SKB and several other waste management organisations have established the international SKB Task Force on Modelling of Groundwater Flow and Transport of Solutes (TF GWFTS) to support and interpret field experiments. An important objective of the task force is to develop, test and improve tools for conceptual understanding and simulating groundwater flow and transport of solutes in fractured rocks. Work is organised in collaborative modelling tasks. This study considers Task 9, which focuses on realistic modelling of coupled matrix diffusion and sorption in heterogeneous crystalline rock matrix at depth. This is done by inverse and predictive modelling of different in-situ transport experiments. The ultimate aim is to develop models that in a more realistic way represent retention in fractured rock. The Long-Term Diffusion and Sorption Experiment (LTDE-SD) was an in-situ radionuclide tracer test performed at the Äspö Hard Rock Laboratory at a depth of about 410 m below sea level. It is one of few recent in-situ studies focusing on tracer transport in the stagnant pore water of the crystalline rock matrix. The experimental results indicated a possible deeper penetration of tracers into the rock matrix than expected and the shape of the penetration profiles were not according to theory. Posiva’s REPRO (rock matrix REtention PROperties) experimental programme has been performed at the ONKALO rock characterisation facility in Finland. The two REPRO experiments considered were the Water Phase Diffusion Experiment, addressing matrix diffusion in gneiss around a single borehole interval, and the Through Diffusion Experiment, which is performed between sections of three boreholes. These three experiments provided an opportunity to improve the conceptual understanding of solute transport in fractured rock and to increase the realism in solute transport modelling, with the ultimate goal of improving safety assessments of deep geological disposal for nuclear waste. Of additional interest is the collective work performed by the task force to conceptually understand and interpret the field experiments, and at the same time increase the realism in solute transport modelling. This study would not have been possible without the support from the waste management organisations and the work by the multiple modelling teams.

Ganga river basin (GRB) in the Indian subcontinent is one of the most heavily irrigated land in the world. According to a book published in 2005 by Central Water Commission (CWC), 57% of the net irrigated land in India lies inside GRB only. Further GRB is also one of the most populous river basins in the world supporting almost 400 million people of India. With increasing use of fertilizers in agriculture and untreated sewage waste from the booming industries, there is need to assess the water quality and the contamination in surface water. We will use Soil Water Assessment Tool (SWAT) to model the hydrology of the river basin. For water quality analysis, SWAT is able to simulate the impact on hydrology, sediment and nutrients load, due to physical changes brought in the large ungauged river basins. We hypothesize that numerous small, rain-fed rivers in the Indo-Gangetic floodplain that are flowing predominantly through agricultural land are important non-point source of Nitrogen(N) and Phosphorus (P) and will control the nutrient budget of large river system. SWAT model will be used to simulate flow and nutrient/sediment concentrations of nitrogen/nitrates, phosphorus and sediment in the upper reach at Uttarkashi and Rishikesh, in the middle reach at Kanpur, Lucknow and Varanasi, and Farakka at the lower reach. SWAT model will be calibrated at daily/monthly time step for flow and monthly scale for water quality parameters. We will analyze the water quality in the basin using widely used Water Quality Index (WQI) considering pH, TDS, BOD, COD, hardness, nitrates, carbonates and silicates. We will use gridded climate data from Indian Meteorological Department (IMD) and water quality data from CWC. SRTM 90 m DEM, 300 m Land use/land cover map from Climate Change Initiative (CCI) and 7 km soil map from Food and Agriculture Organization (FAO).

The nature of the relationship between soil-moisture and subsequent precipitation is debated. Past studies have indicated that it varies by location, but there have been disagreements on feedback sign, strength and statistical significance over the same locations even while using the same data sets due to differences in statistical approaches. Here we re-evaluate estimates of feedback strength using Granger causality (following Tuttle and Salvucci 20016) for SMOS and AMSR-2soil moisture products and find that there is evidence both of there being a positive feedback over the entire nation (SMOS) and of there being a west-to-east gradient of positive to negative values (AMSR-2, similar to what was found by Tuttle). This project has demonstrated that differences arise using identical statistical estimation techniques with different satellite estimates of soil moisture. The passive microwave AMSR-E and AMSR-2 data produce a gradient of positive to negative impact factors across the U.S. while the SMOS data set yields a mostly positive impact factor over the entirety of the U.S. Here we explain this discrepancy by noting that the areas where the sign of the impact differ are areas where the soil moisture perturbations of SMOS and AMSR-2 are anticorrelated, and also that these areas coincide with areas of high vegetation cover, which are well known to challenge remote sensing estimates of moisture.

Key points: • The detrimental impact of preadsorbed water on the methane adsorption capacity and rate is more pronounced than that of water vapor • The distributions of adsorbed methane and water in shale pores were compared between the SAWM and PMMS • Water vapor preferentially enters mesopores (1.5-20 nm), and preadsorbed water mainly occupies micropores (0.3-1.5 nm) Abstract Water plays an essential role in shale gas migration and adsorption, and most studies on the influence of water on shale gas adsorption refer only to moisture-equilibrated shales. To investigate the impact of water vapor on methane adsorption in shales, three experiments were conducted and compared: (1) pure methane adsorption onto dry shale (PMD), (2) pure methane adsorption onto moisture-equilibrated shale (PMMS), and (3) simultaneous adsorption of water vapor and methane (SAWM) onto shale. Comparison of the experimental results reveals that the detrimental impact of water vapor on methane adsorption is inferior to that of preadsorbed water. Two mechanisms, i.e., water blocking and adsorption competition, are responsible for the reduction and difference in the methane adsorption capacity and adsorption rate between the PMMS and SAWM. Compared to the PMD, the methane adsorption capacity decreases by 81-96% in the PMMS, and by 20-49% in the SAWM. Methane adsorption equilibrium is achieved the fastest in the PMD. Before the equilibration degree reaches 95%, methane adsorption during the SAWM progresses more rapidly, while the reverse occurs when the equilibration degree exceeds 95%. The pore size distribution and water film thickness calculations indicate that the impacts of water vapor in the SAWM on micro-to mesopores are weaker than those of preadsorbed water. In the PMMS, adsorbed water mainly

Accurate forecast of solar irradiance remains a major challenge, especially under the influences of aerosols, clouds and aerosol-cloud interactions due to their inadequate parameterizations in numerical prediction models. This study focuses on the impacts of cloud microphysics and the indirect aerosol effect on solar irradiance. The state of art Weather Research and Forecasting model specifically designed for simulating and forecasting solar radiation (WRF-Solar) is employed to investigate the sensitivity of the total solar irradiance and its partitioning into direct and diffuse irradiances to aerosol and cloud properties. First, a number of microphysical schemes will be tested against the measurements of shallow cumulus and stratiform clouds at the DOE ARM SGP site. Efforts will be made to quantify the uncertainty spread. The effects of cloud microphysics on surface solar irradiance will be identified. Second, the indirect aerosol effect on cloud formation and thus surface solar irradiance will be investigated by using the Thompson aerosol aware microphysical scheme and different treatment of aerosols. In particular, we will examine the aerosol indirect effects in different cloud regimes. To address the aforementioned problems, we will introduce a new model evaluation framework based on different WRF-Solar setups (nested WRF, WRF-LES, and single column WRF). In addition, different evaluation metrics will be used, including the RMSE, MAPE, and relative Euclidean distance. The results will provide physical insight into the understanding of aerosol-cloud-radiation interactions and into improving solar radiation forecast in cloudy conditions.

Redox input by subducting slab into deep mantle is of vital importance for deep cycle and isotopic evolution of volatile elements, whose chemically stable forms are controlled by redox state. Lithospheric mantle is crucial in redefining redox state of the Earth’s deep mantle. To constrain to which extent subducted slab can modify redox state of the upper mantle and how much oxygen slab can carry into deep Earth, we investigated redox kinetics of olivine adopting diffusion couple methods at 1 GPa and 1373-1573 K in a piston cylinder apparatus. It is found that redox process in olivine is diffusion-controlled, and diffusing on the order of 10-12 m2/s at 1473 K. The oxidation process in initially reduced olivine is oxygen fugacity (fO2)-independent with activation enthalpy of 235±56 kJ/mol, while the reduction process in initially oxidized olivine is fO2-dependent with an exponent of 2/5. Diffusion profile analysis reveals that redox state of starting material plays decisive role in determining redox mechanism. Below ΔFMQ+1, redox process in olivine is controlled by oxygen grain boundary diffusion, while above ΔFMQ+1, it is rate-limited by faster diffusion species which might be hydrogen related Mg vacancy. The extremely slow redox rate limits the homogenization of the slab and its surrounding mantle as redox state of the upper mantle remains unchanged for over past 3.5 Gyrs. The subducted slab has the ability to efficiently transport oxidized components to the region deeper than the mantle transition zone. A highly underestimated oxygen reservoir may have formed in the deep Earth.

The style of convective force transmission to plates and strain-localization within and underneath plate boundaries remain debated. To address some of the related issues, we analyze a range of deformation indicators in southern California from the surface to the asthenosphere. Present-day surface strain rates can be inferred from geodesy. At seismogenic crustal depths, stress can be inferred from focal mechanisms and splitting of shear waves from local earthquakes via crack-dependent seismic velocities. At larger depths, constraints on rock fabrics are obtained from receiver function anisotropy, Pn and P tomography, surface wave tomography, and splitting of SKS and other teleseismic core phases. We construct a synthesis of deformation-related observations focusing on quantitative comparisons of deformation style. We find consistency with roughly N-S compression and E-W extension near the surface and in the asthenospheric mantle. However, all lithospheric anisotropy indicators show deviations from this pattern. Pn fast axes and dipping foliations from receiver functions are fault-parallel with no localization to fault traces and match post-Farallon block rotations in the Western Transverse Ranges. Local shear wave splitting inferences deviate from the stress orientations inferred from focal mechanisms in significant portions of the area. We interpret these observations as an indication that lithospheric fabric, developed during Farallon subduction and subsequent extension, has not been completely reset by present-day transform motion and may influence the current deformation behavior. This provides a new perspective on the timescales of deformation memory and lithosphere-asthenosphere interactions.

The spectacular fossil plant assemblage preserved in the non-marine Mount Flora Formation of the northern Antarctic Peninsula represents the diverse Jurassic flora that once covered the Gondwanan continents at high paleolatitudes. The depositional facies of the formation plays a key role in the tectonic interpretations and basin evolution models that attempt to reconcile large igneous province magmatism, continental break up, and magmatic arc development throughout the Jurassic and Cretaceous. Limited U-Pb in situ geochronology reported from the Mount Flora Formation and adjacent units lack the necessary resolution to overcome ambiguous correlations and biostratigraphic discrepancies. We present two high-precision U-Pb zircon ages (CA-ID-TIMS method) from a distinct tuffaceous interval of the Mount Flora Formation at Hope Bay, which document a terminal Middle Jurassic age (Callovian Stage) for the formation and its paleoflora. In excess of 1400 new collected fossil plant specimens exhibit a highly diverse Jurassic plant association that dominated the Antarctic Peninsula nearly 17 million years after its disappearance from northern Patagonia. This suggests similar paleoecological conditions were established diachronously throughout basins of southern Gondwana, possibly facilitating floral migrations in response to local climate change. The depositional facies of the Mount Flora Formation, its age proximity to the marine Nordenskjöld Formation in the Antarctic Larsen Basin, and its coincidence with a regional unconformity in the northern Patagonia point out to a complex interplay among magmatic arc development, tectonic extension and continental break up that dominated the geologic and paleoenvironmental evolution of southern Gondwana near the end of the Middle Jurassic.

Regional water storage monitoring is very essential and critical for regional water resource management, hydro-ecological sustainable development and studying interaction between hydrology and climate. We used multi-mission satellite dataset, a global hydrological model, and ground meteorological data to investigate the terrestrial water storage changes (TWSc) in the Qaidam basin (QB). Terrestrial water storage (TWS) exhibited an increasing trend for the past 17 years, and TWSc obtained from different methods or dataset were consistent with precipitation. Through the singular spectrum analysis, we obtained the interannual and seasonal components of TWSc, and significant shifts in the interannual TWSc were observed in the QB. TWS exhibited an increase from 2002 to 2013, a decrease from 2013 to 2016, and an accelerated increase after 2016. Additionally, the study reported that the interannual change in TWS was strongly correlated with the Pacific Decadal Oscillation (PDO), compared to Arctic Oscillation and El Nino-Southern Oscillation.

Accurate fire emissions inventories are crucial to predict the impacts of wildland fires on air quality and atmospheric composition. Two traditional approaches are widely used to calculate fire emissions: a satellite-based top-down approach and a fuels-based bottom-up approach. However, these methods often considerably disagree on the amount of particulate mass emitted from fires. Previously available observational datasets tended to be sparse, and lacked the statistics needed to resolve these methodological discrepancies. Here, we leverage the extensive and comprehensive airborne in situ and remote sensing measurements of smoke plumes from the recent Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign to statistically assess the skill of the two traditional approaches. We use detailed campaign observations to calculate and compare emission rates at an exceptionally high resolution using three separate approaches: top-down, bottom-up, and a novel approach based entirely on integrated airborne in situ measurements. We then compute the daily average of these high-resolution estimates and compare with estimates from lower resolution, global top-down and bottom-up inventories. We uncover strong, linear relationships between all of the high-resolution emission rate estimates in aggregate, however no single approach is capable of capturing the emission characteristics of every fire. Global inventory emission rate estimates exhibited weaker correlations with the high-resolution approaches and displayed evidence of systematic bias. The disparity between the low resolution global inventories and the high resolution approaches is likely caused by high levels of uncertainty in essential variables used in bottom-up inventories and imperfect assumptions in top-down inventories.

The domain nesting of the icosahedral non-hydrostatic (ICON) model has been used operationally at Deutscher Wetterdienst for several years. Now it was also made available for the atmospheric part of the ICON Earth system model. With this new climate configuration, regionally higher resolved simulations without the additional use of a separate regional climate model (RCM) are possible. Simulations were performed for the years 1979-2010 at a global resolution of about 80 km and a subdomain over Europe at 40 km resolution. Two simulations with this setup were evaluated and compared: one with a feedback from the regional subdomain to the global domain (two-way nesting) and one without feedback (one-way nesting). The mean atmospheric state of both simulations on the global scale is only slightly different compared to a reference experiment. However, comparisons to reanalyses show regionally distinct biases. The feedback from the subdomain to the global domain has a similar impact over Europe as a globally higher resolution, indicating a stronger North-Atlantic Oscillation at higher horizontal resolution. Over Europe, the skill is higher in the subdomain than in the global domain, but no systematic advantages can be attributed to the feedback. Artifacts at the lateral boundaries of the regional subdomain, as they are known from RCM simulations, also occur strongly in the simulation without feedback and are eliminated by allowing the feedback. A further reduction of resolution dependency of model physics is supposed to improve particularly the simulation with feedback.

Estuarine dams can result in profound changes to estuarine environments. However, their impact on estuarine currents, stratification, and sediment fluxes is not well understood. To develop a general understanding, an idealized modeling study was carried out using the Coupled-Ocean-Atmosphere-Wave-Sediment Transport Modeling System. Idealized estuarine geometry was based on 10 estuaries with estuarine dams. Tide and river forcing were varied to produce strongly stratified, partially mixed, periodically stratified, and well-mixed estuaries. Each model ran for one year. Next, the models were subject to the construction of an estuarine dam and run for another year. Then, the pre- and post-dam conditions were compared. Results showed that estuarine dams amplify the tidal range and reduce the tidal currents. The post-dam estuaries tended to be salt wedge and strongly stratified types during freshwater discharge, but during no freshwater discharge they became fjord, bay, or periodically stratified types based on the estuarine parameter space. For all estuaries, the estuarine turbidity maximum moved seaward, and the suspended sediment concentrations tended to decrease. While the depth changes depended on the estuary type, the surficial sediment texture shifted to being muddier for all types. In terms of sediment flux mechanisms, the estuarine dam reduced the exchange flow and Stokes transport. The estuarine dam also increased the seaward river runoff for cases with strong river, and increased the landward tidal pumping for cases with strong tides. This study is one of the first to generalize the effect of estuarine dams to a range of estuarine types.

We have studied the focal mechanisms of eleven earthquakes with magnitudes of ML ≥ 3.8 on the continental margin of Egypt and the adjacent onshore region from 1951 to 2020 to identify the stress regime and its spatial variations. The uncertainty parameters of each solution are evaluated using HASH software. The stress pattern obtained from focal solutions in the western province matches a compressional stress field with an NNW-SSE orientated compression axis, which corresponds to the direction of movement of the Nubia plate relative to Eurasia. On the other hand, the stress pattern derived from drilling-induced fractures and borehole breakout measurements is not correlated with the identified stress axis. The focal solutions of the recent earthquakes in the eastern-central province of the Nile Deep-Sea Fan indicate the strike-slip stress regime is the prevailing mode of deformation with an almost horizontal ESE-WSW compression axis and an almost horizontal N-S extension axis. Two responsive conjugate strike-slip faults that include both sinistral and dextral faults accommodate this strike-slip deformation style. The stress regime existing in the eastern-central province directly contradicts the northward convergent of the Nubian-Anatolia plates along the Cypriot arc. The stress pattern deflection in the eastern-central province of the Nile Deep-Sea Fan may be attributed to kinematic adaptation resulting from the deformation in and around the Eratosthenes Seamount rigid block as it impinges on the central part of the Cypriot arc. Toward the Egyptian onshore, the extension pattern was behaving differently from the compression stress pattern of the offshore continental margin.

The Quánjí Block (QB) is a sliver of anomalously old and well-preserved continental crust embedded within the Paleozoic-Mesozoic tectonic collage of the northeastern Tibet Plateau. New geological mapping, stratigraphic logging, and geochronological analysis leads to a refined understanding of QB’s history from Paleoproterozoic to present. Deposited atop a largely Paleoproterozoic basement, the Quánjí Group records rifting and epicratonic cover at 1.7-1.6 Ga. The Xiǎogāolú Group preserved black shale, ribbon-shaped fossil and the Ediacaran‐Cambrian glaciation. Ages from Cambrian Olóngbùlǔkè Group samples in open platform deposits are quite different from ages in underlying units, with a subdued age groups in the Neoproterozoic (880-815 Ma) ages. The apparent change in detrital zircon sources coincides with the regionally expressed Great Unconformity during the Precambrian-Cambrian transition. The new mapping, stratigraphy, and U-Pb geochronology of QB suggest the late Paleoproterozoic to Cambrian history of QB has a remarkable similarity to that of North China Block’s (NCB’s) southern margin, and indicate that the QB has been displaced dextrally from an initial location adjacent to NCB. The transform motion occurred in stages between ca. 350 and 200 Ma.

February-March 2020 was marked by highly anomalous large-scale circulations in the Northern extratropical troposphere and stratosphere. The Atlantic jet reached extreme strength, linked to some of the strongest and most persistent positive values of the Arctic Oscillation index on record, which provided conditions for extreme windstorms hitting Europe. Likewise, the stratospheric polar vortex reached extreme strength that persisted for an unusually long period. Past research indicated that such circulation extremes occurring throughout the troposphere-stratosphere system are dynamically coupled, although the nature of this coupling is still not fully understood and generally difficult to quantify. We employ sets of numerical ensemble simulations to provide statistical characterizations of the mutual coupling of the early 2020 circulation extremes. We find an overall robust coupling between tropospheric and stratospheric anomalies: ensemble members with polar vortex exceeding a certain strength tend to exhibit a stronger tropospheric jet and vice versa. Moreover, members exhibiting a breakdown of the stratospheric circulation (associated with a sudden stratospheric warming) tend to lack periods of persistently enhanced tropospheric circulation. A crucial component in determining the stratospheric vortex strength appears to be the vortex geometry, corresponding to states that promote either reflection or dissipation of planetary waves. Despite these lines of evidence for vertical coupling, our simulations underline the role of internal variability within each atmospheric layer. The circulation extremes during early 2020 may be viewed as resulting from a fortuitous alignment of dynamical evolutions within the troposphere and stratosphere, aided by each layer’s modification of the other layer’s boundary condition.

To explore the repeating mud volcanoes influences on the seismicity behaviors, we measured the spatial distribution z and b value changes with the time in the mud volcanoes developing area. We find a weak correlation between the b-z values and the mud volcanoes. Generally, the z-values anomalies of the mud volcanoes area show unchanged negative values and indicate the seismic quiescence before a strong earthquake, while the b-values show the frequently periodicity fluctuations around the value of 0.5. It may indicate the conjunct triggering relationships between the mud volcanoes and earthquakes stuck. We infered that the mud volcanoes eruptions help to partition and release part of the regional stress accumulation from the earthquake seismogenic structures, thus balanced the local stress in the strata. Keywords: Mud volcano; SW Taiwan; coulomb stress change; b-z-value; conjunct triggering relationship

Equatorial Pacific decadal variability (EPDV) modulates global climate. Although EPDV is suggested to be generated by both air-sea thermodynamically coupled slab ocean models (SOM) and fully coupled dynamic ocean models (DOM), the reason of EPDV simulated by the two distinct hierarchies of models remains unclear. This ambiguity arises from a gap in the dynamical framework between SOM and DOM. To fill the gap, we conducted a novel experiment (Clim-tau) that retains only the effects of thermodynamic coupling and mean ocean current on EPDV (without anomalous ocean current). We showed that in Clim-tau, thermodynamic-driven EPDV as in SOM is largely damped by equatorial Pacific mean upwelling; whereas involving anomalous ocean current as in DOM, the damped EPDV will be further amplified. Finally, we discussed the role of ocean dynamics in the observed EPDV. Our study highlights that SOM may misinterpret the physical mechanisms in the regions where ocean dynamics is important.

Thermobarometry is a fundamental tool to quantitatively interrogate magma plumbing systems and broaden our appreciation of volcanic processes. Developments in random forest-based machine learning lend themselves to a more data-driven approach to clinopyroxene thermobarometry. This can include allowing users to access and filter large experimental datasets that can be tailored to individual applications in Earth Sciences. Here we present a methodological assessment of random forest thermobarometry, using the R freeware package “extraTrees”, by investigating the model performance, tuning hyperparameters, and evaluating different methods for calculating uncertainties. We determine that deviating from the default hyperparameters used in the “extraTrees” package results in little difference in overall model performance (<0.2 kbar and <3 ⁰C difference in mean SEE). However, accuracy is greatly affected by how the final pressure or temperature (PT) value from the voting distribution of trees in the random forest is selected (mean, median or mode). This thus far has been unapproached in machine learning thermobarometry. Using the mean value leads to a higher residual between experimental and predicted PT, whereas using median values produces smaller residuals. Additionally, this work provides two comprehensive R scripts for users to apply the random forest methodology to natural datasets. The first script permits modification and filtering of the model calibration dataset. The second script contains pre-made models in which users can rapidly input their data to recover pressure and temperature estimates. These scripts are open source and can be accessed at https://github.com/corinjorgenson/RandomForest-cpx-thermobarometer.