmental spatial planning of urban coastal regions based on scientific principles in different coastal cities in developing countries.