The role of environmental transmission of typically foodborne pathogens like Shiga toxin-producing (STEC) O157 is increasingly recognized. To gain more insights, we assessed the spatial association between sporadic STEC O157 human infections and the exposure to livestock (i.e. small ruminants, cattle, poultry, and pigs) in a densely populated country: the Netherlands. This was done for the years 2007-2016, using a state-of-the-art spatial analysis method in which hexagonal areas with different sizes (90, 50, 25 and 10 km2) were used in combination with a novel probability of exposure metric: the population-weighted number of animals per hexagon. To identify risk factors for STEC O157 infections and their population attributable fraction (PAF), a spatial regression model was fitted using integrated nested Laplace approximation (INLA). Living in hexagonal areas of 25, 50 and 90 km2 with twice as much population-weighted small ruminants was associated with an increase of the incidence rate of human STEC O157 infections in summer (RR of 1.09 [95%CI;1.01-1.17], RR of 1.17 [95%CI;1.07-1.28] and RR of 1.13 [95%CI;1.01-1.26]), with a PAF of 49% (95%CI;8-72%). Results indicate a potential transmission of STEC O157 from small ruminants to humans via the environment. However, the underlying mechanisms warrant further investigation and could offer new targets for control. Furthermore, the newly proposed exposure metric has potential to improve existing spatial modelling studies on infectious diseases related to livestock exposure, especially in densely populated countries like the Netherlands.

This study builds on Huntley and Ryan (2018) and related prior works on channels and estuaries by considering solutions for the same subtidal dynamics but with alternative integral flow constraints. Prior solutions do not have a truly two-dimensional (2D) flow field, as axial changes in the axial flow are implied. Three constraint types are considered: the Constant case with spatially constant density gradients constrained with section-integrated flow (as in prior works), Semi-Variable case with a constant axial density gradient and laterally variable lateral density gradient constrained with depth-integrated lateral flow, and Variable case with spatially variable density gradients in both directions constrained with depth-integrated axial and lateral flows. The Semi-Variable and Variable cases can produce solutions with truly 2D flow if the depth-integrated lateral flow is set to zero everywhere. Differences among solutions are illustrated with idealized and realistic applications from Huntley and Ryan (2018). For the idealized application, the Constant case and the Semi-Variable case with 2D flow have clear differences in axial velocity and stark contrasts in lateral flow (and density gradients). For the Nares Strait application, the Variable case with observed depth-averaged axial and lateral velocities is best able to represent the fastest observed down-channel velocities, the weak reversed flow on one side of the channel, and the observed lateral flow structure. Overall, selecting different integral constraints on flow conspicuously changes the subtidal flow, opens up new possibilities for truly 2D flow solutions, and provides additional flexibility for representing observed conditions in realistic situations.

Gas hydrate dynamics and the fluid flow systems from two active pockmarks along Vestnesa Ridge (offshore west Svalbard) were investigated through the pore fluid geochemistry obtained during the 2016 MARUM-MeBo 70 drilling cruise. Based on the pore water chloride concentration profiles from Lunde and Lomvi pockmarks, we estimated up to 47% pore space occupied by gas hydrate in the sediments shallower than 11.5 mbsf. These gas hydrates were formed during periods of gaseous methane seepage, but are now in a state of dynamic equilibrium sustained by a relatively low methane supply at present. We detect a saline formation pore fluid around nine meters below seafloor from one of the seepage sites in Lunde pockmark. This formation pore fluid has elevated dissolved chloride concentrations and B/Cl ratios, higher δO and δD isotopic signatures of water and lower δB signatures, which collectively hint to a high temperature modification of this fluid at great depths. By integrating our findings with the previous work from Vestnesa Ridge, we show that the variable fluid phases (gaseous vs. aqueous fluid) and migration pathways are controlled by the sediment properties, such as buried carbonate crusts, and the state of fluid reservoirs.

We performed laboratory experiments to the photochemical evolution induced by long-UV radiations of benzene ices in Titan’s atmosphere. The aim of this study was to investigate if photo-processed benzene ices could lead to the formation of aerosols analog to the ones observed in Titan’s stratosphere. Prior to that, spectroscopic properties of amorphous and crystalline benzene ices were studied as a function of the temperature, using infrared spectroscopy. UV photolysis experiments (l > 230nm) of benzene ices lead to the formation of volatile photo-products of which fulvene is identified and of a residue, dominated by nCH IR features which demonstrate that pure aromatic-based polymeric structures are not sufficient to explain the composition of Titan’s haze layer present in the stratosphere. However, we provide a characterization of long-UV-induced benzene-containing aerosols analogs, which will contribute to Titan’s surface organics layer which is of prime interest in the context of the future Dragonfly space mission.

This study proposes a novel approach that expands the existing QDM (quantile delta mapping) to address spatial bias, using Kriging within a Bayesian framework to assess the impact of using a point reference field. Our focus here is to spatially downscale daily rainfall sequences simulated by regional climate models (RCMs), coupled to the proposed QDM-spatial bias-correction, in which the distribution parameters are first interpolated onto a fine grid (rather than the observed daily rainfall). The proposed model is validated through a cross‐validatory (CV) evaluation using rainfall data from a set of weather stations in South Korea and climate change scenarios simulated by three alternate RCMs. The results demonstrate the efficacy of the proposed model to simulate the bias-corrected daily rainfall sequences over large regions at fine resolutions. A discussion of the potential use of the proposed approach in the field of hydrometeorology is also offered.

Solar Radiation Management (SRM) geoengineering is a proposed response to anthropogenic global warming (AGW)1. Stratospheric aerosol injection (SAI) is one proposed method, reliant on lofting particles into the stratosphere. Engineering reviews related to this technology approach have been sparse, with most major primary analyses now at least five years old. We attempt to bridge this gap – with a short, mainly qualitative review of recent developments in fields of engineering with potential applicability to stratospheric aerosol injection. Our analysis shows that a new conventional aircraft design is still likely to be the most dependable and affordable technology solution, with hybrid airships a potential challenger. Rockets, gas guns and MAGLEV/coilguns show some potential, although they lack the level flight capability preferred for direct aerosol distribution, without substantial additional engineering. Should very high-altitude access be required, rockets, hybrid rockets, and light-gas guns offer the required capability. Costs and performance for tethered balloons remain highly uncertain. No other methods are found to be promising. Nevertheless, the extreme accessibility of disposable balloons suggests that this method may be used primarily for reasons of political leverage, as opposed to being an optimal engineering solution.

The demand for water supply and sanitation services is growing fast owing to the interactive effects of demographic growth, economic development and improvements in living standards. Increasing urbanisation has been a worldwide trend since the beginning of the twentieth century, and its increase continues. A long-term sustainable water management system (SWMS) is the solution to ensuring the water rights and water security of citizens are met. The concept of an integrated urban water management system (IUWM) guides the utilities in planning the water system at a hydrological cycle level. The input of Information and Communication Technology (ICT) and the Internet of Things (IOT) in water management has added a smart quotient to the entire water management scenario. Smartness in water management has increased the overall performance of the system. The global practice of water management in smart cities is based on IUWM combined with smartness in the system. Financing, technology and infrastructure along with governance-which drives the policies, laws and institutional framework-are key drivers of SWMS and IUWM. There is no uniform definition of governance which can guide the governance of IUWM and SWMS.

We quantify the evolving spatial distribution of fracture networks throughout six in situ X-ray tomography triaxial compression experiments on monzonite and granite at confining stresses of 5-35 MPa. We first assess whether one dominant fracture continually grows at the expense of others by tracking the proportion of the maximum fracture volume to the total fracture volume. This metric does not increase monotonically. We next examine if the set of the largest fractures continually dominates deformation by tracking the proportion of the cumulative volume of fractures with volumes >90th percentile to the total fracture volume. This metric indicates that the fracture networks tend to increase in localization toward the largest set of fractures for up to 80% of the experimental time (differential stress), consistent with observations from southern California of localizing and delocalizing seismicity. Experiments with higher confining stress tend to have greater localization. To further assess the fracture networks localization, we compare the geometry of the set of the largest fractures to a plane. We find the best fit plane through the fractures with volumes >90th percentile immediately preceding failure, and calculate the distance between these fractures and the plane, and the r2 score of the fractures and the plane throughout each experiment. The r2 scores and the distance indicate greater localization in the monzonite experiments than in the granite experiments. The smaller mean grain size of the minerals in the granite may produce more sites of fracture nucleation and termination, leading to more delocalized fracture networks that deviate further from a plane. The higher applied confining stress in the monzonite experiments (25-35 MPa) relative to the granite experiments (5-10 MPa) may also contribute to the more localized fracture networks in the monzonite experiments. The evolution of the clustering the fractures toward the plane and the Gini coefficient, which measures the deviation of a population from uniformity, closely match each other. Tracking these metrics of localization also reveals that macroscopic yielding appears to occur when the rate of fracture network localization increases.

A new model of cosmogenic tritium (H) production in the atmosphere is presented. The model belongs to the CRAC (Cosmic-Ray Atmospheric Cascade) family and is named as CRAC:3H. It is based on a full Monte-Carlo simulation of the cosmic-ray induced atmospheric cascade using the Geant4 toolkit. The CRAC:3H model is able, for the first time, to compute tritium production at any location and time, for any given energy spectrum of the primary incident cosmic ray particles, explicitly treating, also for the first time, particles heavier than protons. This model provides a useful tool for the use of H as a tracer of atmospheric and hydrological circulation. A numerical recipe for practical use of the model is appended.

Natural factors and non-pharmaceutical interventions (NPIs) have effect on COVID-19 transmission, but it’s difficult to separate these two factors. The Compound natural factor (CNF) model is proposed to deal with this problem. In this model, the weight of single natural factors (SNFs) could be expressed the coupling relationship (CR) among them. Then, CR is iteratively optimized by Elitism-based compact genetic algorithms (ECGAs). Considering optimal coupling relationship of SNFs, CNF has a strong correlation (r=0.56) with the COVID-19 infection rate. However, CNF does not have much correlation with mortality (r=-0.25) and recovery rate (r=-0.46), due to slight change of weather in hospitals. Therefore, a linear weighted CNF model is constructed to forecast the impending infection rate. As a result, NPIs effect have been eliminated in the predicted infection rate by the CNF model, which is only the result of climate change. If China ignored NPIs, COVID-19 virus would transmit in the CNF forecast way as climate changes. This model built on Chinese cases provides a new perspective to forecast the global infection rate which is only under the intervention of natural factors.

La Nina events influence the tropical Indian Ocean (TIO) sea surface temperature, sea level and heat content significantly. However, proper quantification in the context of ocean heat transport in the TIO and its persistence is lacking. So, in this study, we have chosen the La Nina events which persist for more than 24-months to study the effects of such events in the TIO using observational and reanalysis data. It is found that prolonged La Nina events promote intensification of cooling anomaly and sea-level-low in the thermocline ridge region of the Indian Ocean (TRIO) and its eastward extension from its climatological location (the southwestern TIO). This happens as a response to the cyclonic wind generated in the southeastern TIO and the associated upwelling Rossby waves which propagate westward to shoal the thermocline in the TRIO region and also extending it eastward while intensifying the cooling and sea level low there. Whereas, in the eastern Equatorial Indian Ocean (EIO) and Bay of Bengal (BoB) a deepening of thermocline, east-west thermocline gradient, anomalous sub-surface warming, increase in the upper ocean heat content and sea-level rise are in the characteristic features of all the prolonged La Nina events. Intense cooling and anomalous sea level low in the Arabian Sea (AS) and intense warming and thermocline deepening in the head bay and the eastward extension of the TRIO regions are found to be unique features of these prolonged La Niña events. These prolonged La Niña events support cross-equatorial Sverdrup transport near the eastern boundary of EIO. This suggests a pathway of warm western Pacific waters accumulated in southeastern EIO entering the north Indian Ocean increasing the heat-content of BoB especially in the 50m—150m depth. The warming (cooling) of the BoB (AS) is speculated to enhance (suppress) pre and post monsoon cyclones over these regions by modulating the tropical cyclone heat potential during these prolonged La Nina events.

Injection of CO2 for geologic carbon sequestration (GCS) into deep sedimentary formations involves fluid pressure increases that engage hydromechanical processes that can cause seismicity by activation of existing faults. In this work, we use a coupled multiphase fluid flow and geomechanical simulator to model spatiotemporal fluid pressure and stress changes in order to study the poroelastic effect of CO2 injection on faults in crystalline basement rock below the injection zone. The seismicity rate along features interpreted to be basement faults is modeled using Dieterich’s rate-and-state earthquake nucleation model. The methodology is applied to microseismicity detected during CO2 injection into the Mount Simon formation during the Illinois Basin – Decatur Project. The modeling accurately captures an observed reduction in seismicity rate when the injection in the second well was into a slightly shallower zone above the base of the Mount Simon formation. Moreover, the modeling shows that it is important to consider poroelastic stress changes, in addition to fluid pressure changes for accurately modeling of the observed seismicity rate.

Abstract Background, Aims and Scope. Wetland soil is one of the largest natural contributors to methane emissions, which is a prevalent greenhouse gas. The vertical flux pattern of methane in soils is unclear. To investigate the relationship between methane vertical flux, soil total organic carbon (TOC) and methanogen, we were monitored in the riparian buffer of a wetland park from August 2018 to January 2020. The objectives of this study were to (1) analyze the vertical variation in methane fluxes within the riparian buffer and (2) investigate the vertical space relationships between methane fluxes, TOC and methanogens. Furthermore, the results of this study could provide better information for understanding the vertical linkage between methane, TOC and methanogens. Methods. The study area is the Living Water Garden (LWG), a wetland park in Chengdu, Sichuan Province, western China (30◦40’ N, 104◦05’ E), which is a city park using a constructed wetland system (CW) to treat polluted water from the Jin River. The sampling site is close to the park inlet, located on the bank of the Jin River, a flat riparian buffer with an area of about 100 m2 (Fig. 1c, the red dashed box). Methane flux was measured once per month (in mid-month) using a portable greenhouse gas flux measurement system (WS-L1820, WEST Ltd., Italy). The sampling frequency is one time on a selected day and the sampling time was between 11:00 am and 12:00 am. There are 6 selected monitoring sites with 4 monitoring depths including surface, 5cm, 10cm and 15cm. Soil sampling and methane flux measurements are performed on the same days. After methane flux monitoring, soil samples were collected. Soil sampling sites were also same as the methane monitoring sites. At each sampling site, soil samples were excavated at depths of 0-5 cm, 5-10 cm and 10-15 cm. Gene copies of the methanogens (mcrA) were determined by q-PCR on the ABI 9700 Real-Time PCR system. Sequencing data was processed using the quantitative insights into the microbial ecology (QIIME) pipeline. SPSS software (version 21, SPSS Inc., USA) and the software package R (R Foundation for Statistical Computing, Austria) were used for statistical analyses and data graphing. Structural equation model (SEM) was conducted using the AMOS statistical software (version 21, IBM SPSS, USA). Results. During the study period, the average surface methane emission was 81.86 mg m-2 h-1 and ranged from 20.42 mg m-2 h-1 to 190.75 mg m-2 h-1. Cumulative methane emissions from studied area was 7.26 kg CO2eq m−2 year−1 and the global warming potential (GWP) was at a moderate level. The results reveal that the Methanobacteriaceae, Methanosarcinaceae and Methanoregulaceae were the major methanogenic microorganisms in the study area. The mathematical regression of methane flux (z, mg m-2 h-1) with soil depth (x, cm) and TOC (y, g kg-1) was as follows: z = 52860.66 + 54.44x - 2.96x2 - 26788.64y + 4487.80y2 - 249.34y3 (R2=0.82). It indicates that the relatio

The Nansha Islands comprise the largest atoll archipelago in the South China Sea that accommodates 15% of global atolls. In contrast to the reef flats of the Indo-Pacific region that commonly have grown close to modern sea level, a considerable portion of the atoll rims here consists of reef flats as deep as 6-20 m. To better understand whether these deep reefs are relict features abandoned by sea-level rise or host to modern physical reworking, we conducted an 8.5-month mooring observation of hydrodynamics on the 12-m-deep southwest-facing reef flat of Tiexian reef. These measurements show a predominance of seasonal-varying strong waves and stable currents, in line with short-term observations at three other deep-reef-flats nearby. While the reef flat was protected from the northeast monsoon from January to May, the southwest monsoon from June to September resulted in prolonged exposure to large waves and more vigorous cross-flat currents (mean Hs of 1.3 m; orbital velocity 0.22 m/s), resulting in consistently large near-bed shear stresses (mean of 0.6 N/m2 on reef sediments and maximum of 18.9 N/m2 on coral reefs) that are capable of entraining sediment for almost the entire monsoon season. Assuming a mere ratio of 1-10% mobile sediment would result in rim height deflation on the order of 0.5-5 cm/y. Such values similar to potential rates of reef accretion imply that modern processes could play a significant role in the maintenance of the deep reef flats, which can be surprisingly active environments with living coral colonies and coral debris coverage.

The Highland Lakes on the Colorado River in Texas, specifically lakes Buchanan and Travis, supply water for the Austin metropolitan area. The population of the Austin area is projected to reach 4.5 million by 2040, which will lead to an increased water demand. The goal of this study is to generate a long-term hydroclimate dataset using hydrological modeling, and to examine the observed trends and their causes to help understand the changes in runoff in the lower Colorado River basin. The lower Colorado River basin includes the main stem of the Colorado River and four sub-watersheds – Pecan Bayou, San Saba River, Llano River and Pedernales River. The Distributed Hydrology Soil Vegetation Model (DHSVM) includes a 300-meter spatial resolution and a 12-hour time step from 1950-2018 to simulate soil moisture, evapotranspiration, runoff and streamflow. The model parameters are calibrated during the period of 1951-1990 by comparing the simulated streamflow with observed naturalized flows using three statistical criteria: relative bias (RB), coefficient of determination (R2), and the Nash-Sutcliffe efficiency (NSE). The simulated streamflows are further validated against naturalized flows over the period of 1991-2015. The streamflow trends, along with other hydroclimate variables, are examined and compared across all watersheds during the study period. In addition, sensitivity analyses are conducted to evaluate how changing temperatures and precipitation will affect streamflow in the watersheds. This long-term hydroclimate dataset for the lower Colorado River basin not only provides a comprehensive understanding of historical trends, but also serves as a baseline for future analysis.

This manuscript compares aerosol size distributions and microphysical property measurements from the Raman lidar BASIL and from aircraft sensors during HyMeX-SOP1. The attention was focused on a measurement session on 02 October 2012, with BASIL measurements revealing the presence of a lower aerosol layer extending up to 3.3 km and an elevated layer with extending from 3.6 km to 4.6 km. Aerosol size distributions and microphysical characteristics were determined from three-wavelength particle backscattering and extinction profile measurements through a retrieval approach based on Tikhonov regularization. A good agreement is found between BASIL retrievals and the microphysical sensors’ measurements for all considered aerosol dimensional and microphysical characteristics. Specifically, BASIL and in-situ volume concentration values are 1-3.5 mm3cm-3 in the lower layer and 2-4 mm3cm-3 in the upper layer. Furthermore, effective radius values from BASIL and the in-situ sensors’ measurements are in the range 0.2-0.6 mm both in the lower and upper layer. Particle size distributions were determined at 2.2, 2.8, 4 and 4.3 km, with again a good agreement between the Raman lidar and the microphysical sensors throughout the considered height interval. These results, in combination with Lagrangian back-trajectory analyses and chemical composition measurements, indicate that aerosols below 3 km were possibly originated by forest fires in North America or by anthropogenic activities in North-Eastern Europe, while aerosols above 3 km were originated over the North Atlantic and presumably include both a marine and an organic component. This interpretation is compatible with the lidar retrieved profiles of particle complex refractive index.

Lower atmosphere variations in the martian water vapour and hydrogen abundance during the Mars Year (MY) 34 C storm from LS=326.1◦-333.5◦ and their associated effect on hydrogen escape are investigated using a multi-spacecraft assimilation of atmospheric retrievals into a Martian global circulation model. Elevation of the hygropause and associated increase in middle atmosphere hydrogen at the peak of the MY 34 C storm led to a hydrogen escape rate of around 1.4×109 cm−2s−1 , meaning the MY 34 C storm enhanced water loss rates on Mars to levels observed during global-scale dust storms. The water loss rate during the MY 34 C storm (a loss of 15% of the total annual water loss during only 5% of the year) was three times stronger than the weak MY 30 C storm assimilation, demonstrating that interannual variations in C storm strength must be considered when calculating the integrated loss of water on Mars.

The comparative analysis of three thunderstorms on Aragats in May 2021 demonstrates that relativistic runaway electron avalanches (RREAs) are developing in large areas of the thunderous atmosphere. In the active storm zone, RREAs last tens of seconds to a few minutes, until lightning flashes terminate electron acceleration. Thus, RREAs development is paired with lightning activity, creating huge electron fluxes preceding the development of lightning leaders. If the lightning activity is far from the detector site, measured particle fluxes (thunderstorm ground enhancements - TGEs) are smoothly enhanced and decayed when the atmospheric conditions cannot anymore sustain the electron runaway process. The TGE has a symmetrical shape and can last up to 10 minutes and more. The differential energy spectra of electrons and gamma rays recovered by particle spectrometers are used to estimate the heigh of a strong accelerating electric field region, which can extend down to tens meters above the earth’s surface.