bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnosing spatial and temporal variations in the response of carbon use efficiency to vegetation states and climate across terrestrial ecosystems
Authors: Zhang Yahai , Koirala Sujan , Ye Aizhong , Yang Hui , Carvalhais Nuno
Published: February 2023

        Carbon use efficiency (CUE) of vegetation is a property emerging from physiological processes, a key parameter to determine vegetation growth, which ultimately reflects the relative potential of terrestrial ecosystems to store atmospheric carbon in biomass. Large uncertainties were found in global CUE estimated by remote sensing data models or process-based models, especially across plant functional types (PFTs) and regarding seasonal variations. This study explores the specific effects of climate and vegetation state on CUE based on a model-data integration approach by analyzing outputs from a terrestrial ecosystem model driven with local meteorological variables and constrained by in situ observations of vegetation biomass, as well as carbon and water fluxes from eddy covariance measurements. We leverage on a modular model-data-integration framework – SINDBAD – that allows for an integrated model selection, parameterization and evaluation approach based on in situ observations. In addition, various other simulations based on global observations and global modeling approaches, including MODIS, GLASS, Trendy, MsTMIP, and CMIP6, are further explored with the aim of examining spatial and temporal patterns of CUE to better understand the modelled biological and climate controls of CUE.        The range of global annual CUE values for the 50 models between 2001 and 2010 is 0.3083 to 0.5920. Our study shows that adding constraints on modelled vegetation biomass, in general, brings slight deterioration to the simulation of carbon fluxes but significantly changes the patterns of CUE. In general, biomass constraints decrease the emerging CUE estimates, even in non-forested sites in the Northern Hemisphere. The vegetation state constraints increase 14.42% of sites distributed at 0.2-0.4 median CUE yearly values and decrease 14.92% of sites distributed at 0.4-0.6. Constraints on vegetation carbon stocks result in changes in modelled autotrophic respiration, which change more significantly across sites than gross primary productivity. The information provided by the vegetation state variables results generally in lower wood and slow litter turnover rate, and an increased sensitivity of CUE to moisture and adaptation to temperature. Ultimately, here we provide model-based results for investigating the mechanisms behind the spatial and temporal variability of CUE, potentially contributing to a better quantified CUE variation globally.
Determination of pitch-angle diffusion coefficient from bi-Maxwellian velocity distribution functions
Authors: Dubart Maxime , Battarbee Markus , Ganse Urs , Osmane Adnane , Spanier Felix , Alho Markku , Cozzani Giulia , Bussov Maarja , Horaites Konstantinos , Pfau-Kempf Yann , Suni Jonas , Tarvus Vertti , Turc Lucile , Zaitsev Ivan , Zhou Hongyang , Palmroth Minna
Published: February 2023

Pitch-angle diffusion is one of the main processes of isotropisation of ions in the Earth's magnetosheath. It results from the proton cyclotron and mirror instabilities, arising from temperature anisotropy in the magnetosheath, and is governed by the pitch-angle diffusion coefficient Dμμ. We have previously developed a sub-grid model to describe pitch-angle diffusion in global-hybrid Vlasov simulations when coarse spatial grid resolution leads to a lack of diffusion. In this study, we present an analytical solution for a pitch-angle diffusion coefficient derived from bi-Maxwellian velocity distribution functions in order to apply this solution to the sub-grid model. This will allow us to model accurately the isotropisation of the distribution functions and to reduce the temperature anisotropy of the plasma while saving computational resources. 
Fingerprints of the COVID-19 economic downturn and recovery on ozone anomalies at remote high-altitude sites in North America and Western Europe
Authors: Putero Davide , Cooper Owen R. , Beachley Gregory , Chang Kai-Lan , Couret Cédric , Effertz Peter , Jaffe Dan , Lynch Jason , Petropavlovskikh Irina , Puchalski Melissa , Sharac Timothy , Sive Barkley C. , Steinbacher Martin , Torres Carlos , Cristofanelli Paolo
Published: February 2023

With a few exceptions, most of the studies on tropospheric ozone (O3) variability following the restriction measures related to the spread of COVID-19 focused on emissions-prone or urban environments. In this work, we investigated the impact of the pandemic restriction measures on surface O3 at several high-altitude remote and rural sites across North America and Western Europe. O3 monthly anomalies, computed with respect to the baseline period 2000–2019, were calculated for 2020 and 2021, to explore the impact of the economic downturn in 2020 and the economic recovery in 2021. A total of 41 high-altitude sites were analyzed: 5 remote stations in western Europe, 19 rural sites in the western US, 4 sites in the western US downwind of highly polluted areas, 4 sites in the eastern US, plus 9 remote sites across the globe to provide a "global" picture for comparison. In 2020, most of European high-altitude sites showed persistent negative anomalies for spring (March-May, i.e., MAM; average of -1.8 ppb) and summer (June-August, i.e., JJA; -2.7 ppb), except for April (1.8 ppb). The pattern was similar in 2021 (-1.8 ppb for both MAM and JJA), except for June (1.8 ppb). The sites in the western US showed similar behavior, with negative anomalies in 2020 (-2.1 ppb for MAM and -0.5 ppb for JJA), and 2021 (-0.5 ppb for MAM). However, the JJA seasonal average was influenced by strong positive anomalies in July, due to the large spread of wildfires in the western US. The polluted rural sites in the western US showed a negative O3 anomaly for MAM 2020, and a slight recovery in 2021, resulting in a positive anomaly for MAM and alternating positive and negative anomalies in JJA. The eastern US sites were characterized by below baseline numbers for both MAM and JJA 2020, while in 2021 the negative values generated a "dipole" structure, with the western sites influenced by the presence of wildfires. Concerning the rest of the world, a global picture could not be drawn, as the sites, spanning a range of different environments, did not show consistent anomalies across the globe. A few sites did not experience any relevant variations (e.g., the Antarctic sites), while others showed signals of influence from the surrounding environment, or behaviors like those observed for European and US remote sites. We also attempted anomaly attribution by analyzing the behavior of several O3 precursors (e.g., surface and columnar CO, NO, and NO2) from the CAMS reanalysis, and the patterns of emissions reductions for 2019, 2020, and 2021.
Reservoir compaction: What role does petrographic heterogeneity play in the Groningen Gas field?
Authors: Mulder Sebastian , Miocic Johannes
Published: February 2023

Fluid extraction from geological formations for purposes of subsurface utilization (e.g. hydrocarbon production, fluid storage, geothermal energy production) leads to pore pressure drop in reservoirs. The weight of the rock layers above the reservoir is partially carried by both the reservoir pore pressure and by the reservoir rock itself. Therefore, if fluids are extracted from the subsurface, the reservoir will experience an increase in compressional stress, which may lead to compaction of the reservoir rock. One type of reservoir rock that are highly susceptible to diagenetic processes and compaction due to pore pressure changes are porous sandstones. As the compressional strength of sandstone reservoirs is directly related to the petrographic composition of the rock, understanding the impact of mineralogical composition and textural relationships on reservoir compaction is key. An example of a sandstone reservoir where production related compaction occurs and is associated with surface subsidence and seismicity is the Groningen gas field, situated in the north-eastern part of the Netherlands. However, a detailed model for the reservoir petrography does not exist for the Groningen gas field. The aim of this study is to identify petrographic controls that have an impact on geomechanical behaviour of the gas field by means of optical microscopy (OM) and scanning electron microscopy (SEM) in order to develop a predictive petrographic model. Grain properties, grain displacement, grain contacts, packing texture and paragenetic sequences are studied on a selection of cored wells in the gas field. Mineralogical composition and diagenetic history is determined by OM and its subsequent impact on sandstone compaction. Different phases of clay have been identified by FESEM and EDS that surround clays and occupy the pore space, which locally inhibits cementation of quartz, feldspar or dolomite. Therefore,  the timing and extent of clay growth likely play an important role for the geomechanical stability of the reservoir sandstones. This project will contribute to our understanding of the reservoir heterogeneity of the Groningen gas field and improves our knowledge of subsurface response to subsurface utilisation.
Emission Inventories for 76 Cities In India for Clean Air Strategies
Authors: Singh Pratima , Banerjee Anirban , Kumar Udhaya , Tiwari Amishi , Gautam Hrishikesh , Mishra Sameer
Published: February 2023

Understanding polluting sources, for improving Air Quality (AQ) levels at the city/airshed level is required to solve the air pollution challenge. Scientific evidence like Emission Inventory (EI); identification of efficient technologies; implementation roadmap; and cost and resources required, are needed to develop clean air strategies.This study considered 76 Non-Attainment (NA) cities in India, for developing EI at an airshed level. Various polluting sectors and activities were identified. Data from various sources and ground surveys were used to generate evidence. The EI was developed for the base year 2019 for 4 pollutants– Particulate Matter (PM10 and PM2.5), Sulphur dioxide (SO2), and oxides of Nitrogen (NOX). Based on the city EI, sector-specific technologies and control measures were identified and prioritized using Techno-Economic Assessment (TEA) and the emission reduction potential. Gap Analysis was conducted to identify sectoral targets for reducing emissions.The Emission load varied for types of cities (tier I, II, or III) based on landscape, and anthropogenic activities. It was observed that city-level PM2.5 emissions from three sectors - transportation (tailpipe: 30%-50%; road dust: 8%-17%); domestic (14%-30%); and Industries (6%-29%) were high for all the cities. In a few cities, heavy industries within the city boundary dominated the industrial share in the city’s total PM2.5 emission load (34%-88%). Hence, heavy industries were excluded from the analysis to better understand the city's emission level. The study helped to understand the city vs airshed emission load. In 46% of the cities, it was found that the airshed emission load (excluding city emission) was high due to the presence of heavy industries.Using TEA, the study estimated the associated cost of the identified control measures feasible for implementation at the city level. The required cost was based on the existing gaps in the current infrastructure needs of the city. In tier 2 cities, the transportation sector required heavy infrastructure. Capital investment, for transportation, was estimated between INR 300 – 800 Cr on measures such as a) improving public transportation, b) LNG for freight transport, and c) replacing older vehicles. However, in tier 3 cities increasing LPG connections and strategies to reduce solid fuel usage (advanced chullah’s) were found to be critical interventions, which required investment of less than 50cr. The study also carried out emission reduction scenarios till 2030. In comparison to the business-as-usual scenario, under a high emission reduction scenario, PM2.5 emission reduction for tier 2 cities were up to 45%, and for tier 3 cities up to 54%. The study found that developing clean air strategies need to adopt an airshed approach.
Electron-scale reconnecting current sheet formed within the lower hybrid wave-active region of Kelvin-Helmholtz waves
Authors: Blasl Kevin Alexander , Nakamura Takuma , Nakamura Rumi , Settino Adriana , Vörös Zoltan , Hosner Martin , Schmid Daniel , Volwerk Martin , Roberts Owen Wyn , Panov Evgeny , Liu Yi-Hsin , Plaschke Ferdinand , Hasegawa Hiroshi , Stawarz Julia , Holmes Justin Craig
Published: February 2023

The Kelvin-Helmholtz instability (KHI) excited at the Earth’s magnetopause has been considered responsible for causing efficient mass and energy transfer across the magnetopause. Theoretical, numerical and observational studies have revealed that the evolution of the KHI and the resulting nonlinear vortex flow involve secondary processes. As a unique case of such multi-scale and inter-process couplings, we recently reported observations of the MHD-scale KH waves and embedded smaller-scale phenomena in data from NASA’s Magnetospheric Multiscale (MMS) mission at the dusk- flank magnetopause during southward interplanetary magnetic field (IMF) conditions. Given quantitative consistencies with corresponding fully-kinetic particle-in-cell (PIC) simulations designed for this event, the MMS observations demonstrate the onset of the Lower-Hybrid Drift Instability (LHDI) during the nonlinear phase of the KHI and the subsequent turbulence and mixing of plasmas near the boundary layer.In this study, we further explored this southward IMF KHI event and found signatures of magnetic reconnection in an electron-scale current sheet observed in the KH vortex-driven LHDI turbulence. This reconnection event was observed under high guide field conditions and features a super-Alfvénic electron outflow, a Hall perturbation of the magnetic field and enhanced energy conversion. Results from a high-resolution PIC simulation designed for this reconnecting current sheet suggest a highly dynamical current sheet evolution, quantitatively consistent with the observations made by MMS.In addition, results from statistical studies utilizing data from several KH wave/vortex edge crossings throughout this southward IMF KH event show that the formation of electron-scale current sheets due to the interplay of the KHI and LHDI would be a ubiquitous phenomenon at least under the observed conditions of this magnetopause event and thus an important factor in the study of cross-scale energy transfer of the KHI.
Multiinstrumental observations of traveling ionospheric disturbances over Europe
Authors: Buresova Dalia , Panasenko Sergii V. , D. Aksonova Kateryna , Bogomaz Oleksandr V. , Zhivolup Taras G. , Koloskov Alexander V.
Published: February 2023

The paper presents results of the analysis of the TID activity and changes in the regular ionospheric variability observed over central and eastern Europe during geomagnetically quiet days, and during CME and CIR/HSSS-related storms. We analyzed main ionospheric parameters retrieved from manually scaled ionograms obtained at several central and eastern European locations and incoherent scatter radar data (Kharkiv, Ukraina). Large scale traveling ionospheric disturbance (LSTIDs) are thought to be mostly originated in the auroral zone in consequence of increased geomagnetic activity. Although there have been numerous studies of TIDs, current knowledge is often based on observing only limited set of parameters and two-dimensional characteristics (for example, total electron content by GNSS receivers or airglow brightness by all-sky imagers). Incoherent scatter technique enables simultaneous studies of altitudinal characteristics of TIDs in several parameters like electron density, electron and ion temperature and plasma drift, thus providing important information needed to investigate TIDs, their propagation and consider probable association of TIDs with their sources. This technique also yields all components of wave vector, provided that the radar has the ability to operate in multi-beam mode. In order to obtain quantitative information on the likeliness and morphology of the passage of LSTIDs over Europe at about 40 events were examined lasting between 8 and 24 hours each. In this paper we focused mainly on a couple of geomagnetic disturbances (depending on the incoherent scatter radar data availability). Most of the observed storm-related TIDs had periods of 60-180 min (LSTIDs). During the analyzed storms we also observed extraordinary spreads and plasma bubbles at the F region heights.
Experimental Study on the Control Effect of Different Types of Warping Dams on Sediment
Authors: xue shaobo
Published: February 2023

In order to quantitatively reveal the influence of check dam measures configuration on the runoff formation and evolution process in the Huangqiu area, artificial rainfall simulation experiments were used in indoor small watersheds, and small watersheds under different check dam measures deployment scenarios (no dam, single dam, double dam) were tested. The characteristics of hydrodynamics and erosion dynamics of the runoff at the outlet section of the watershed are studied. The results show that the check dam has a significant impact on the river basin runoff and sediment transport process. After the check dam is laid out, the average runoff is reduced by 71.58%, and the average sediment production rate is reduced by 85.60%. decrease to varying degrees. Based on the random forest algorithm, the relative importance of the hydrodynamic and erosion dynamic parameters affecting the sediment yield and sediment particle size is sorted, and the Reynolds number Re and runoff erosion power are relatively important factors affecting the erosion sediment yield and particle sorting motivation factor. The research results provide theoretical and technical support for the construction and development of check dams in the Loess Plateau.
Sensitivity analysis of model parameters for geothermal energy applications in deep mines of thermal-hydraulic-mechanical coupling of spatially heterogeneous settings
Authors: Zhang Le , Hermans Thomas , Daniilidis Alexandros , Dieudonné Anne-Catherine
Published: February 2023

With the increasing demand for mineral and alternative energy resources, as well as the gradual depletion of shallow resources, the exploitation and utilization of mineral resources and geothermal energy in deep strata is an effective way to solve the problem of resource shortage. In recent years, as a new type of resource mining mode, the co-mining of deep mineral and geothermal energy has developed rapidly. This method is effective in solving the of deep mines and can also provide convenience for geothermal exploitation with the help of the original equipment of the mine. However, in deep mines, the interaction of high temperature, high geomechanical stress and high-water pressure might lead to rock failure because of the co-mining of mineral and geothermal resources. The huge uncertainty of underground parameters also makes the engineering environment difficult to predict.We have established a Thermal-hydraulic-mechanical coupling framework of co-mining of deep mineral and geothermal energy considering uncertainty in the model parameters including porosity, rock permeability, thermal parameters (heat capacity and heat conductivity), Young's modulus and their spatial heterogeneity, as well as boundary condition. 500 samples were generated within the prior uncertainty ranges, by means of Monte Carlo simulations, and simulated the spatial and temporal distribution of the temperature, pressure and principal stresses field for each sample with COMSOL. Using the distance-based global sensitivity analysis, the most sensitive parameters for deep mining are identified, and the heat storage capacity of the system is evaluated, including uncertainty.
The phase of midlevel and lowlevel clouds over the Southern Ocean and the Arctic Ocean and their dependence on cloud top temperature, sea ice, and aerosol concentrations
Authors: Dietel Barbara , Sourdeval Odran , Hoose Corinna
Published: February 2023

The accurate representation of clouds and their phase is crucial to enable a correct representation of the Earth’s radiation balance. This has been demonstrated by large radiative errors in global models over the Southern Ocean mainly caused by an incorrect representation of supercooled liquid lowlevel clouds. In contrast to lowlevel clouds, midlevel clouds are rarely investigated. To fill this gap, this study investigates active satellite observations of midlevel clouds over the Southern Ocean and the Arctic Ocean from 2007 and 2008 with a comprehensive comparison to observations of lowlevel clouds. Midlevel and lowlevel clouds are distinguished by cloud base height. The DARDAR dataset provides a detailed phase categorization based on CloudSat and CALIPSO measurements. We have analyzed the cloud phase partitioning as a function of cloud top temperature, vertical cloud thickness, and the horizontal cloud extent. A local minimum in the mean liquid fraction within a cloud column can be observed for a cloud top temperature of -15 °C. An exception to this observation occurs for lowlevel clouds over the Arctic Ocean, which feature a plateau instead of a minimum. This hints at processes producing ice at these temperatures, which could be habit dependent vapor growth, secondary ice production, or a combination of both processes, as already discussed in other studies. Furthermore, daily sea ice concentrations from a passive microwave instrument are collocated to investigate their correlation with the cloud phase. At equal cloud top temperature, lowlevel clouds over the Southern Ocean and the Arctic Ocean have a higher liquid fraction, if they occur over sea ice. Midlevel clouds over the Southern Ocean show the same behaviour, while midlevel clouds over the Arctic Ocean show no significant phase dependence on the sea ice concentration. In addition, collocated CAMS reanalysis data are used to investigate the influence of different concentrations of various aerosol types such as sea salt, dust, black carbon, or organic matter on the cloud phase. Preliminary results show a stronger influence of the mixing ratio of sea salt on the phase of lowlevel clouds, but also the phase of midlevel clouds over the Southern Ocean seems to be influenced. Future work will further investigate the influence of different parameters, such as sea ice concentration, aerosol concentration, and cloud top temperature on the cloud phase by applying a machine learning model and exploring the relative importance of these parameters for the cloud phase, as well as their interactions and synergies.
Interactions among earthworms species affect soil functioning
Authors: Lerch Thomas Z. , Araujo José H.R. , Capowiez Yvan , Pando Anne , Hartmann Christian , Dupont Lise
Published: February 2023

Earthworms are involved in the regulation of many soil ecosystem services. Their communities are often composed of several species but the role of each species and the potential interactions among these species on soil functioning is still poorly understood. The aim of this study was to test the hypothesis that the higher the earthworm diversity, the stronger the effect on soil processes and plant growth. A second assumption relied on the fact that earthworm effects depend on soil texture. To test our hypotheses, a laboratory controlled experiment was conducted on 5L mesocosms filled with 3 grassland soils with different textures (from sandy to loamy), covered by a layer of green waste compost. In each soil, 8 combinations of 3 different species of earthworms (Lumbricus terrestris, Lumbricus castaneus, and Allolobophora chlorotica) were tested. The experiment lasted about 14 months during which the CO2 and the water holding capacity were recorded. Then, Lolium perenne were grown during 6 months. At the end of the experiment, analyses of soil porosity and aggregation were performed by X-ray-tomography followed by dry sieving. Results obtained shows that the assembly of the 3 species had the strongest effects on compost mineralization and hydric properties, depending on the soil texture. The analyses of the soil physical structure revealed that interactions between earthworm species lead to significant changes in the soil porosity and aggregation profiles. The ongoing analyses of plant biomass will determine whether the demonstrated changes in soil properties will result in changes in plant growth and physiology.
Geochemical interaction between slab-derived melts and mantle at high pressure in subduction zones
Authors: Malaspina Nadia , Borghini Giulio , Zanchetta Stefano , Tumiati Simone
Published: February 2023

The fate of crust-derived melts at warm subduction zones and the transport mechanism of crustal components to the supra-subduction mantle is still matter of debate. Borgo outcrop of Monte Duria Area (Adula-Cima Lunga unit, Central Alps, Italy) is an excellent case study of melt-peridotite interaction occurred under a deformation regime at high pressure, that enabled the combination of porous and focused flow of eclogite-derived melts into garnet peridotites. Migmatised eclogites are in direct contact with retrogressed garnet peridotites and experienced a common high pressure (2.8 GPa - 750 °C) and post-peak (0.8–1.0 GPa - 850 °C) static equilibration. The contact is marked by a tremolitite layer, also occurring as boudins parallel to the garnet layering in the peridotites, derived from a garnet websterite precursor after the interaction between eclogitic melts and peridotites at high pressure. LREE concentrations of retrogressed websterites along a 120 m length profile starting from the eclogite-peridotite contact to the inner part of the peridotite, show a progressive enrichment coupled with a peculiar fractionation. Numerical modelling assuming the eclogitic leucosome as the starting percolating melt reproduces the REE enrichment and LREE-HREE fractionation observed in retrogressed websterites bulks within the first 30 m by two steps of melt-peridotite reaction: a high peridotite assimilation at eclogite-peridotite boundary, followed by reactive melt percolation within the peridotite assuming variable amounts of olivine assimilation and pyroxene + amphibole/phlogopite crystallisation. The numerical simulation aims to model the effect of interaction between crust-derived melts produced by partial melting of mafic slab component with suprasubduction mantle peridotites at sub-arc depths. The comparison between the REE composition of the retrogressed garnet websterites along the profile and the result of our model suggests that reactive melt infiltration at HP is a plausible mechanism to modify the REE budged of mantle peridotites that lie on top of the subducting crustal slab, which show peculiar LREE “spoon-like” fractionations. Moreover, the melt/peridotite interaction and the percolation of slab-derived melts into the overlying mantle may strongly modify the overall REE abundance and LREE/HREE fractionation (e.g., CeN/YbN) of the residual crustal melt within the first 30 m of slab/mantle interface.
Weather pattern dynamics over western Europe under climate change: predictability, information entropy and production
Authors: Vannitsem Stéphane
Published: February 2023

The impact of climate change on weather pattern dynamics over the North Atlantic is explored through the lens of the information theory of forced dissipative dynamical systems.The predictability problem is first tackled by investigating the evolution of block entropies on observational time series of weather patterns produced by the Met Office, which reveals that predictability is increasing as a function of time in the observations during the 19th century and beginning of the 20th century, while the trend is reversed at the end of the 20th century and beginning of the 21st century. This feature is also investigated in the 15-member ensemble of the UK Met Office CMIP5 model for the 20th and 21st centuries under two climate change scenarios, revealing a wide range of possible evolutions depending on the realization considered, with an overall decrease in predictability in the 21st century for both scenarios.Lower bounds of the information entropy production are also extracted, providing information on the degree of time asymmetry and irreversibility of the dynamics. The analysis of the UK Met Office model runs suggests that the information entropy production will increase by the end of the 21st century, by a factor of 10% in the Representative Carbon Pathway RCP2.6 scenario and a factor of 30 %–40% in the RCP8.5 one, as compared to the beginning of the 20th century. This allows one to make the conjecture that the degree of irreversibility is increasing, and hence heat production and dissipation will also increase under climate change, corroborating earlier findings based on the analysis of the thermodynamic entropy production.
Understanding the interaction between maize water use efficiency and nutrient uptake in irrigated cropping systems, a basis for predicting and improving Zambia’s productivity in a changing climate
Authors: Mwape Mumba , Said Hami , Phiri Elijah , Heiling Maria , Dercon Gerd , Resch Christian
Published: February 2023

Agriculture is a key to the Zambian economy, contributing 20% to the country’s GDP and 12% to the national export earnings. However, climate change has a negative impact on Zambian agriculture production. In line with its Vision 2030 to have an efficient, competitive, sustainable and export-led agriculture sector, Zambia is aiming to improve irrigated agriculture through large investment in irrigation. Considering climate change and variability, it is important to adopt best water and nutrient management practices for sustainable use of agricultural resources. Maize being the major staple crop of Zambia, a study was carried out to improve irrigation management by optimizing water and nitrogen use efficiency for maximum maize productivity at field level under varying water and fertilizer applications. To achieve this goal, our study used and adapted nuclear (neutron probe) and isotope (15N and 13C) techniques to the Zambian agro-ecological conditions. Drip irrigation was used as the targeted system. The experiment was implemented based on three water application levels, i.e., deficit (50% and 75% Evapotranspiration) versus optimal (100% Evapotranspiration)and three nitrogen (N) levels (140 kg.ha-1, 112 kg.ha-1 and 84 kg.ha-1, widely practiced being 112 kg.ha-1). Maize was grown as a sole crop, under drip irrigation, in rotation with a legume over the dry season of Zambia in 2021 and 2022. For both years, maize yield was ranging between 2 and 7 ton.ha-1. Results showed that deficit irrigation can be practiced without a significant negative impact on yield (with higher N levels showing significantly higher yields under deficit irrigation) and nitrogen use efficiency. The total N yield and agronomic water use efficiency were significantly higher, up to 1.5 and 3 times respectively, under deficit irrigation as compared to the optimal. Intrinsic water stress (d 13C results) was higher, though not statistically significant, under deficit irrigation. Thus, considering climate change and sustainable use of resources, deficit irrigation should be considered as the option to achieve higher yield and food security.
Free energy of soil water – a superior perspective on storage dynamics and its sensitivity to soil hydraulic properties and topography
Authors: Zehe Erwin , Hoffmeister Svenja , Loritz Ralf
Published: February 2023

Soil moisture measurements are very popular. Yet they provide a very incomplete picture about the state of the partially saturated zone and the capillary binding of soil water. Here we propose that the free energy of the soil water stock offers a superior perspective on storage dynamics, as it combines soil water content, gravity potential and matric potential data. Based on this new state variable, we show that the partially saturated zone is characterized by a system-specific balance of storage and release corresponding to local state of minimum free energy. The latter depends on the soil water retention curve and topography/depth to groundwater. In the absence of an external rainfall or radiative forcing, the system will thus naturally relax back to and persist in this equilibrium. Hydrological systems are however not isolated, they are frequently forced out of their equilibrium either by rainfall or by radiation driven evaporation. Here we show that the corresponding storage dynamics manifests as deviations of the free energy from and relaxations back the local equilibrium and that the latter separates two different regimes, which are either associated with a storage excess and overshoot of potential energy or a storage deficit and overshoot of capillary binding energy. We demonstrate that these pseudo oscillations are distinctly different in different hydrological landscapes. As the free energy state of the soil water stock, the storage equilibrium and the ranges of both storage regimes depend jointly on depth to groundwater and the soil water retention curve, we combine both controls into a hydrological system characteristics we call the ‘energy state function’ of the soil. We show that the latter allows an insightful inter-comparison of storage dynamics with in different hydrological landscapes, and a priory estimate of depth to groundwater, based on available soil moisture and matric potential data. Finally, we demonstrate a threshold-like relation between the free energy of soil water in the riparian zone and streamflow generation, where the tipping points coincides with the transition from a storage deficit to a storage excess.
How Vertical Wind Shear Impacts Tropical Cyclone by Different Thermodynamic Pathways: Energetics and Lagrangian Analysis
Authors: Liu Zi-Qi , Tan Zhe-Min
Published: February 2023

The variation of the thermodynamic cycle and energy of tropical cyclones (TCs) under vertical wind shear (VWS) is analyzed, and its associated TC thermal and dynamical structure evolutions are explored. The thermodynamic cycles extracted using the Mean Airflow as Lagrangian Dynamics Approximation (MAFALDA) method show that the maximum energy obtained by the TC decreases with the reduction of storm intensity in VWS. The thermodynamic cycles of sheared TC experience a two-stage evolution. During the early stage, the ascending branch of the MAFALDA cycle shifts toward lower entropy, which is attributed to the reduction of the entropy in the eyewall and the increase of the upward motion and entropy outside the eyewall. In the latter stage, the entropy increases, and the downward motion weakens in the ambient and upper troposphere, allowing the descending legs shifts toward high values of entropy. A backward Lagrangian diagnostic of air parcels associated with variations in thermodynamic cycles is employed to analyze the relative importance of distinct pathways. In addition to the low-, mid-, and upper-level ventilation pathways, the enhanced inner and outer rainbands, outward advection of high entropy air in mid- and upper-troposphere eyewall, the outflow layer with reduced height, and the inflow below the outflow layer are also important for the reduction of the energy gained by TC.
Characteristics of a rapid landsliding area along Jinsha River revealed by multi-temporal remote sensing and its risks
Authors: Yao Jiaming , Lan Hengxing , Li Langping , Cao Yiming , Wu Yuming , Zhang Yixing , Zhou Chaodong
Published: February 2023

Large paleolandslides are developed in the upper reaches of Jinsha River, which seriously threaten the safety of nearby residents and engineering facilities. It is important to study the movement characteristics of these landslides. In this work, we inspect the deformation characteristics of a rapid landsliding area along the Jinsha River by using multi-temporal remote sensing, and analyzed its future development. Surface deformations and damage features between January 2016 and October 2020 were obtained using multi-temporal InSAR and multi-temporal correlations of optical images, respectively. Deformation and failure signs obtained from the field investigation were highly consistent. Results showed that cumulative deformation of the landsliding area is more than 50 cm, and the landsliding area is undergoing an accelerated deformation stage. The external rainfall condition is an important factor controlling the deformation. The increase of rainfall will accelerate the deformation of slope. The geological conditions of the slope itself affect the deformation of landslide. Due to fault development and groundwater enrichment, slopes are more likely to slide along weak structural plane. The Jinsha River continuously scours the concave bank of the slope, causing local collapses and forming local free surfaces. Numerical simulation results show that once the landsliding area fails, the landslide body may form a 4 km long dammed lake, and the water level could rise about 200 m.
Fault damage zone growth in analog models: typology and segment selection process into fault corridors
Authors: Mayolle Sylvain , Soliva Roger , Dominguez Stéphane , Wibberley Christopher
Published: February 2023

A better understanding of stress perturbation around faults, strain propagation, and fluid flow in the upper crust require characterization of the evolution of fault damage zones. Numerous studies provide significant amounts of data and description from a broad variety of faults, however, fault damage evolution is not clearly understood.In this study, we investigate experimentally damage zones dynamic evolution during normal faults population growth. With this aim, we used a sandbox type device and multilayered analog model, monitored by high-resolution cameras. Several types of damage zones are evidenced and we performed an accurate description of their growth from initiation to mature damage. New damage types including conjugate link damage and graben damage are described for the first time and show similarities with observations in nature. We highlight the new concept of “fault system damage” as the increase of deformation and secondary fault density by the interaction of major faults. We also show that fault damage zones grow by segment linkage into corridors of fault segments formed in the first stages of model deformation. Based on these observations, we propose and discuss the new concept of “segment selection in corridors” as the process of the onset of fault maturation and their damage zone development.
Historical activity of an onshore subduction thrust and related geomorphic changes, northeastern Nankai subduction zone
Authors: Ishiyama Tatsuya , Nakanishi Toshimichi , Hirouchi Daisuke , Matsuta Nobuhisa , Kato Naoko , Sato Hiroshi
Published: February 2023

We show new geomorphic and geologic evidence for historical activity of the onshore deformation front of the Nankai subduction zone, constrained by Holocene tectonic geomorphology, high-resolution borehole stratigraphy, and seismic reflection profile.  Borehole transect across a newly recognized late Holocene fold scarp contains middle to late Holocene fluvial sedimentary units. Structures of these units correlated based on sedimentary facies, diatom assemblages and radiocarbon dating illuminates that around 12-15th century to middle Holocene units are repeatedly folded and cut by a shallowly dipping thrust fault, suggesting multiple seismic events.  In addition, a new high-resolution seismic reflection profile suggests that these structures are associated with west-dipping imbricate thrust faults comprising a deformation front of the onshore subduction zone. This historical fault activity is also consistent with land use changes linked with pre- and post-earthquake flood events revealed by geographic analysis on early-modern maps drawn in early to middle 19th century and contemporaneous documents.  These multidisciplinary observations suggest that the onshore deformation front activated during the AD 1854 Ansei Tokai megathrust earthquake (M8.4),  the most recent historical event,  comprising the northern end of the ruptured area. 
The Complex Relationship between Seismic Velocity and Volcanic, Tectonic, and Environmental Forcings Illustrated by 23 Years of Data at Mt. St. Helens
Authors: Makus Peter , Denolle Marine , Sens-Schönfelder Christoph , Köpfli Manuela , Tilmann Frederik
Published: February 2023

Mt. St. Helens is an explosively erupting volcano located in close vicinity to major metropolitan centres on the US Westcoast. In recent history, Mt. St. Helens erupted twice, in 2004 and 1980, causing more than 50 fatalities and over one billion USD of damage. Mt. St. Helens is also home to the only advancing glacier in the US, making it a unique site for geophysical measurements. Here, we present a seismic velocity change time-series (dv/v) of an unprecedented length covering the years 1998-2021. We quantify dv/v by applying the method of ambient seismic noise interferometry to waveform data recorded from a combination of various permanent and temporary seismic stations of the Pacific Northwest Seismic Network (PNSN). Due to its ubiquitous nature, ambient seismic noise allows for far denser temporal sampling than, e.g., active source or earthquake coda interferometry. However, source variability related, for example, to volcanic tremor activity affects the results retrieved by this method and can lead to decreased reliability. In this study, we focus on the impact of the complex dynamics at Mt. St. Helens on dv/v specifically by setting it into context with ground deformation, meteorological changes, and volcanic activity with the ultimate goal of unravelling the complex physical relationship between different forcings and the seismic velocity.
SarXarray: an Xarray extension for SLC SAR data processing
Authors: Ku Ou , Nattino Francesco , Grootes Meiert , Chandramouli Pranav , van Leijen Freek
Published: February 2023

Satellite-based Interferometric Synthetic Aperture Radar (InSAR) plays a significant role for numerous surface motion monitoring applications, e.g. civil-infrastructure stability, hydrocarbons extraction, etc. InSAR monitoring is based on a coregistered stack of Single Look Complex (SLC) SAR images. Due to the long temporal coverage, broad spatial coverage and high spatio-temporal resolution of an SLC SAR stack, handling it in an efficient way is a common challenge within the community. Aiming to meet this need, we present SarXarray: an open-source Xarray extension for SLC SAR stack processing. SarXarray provides a Python interface to read and write a coregistered stack of SLC SAR data, with basic SAR processing functions. It utilizes Xarray’s support on labeled multi-dimensional datasets to stress the space-time character of an SLC SAR stack. It also leverages Dask to perform lazy evaluation of the operations. SarXarray can be integrated to existing Python workflows in a flexible way. We provide a case study of creating a SAR Mean Reflectivity Map to demonstrate the functionality of SarXarray.
Validation of GPS III antenna patterns
Authors: Steigenberger Peter , Thoelert Steffen , Dach Rolf , Montenbruck Oliver
Published: February 2023

GPS III is the latest generation of modernized satellites of the Global Positioning System. Five GPS III satellites have already been launched between December 2018 and June 2021 and three further GPS III spacecraft are available for launch. Starting in 2019, satellite antenna phase center offsets (PCOs) for the L1, L2, and L5 frequency bands have been published by the manufacturer Lockheed Martin for the individual spacecraft launched so far. These PCOs are included in the igs20.atx antenna phase center model of the International GNSS Service (IGS). They are complemented by nadir-dependent phase center variations (PCVs) estimated by the Center for Orbit Determination in Europe (CODE) and the European Space Operations Center (ESOC). In Fall 2022, manufacturer-calibrated nadir- and azimuth-dependent directivity and phase patterns were, furthermore made available, which provide a more complete description of the antenna characteristics.This contribution aims at a validation of these satellite antenna metadata. As a reference, satellite antenna PCOs and PCVs are estimated from L1/L2 and L1/L5 ionosphere-free linear combinations of a global network of GNSS tracking stations. These are compared to the ground calibrations of the GPS III transmit antennas obtained in an anechoic chamber. The manufacturer-provided directivity patterns for the main lobe of the GPS III transmit antennas can be validated with observations of a directional high-gain antenna. The 30 m dish antenna of the German Aerospace Center (DLR) located in Weilheim, Germany, was used to obtain equivalent isotropic radiated power (EIRP) measurements of all GPS III spacecraft. Repeated measurements are used to evaluate the measurement precision and elevation-dependent RMS differences allow for an assessment of the consistency of the EIRP measurements and the pre-flight gain calibrations.
Mechanisms of Solute Mixing in Darcy’s scale Heterogeneous Formations
Authors: Dell Oca Aronne , Dentz Marco
Published: February 2023

Solute mixing in porous media plays a fundamental role in a variety of applications, e.g., environmental risk assessment, geochemical reactive transport. Mixing dynamics are strongly impacted by the medium heterogeneity, which leads to inhomogeneity of solute concentration within the spreading and the mixing volume. Considering Darcy scale heterogeneous formations, we develop a randomly dispersive lamellae approach in which the variability in the dispersion rates of the lamellae that constitute a solute plume is recognized as a fundamental aspect of the mixing dynamics. The framework allows representing the inhomogeneity of the concentration distribution within the mixing volume before the late time well-mixed condition is reached. Furthermore, in light of the hidden (data scarcity) and heterogeneous nature of environmental porous formations, the degree of mixing of a solute plume is uncertain. The proposed randomly dispersive lamellae framework represents a strategy to quantify the latter. We test our approach for mildly to highly heterogeneous formations.