Lava tubes can offer protection for human crews and their equipment on other solar system bodies, in particular from radiation threats and extreme surface temperatures. Developing strategies to survey regions of other terrestrial bodies (such as the Moon or Mars) for tubes suitable for potential habitation will likely become an important part in planning future space exploration projects. A variety of surface geophysical techniques, such as ground penetrating radar (GPR) have the potential to help recognize and map tubes. GPR shows promise for providing high resolution information on tube geometries. To investigate GPR’s capacity and limitations, we use GPR, as well as comparative methods of seismic and magnetic surveys, in conjunction with LiDAR mapping of tube interiors at the Lava Beds National Monument (LBNM) in California, USA. LBNM offers a wide variety of tube geometries and textures. We have collected 2D GPR profiles and small 3D GPR grids (of parallel 2D lines) with antenna frequencies of 100 and 200 MHz on four lava tubes with different geometries, textures and at different depths. Challenges in recovering tube geometries include wave scattering in fractured rock covering tubes, irregular and “drippy” ceilings and walls, and blocky floors. Our primary results show that the top of the LBNM tubes can generally be resolved in the GPR data, while resolving the bottom is more challenging. The utility of various GPR processing techniques can be directly assessed by comparing resolved GPR images against the LiDAR-measured tube geometries.

We present a new statistical interpolation method to estimate fire perimeters from Active Fires detection data from satellite-based sensors, such as MODIS, VIIRS, and GOES-16. Active Fires data is available at varying temporal and spatial resolutions (375m and up several times a day, or 2km every 15 minutes), but pixels are often missing due to clouds or incomplete data. The question arises how to fill in the missing pixels, which is useful, e.g., to distinguish in an automated fashion between a single large fire visible as separate clusters of detection pixels because of cloud cover, and separate fires. We process the satellite data into information when was fire first detected at a location, and when was clear ground without fire detected at the location last. We are then looking for the most likely fire arrival time, which satisfies such constraints. Models at various levels of complexity are possible. Our base assumption in the absence of information to the contrary is that the fire keeps progressing without change, which is expressed as the assumption that the gradient of the fire arrival time is approximately constant. The method is then formulated as an optimization problem to minimize the total change in the gradient of the fire arrival time subject to the constraints given by the data. We consider probabilistic interpretations of the method as well as extensions, such as soft constraints to accommodate the uncertainty of the detection and the uncertainty where exactly the fire is within the pixel. This method is statistical in nature and it does not use fuel information or a fire propagation model. The results are demonstrated on satellite observations of large wildfires in the U.S. in summer 2018 and compared with ground and aerial data.

Global maps of maximum bottom particle concentration, benthic nepheloid layer thickness, and integrated particle mass in benthic nepheloid layers (BNL) based on 2412 global profiles collected using the Lamont Thorndike nephelometer from 1964-1984 are compared with maps of those same properties compiled from 6,392 global profiles measured by transmissometers from 1979 to 2016. Outputs from both instruments were converted to particulate matter concentration (PM). We present here a visual global comparison of the location and intensity of BNLs measured with these two independent instruments over slightly overlapping decadal time periods and combine the data sets in order to expand the time scale of global in situ measurements of BNLs, and to gain insight about the factors creating/sustaining BNLs. The similarity between general locations of high and low particle concentration BNLs during the two time periods indicates that the driving forces of erosion and resuspension of bottom sediments are spatially persistent during recent decadal time spans, though in areas of strong BNLs, intensity is highly episodic. Topography and well-developed current systems play a role. These maps can be used to better understand deep ocean sediment dynamics, linkage with upper ocean dynamics, the potential for scavenging of adsorption-prone elements near the seafloor, and provide a comprehensive comparison of these data sets on a global scale. During both time periods, BNLs are weak or absent in most of the Pacific, Indian, and Atlantic basins away from continental margins. High surface eddy kinetic energy is associated with the Kuroshio Current east of Japan. Both data sets show weak BNLs south of the Kuroshio, but no transmissometer data have been collected beneath the Kuroshio itself. Sparse nephelometer data show moderate BNLs just north of the Kuroshio Extension, but with much lower concentrations than beneath the Gulf Stream. Strong BNLs are found in areas where eddy kinetic energy in overlying waters, mean kinetic energy near bottom, and energy dissipation within the bottom boundary layer are high. Areas of strongest BNLs include the Western North Atlantic, Argentine Basin, areas around South Africa tied to the Agulhas Current region, and somewhat random locations in the Antarctic Circumpolar Current of the Southern Ocean.

The Mercury’s magnetic fields are known to be weaker than that predicted by conventional dynamo models. In order to explain the Mercury’s weak magnetic field, several models are proposed (Stanley and Glatzmaier, 2010). One of them is the thermoelectric dynamo, which drive the dynamo via the thermoelectric force (Stevenson, 1987). The field strength is proportional to the relative Seebeck coefficient between the core and the mantle. Because the Seebeck coefficient of insulators is more than one order larger than that of metals, the Seebeck coefficient of Mercury’s mantle is the central parameter. Therefore, we investigated the Seebeck coefficient of mantle minerals from the first-principles calculations. The structure relaxation and band structure calculations were conducted by using the Quantum ESPRESSO package. The bandgap energy was calibrated by means of the quasiparticles self-consistent GW (QSGW) approximation adopted in the ecalj package. The Seebeck coefficient was calculated via the Boltzmann equation implemented in the BoltzTraP package. The results indicate that the Seebeck coefficient of forsterite with a small amount of dopant exhibit comparable to that previously thought (|S| ~ 1000 μV/K). This value may constrain the upper limit. The Mercury’s mantle may contain ~3wt% FeO (Robinson and Taylor, 2001). The Fe substitution and O vacancy act as donor, which is predicted to reduce the Seebeck coefficient, significantly. The field strength also depends on the electrical conductivity of the mangle. Recent high pressure experiments suggest that the electrical conductivity of the Earth’s mantle is ~ 10^-2 Sm. Considering the both of the Seebeck coefficient and the electrical conductivity of mantle material, the field strength is calculated to be ~ 0.1 nT, which is significantly weaker than the observed value of 300 nT. Therefore, we conclude that the thermoelectric dynamo cannot generate the Mercury’s magnetic fields.

Ambient air quality (AQ) is an environmental and socio-economic issue increasingly decisive in the sustainable development of a territory. At low density territories of Continental Portugal, a good AQ can contribute to the development of various sectors of activity like health and wellness tourism and organic farming, affecting positively the socio-economic situation. The main goal of this study was to build information on ozone concentration in ambient air for the present and on a climate change scenario. The territory case study – the “cerne do Entre-Norte-e-Centro”–, consists of seven municipalities: Aguiar da Beira, Castro Daire, Moimenta da Beira, Sátão, Sernancelhe, Tarouca and Vila Nova de Paiva. Geographically it belongs to the North and Centre of Mainland Portugal (NUTS II) and the Douro and Dão-Lafões subregions (NUTS III). In this area (151.195 hectares) there is not any station of AQ monitoring. Data provided by the Portuguese Air Quality Network was analysed to determine the spatio-temporal evolution of different pollutants covered by actual Portuguese legislation, with special focus on ozone and nitrogen dioxide. This information was compared with the data provided by Copernicus Atmosphere Monitoring Service. It was build hazard and vulnerability charts as well as the chart of risk to the territory under study. This knowledge will improve the decision-making process in terms of public politics. In addition it contributes to an increased visibility and attractiveness of this area, as a tourism destination through environmental differentiation in this endogenous resource.

Weather extremes have gained great attention to the general public and policy makers recently. Extratropical cyclones, frontal systems and atmospheric rivers are central components of weather over mid latitudes. These phenomena are associated with compound weather conditions, including dramatic changes in temperature, wind and extreme precipitation. In fact, wind extremes and heavy precipitation events occurring in the winter over land in the mid latitudes are mostly associated with extratropical cyclones. It is well known that the Iberian Peninsula, due to its location, is prone to the occurrence of these compound extreme events and associated hazards (Liberato et al., 2013; 2014). In this project our aim is to explore the usage of expert crowdsourcing for annotating weather systems associated to compound hydrometeorological extreme events over the Euro-Atlantic region, so automated methods and computational resources can be optimized in a future hybrid approach. This approach allows a sharing of lessons learned and a common design ground. Atmospheric phenomena annotation aims at bringing new dimensions to current big data problems in climate and atmospheric sciences. Today big data full potential in weather and climate science domain is still restricted by the poor semantic knowledge of data gathered and the inability to correlate data with other domains. Acknowledgements: This work is supported by the Portuguese Science and Technology Foundation (Fundação para a Ciência e Tecnologia – FCT), under the projects UID/GEO/50019/2013 – Instituto Dom Luiz and CMU/CS/0012/2017 – “eCSAAP - expert Crowdsourcing for Semantic Annotation of Atmospheric Phenomena”. Liberato et al. 2013 Nat. Hazards Earth Syst. Sci., 13:2239-2251 doi: 10.5194/nhess-13-2239-2013 Liberato 2014 Weather and Climate Extremes, 5-6: 16-28 doi: 10.1016/j.wace.2014.06.002

Ambient air quality is an increasingly prominent environmental factor within the sustainable development of an urban territory, due to a growing awareness on the harmful and transboundary nature of its effects. The main objective of this work was to build knowledge on the quality of ambient air and climate, in the metropolitan area of Brasília/DF, the capital of Brazil. The experimental procedure was designed so as to allow the response to this objective: a) appealed to the temporal series of pollutants measured in the existing regulatory network in this urban area, in the last 10 years; and the data from the National Institute of Meteorology – NIMET; b) correlated statistically all data analyzed. We found a poor spatial coverage of the network for monitoring of ambient air quality in urban area. The only pollutants measured continuously in Brasília/DF are respirable particles (PM10), which is manifestly insufficient, taking into account the different types of sources found. In this way, it is crucial to raise the level of knowledge about the quality of the resource “air” in this city to become more effective and efficient management. The information now obtained constitutes the basis for developing an urban strategy to increase the resilience of populations potentially affected by this problem, i.e., aims to guide the process of ambient air quality management of this Brazilian city to enable you to hold (when good) or, in other cases are initiated investigations/actions that improve.

The latest launched Sentinel satellite mission, the Sentinel-5 Precursor (Sentinel-5P) is one of the European Space Agency’s (ESA) new mission family – Sentinels. The sole payload on Sentinel-5P is the TROPspheric Monitoring Instrument (TROPOMI), which is a nadir-viewing 108 degree Field-of-View push-broom grating hyperspectral spectrometer, covering the wavelength of ultraviolet-visible (270 nm to 495 nm), near infrared (675 nm to 775 nm), and shortwave infrared (2305 nm - 2385 nm). Sentinel-5P is the first of the Atmospheric Composition Sentinels and is providing measurements of ozone, NO2, SO2, CH4, CO, formaldehyde, aerosols and cloud at high spatial, temporal and spectral resolutions. The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is one of the 12 Distributed Active Archive Centers (DAACs) within NASA’s Earth Observing System Data and Information System (EOSDIS). The GES DISC archives and supports over a thousand data collections in the Focus Areas of Atmospheric Composition, Water & Energy Cycles, and Climate Variability. Under the End User License Agreement between NASA and ESA, GES DISC is curating TROPOMI Level-1B and Level-2 products and providing information services through enhanced tools and services that offer facile solutions for complex Earth science data and applications. This presentation will demonstrate up-to-date TROPOMI products including earthview radiance, solar irradiance, aerosol layer height, Carbon Monoxide, Nitrogen Dioxide, and cloud, as well as easy ways to access, visualize and subset TROPOMI data.

If a kick is not detected and circulated properly out of the wellbore with heavier mud weight, it leads to blowouts. In this case, reservoir fluids gush out of the well uncontrollably without restriction leading to loss of control. This may lead to fractures initiating in the post-blowout capping stages, just below the casing shoe, propagating upwards creating a channel through which reservoir fluids can flow to the ocean floor. Being able to model these fracture failures will help understand wellbore integrity problems from loss of control situations and predict the possibility of broaching preventing many ecological disasters like the 1969 Santa Barbara oil spill from Union Oil’s A-21 well. The hypothesis tested is that fracture initiation from a wellbore in a loss of control situation can be predicted through analysis of the near-wellbore stress field, with knowledge of the in-situ stress state and the properties of the formation and the borehole assembly. A 3D numerical model is employed to assess whether a fracture will initiate. This is done by considering the stressfield at the casing shoe; the point most vulnerable to tensile fracture failure downhole. In-situ stress state, wellbore pressure, casing shoe depth and the casing, cement, and formation’s mechanical properties are independent variables that are shown to control fracture initiation; the dependent variable. A reservoir model is used to predict pressure build-up during capping procedures. A case study on Gulf of Mexico is presented with input wellbore pressure data generated using a worst case discharge model. Wellbore pressure drop during uncontrolled discharge from a well can cause casing collapse failures and subsequently pressure build-up in the post-blowout capping stage, may initiate fractures which can lead fluid leakage to the surface either through the cement or the interfaces with the casing and the formation. The region of the in-situ stress states where fracture initiation will occur is shown in dimensionless plots. This is useful for drilling and wellbore integrity teams. When targeting highly-pressured formations as in deepwater, wellbore architecture must be made with considerations of the wellbore pressures generated from loss of control situations like blowouts. Research reported in this publication was supported by an Early-Career Research Fellowship from the Gulf Research Program of the National Academies of Sciences, Engineering, and Medicine. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Gulf Research Program of the National Academies of Sciences, Engineering, and Medicine.

Coastal areas are highly vulnerable to flooding, due to hydrological extreme events such heavy rainfalls and/or storm surges which are supposed to be increasing in the next future due to the emission in atmosphere of anthropogenic greenhouse gases. In this study, in order to assess the future hydraulic risk in coastal regions, as well as, to identify optimal defense/adaptation policies, a risk analysis model is developed to calculate the present day and future flood risk, accounting for climate change uncertainties and mitigation measures. Such model juxtaposes a number of coupled/nested models as: a) a stacking daily rainfall downscaling model which combines simulations from multiple predictive models, as Random Forest, extreme gradient boosting and Non-homogeneous Hidden Markov Model (NHMM) (Cioffi et al. 2018); b) a Bivariate Point Process model (BPPM) (Zheng et al., 2014) that calculates Joint probability density function between extreme daily rainfall amount and daily extreme storm tide depth; c) a simulation-optimization model - in which multi-objective GA optimization model (Deb et al., 2002) and 2D hydraulic model are combined (Cioffi et al. 2018) - calculates sets of Pareto optimal solutions which are obtained by defining two optimality criteria consisting in: minimizing both the cost of the flood defense infrastructure system and the flooding hydraulic risk. ; d) a mathematical decision model which is aimed to identify the best policies of mitigation of hydraulic risk and the timing, taking into account the uncertainties in hydrological extreme event predictions. The risk analysis model is applied to the study case of Mazzocchio area which is the most depressed area (about 10000 ha) within the Pontinia Plain, a large reclamation region in the south of Lazio (Italy), particularly vulnerable to extreme events - as extreme rainfall amount and sea level rise due to storm surge at the sea outfall of the river- which in the past caused the crisis of hydraulic network system with flooding of large areas and collapse of levees. XXI Century projections of daily rainfall amount and sea level for the RCP 8.5-IPCC scenarios were performed using ensemble of 35 GCM simulations (CESM1 CAM5 BGC 20C + RCP8.5 Large Ensemble) (Kay et al., 2015).

i) Within the framework of 3D resistive MHD, we simulate the formation of a plasma jet with the morphology, upward velocity and timescale formation similar to those expected for Type II spicules as described in González-Avilés et al. (2018a). ii) In this paper we analyze the transverse displacements and rotational type motion of the jet. iii) We calculate time series of the velocity components in different points near to the jet for various heights and find transverse oscillations in agreement with spicule observations. iv) By analyzing temperature isosurfaces, we find that the line-ofsight (LOS) is approximately perpendicular to the jet axis. v) The jet shows a red-blue shift pattern caused by rotational motion

The Stratospheric Aerosol and Gas Experiment operating on the International Space Station (SAGE III/ISS) is an occultation instrument that retrieves aerosol extinction and ozone, water vapor, and other trace gas concentrations. Water vapor in the stratosphere plays a significant role in ozone depletion and global temperature regulation making it an important species to monitor. The new SAGE III/ISS instrument provides high quality, vertically resolved profiles of water vapor throughout the stratosphere and upper troposphere. A discussion is presented on the sensitivity of the SAGE III/ISS instrument to water vapor and provide an early evaluation of the retrieved profiles.

Extreme weather and migratory events have been topics of great interest for decades. More recently, a debate has emerged whether the human impact of climate change can lead to armed conflict, and how conflict and extreme climate events interact in inducing large-scale displacement. This paper explores the relationship between conflict and displacement in the context of droughts and floods across Somalia, a country in the East Africa region, in which the population has historically been using migration as coping strategy for the effects of recurring climatic extremes and socio-economic uncertainties. Since 2015, Somalia has been affected by a humanitarian crisis, paired with on-going conflict, which subsequently reduced resilience of its population. Applying panel econometric methods to monthly within-country migration observations from 18 regions together with spatio-temporal conflict and weather data, this paper quantifies the impacts of conflict and extreme weather events on within-country displacement over the period of 2016 to 2018. It combines and analyses conflict-, drought- and flood-related displacement data from the UNHCR-led Protection & Return Monitoring Network (PRMN), disaggregated conflict data from the Armed Conflict Location & Event Data Project (ACLED) with gridded climate estimate data. Empirical evidence suggests significant interaction effects between conflict and extreme weather events on migration, where pre-existing conflict conditions act as accelerators of climate-induced displacement.

Unsaturated fractured aquifer systems offer a domain for complex gravity-driven flow dynamics leading to the development of preferential flow along fracture networks that often strongly contributes to rapid mass fluxes. This behaviour is difficult to recover by volume-effective modeling approaches (e.g. Richards equation) due to the non-linear nature of free-surface flows and mass partitioning processes at unsaturated fracture intersections. The application of well-controlled laboratory experiments enables to isolate single aspects of the mass redistribution process that ultimately affects travel time distributions across scales. We use custom-made acrylic cubes (20 cm x 20 cm x 20 cm) in analogue percolation experiments to create simple fracture networks with single or multiple horizontal fractures. A high precision multichannel dispenser produces gravity-driven free surface flow (droplets; rivulets) at flow rates ranging from 1 ml/min to 5 ml/min. Hereby, total inflow rates are kept constant while the fluid is injected via 15 (droplet flow) or 3 inlets (rivulet flow) to reduce the impact of erratic flow dynamics. Normalized fracture inflow rates (Q_f/Q_0) are calculated and compared for aperture widths d_f of 1 mm and 2.5 mm. A higher efficiency in filling an unsaturated fracture by rivulet flow observed in former studies can be confirmed. The onset of a capillary driven Washburn-type flow is determined and recovered by an analytical solution. In order to upscale the dynamics and enable the prediction of mass partitioning for arbitrary-sized fracture cascades a Gaussian transfer function is derived that reproduces the repetitive filling of fractures, where rivulet flow is the prevailing regime. Results show good agreement with experimental data for all tested aperture widths.

Experimental study of the phase and amplitude observations of sub-ionospheric very low and low frequency signals is performed to analyze the response of the lower ionosphere during the August 21, 2017 total solar eclipse in the United States of America. Three subionospheric wave paths have been investigated. The length of the paths varied from 2200 to 6500 km, signal frequencies were 21.4 kHz, 25.2 kHz and 40.8 kHz. Two paths crossed the region of total eclipse and the third path was in the region of 40-60% of obscuration. None of the signals revealed any noticeable amplitude changes during the eclipse while negative phase anomalies (from -35° to -95°) were detected for all three paths. It was shown that the effective reflection height of the ionosphere in low and middle latitudes has been increased by 3.5-5 km during the eclipse.

Random and small-scale subsurface heterogeneities in velocity and/or density scatter the seismic wavefield when they have scale lengths on the order of the seismic wavelength. Seismic scattering is considered the origin of coda waves. Such inhomogeneities have an important effect on propagating waves, as they generate traveltime and amplitude fluctuations and may be the cause of attenuation or excitation of secondary waves. Understanding the effect of small-scale heterogeneities on the seismic wavefield is important for the characterization of the seismic source (e.g. source parameters of underground nuclear explosions) and to improve our knowledge of the Earth’s structure along the raypath. Several approaches and methods have been suggested to study the scattering of seismic waves and characterise subsurface heterogeneities. Here, we apply a combination of the analysis of the incoherent wavefield component and the coda decay with time to a dataset of over 350 teleseismic events (over 20000 traces) recorded at three seismic arrays (Warramunga, Alice Springs and Pilbara) in Australia. This combination allow us to obtain a series of parameters (correlation length, RMS velocity fluctuations of the heterogeneities and thickness of the scattering layer) that give us a measure of the spatial scale and the magnitude of the heterogeneities present in the lithosphere beneath the arrays. This is the first time such a large dataset is used for a study of these characteristics. Our new results show similar structures and scattering strength for Alice Springs and Warramunga, while revealing a different tectonic signature and stronger scattering in the case of Pilbara, possibly caused by the different thicknesses of crust and lithosphere between these regions and its different tectonic history. These stochastic models of the lithosphere are the first step in the development of a technique analogous to adaptive optics which, in this case, aims at removing the effect of the small-scale, near receiver structure from recorded wavefields, thus enabling us to improve our source characterization and to more clearly image the Earth’s interior.

Groundwater fluoride is the major cause of the endemic fluorosis. Global fluorosis data indicate that that granitic aquifer which fractures controlled hydrology is highly susceptible to contaminate groundwater with high fluoride. Till date there has not been any sincere effort to understand the type of granitic aquifer based on the different type of the granites and their fluoride content. The present paper assesses the different types of granites and their fluoride content. Dissolution of fluoride from these rock types are the major source of high fluoride contamination in the groundwater. The granitic aquifers are also dominated by fracture control hydrology which enhances the chances of rock water interaction and dissolution of fluoride. The mineralogy of the rocks is also favorable due to the presence of biotite and muscovite which are found to have high affinity to donate fluoride during rock water interaction as shown by the following equation. KAl2[AlSi3O10]F2+2OH- = KAl2[AlSi3O10]OH-+2F- (Muscovite) KMg3[AlSi3O10] F2+2 OH- = KMg3[AlSi3O10]OH-+2F- (Biotite) Delineation of the type of aquifer and the geochemistry of the granitic rocks needs to assess to understand the geogenic causes of fluoride in the granitic aquifer along with the water chemistry (pH>8) which enhances the rate of dissolution of fluoride during rock water interaction. Further estimation can be made by the application pf isotopic data particularly 18O, 2H, 3H, 34S isotope which can quantitatively estimate the sources of fluoride and contribution from different sources as well as rock water interaction time.

High concentration of fluoride in the groundwater is observed to be associated with granitic aquifers as well as near phosphate mines around the globe. The present work is a hydrogeological study of the ground water of Beldih phosphate mines in India. Being located in the Singhbhum shear zone the area has a complex tectonic history and is dominated by phosphate, alkali granites, amphibolites, and granitic gneiss with higer abundance of fluoride bearing minerals like apatite and biotite. Total of 12 water samples were collected for a preliminary study to assess the spatial variation of fluoride in ground water and surface water with an aim to understand the effect of phosphate mines in elevating fluorosis in adjoining areas. The groundwater chemistry shows a trend that the concentration of fluoride and nitrate gets elevated as we approach towards the open cast phosphate mines. From the spatial observation combined with the water chemistry and geology it is evident that the apatite dissolution is the prime cause of the elevation in fluoride concentration. However presence of iron in the lithology controls the fluoride level to some extent. Since the area is effected with high fluorosis its can be concluded that the groundwater geochemistry along with the air borne fluoride present in the phosphate dust are the major cause of the fluorosis. The exploration of phosphate must be carried out with out most environmental care and the mitigation of post mining effect should be planned before mining operation. Fluorosis is an irreparable health hazard and a major geohealth concern that has already affected a large amount of population.