This study provides insights on the composition and variability of atmospheric aerosols over the United Arab Emirates (UAE) by analyzing the atmospheric conditions together with 14-years (2006-2019) of aerosol optical depth (AOD) retrieved from CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) satellite, and 7 years of AOD measured from the ground-based Aerosol Robotic Network. We found that mineral dust is the most prevailing aerosol subtype. In addition, polluted dust and polluted continental aerosols are observed mostly in the cold season. The AOD is higher in spring and summer, when the atmospheric conditions are more favourable to the occurrence of dust events. Moreover, there is another peak in winter associated with dust storms triggered by mid-latitude baroclinic systems. In summer’s daytime, extinction coefficients in excess of 0.2 km-1 are observed up to 3-4 km above the surface, as a result of the warmer and windier conditions. In the cold season and at night, the dust layers are confined to the lower atmosphere below 2 km. On a climatological time scale, we found that the AOD over the UAE has been decreasing since 2009, possibly due to the increasing trend in precipitation and changes in land use. This study highlights the large contribution of dust aerosols to the total aerosol load over the UAE and stresses on the need to account for mineral dust aerosols in climate-air pollution related studies as well as weather and air quality forecasts.

We couple short-term (i.e. the co-seismic) and long-term (i.e. the inter-seismic) phase of an earthquake, in order to investigate how induced static stress changes during the co-seismic phase of an earthquake cycle influence the dynamics of strain accumulation during the inter-seismic phase. We perform dynamic rupture simulations on complex strike slip faults in 2D, incorporating off-fault plastic failure and strong dynamic weakening on the fault governed by the slip weakening law. Our strike slip fault has a self-similar fractal profile with RMS height taken from observational studies. Our dynamic rupture simulation results show that the stresses in the region surrounding the fault are highly complex and heterogeneous. This heterogeneity in stresses is mainly related to roughness of fault profile and at distances where fault roughness effects are not dominant, the stresses are mostly uniform. We extract these complex stresses together with the plastic deformation from the dynamic model and use them as the input to run the long-term tectonic model (LTM). This provides us insight into the dynamics of off-fault plastic deformation in the loading phase of an earthquake. Our LTM results show that most of the shear zones (i.e. new features e.g. fractures and faults) develop and grow at oblique angles to the main fault while considerable amount of damage keeps accumulating along the immediate sides of the fault profile. The development and growth of these new features occurs in the locations where geometrical bends in the fault profile has caused the deformation in the dynamic phase to be localized. This localized deformation due to fault roughness acts as a seed for the development of new features. We conclude that the complex damage pattern in the fault damage zones (observed in observational studies) is mainly due to the fault surface roughness effects. During the co-seismic phase, the stresses concentrate near the fault bends due to rough fault profile. During the inter-seismic phase, these locations are favored for the development of new features during the inter-seismic phase the earthquake.

The nature of convective organization remains elusive, despite its importance for understanding the role of clouds in climate systems. This study reports a new type of large-scale structure formed by the self-organization of deep moist atmospheric convection in radiative-convective equilibrium. To understand the natural behavior of convection unaffected by the computational domain, we conducted cloud-resolving simulations by systematically increasing the horizontal domain size to approximately 25,000 km. We found that if the domain side length exceeded 5,000 km, the domain-averaged thermodynamic fields and the horizontal characteristic length converged in quasi-equilibrium; the cloud aggregation area exhibited a mesh-like pattern, analogous to the shallow convective organizations despite their different scales. Its characteristic length is estimated to be approximately 3,000–4,000 km. The results suggest that this length scale is related to the upper-limit size of mesoscale convective systems or the scale of supercloud clusters in a real tropical atmosphere.

We present a comparison of the detailed present-day crust to upper-mantle (400km) structure in the Western Mediterranean along two transects in Alboran and Algerian domains. The transect across the Alboran domain is NW-SE oriented crossing the Betics and the Alboran Basin and the northern margin of Africa between the Tell and Rif mountains. The Algerian domain transect is also NW-SE oriented crossing the Valencia Trough, the Balearic Promontory, the Algerian basin and ending in the Tell-Atlas Mountains in the northern margin of Africa. The structure is computed using integrated geophysical-petrological modelling tool (LitMod2D) which combines petrological, geochemical and geophysical dataset in a self-consistent framework. We model thermal, compositional, density and seismological structure, also incorporating slabs imaged by seismic tomography, constrained by simultaneously fitting elevation, gravity, geoid, surface heat flow and seismic tomography models to reduce the uncertainties in the modelling. Preliminary results suggest that crust is thickest beneath the Betics and thins beneath the Alboran basin within a distance of ~100 km. Farther SE, crust gradually thickens beneath the north margin of Africa, between Tell and Rif mountains over ~300 km distance. The LAB shows a similar trend though it is affected by the presence of the slab underneath Betics. For the Algerian domain transect, maximum crustal thickness occurs beneath the Tell-Atlas Mountains with noticeable variations across the Algerian basin, Balearic Promontory and Valencia Trough, the LAB showing a similar tendency. Comparing the modelled geometries suggests that both transects have opposite trends with the deepest Moho and LAB in the NW side of the Alboran transect and in the SE side of the Algerian transect, imposing important restrictions on the geodynamic evolution of the Western Mediterranean.

Global studies of climate change impacts that use future climate model projections also require projections of land surface changes. Simulated land surface performance in Earth System models is often affected by climate biases of the atmospheric models, leading to errors in land surface projections. Here we run the JULES-ES land surface model with ISIMIP2b bias-corrected climate model data from 4 global climate models (GCMs). The bias correction reduces the impact of the climate biases present in individual models. We evaluate JULES-ES performance against present-day observations to demonstrate its usefulness for providing required information for impacts such as fire and river flow. We simulate a historical and two future scenarios; a mitigation scenario RCP2.6 and RCP6.0, which has very little mitigation. We include a standard JULES-ES configuration without fire as a contribution to ISIMIP2b and JULES-ES with fire as a potential future development. Simulations for gross primary productivity, evapotranspiration (ET) and albedo compare well against observations. Including fire improves the simulations, especially for ET and albedo and vegetation distribution, with some degradation in shrub cover and river flow. This configuration represents some of the most current earth system science for land surface modelling. The suite associated with this configuration provides a basis for past and future phases of ISIMIP, providing a simulation setup, postprocessing and initial evaluation using ILAMB. This suite ensures that it is as straightforward, reproducible and transparent as possible to follow the protocols and participate fully in ISIMIP using JULES.

Wildfires expose populations to increased morbidity and mortality due to the increase of air pollutant emissions. This study assesses the impact of wildfire exposure in Portugal. In this work, we analyze the effects of the wildfire seasons (June-July-August-September-October) on monthly mortality by using data from atmospheric composition reanalysis, air quality stations, remote sensing, and mortality for exposure assessment, cluster analyses and regression models. Cluster analysis separated the months within fire seasons with extreme atmospheric conditions (months with more frequency of lower relative humidity and higher temperature, higher pollutant concentrations and higher wildfire activities), Cluster 1, from months with cleaner air and stable atmospheric conditions, Cluster 2. Linear regression showed statistically significant (p-value < 0.05) correlation (r) between Cluster 1 and cardiorespiratory mortalities due to Diseases of the Respiratory System (DRS), Pneumonia (PNEU), Chronic Obstructive Pulmonary Disease (COPD) and Diseases of the Circulatory System (DCS) (rDRS = 0.49; rPNEU = 0.42; rCOPD = 0.44; rDCS = 0.45). Cluster 2 presented no significant statistical correlation between atmospheric conditions and health outcomes. Results shows epidemiological evidence that heat stress combined with air pollution during wildfire season are contributing to increase disease burden. Besides that, we performed smoke forecasts over Portugal by using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model with satellite‐based fire emission. Forecasted PM10 and PM2.5 concentration reproduced the behavior of the observations (NRMSEPM10 = 3.70, rPM10 = 0.75; NRMSEPM2.5 = 1.51, rPM2.5 = 0.46) during October 15-16th, 2017, fire episode. BC results matches with satellite observations.

We use high-resolution earthquake locations to characterize the three-dimensional structure of active faults and how it evolves with fault structural maturity. We investigate the distribution of aftershocks of several recent large earthquakes that occurred on crustal strike slip faults of various structural maturity (i.e. various cumulative fault displacement, length, initiation age and slip rate). Aftershocks define a tabular zone of shear deformation surrounding the mainshock rupture plane. Comparing this to geological observations, we conclude that this results from the re-activation of secondary faults. We observe a rapid fall off of the number of aftershocks at a distance range of 0.06-0.25 km from the main fault surface of mature faults, and 0.7-1.5 km from the fault surface of immature faults. The total width of the active shear deformation zone surrounding the main fault plane reaches ~1.5 km and 2.5-6 km for mature and immature faults, respectively. We find that the width of the shear deformation zone decreases as a power law with cumulative fault displacement. Comparing with an existing dynamic rough fault model, we show that the narrowing of the shear deformation zone agrees quantitatively with earlier estimates of the smoothing of faults with displacement, both of which are aspects of fault wear. We compare this evolution of fault structure with several attributes of earthquakes, and find that earthquake stress drop decreases with fault displacement and hence with increased smoothness.

Interannual changes in spectral irradiance at UV wavelengths is one of sources of solar-driven decadal variability in the atmosphere and in particular in the stratosphere as most of these changes happen at UV wavelengths. In last recent years, it has been suggested that energetic electron precipitation (EEP) also contributes not only to alter the chemical composition of the middle atmosphere but also its dynamical variability through changes in stratospheric ozone. In this study we investigate the effects of the two forcings and their interactions. We employ 35-year long integrations of the atmospheric version of the Whole Atmosphere Community Climate Model version 5 with different idealized and stationary solar and geomagnetic forcing terms. Four experiments are carried out combining high (H) and low (L) solar radiative forcing and high (7) and low (3) EEP associated with geomagnetic activity: H7 (with high radiative forcing and high EEP), H3 (high/low), L7 (low/high), and L3 (low/low). We find that the extension, the seasonality, and the significance of the effects of these two forcing terms on the atmospheric variables like temperature, NOx, and ozone are dependent on the joint effects of both forcing terms. The effect of the impact on NOx, ozone and temperature was measured, on constant pressure levels, by means of a Monte Carlo test. Under minimum solar conditions EEP affects mainly the NOx field on constant pressure levels, even though vertical cross sections show statistically significant effects on temperature and ozone in the southern hemisphere during austral winter and the following spring. Under solar maximum condition the effect of EEP becomes important. Ozone depletion (augmentation) in the upper levels of the stratosphere due to more (less) NOx, produced by EEP, allows UV radiation to produce more (less) ozone in the lower levels of the stratosphere. Solar irradiance hence plays an important role in modulating the impact of geomagnetic activity on climate variables.

Social Learning contributes as a guiding proposal for the joint intervention of the local actors and dissemination of methodologies and collaborative activities in socioenvironmental diagnoses. Its principles are active involvement, consultation and public access to participation. Several participatory tools have been developed and have been applied within the principles of Social Learning, such as local socioenvironmental agendas, action research, role playing; world café, participatory monitoring of the streams and socioenvironmental mapping. This article presents the last one applied in different contexts and with different groups of social actors, always aiming to elaborate a participatory diagnosis of the place and reality to identify the wicked problems. Socioenvironmental mapping is a didactic-pedagogical resource used to reflect and rethink about the place. It contributes to elaborate a diagnosis of the local reality and it subsidizes the reflection on the forms of the land use and occupation and its implications for the quality of life of its inhabitants, fostering discussions, possibilities of actions to solve problems and conflicts to improve the quality of life in communities. The map is a product of collective and collaborative construction of the participants. It contributes to transform information into knowledge and establish a bridge between scientific and local knowledge. Consider the following procedures: a) the reality in which the individual lives and how he deals with his immediate environment and his understanding of it, as a starting point; b) the possibility of re-elaborating the individual’s initial understanding of his / her place; c) the way to the development of different types of knowledge for the construction of more elaborate and more critical knowledge. We have applied this methodology with teaching formation, social control and conservation area with positive results of empowering the communities.

Coalbed Methane is an attractive source of energy to mitigate the growing energy demand of India. It is often abbreviated as unconventional source of energy. In this paper two bore hole samples (J/01 & J/02) were collected and characterized for the isotherm studies to know the sorption capacity of the coal. Pure gas isotherm was constructed based on the manomateric method. Pure gas isotherm was constructed in indigenously fabricated setup. Langmuir model was used for the prediction of sorption capacity at particular pressure. Langmuir constants (PL & VL) were calculated using regression analysis. It was found that volume wise CO2 has 2.09 to 2.75 times more adsorption capacity than coal.Once pure gas isotherm was drawn and PL and VL was calculated. Langmuir constants were given as follows: CH4 -VL (scf/ton) of J/01 and J/02 are 227.27 and 454.55 respectively CH4 -PL (psi) of J/01 and J/02 are 128.54 and 173.68 CO2-VL (scf/ton) of J/01 and J/02 are 476.19 1250 respectively CO2-PL(psi) of J/01 and J/02 are 133.33 596.13 Binary mixture of CH4 and CO2 was modelled at different gas mixtures and at pressure of 2000 psi. Multicomponent iterative model (MIA) was proposed using Newton Raphson iteration to study the co adsorption isotherm of CH4 and CO2 at different binary mixtures. It was found that one CO2 mole fraction increases in gas phase. For sample J/01 Enhanced Coalbed Methane (ECBM) recovery will occur after 27.4 % of CO2 in gas phase while ECBM recovery will occur after 13.03% of CO2 in gas phase. Pure component isotherm and co adsorption isotherm is given in figure 1 & 2.

Exploring the connections between injection wells and seismic migration patterns is key to understanding processes controlling growth of fluid-injection induced seismicity. Numerous seismic clusters in Oklahoma have been associated with wastewater disposal operations, providing a unique opportunity to investigate migration directions of each cluster with respect to the injection-well locations. We introduce new directivity migration parameters to identify and quantify lateral migration toward or away from the injection wells. We take into account cumulative volume and injection rate from multiple injection wells. Our results suggest a relationship between migration patterns and the cluster-well distances, and unclear relationship with injected volume and equivalent magnitudes. Migration away from injection wells is found for distances shorter than 5-13 km, while an opposite migration towards the wells is observed for larger distances, suggesting an increasing influence of poroelastic stress changes. This finding is more stable when considering cumulative injected volume instead of injection rate.

A document by Yunyao Li. Click on the document to view its contents.

The spatio-temporal variability of river processes is governed by the balance between basin scale sediment supply and channel transport capacity. This balance is being altered by rampant sediment mining from the rivers which results in channel alteration and loss of physical habitat. The sediment mining guidelines are mostly based on empirical approaches and do not consider the spatio-temporal variability of river processes. This study includes hydrologic and geomorphic analysis to understand sediment dynamics and to suggest guidelines for sediment mining. The study was carried out in the 1312 km long Narmada River basin, Central India using hydrological data (1987-2015), SRTM DEM and LULC data. We identified the major aggrading river reaches (100s of km long) on the basis of reach scale sediment mass balance analysis. These reaches are dominantly aggrading at the rate of ~50,000 tons/km/yr. Sediment yield values were used to identify major erosion hot spots in the river basin and its contribution to spatial variability in aggradation-degradation processes in the river channel. This spatial variability within channel was also ascertained through stream power and sediment supply relationship. Further, temporal variability in channel processes was observed in the aggrading reaches. This variability is mostly governed by sediment concentration. Higher sediment concentration (~1.5 g/l) in a given month may change degrading reaches into aggrading reaches. Spatial variability within aggrading reaches and sediment contribution from different sub-basins was further assessed through application of semi-distributed process based Soil and Water Assessment Tool (SWAT). SWAT-CUP yielded good calibration results (~ 40% of the measured data bracketed under the 95PPU envelope, for discharge and sediment load). SWAT was found to be suitable to analyze sediment yield distribution at HRU scale in the Narmada River basin, except for smaller and steeper subbasins where hillslope processes dominate. Further, spatial variability within these reaches was identified by analysis of bar dynamics. Satellite data based change detection analysis was used to identify aggrading channel bars. These bars may be focused for sand mining operations within the aggrading reaches, although limited to ~20% change in the sediment bar area.

Grain-scale pore geometry primarily controls the fluid distribution in rocks, affecting material transport and geophysical response. The dihedral angle (Θ) in the olivine–fluid system is a key parameter determining the pore fluid geometry in mantle wedges. Both curved and faceted olivine–fluid interfaces define Θ in the system, generating the faceted–faceted (FF), faceted–curved (FC), and curved–curved (CC) angles. However, the effect of faceting on Θ under various pressure and temperature (P–T) conditions and fluid compositions have not been constrained, and its mineralogical understanding is unresolved. This study evaluates the facet-bearing Θ and their proportions in olivine–multicomponent aqueous fluid systems. Our results show that 1/3 of olivine–fluid Θ are facet-bearing angles irrelative to the P–T conditions and fluid compositions. Faceting produces larger dihedral angles than the CC angles. The grain boundary plane (GBP) distribution reveals that the GBPs of faceted interfaces at triple junctions were subjected to low Miller Index faces ((100), (010), and (101)). Moreover, calculating the FF angles from two adjacent low Miller index planes highly reproduces measured angle values based on the olivine crystal habit. Therefore, our study suggests that the FF angle is strongly affected by olivine crystallography. The presence of faceting increases Θ and critical fluid fraction (Φc) for percolation, thus decreases the permeability. In the mantle wedge, where olivine crystallographic preferred orientation (CPO) is expected, increasing the FF angle proportion with associated changes in fluid pore morphology will lead to the permeability anisotropy and consequent geophysical anomalies.

Sub-cloud turbulent kinetic energy has been used to parameterize the cloud-base updraft velocity (wb) in cumulus parameterizations. The validity of this idea has never been proved in observations. Instead, it was challenged by recent Doppler lidar observations showing a poor correlation between the two. We argue that the low correlation is likely caused by the difficulty of a fixed-point lidar to measure ensemble properties of cumulus fields. Taking advantage of the stationarity and ergodicity of early-afternoon convection, we developed a lidar sampling methodology to measure wb of a shallow cumulus (ShCu) ensemble (not a single ShCu). By analyzing 128 ShCu ensembles over the Southern Great Plains, we show that the ensemble properties of sub-cloud turbulence explain nearly half of the variability in ensemble-mean wb, demonstrating the ability of sub-cloud turbulence to dictate wb. The derived empirical formulas will be useful for developing cumulus parameterizations and satellite inference of wb.

The widespread High Arctic Large Igneous Province (HALIP) exhibits prolonged melting over more than 50 Myr, an observation that is difficult to reconcile with the classic view of large igneous provinces and associated melting in plume heads. Hence, the suggested plume-related origin and classification of HALIP as a large igneous province have been questioned. Here, we use numerical models that include melting and melt migration to investigate a rising plume interacting with variable lithosphere thickness, i.e. an extended-basin-to-craton setting. Models reveal significant spatial and temporal variations in melt volumes and pulses of melt production, including protracted melting for at least about 30-40 Myr, but only if migrating melt transports heat upwards and enhances local lithospheric thinning. Plume material deflected from underneath the Greenland craton can then re-activate melting zones below the previously plume-influenced Sverdrup Basin, even though the plume is already ~500 km away. Hence, melting zones may not represent the location of the deeper plume stem at a given time. Plume flux pulses associated with mantle processes or magma processes within the crust may alter the timing and volume of secondary pulses and their surface expression. Our models suggest that HALIP magmatism is expected to exhibit plume-related trace element signatures throughout time, but potentially shift from mostly tholeiitic magmas in the first pulse towards more alkalic compositions for secondary pulses, with regional variations in timing of magma types. We propose that the prolonged period of rejuvenated magmatism of HALIP is consistent with plume impingement on a cratonic edge.

The Kuroshio-Oyashio Extension and Gulf Stream oceanic frontal zones with sharp sea-surface temperature gradients are characterized by enhanced activity of synoptic-scale cyclones and anticyclones and vigorous air-sea exchange of heat and moisture in the cold season. However, the air-sea exchanges attributed separately to cyclones and anticyclones have not been assessed. Here we quantify cyclonic and anticyclonic contributions around the oceanic frontal zones to surface turbulent heat fluxes, precipitation, and the associated hydrological cycle. The evaluation reveals that precipitation exceeds evaporation climatologically within cyclonic domains while evaporation dominates within anticyclonic domains. These features as well as the net moisture transport from anticyclonic to cyclonic domains are all enhanced in the presence of the frontal zones. Oceanic frontal zones thus climatologically act to strengthen the hydrological cycle through increasing low-level storm-track activity and specific humidity. These findings aid our understanding of the relationship between midlatitude air-sea interactions on synoptic- and longer-time scales.

Rabaul in Papua-New-Guinea is an extremely active andesitic caldera complex that displays a large spectrum of eruption styles. Since 1878, four sub-plinian VEI-4 and ten VEI1–3 (effusive, strombolian, vulcanian) eruptions occurred from Tavurvur and Vulcan, the two main active vents. We study the lava flows, bombs and pumices from five of these eruptions to investigate magma ascent rates and volatile outgassing during ascent. We measured total and connected porosities, permeability, and bubble connectivity that we relate with crystallinity, MND (Microlite Number Density) and MSD (Microlite Size Distribution) of plagioclases and orthopyroxenes. From the application of existing percolation models, we find that explosive products yield a percolation threshold between 50-60 vol% total porosity, while petrophysical parameters of effusive products and some of the bombs can be explained by bubble collapse driven by surface tension. Permeabilities range from 10 -10 m for pumices and bomb cores, while they range from 10 -10 m for bomb rinds and the lava flow. Sub-plinian products show low phenocryst contents (5-15 vol%), microlites generated by nucleation-driven crystallization, or glassy textures due to a lag in kinetic crystallization. Bombs and the lava flow on the other hand, show medium to high phenocryst contents (15-40 vol%) and microlites that crystallized by growth-dominated processes. Sub-plinian MSDs can be interpreted as a partial record of drastic magma acceleration, while bombs and lava flows show slower, more gradual ascent patterns. We estimate that magma feeding sub-plinian eruptions ascends 2-3 orders of magnitude faster than magma feeding vulcanian/effusive eruptions (~1 versus 10 MPa/s). The faster rising speeds cannot be estimated using MNDs due to the important lag in kinetic crystallization, but are instead estimated by the average dimension of pyroclasts and their characteristic timescale of permeable gas escape. Combining petrophysical and textural measurements we suggest that slight changes of initial conditions in the reservoir, such as phenocryst content, can have profound impacts on the ascent rate and generate positive or negative feedback reactions leading to powerful sub-plinian activity or intermittent vulcanian/ quiet effusive activity respectively.