Understanding the stress distribution around shallow magma chambers is vital for predicting eruption sites and magma propagation directions. To achieve accurate predictions, comprehensive insight into the stress field surrounding magma chambers and near the surface is essential. Existing stress models for magma chamber inflation often assume a homogenous elastic half-space or a heterogeneous crust with varying mechanical properties in horizontal layers. However, as many volcanoes have complex, non-horizontal, and heterogeneous layers, we enhance these assumptions by considering mechanically diverse layers with varying dips. We employed the Finite Element Method (FEM) to create numerical models simulating two chamber shapes: a circular form and a sill-like ellipse. The primary condition was a 10 MPa excess pressure within the magma chamber, generating the stress field. Layers dips by 20-degree increments, with differing elastic moduli, represented by stiffness ratios (EU/EL) ranging from 0.01 to 100. Our findings validate prior research on heterogeneous crustal modeling, showing that high stiffness ratios disrupt stress within layers and induce local stress rotations at mismatched interfaces. Layer inclination further influences stress fields, shifting the location of maximum stress concentration over varying distances. This study underscores the significance of accurately understanding mechanical properties, layer dip in volcanoes, and magma chamber geometry. Improving predictions of future eruption vents in active volcanoes, particularly in the Andes with its deformed, folded, and non-horizontal stratified crust, hinges on this knowledge. By expanding stress models to incorporate complex geological structures, we enhance our ability to forecast eruption sites and the paths of magma propagation accurately.

We report results of our analysis of a solar wind reconnecting current sheet (RCS) and its solar wind magnetic hole observed on 20 November 2018. In the solar wind, the normal vector to the current sheet plane makes an angle of 32° with the Sun-Earth line. A combination of tilted current sheet plane and foreshock effects cause an asymmetric interaction with the bow shock, such that the structure arrives at the quasi-perpendicular side of the bow shock before the quasi-parallel side. The solar wind flow slowdown and deflection during the bow shock crossing significantly disrupt the reconnection exhausts within the RCS. Unlike localized magnetosheath jets, the solar wind RCS has a global impact on the bow shock and the magnetopause. Plasma flow deflection in the magnetosheath also increases with the passage of the RCS. The magnetic field strength inside the magnetic hole decreases by ~69 percent in the solar wind, with a similar depression rate observed inside the magnetosheath due to this structure. The ion density and temperature both increase within the current sheet to form a roughly pressure balanced structure. Field rotation and change in the dynamic pressure during this event modify the reconnection zones at the magnetopause and cause an inward motion of this boundary.

Jupiter displays many distinct auroral structures, among which auroral dawn storms and auroral injections are often observed contemporaneously. However, it is unclear if the contemporaneous nature of the observations is a coincidence or part of an underlying physical connection. We show six clear examples from a recent Hubble Space Telescope campaign (GO-14634) that each display both auroral dawn storms and auroral injection signatures. We found that these conjugate phenomena could exist during intervals of either relatively low or high auroral activity, as evidenced by the varied levels of total auroral power. In-situ observations of the magnetosphere by Juno, show a strong magnetic reconnection event inside of 45 Jupiter Radii (RJ) on the predawn sector, followed by two dipolarization events within the following two hours, coincident with the auroral dawn storm and auroral injection event. We therefore suggest that the auroral dawn storm is the manifestation of magnetic reconnection in the dawnside magnetosphere. The dipolarization region mapped to the auroral injection, strongly suggesting that this was associated with the auroral injection. Since magnetic reconnection and dipolarization are physically connected, we therefore suggest that the often-conjugate auroral dawn storm and auroral injection events are also physically connected consequences.

Radiation-topography interaction plays an important role in the surface energy balance over the Tibetan Plateau (TP). However, the impacts of such interaction over the TP on climate locally and in the Asian regions remain unclear. This study uses the Energy Exascale Earth System Model (E3SM) to evaluate the regional and teleconnected impacts of radiation-topography interaction over the TP. Land-atmosphere coupled experiments show that topography regulates the surface energy balance, snow processes, and surface climate over the TP across seasons. Accounting for radiation-topography interaction overall improves E3SM’s performance in simulating surface climate. The winter cold bias in air temperature decreases from -4.48 K to -3.70 K, and the wet bias in summer precipitation is mitigated in southern TP. The TP’s radiation-topography interaction further reduces the South and East Asian summer precipitation biases. Our results demonstrate the topographic roles in regional climate over the TP and highlight its teleconnected climate impacts.

The North Anatolian Fault (NAF) has produced numerous major earthquakes. After decades of quiescence, the Mw 6.8 Elazig earthquake (January 24, 2020) has recently reminded us that the East Anatolian Fault (EAF) is also capable of producing significant earthquakes. To better estimate the seismic hazard associated with these two faults, we jointly invert Interferometric Synthetic Aperture Radar (InSAR) and GPS data to image the spatial distribution of interseismic coupling along the eastern part of both the North and East Anatolian Faults. We perform the inversion in a Bayesian framework, enabling to estimate uncertainties on both long-term relative plate motion and coupling. We find that coupling is high and deep (0-20 km) on the NAF and heterogeneous and superficial (0-5 km) on the EAF. Our model predicts that the Elazig earthquake released between 200 and 250 years of accumulated moment, suggesting a bi-centennial recurrence time.

Circulation in the Southern Ocean is unique. The strong wind stress forcing and buoyancy fluxes, in concert with the lack of continental boundaries, conspire to drive the Antarctic Circumpolar Current replete with an intense eddy field. The effect of Southern Ocean eddies on the ocean circulation is significant – they modulate the momentum balance of the zonal flow, and the meridional transport of tracers and mass. The strength of the eddy field is controlled by a combination of forcing (primarily thought to be wind stress) and intrinsic, chaotic, variability associated with the turbulent flow field itself. Here, we present results from an eddy-permitting ensemble of ocean model simulations to investigate the relative contribution of forced and intrinsic processes in governing the variability of Southern Ocean eddy kinetic energy. We find that variations of the eddy field are mostly random, even on longer (interannual) timescales. Where correlations between the wind stress forcing and the eddy field exist, these interactions are dominated by two distinct timescales – a fast baroclinic instability response; and a multi-year process owing to feedback between bathymetry and the mean flow. These results suggest that understanding Southern Ocean eddy dynamics and its larger-scale impacts requires an ensemble approach to eliminate intrinsic variability, and therefore may not yield robust conclusions from observations alone.

The eruption of the Hunga Tonga – Hunga Ha’apai (HTHH) volcano on January 15, 2022 injected large amounts of water vapor directly into the stratosphere. While normal background levels of stratospheric water vapor are not detectable in radio occultation (RO) measurements, effects of the HTHH eruption are clearly observed as anomalous refractivity profiles from COSMIC-2, suggesting the possibility of detecting the HTHH water vapor signal. To separate temperature vs. water vapor effects on refractivity, we use co-located temperature observations from the Microwave Limb Sounder (MLS) to constrain a simplified water vapor retrieval. Our results show enhancements of water vapor up to ~1500-2300 ppmv in the stratosphere (~29-33 km) in the days following the HTHH eruption, with propagating patterns that follow the dispersing volcanic plume. The stratospheric water vapor profiles derived from RO are in reasonable agreement with limited radiosonde observations over Australia.

A document by Zuhriddin Juraev. Click on the document to view its contents.

Clouds have been recognized to enhance surface melt on the Greenland Ice Sheet (GrIS). However, quantitative estimates of the effects of clouds on the GrIS melt area and ice-sheet-wide surface mass balance are still lacking. Here we assess the effects of clouds with the state-of-the-art regional climate model NHM-SMAP forced by the JRA-55 reanalysis [1], conducting a numerical sensitivity test in which adiabatic atmospheric conditions as well as zero cloud water/ice amounts are assumed (i.e., clear-sky conditions), although the precipitation rate is the same as in the control all-sky simulation. By including or excluding clouds, we quantify time-integrated feedbacks for the first time. We find that clouds were responsible for a 3.1%, 0.3%, and 0.7% increase in surface melt extent (of the total GrIS area) in 2012, 2013, and 2014, respectively. During the same periods, clouds reduced solar heating and thus daily runoff by 1.6, 0.8, and 1.0 Gt day–1, respectively: clouds did not enhance surface mass loss. In the ablation areas, the presence of clouds results in a reduction of downward latent heat flux at the snow/ice surface so that much less energy is available for the surface melt, which highlights the importance of indirect time-integrated feedbacks of cloud radiative effects. Reference [1] Niwano et al. (2018) NHM-SMAP: Spatially and temporally high resolution non-hydrostatic atmospheric model coupled with detailed snow process model for Greenland Ice Sheet. The Cryosphere, 12, 635-655, doi:10.5194/tc-12-635-2018.

The ROTI index based on the variation of the TEC is used to detect and characterize the ionospheric irregularities. In the present work, we present a comparative study of five different methodologies to ROTI calculation in order to evaluate the most suitable for the Brazilian region. This was performed over three GNSS stations at different latitudes: São Luís (SALU, 2°31′ S, 44°16′ W; dip: -6.60°) that is located near the dip equator; Cachoeira Paulista (CHPI, 22°40’ S, 44°59’ W; dip: -35.99°) which set close to the southern crest of the EIA at low latitude); and Santa Maria (SMAR, 29° 41′ S, 53° 48′ W, dip: -43.51°) a low-to-mid latitude station close to center of the SAMA region. The period of analysis covered January and December 2015. Our results show that only one out of the five techniques proposed seems to be appropriated for ROTI construction in the Brazilian sector. Our results are supported by comparison of the ROTI with TEC maps obtained over Brazil, ionograms acquired at Fortaleza (FZA0M), SALU, and CHPI ionosonde stations, and All-Sky imagers collected at the São João do Cariri, and CHPI. In addition, we were able to observe the typical irregularities of the Brazilian ionosphere by using the ROTI which we have classified as EPB.

Wildfires and land use play a central role in the long-term carbon (C) dynamics of forested ecosystems of the United States. Important processes include fire suppression during the 20th century and a recent increase in fire activity, partly due to climatic extreme events. Although the historical fire narrative in the U.S. is well understood, its links to changes in forest biomass, resource use and consumption remain understudied. We reconstruct long-term trends in biomass burned, and biomass use by humans, integrating various data sources at different scales (national scale 1926-2017, regional level 1941-2017). We investigate the linear correlation of wildfires and forest biomass C stocks in comparison to forest uses, i.e., the extraction of woody biomass and forest grazing, and potential net primary production (NPPpot). During the 20th century, the reduction in burned biomass and increase in NPPpot coincide with forest regrowth in the Eastern U.S., allowing for increased wood harvest. Only in the Western U.S. these dynamics are less pronounced, indicating that forest fires and biomass harvest were less decisive factors for forest C stock developments in this section. In recent decades, linkages between forest change and wildfires are less straight-forward in all regions, indicating that past fire suppression levels are less efficient in present-day forests. Instead, the reduction of harvest in 3 of 4 regions was correlated to stock increase. We conclude that under changing climate, present-day fire and forest management practices might be unsuitable for ensuring both additional forest C sink potential and expanded wood use.

Solar eruptions cause geomagnetic storms in the near-Earth environment, creating spectacular aurorae visible to the human eye and invisible dynamic changes permeating all of geospace. Just equatorward of the aurora, radars and satellites often observe intense westward plasma flows called subauroral polarization streams (SAPS) in the dusk-to-midnight ionosphere. SAPS occur across a narrow latitudinal range and lead to intense frictional heating of the ionospheric plasma and atmospheric neutral gas. SAPS also generate small-scale plasma waves and density irregularities that interfere with radio communications. As opposed to the commonly observed duskside SAPS, intense eastward subauroral plasma flows in the morning sector were recently discovered to have occurred during a super storm on 20 November 2003. However, the origin of these flows termed “dawnside SAPS” could not be explained by the same mechanism that causes SAPS on the duskside and has remained a mystery. Through real-event global geospace simulations, here we demonstrate that dawnside SAPS can only occur during major storm conditions. During these times the magnetospheric plasma convection is so strong as to effectively transport ions to the dawnside, whereas they are typically deflected to the dusk by the energy-dependent drifts. Ring current pressure then builds up on the dawnside and drives field-aligned currents that connect to the subauroral ionosphere, where eastward SAPS are generated. The origin of dawnside SAPS explicated in this study advances our understanding of how the geospace system responds to strongly disturbed solar wind driving conditions that can have severe detrimental impacts on human society and infrastructure.

Global biodiversity is lost at an unprecedented ratio driven by climate change and land-use change. However, little is known about the combined effects of climate and land-use change on future biodiversity on a global scale. Here, we first build the indices of land-use naturalness and the land-use intensity to depict the land-use change on a global scale. By using random forest models, we establish the empirical relationship to quantify this combined effect and further predict future changes of terrestrial vertebrates can be predicated under the Shared Socio-economic Pathways (SSPs). The relative contributions of climate change and land-use change to terrestrial vertebrates are finally separated through quantitative analysis. We find that future land-use change contributes to 48.52% of richness changes, slightly lower than that of climate change. Nearly 45.82% of the Earth’s land will suffer richness losses of terrestrial vertebrates by 2050 even under the middle-high scenario of SSP3, mainly located at low latitudes, such as Southeast Asia, Latin America and sub-Saharan Africa. Moreover, the analysis at the country-specific level reveals that nearly half of the world’s countries would experience species richness loss in the nearby future. These findings make clear that both climate change and land-use change pose comparably significant threats to global biodiversity. More immediate attention and effective actions are urgently needed from local governments for vulnerable regions.

A document by Daniel Michael Gilford, PhD. Click on the document to view its contents.

The objective of the study is to assess the familiarity and the use of preprint servers by researchers to share their work. Data collection was conducted by Wiley through an online survey in May and June 2020. 44% of survey respondents (out of a total of 1,905) indicated they are not at all familiar with preprint servers. Most of the researchers surveyed indicated multiple reasons to upload their research on a preprint server. The most popular reasons were to get feedback on their work (46%) and for faster dissemination of their research (45%). 55% of respondents indicated that they have never uploaded any research outputs on preprint servers. This study and our key findings show that there is a need to share the benefits of preprints and to explain to researchers how servers work.

We investigate 85 129 MODIS satellite active fire events from 2007 to 2015 in the Niger Delta of Nigeria. The region is the oil base for Nigerian economy and the hub of oil exploration where oil facilities (i.e. flowlines, flow stations, trunklines, oil wells and oil fields) are domiciled, and from where crude oil and refined products are transported to different Nigerian locations through a network of pipeline systems. Pipeline and other oil facilities are consistently susceptible to oil leaks due to operational or maintenance error, and by acts of deliberate sabotage of the pipeline equipment which often result in explosions and fire outbreaks. We used ground oil spill reports obtained from the National Oil Spill Detection and Response Agency (NOSDRA) database (see www.oilspillmonitor.ng) to validate MODIS satellite data. NOSDRA database shows an estimate of 10 000 spill events from 2007 - 2015. The spill events were filtered to include largest spills by volume and events occurring only in the Niger Delta (i.e. 386 spills). By projecting both MODIS fire and spill as ‘input vector’ layers with ‘Points’ geometry, and the Nigerian pipeline networks as ‘from vector’ layers with ‘LineString’ geometry in a geographical information system, we extracted the nearest MODIS events (i.e. 2192) closed to the pipelines by 1000m distance in spatial vector analysis. The extraction process that defined the nearest distance to the pipelines is based on the global practices of the Right of Way (ROW) in pipeline management that earmarked 30m strip of land to the pipeline. The KML files of the extracted fires in a Google map validated their source origin to be from oil facilities. Land cover mapping confirmed fire anomalies. The aim of the study is to propose a near-real-time monitoring of spill events along pipeline routes using 250 m spatial resolution of MODIS active fire detection sensor when such spills are accompanied by fire events in the study location.

Solar Energetic Particles (SEP) are one of the major sources of the martian radiation environment. It is important to understand the SEP-induced martian radiation environment for future human habitats on Mars. Due to the lack of global intrinsic magnetic field, SEPs can directly propagate through and interact with its atmosphere before reaching the surface and subsurface of Mars. Since Mars has many high mountains and low-altitude craters where the atmospheric thickness can be more than 10 times different from one another, the SEP-resulted surface radiation level may be very different from one location to another. We thus consider the influence of the atmospheric depths on the martian radiation levels including the absorbed dose, dose equivalent, and (human-)body effective dose induced by SEPs at varying heights above and below the martian surface. The state-of-the-art Atmospheric Radiation Interaction Simulator based on GEometry And Tracking Monte-Carlo method (AtRIS/GEANT4) has been employed for simulating particle interactions with the martian atmosphere and terrain. We find that even the thinnest martian atmosphere reduces radiation dose from that in deep space by at least 65\%, and the shielding effect increases for denser atmosphere. Furthermore, we present a method to quickly forecast the SEP-induced radiation in different regions of Mars with different surface pressures.

A document by Raf Antwerpen. Click on the document to view its contents.