bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon dynamics in the Brazilian Cerrado: stocks and fluxes estimated by a model data fusion framework (CARDAMOM)
Authors: Sousa-Neto Eráclito , Smallman Luke , Ometto Jean , Williams Mathew
Published: March 2020

Savannas are a major component of the world’s vegetation and cover a land surface of about 15 Mkm2, accounting for about 30% of the terrestrial primary production. In the South America, the Brazilian Savanna (Cerrado) is the second largest biome (2 Mkm2), after the Amazon biome, and a hotspot of biodiversity. The Cerrado region is heterogeneous, with savanna vegetation ranging from open grassland, through a gradient of increasing tree density to nearly closed-canopy woodland. The cerrado vegetation is markedly seasonal in phenology and is often burned, either naturally or as part of a management cycle. Due its large occupation, Cerrado have the potential to influence the regional and possibly the global energy, water and carbon (C) balances. The allocation of the net primary productivity (NPP) of an ecosystem between canopy, woody tissue and fine roots is an important descriptor of the functioning of an ecosystem, and an important feature to correctly represent in terrestrial ecosystem models for carbon rates estimation, as well as their residence time, variation with climate and disturbance, and in order to make better forecasts. Such estimation in Cerrado regions remains still difficult given the lack of important soil and vegetation data. Previous studies have showed that the fluxes of water and C are closely related to each other, and to the diurnal cycle of solar radiation. However, there is no study clearly assessing the allocation of C through the different types of vegetation, either in the different types of physiognomies. To help estimating the C flows across the different C pools and types of vegetation, we are using Carbon Data Model Framework (CARDAMOM) which is a computer programme that retrieves terrestrial carbon (C) cycle variables by combining C cycle observations with a mass balance model. CARDAMOM produces global dynamic estimates of plant and soil C pools, their exchanges with each other and with the atmosphere, and C cycling variables for processes driving change. It also produces a C cycle analysis consistent with C measurements and climate, and it is suited for using with global-scale satellite observations such as aboveground biomass (ABG) or leaf area index (LAI). For that, we count on field data available (AGB, BGB) and satellite data (LAI, AGB, soil C), which will help to present robust analyses of C cycling across gradients of biomass in the Brazilian Cerrado.
Automated water status monitoring in grapevines
Authors: Spano Donatella , Locascio Mauro , Marras Serena , Snyder Richard L , Mameli Massimiliano Giuseppe , Satta Daniela , Fernandes de Oliveira Ana , Barbaro Massimo , Meloni Paolo , Sirca Costantino
Published: March 2020

The wine market is increasing in economic importance, so it is crucial for producers to be competitive, efficient, and productive. In addition, climate change requires the adoption of adaptive strategies for a more efficient management of natural resources. Especially in semi-arid regions, the limitation in water availability for crop farming requires adaptive strategies aiming to optimize water productivity. Knowing the optimal moment for irrigation and the water amount to apply is essential information for deficit irrigation of wine grapes. Stem water potential measurements, using the pressure chamber approach, provide an accurate technique for determining plant water status and timing irrigation. In combination with accurate ET measurements, the plant-based measurements offer the information needed to establish water saving deficit irrigation schedules. Collecting stem water potential data, however, is time-consuming and labour-intensive. This work presents the preliminary results of a comparison between new plant-based sensors, which continuously monitor the water status using an automated platform.  A field study was conducted on a representative vineyard located in the Mediterranean Basin (Sardinia, Italy). Sensor data were compared to measurements of stem water potential. Two treatments were employed in the experiment: i) mild to moderate water stress conditions were applied from fruit set until ripening; ii) no irrigation from bunch closure until harvest, which resulted in moderate to severe water deficit conditions. In both treatments, stem water potential measurements were monitored weekly on adult leaves with a pump-up pressure chamber, while the T-Max method was used to determine the xylem sap flow. Leaf thickness, an indirect measurement of leaf turgor, was measured with a commercial sensor. Preliminary results showed a good potential for these promising techniques that may monitor proxies of the vine water status in an automated way, giving useful and user-friendly information for planning efficient irrigation schedules. In addition, micrometeorological  measurements provide a method for assessing the actual ET rates between irrigation events, and this effort will be studied in future field experiments. Preliminary results showed a good potential for these promising techniques that may monitor proxies of the vine water status in an automated way that, in conjunction with reliable ET estimates, provide the information needed to determine user-friendly information for planning efficient irrigation schedules for deficit irrigated wine grapes.
Separating tropospheric and stratospheric BrO columns over the Arctic using TROPOMI data
Authors: Schöne Moritz , Sihler Holger , Warnach Simon , Borger Christian , Beirle Steffen , Wagner Thomas , Platt Ulrich
Published: March 2020

Halogen radicals can drastically alter the atmospheric chemistry. In the polar regions, this is made evident, among others, by the almost complete destruction of boundary layer ozone during polar springs. These recurrent episodes of catalytic ozone depletion, referred to as Ozone Depletion Events (ODE), are caused by enhanced concentrations of reactive bromine compounds. The proposed mechanism by which these are released into the atmosphere is called bromine explosions -  reactive bromine is formed autocatalytically from the condensed phase. Enhanced bromine oxide concentrations have been observed by ground-based measurements as well as from aircraft and satellite, where the large spatial coverage allows to study the spatial extent of the phenomenon and its correlation with meteorological data as well as climate change.

The spatial resolution of S-5P/TROPOMI of 3,5 km x 7 km allows improved localization of these events and to resolve finer structures compared to previous satellite measurements. Together with the better than daily coverage over the polar regions, this allows investigations of the spatio-temporal variability of enhanced BrO levels and their relation to different possible bromine sources and release mechanisms.

We present tropospheric BrO column densities retrieved from TROPOMI data using Differential Optical Absorption Spectroscopy (DOAS). Building on methods from statistical data analysis and machine learning, we separate the tropospheric partial column from the total column using solely data (BrO, O3 and NO2) measured by satellite. The observations are discussed with regards to sea ice coverage and meteorological influences.
Transdisciplinary research towards transsectoral implementation
Authors: Regelsberger Martin , Allesch Astrid , Becsi Benedikt , Germann Verena , Gratzer Georg , Gühnemann Astrid , Hundscheid Laura , Körfgen Annemarie , Kozina Christian , Kreiner Helmuth , Lindenthal Thomas , Manderscheid Maximilian , Rammler Sophia-Marie , Scherz Marco , Schwarzl Ingeborg , Toth Werner , Vacik Harald
Published: March 2020

Research is ever deepening its knowledge in a multitude of fields. Such research contributes in great depth to identifying and understanding problems (e.g. in the field of climate change). However, when it comes to societal implementation, it may ultimately lead to zero knowledge at infinite depth, as it has been ironically put. To tackle sustainability, respectively to achieve the 17 sustainable development goals (SDGs) set by the UN, science has to come together and work in transdisciplinary teams. Scientists are poorly prepared for such an exercise and standard procedures of scientific work, sharing and publication of results in specialised conferences and journals do not help.

In view of this problem, the Austrian Alliance of Sustainable Universities and research centres has created a project, UniNEtZ (Universities and Sustainable Development Goals), to jointly address the issues raised by the SDGs and develop suggestions for policies in a multidisciplinary approach. In order to facilitate this for the scientists involved, UniNEtZ is preparing collaborative measures and methods to address the issue of cooperation between disciplines to guarantee that all important interactions among SDGs are considered and addressed in equal detail. It is expected that changes in the way science and scientists are used to work together are necessary to achieve that. The developed concepts will be published in a handbook for UniNEtZ,

In a next step, the  handbook also hints at the need for municipal, regional, and national administrations to transition towards a kind of governance, that enables implementation of policies towards the SDGs. Current hierarchically organised structures don’t seem ideal for the kind of transsectoral cooperation that will be needed to implement the expected measures.

The contribution presents the findings of this work on cooperative research and governance structures.

Keywords: SDGs, Sustainable Development Goals, transdisciplinary research, transsectoral implementation
Linking Isotope Exchange and Fe(II)-Catalyzed Ligand-Controlled Dissolution of Iron(hydr)oxides
Authors: Biswakarma Jagannath , Kang Kyounglim , Schenkeveld Walter D.C. , Kraemer Stephan M. , Hering Janet G. , Hug Stephan J.
Published: March 2020

Dissolution of iron(oxyhydr)oxides is a key biogeochemical process that affects the cycling and bioavailability of iron (Fe). Recently, we demonstrated that submicromolar concentrations of Fe(II) accelerate dissolution of Fe(III)(hydr)oxides with the synthetic ligands ethylenediaminetetraacetate (EDTA) and hydroxybenzyl ethylenediaminediacetic acid (HBED) and also with the biogenic ligand desferrioxamine-B (DFOB) in anoxic conditions at circumneutral pH. The catalytic effect of Fe(II) was explained by electron transfer (ET) to surface Fe(III) and accelerated detachment of surface Fe(III)-ligand complexes. However, the extent of ET on the mineral surface before and during accelerated dissolution remained unclear. Here we describe the extent of ET by investigating dissolution and isotope exchange with lepidocrocite (Lp) and goethite (Gt) and varying concentrations of Fe(II), 57Fe(II), and DFOB. Most experiments were conducted under anoxic conditions at pH 7.0 in bicarbonate-CO2-buffered suspensions.

Our results show that in anoxic carbonate-buffered suspensions, 1-5 µM Fe(II) increased the rates of Lp dissolution at pH 7.0 by up to 60-fold. The addition of 20 or 50 µM DFOB after 57Fe(II) led to accelerated detachment of 56Fe(III) from Lp and release of already adsorbed/exchanged 57Fe into the solution. A kinetic model considering exchange of charge on the surface between 57Fe(II) and 56Fe(III), before and during dissolution, was developed to explain the observed results. The rates for ET and isotope exchange before and during accelerated dissolution are very different for Lp and Gt, presumably reflecting the differences in structure and mineralogy.

This study contributes to the quantification of ET from added Fe(II) to the surface of Fe(III)(hydr)oxides and of the acceleration of overall non-reductive dissolution by traces of Fe(II) in anoxic environments. In this presentation, the key findings of the isotope exchange and dissolution studies with Lp and Gt will be presented in order to highlight the importance of interfacial Fe(II)/Fe(III) ET  processes occurring at (sub)oxic-anoxic interfaces of soils and sediments.
A reduced-order model of the zonal jets problem in the Southern Ocean
Authors: Naghibi Elnaz , Karabasov Sergey , Kamenkovich Igor
Published: March 2020

We introduce a reduced-order model of the underlying dynamics of zonal jets in the Southern Ocean. The model is based on multi-scale decomposition in the vorticity equation and explains how large-scale forcing breaks down into mesoscale eddies and alternating zonal jets. In this reduced-order model, we average the vorticity equation both in time and in the zonal direction and utilize eddy viscosity parametrization for turbulence closure. For verification, we compare our results with two high-fidelity models: i) the quasi-geostrophic model of a shear-driven periodic channel flow and ii) primitive equation HYCOM (HYbrid Coordinate Ocean Model) simulations of the Southern Ocean.
Estimation of corn harvest date in South Korea based on the accumulated temperature
Authors: Hur Jina , Shim Kyo-Moon , Kim Yongseok , Jo Sera
Published: March 2020

This study was estimated harvest date of corn in South Korea based on the temperature index called the accumulated temperature. The accumulated temperature was calculated using observed daily mean temperature. We assumed a unified seeding date, 5 April, across the South Korea. The daily mean temperatures from 61 weather stations provided by the Korean Meteorological Administration were obtained for the period 2009-2018 (10 years). We used 1,650℃ as the criterion of the accumulated temperature to identify harvest date of corn for early-cultivated variety. The accumulated temperature over the most areas generally meted the criterion (1,650℃) in early July. In case of 2018, 66% area of Gang-won province, major corn producer, become suitable to harvest corn in July, peaking in the middle July (51%). The harvest date has been accelerating due to increase in daily mean temperature during the recent 10 years. This study infers that changes in farming activities are needed through reflecting the environmental change.        

 

Acknowledgements

: This study was carried out with the support of “Research Program for Agricultural Science & Technology Development (Project No. PJ014882)”, National Institute of Agricultural Sciences, Rural Development Administration, Republic of Korea.

 
Asbestos determination in ophiolitic rocks by Image Analysis coupled with Raman Spectroscopy
Authors: Trapasso Francesca , Tempesta Emanuela , Passeri Daniele , Belardi Girolamo , Petriglieri Jasmine Rita , Avataneo Chiara , Compagnoni Roberto , Piana Fabrizio , Turci Francesco
Published: March 2020

The determination of the asbestos content in ophiolitic rocks is carried out by well-known and standardized analytical techniques (SEM-EDS according to Italian regulation on environmental parameters on spoils, waste and rock and soil). Despite the high resolution and the possibility to obtain elemental information, SEM-EDS is not always able to discriminate serpentine minerals, including chrysotile and non-regulated fibrous antigorite, lizardite, and possibly polygonal serpentine.

Moreover, the analytical procedures using electron microscopies are time-consuming and show an intrinsic lack of statistical representativeness, due to the low portion of the analytical sample that is effectively analyzed. Conversely, optical microscopy delivers fast results affected by a lower resolution and unreliable mineral fibre identification. Many sectors related to the realization of geo-engineering projects would take enormous advantages from a more efficient and statistically-sound approach.

To evaluate the results obtained from a state-of-the-art optical microscope with automatic image analysis in-line with micro-Raman spectrometer, we designed a study to comparatively determine the asbestos content from a large set of samples deriving from asbestos-bearing rock of the ophiolitic domain. The performance of a Malvern G3 Morphology microscope equipped with a 850 nm laser Raman spectrometer was tested on 40 samples. The same samples, prepared from ophiolitic rocks from the Ligurian Alps comminuted down to top-size = 100 μm, were parallelly analyzed and results compared with SEM-EDS quantitative method described by Italian regulation (Ministerial Decree 6 September 1994, All 1B).
Bayesian Spatio-temporal Geostatistics-based Method for Multiple Satellite Products Fusion and Downscaling
Authors: Bo Yanchen
Published: March 2020

High-level satellite remote sensing products of Earth surface play an irreplaceable role in global climate change, hydrological cycle modeling and water resources management, environment monitoring and assessment. Earth surface high-level remote sensing products released by NASA, ESA and other agencies are routinely derived from any single remote sensor. Due to the cloud contamination and limitations of retrieval algorithms, the remote sensing products derived from single remote senor are suspected to the incompleteness, low accuracy and less consistency in space and time. Some land surface remote sensing products, such as soil moisture products derived from passive microwave remote sensing data have too coarse spatial resolution to be applied at local scale. Fusion and downscaling is an effective way of improving the quality of satellite remote sensing products.

We developed a Bayesian spatio-temporal geostatistics-based framework for multiple remote sensing products fusion and downscaling. Compared to the existing methods, the presented method has 2 major advantages. The first is that the method was developed in the Bayesian paradigm, so the uncertainties of the multiple remote sensing products being fused or downscaled could be quantified and explicitly expressed in the fusion and downscaling algorithms. The second advantage is that the spatio-temporal autocorrelation is exploited in the fusion approach so that more complete products could be produced by geostatistical estimation.

This method has been applied to the fusion of multiple satellite AOD products, multiple satellite SST products, multiple satellite LST products and downscaling of 25 km spatial resolution soil moisture products. The results were evaluated in both spatio-temporal completeness and accuracy.
Merging different resolution rainfall products to support landslide prediction over Nepal
Authors: Smith Paul , Buytaert Wouter , Paul Jonathan , Allen Simon
Published: March 2020

Landslides within Nepal result both from human interventions, intensive rainfall and tectonic activity. This work presents the steps taken towards the development of a Territorial landslide early warning system (Te-LEWSs) for predicting the relative probability of the occurrence of precipitation driven landslides in the west of Nepal. Since precipitation triggers may be dominated by intense short periods of rainfall focus is given to testing the use of relationships between high resolution local observed precipitation, satellite data and Numerical Weather Models output in the development of the forecasting model. Our results show the relative importance of these alongside the significance of human activity when the model is compared against observed data sets.
Re-envisioning data repositories for the 21st century
Authors: Diggs Stephen , Kinkade Danie
Published: March 2020

Finding and integrating geoscience data that are fit for use can alter the scope and even the type of science exploration undertaken. Most of these difficulties in data discovery and use are due to a technical incompatibilities in the various data repositories that comprise the data system for a particular scientific problem.  We believe these obstacles to be unnecessary attributes of individual data centers that were created more than 20 years ago. This aspirational presentation charts a new way forward for data curators and users alike, and by employing technical advances in adjacent disciples, promises a new era of scientific discovery enabled by re-envisioned 21st century data repositories.
Reconciling the multiple impacts of land use change on soil carbon, nitrogen, phosphorus and sulphur cycles
Authors: Colocho Hurtarte Luis Carlos , Wang Liming , Prietzel Jörg
Published: March 2020

Predicted changes in land use in mountain ecosystems due to agricultural and climatic pressure have the potential to change the abiotic controls of soil organic matter storage (i.e. temperature, and humidity). Yet an integrated assessment of the impact of land use change on site abiotic varibles (temperature, humidity) and its relation to the molecular composition of carbon (C), nitrogen (N), sulphur (S) and phosphorus (P) is lacking. In this study, we used a natural land use gradient (forest [F], degraded forest [DF] and alpine pasture [AP]) within the Karwendel mountain range as a model system to  analyse the C, N,S and P dynamics. At these sites, we measured climatic variables (air temperature and humidity and soil temperature at three depths) through a whole year and determined significant changes in soil temperature after conversion to alpine pasture. Soils were sampled at the organic and mineral horizons of each site and thereafter analysed for its C, N, S and P total concentrations, pH and sugar and amino sugars content. Thereafter, the molecular composition of C,N,S and P in the soils  was analysed combining synchrotron-based X-ray absorption near edge structure (XANES) spectroscopy and liquid state 31P-NMR spectroscopy. Our results show that although forest to alpine pasture conversion led to losses of C no changes of N, P or S concentrations where observed. These analyses show that with conversion to alpine pasture the SOM changes to a more decomposed state (increase of Alkyl:O-Alkyl ratio), which is accompanied by an increase of Amidic and Pyrrolic-N and an increase of sulfate-S. Moreover, the nominal oxidation state (NOS) of each analysed element, calculated from the spectral data shows a decrease, which might be due to higher decomposition rates in alpine pasture.  This shows that molecular changes in C,N,S and P occur after land use change in the topsoil, and are majorly depended on the soil temperature.  Moreover, this indicates changes that soil microorganisms were affected by land use change, which will be explored further by aminosugar analysis and PLFA. Our results show the rapid molecular changes of soil C,N,S and P after to land use.
Lateral boundary relaxation and large scale nudging in RCM runs
Authors: Mesinger Fedor , Veljovic Katarina , Chou Sin Chan
Published: March 2020

Almost universally, in Regional Climate Modeling (RCM) integrations, Davies’ relaxation lateral boundary conditions are applied. They force variables in a number of rows around the boundary to conform to the driver global model values, completely at the boundary, and less and less toward the inside of the integration domain. Very often, in addition, investigators apply so-called large scale or spectral nudging inside the domain, forcing the integration variables not to depart much from those of the driver model.

It is pointed out that there is no scientific basis for these two practices. So why are they used? In particular for the former of these two, it is suggested that reasons must be either a belief that this is a practice RCM should follow, or a technique to address numerical issues of the limited area model used, or a combination of the two.  For the latter, a belief only.

Examples are shown that, in the absence of these two stratagems, the limited area model can improve on large scales inside its domain. This demonstrates that their use, aimed to force variables inside the domain not to depart much from the driver model data, should be detrimental, if possible numerical issues of the model used were to be remedied.
Assessment of soft and hard linking approaches of integrated water-energy simulation
Authors: Etichia Mikiyas , Alejandro Martinez Eduardo , Harou Julien , Panteli Mathaios
Published: March 2020

The strong synergies between water and energy use are becoming increasingly evident nowadays. It is becoming more and more apparent that significant benefits can be gained if both resources are managed in an integrated manner, which can be critical to improve efficiencies, reduce trade-offs, and find better and more sustainable solutions to future energy and water resources scarcity problems. Two types of approaches have drawn attention to integrate water and power system models, namely soft-link and hard-link approaches. Soft-linking approaches involve iterations, wherein the two system models are simulated independently, and their outputs (e.g., water available for hydropower generation) are passed to the other model until convergence is reached. In hard-link approaches, both the water and power systems are simulated with a single optimization model. More research to understand better the implications of different water-energy linking approaches, their computational cost, flexibility, and scalability are critically needed.

In this work water and energy system network models are linked with varying levels of integration (i.e., gradually moving from soft to hard link approaches) to demonstrate the advantages and disadvantages of the different types of links. The water and energy model includes multi-purpose storage reservoirs, irrigation, and domestic water users, renewable energy sources, and conventional power generators. Results show that soft linking approaches are more suitable for water-energy systems with fixed reservoir operation rules. Hard linking approaches are proven to be more suitable for cases with well established water and energy markets and can be computationally cheaper than soft linking approaches. Better joint simulation will help investigate better ways to manage and invest in water-energy systems.
Ongoing Development and Applications of the Grell-Freitas Cumulus Parameterization
Authors: Grell Georg , Barnes Hannah , Freitas Saulo , Li Haiqin
Published: March 2020

We will present some recent improvements to the GF parameterization. These include two features that were added to the Grell-Freitas (GF) Cumulus Parameterization to improve the representation of the particle size distribution and to allow parameterized deep convection to propagate. These also include the treatment of tracer transport, wet scavenging, and aqueous phase chemistry, and improvements on interactions with aerosols. A more complete implementation for transport and treatment of atmospheric composition variables was necessary to complement recent new developments at NOAA/ESRL coupling chemical modules within the NWP model.

Estimates of cloud water and ice crystal number concentrations are added to GF base on the water-friendly aerosol content, temperature, and the cloud water and ice crystal mixing ratios. This modification is designed to diminish the artificial modification of the particle size distribution that occurs when the single moment cumulus schemes are used with the double-moment microphysics schemes. Simulations demonstrate that the addition of GF ice number concentrations substantially increases ice content aloft in the tropics, which shifts the outgoing longwave radiation distribution towards colder brightness temperatures.

The key modification used to enable the propagation of parameterized deep convective is the addition of an advected scalar that represents the cloud base mass flux associated with GF downdrafts. Our implementation of this advected scalar allows the impact of downdrafts from previous time steps to foster propagation. Evaluation and tuning of the new downdraft mass advection term is ongoing.
An Interoperable Low-Code Modelling Framework for Integrated Spatial Modelling
Authors: Herzig Alexander , Zoerner Jan , Dymond John , Smith Hugh , Phillips Chris
Published: March 2020

An Interoperable Low-Code Modelling Framework for Integrated Spatial Modelling

Alexander Herzig, Jan Zoerner, John Dymond, Hugh Smith, Chris Phillips
Manaaki Whenua – Landcare Research New Zealand

Modelling complex environmental systems, such as earth surface processes, requires the representation and quantification of multiple individual but connected processes. In the Smarter Targeting Erosion Control (STEC) research programme, we are looking to improve understanding of where erosion occurs, how much and what type of sediment is produced and by which processes, how sediment moves through catchments, and how erosion and sediment transport can be targeted and mitigated cost-effectively. Different research groups involved in the programme will develop different model components representing different processes. To be able to assess the impact of sediment on water quality attributes in the river and for develop effective erosion control measures, the individual models need to be integrated to a composite model. 
In this paper we focus on the technical aspects and seamless integration of individual model components utilising the Basic Model Interface (BMI, Peckham et al. 2013) as interoperability standard and the extension of the LUMASS spatial modelling environment into a BMI-compliant model coupling framework. LUMASS provides a low-code visual development environment for building complex hierarchical system dynamics models that can be run in HPC environments and support sequential and parallel processing of large datasets. Each model developed in the framework can be exposed to other models and frameworks through the BMI-compliant LUMASS engine, without requiring any additional programming, thus greatly simplifying the development of interoperable model components. Here, we concentrate on the integration of BMI-compliant external model components and how they are coupled into the overall model structure. 
In the STEC programme, we use LUMASS for both the implementation of model components representing individual soil erosion processes, such as landslides, earthflows, and surficial erosion and for the integration (i.e. coupling) of other (external) BMI-compliant model components into a composite model. Using available (prototype) models we will demonstrate how LUMASS’ visual development environment can be used to build interoperable integrated component models with very little coding requirements. 

Peckham SD, Hutton EWH, Boyana N 2013. A Component-based approach to integrated modelling in the geosciences: The design of CSDMS. Computers & Geosciences 53: 3—12. http://dx.doi.org/10.1016/j.cageo.2012.04.002 

LUMASS: https://bitbucket.org/landcareresearch/lumass 
Hysteresis in self-organized mesoscale convective systems driven by diurnal temperature oscillations
Authors: Jensen Gorm Gruner , Haerter Jan
Published: March 2020

Self-aggregation of convective cloud activity has attracted a lot of attention due to its role in the emergence of large scale weather phenomena such as the formation of hurricanes. Simulations with uniform boundary conditions show self-aggregation ocurring on the time-scale of a few weeks [1]. Recently, numerical experiments demonstrated that spatial clustering can form withing a few days, when the system is driven by diurnal temperature oscillations [2]. These simulations indicate that there may be a discontinuous phase transition between the clustered and the non-clustered state, i.e. that a threshold for the amplitudes of diurnal temperature oscillations exist, below which clustering does not emerge. A conceptual model has been proposed, suggesting that the phase transition might give rise to hysteresis in the sense that clustering emerging at high temperature amplitudes might persist if the amplitude is subsequently reduced to a level below the critical threshold.

Here we test the hysteresis–hypothesis explicitly by performing cloud-resolving simulations with a high-amplitude transient period followed by a period with a low diurnal temperature amplitude. In reality, diurnal temperature oscillations have significantly larger amplitudes over land than over the ocean. The existence of hysteresis effects in the convective cloud clustering could have profound implications: clusters formed over land, where diurnal temperature variations are large, could persist over the ocean when transported there by large-scale wind advection. Once present, the clusters could even intensify over the ocean—with possible implications for cyclogenesis.

[1] CJ Muller and IM Held, Journal of the Atmospheric Sciences, 69(8):2551–2565, 2012.
[2] arXiv:2001.04740 [physics.ao-ph]
EnKF estimation of the viscoelastic deformation and the viscosity
Authors: Ohtani Makiko
Published: March 2020

Following large earthquakes, postseismic crustal deformations are often observed for more than years. They include the afterslip and the viscoelastic deformation of the crust and the upper mantle, activated by the coseismic stress change. The viscoelastic deformation gives the stress change on the neighboring faults, hence affects the seismic activity of the surrounding area, for a long period after the large earthquake. So, estimating the viscoelastic deformation after the large earthquakes is important.

In order to estimate the time evolution of the viscoelastic deformation after a large earthquake, we also need to know the viscoelastic structure around the area. Recently, the Ensemble Kalman filter method (EnKF), a sequential data assimilation method, starts to be used for the crustal deformation data to estimate the physical variables (van Dinther et al., 2019, Hirahara and Nishikiori, 2019). With data assimilation, we get a more provable estimation by combining the data and the time-forward model than only using the data. Hirahara and Nishikiori (2019) used synthetic data and showed that EnKF could effectively estimate the frictional parameters on the SSE (slow slip event) fault, addition to the slip velocity. In the present study, I applied EnKF to estimate the viscosity and the inelastic strain after a large earthquake, both the physical property and the variables.

First, I constructed the forward model simulating the evolution of the viscoelastic deformation, following the equivalent body force method (Barbot and Fialko, 2010; Barbot et al., 2017). This method is appropriate for applying EnKF, because the ground surface deformation rate is represented by the inelastic strain at the moment, and the history of the strain is not required. Then, we applied EnKF based on the forward model and executed some numerical experiments using a synthetic postseismic crustal deformation data.

In this presentation, I show the result of a simple setting. I assumed the medium to be two layers with a homogeneous viscoelastic region underlying an elastic region. The synthetic data is made by giving a slip on a fault at time t = 0 and simulating the time evolution of the ground surface deformation. For assimilation, I assumed that the slip on the fault and the stress distribution just after the large earthquake is known. Then we executed the assimilation every 30 days after the large earthquake. I found that I can get a good estimation of the viscosity after t > 150 days.
Fully Lagrangian Method For Shear Band Capturing
Authors: Krapivin Kirill
Published: March 2020

KeyWords: FEM, Legandre element, plasticity, localization, shear band

 

The phenomenon of strain localization is widespread and can reveal both during the geodynamic sliding

of plates at macro scale length and at scales, character to a wells and mining. Herein we propose

accurate way to solve problems based on the spectral Legendre element with incremental formulation,

elastoplastic deformations, a consistent linearized matrix for governing relations. Two models of materials

are taken into account: the Drucker-Prager (pressure dependent) model and the Mises (pressure

insensitive) model. This report presents a qualitative and quantitative analysis of the kinematic pattern of

the lines of plastic deformations at different characteristic scales and types of stress states. It is shown for

general case pressure dependent Drucker-Prager model, in contrast to Mises model, solution can not possess

symmetric and continuous values: both radial and hoop stresses in the case of thick-walled cylinder

under compression can have periodic symmetry, but are discontinuous along the thickness.
Sensitivity kernels for coda-wave interferometry in a three-dimensional scalar scattering media
Authors: Barajas Andres , Margerin Ludovic , Campillo Michel
Published: March 2020

The ambient seismic noise has proven to be a powerful tool to assess velocity changes within the ground using coda-wave interferometry (CWI). CWI is based on the analysis of small waveform changes in the coda of the signals. Localizing and imaging the source that generates changes can be done with the help of sensitivity kernels which contain information on how each part of the surrounding medium contributes to the overall waveform perturbation that is recorded at a receiver. Although progress has been made in the theory of sensitivity kernels in the case of a full elastic space,  the inclusion of a free surface has proven to be difficult. Indeed, the free surface couples body waves and surface waves, which affects the sensitivity of coda waves with respect to the full-space case. Furthermore, one expects the depth sensitivity of coda waves to be strongly dependent on the relative contribution of surface and body waves, which depends on the lapse-time, source-receiver distance and scattering properties of the medium. Using the Monte-Carlo method, we compute traveltime-sensitivity kernels in a 3D scalar problem that includes body and surface waves, based on a recent theoretical model that integrates both through a mixed boundary condition. From these results, we assess the impact of the depth of a velocity perturbation on the recorded signals at the surface. Our results will be compared with previous numerical approaches from the literature. 
Spatial simulation of water supply service flow in Ningxia, China
Authors: Xu Jie , Xie Gaodi , Xiao Yu , Liu Jingya , Qin Keyu , Wang Yangyang , Zhang Changshun
Published: March 2020

Transregional Ecosystem Service (ES) flows are ubiquitous and are receiving more attention in an increasingly metacoupled world. Water has typical flow properties and is a common flow medium of Water-related Ecosystem Services (WES), such as water supply, water conservation, etc. Ningxia is in a transition zone from semi-arid to arid areas of the Yellow River basin of China. Its role in the water transfer from the Qinghai-Tibet Plateau to the downstream city and agriculture is important in allocating the scarce water resources in (semi-)arid regions. This study described the water flow process to/from Ningxia and revealed the supply-demand balance of water in Ningxia and its adjacent basins. On the grid scale, the total dynamic residual water in Ningxia from 2000 to 2015 was 2.20×1012 m3~6.26×1012 m3. However, there was still a dynamic water demand gap of -72.25×108 m3 ~ -59.08×108 m3, which could only be supplemented by manual water intake. At the regional scale, Ningxia had two sides, which was both the beneficiary of the upper Xiaheyan basin, Qingshui River - Kushui River basin, Xiaheyan - Shizuishan basin, Hexi Inland River-Shiyang River basin, Hexi Inland Rive-Hexi desert basin and internal flow area, and the supplier of the downstream Shizuishan - Hekou town, Longmen to Sanmenxia subbasin. As the benefitting district, the total net inflow water supply service in the supply area from 2000 to 2015 was 135.86×108 m3 ~ 294.22×108 m3, among which the non-Ningxia region in the sub-basin above the Xiaheyan basin was the main source region of water supply service in Ningxia. As the supply area, the net outflow volume of water supply service in Ningxia from 2000 to 2015 was 72.83×108 m3~200.46×108 m3, mainly flowing to non-Ningxia regions from Shizuishan to Hekou town. Overall, the net volume of water supply service flowing into Ningxia from 2000 to 2015 ranged from 63.03×108 m3 to 93.76×108 m3. This study can enhance the understanding of trans-boundary telecoupling relationship of WES in Ningxia and contribute to form a foundation for interregional management and allocation of WES in (semi-)arid regions to promote equity in sustainable regional development.
Comparison of high rate GNSS and GNSS-R measurements for detecting tidal bores in the Garonne River
Authors: Zeiger Pierre , Darrozes José , Frappart Frédéric , Ramillien Guillaume , Lestarquit Laurent , Bonneton Philippe , Bonneton Natalie , Ballu Valérie
Published: March 2020

The Reflected Global Navigation Satellite System (GNSS-R) is a bi-static radar system in which the receiver collect GNSS signals reflected from the Earth surface and compares them with corresponding direct signals. Measurements can be performed on the waveforms to determine the elevation of the free surface, leading to applications such as ocean altimetry, inland water level variations, soil moisture, snow depth and atmospheric water changes. This study presents the potential of in-situ GNSS-R for tidal bore detection and characterization, and compares it to high rate GNSS observations and other reference datasets.

The data we used were acquired on 17th and 18th October 2016 in the Garonne River, at 126 km upstream the mouth of the Gironde estuary. We processed GNSS-based elevations from data acquired on a buoy at a 20 Hz sampling rate using differential GNSS (DGNSS) technique. Acoustic Doppler Current Profiler (ADCP) measurements as well as pressure data were used for validation purposes. These techniques show good results in estimating the amplitude of the first wave, the period of the tidal bore and the oceanic tides. All of these datasets were compared to the retrieval of GNSS-R signals above the river. We have processed the changes in water height throughout the acquisition using Larson et al. (2013) and Roussel et al. (2015) techniques. We finally separate the atmospheric component from the tidal bore and the oceanic tides ones.

 

Larson, K. M., Löfgren, J. S., and Haas, R. (2013). Coastal sea level measurements using a single geodetic gps receiver. Advances in Space Research, 51(8):1301–1310.

Roussel, N., Ramillien, G., Frappart, F. et al. (2015). Sea level monitoring and sea state estimate using a single geodetic receiver. Remote Sensing of Environment, 171:261 – 277.
A Comprehensive Study of Superstorms from 1957 to present
Authors: Meng Xing , Tsurutani Bruce , Mannucci Anthony
Published: March 2020

We present a comprehensive study of all 39 superstorms (minimum Dst ≤ −250 nT) occurring from 1957 to present including analyzing their main phase developments, seasonal and solar cycle dependences, as well as their solar and interplanetary causes. We find that 87% of the superstorms have a multistep main phase development or are built upon preceding geomagnetic activities, and 90% of the superstorms occurred either near solar maximum or during the declining phase.  For the superstorm association with solar activities, 54% of the superstorms were associated with X‐class solar flares, 36% were associated with M‐class flares, and 5% with C‐class flares. All solar flares related to superstorms occurred in active regions, indicating the importance of active regions to superstorms. Most flares were located in the central meridian or slightly west of it as expected. For the interplanetary conditions leading to the development of the superstorm main phase, 95% of the 19 superstorms with available solar wind data are solely caused or partially caused by the sheath anti-sunward of an interplanetary coronal mass ejection (ICME), indicating the importance of the sheath structure in driving superstorms. For eight superstorms that have identifiable interplanetary shocks preceding the ICMEs, the shock normal angles were almost all quasi‐perpendicular. Larger shock normal angles statistically corresponded to greater superstorm intensities.
Comparison of Mehlich 3, AL and artificial root exudates containing extractants for soil phosphorus analysis
Authors: Tonutare Tonu , Kaldmae Gert , Köster Tiina , Krebstein Kadri , Rodima Ako
Published: March 2020

Due to increase of fertilizers prices and tightening of environmental protection requirements the need for efficient use of fertilizers has increased. At moment over the word huge number of different methods for determination of soil plant available phosphorus (PAP) are in use. Due to unequal extraction ability of extractants have each method own specific gradation to evaluate the soil P class. Allmost all widely used PAP extraction methods are developed in last century, mostly more than fifty years ago and often there is not possible to found information how the P status classes and fertilizer recommendations are determined for each method is determined.

The content of PAP in soil is difficult to estimate because soil pH has a strong effect to soil  - solution chemistry. Therefore extracting  soils with higly buffered solutions as for example Mehlich 3 can give overestimated results. The acidic Mehlich  3 extactant can solubilize relatively insoluble Ca- Fe- and Al phosphates. Also the AL (acetate-lactate) method uses the buffered extraction solution and may influence the amount of extracted PAP. The most realistic conditions for PAP extraction can give the extraction solution which mimic the soil environment that has actively growing roots. 

The aim of our research was to investigate the extraction of PAP with extragent similar by chemical composition to soil solution with root exudates proposed by Haney et al (2010).  The obtained results were compared with Mehlich 3 and AL methods results.    

Ref.: Haney, R.L., Haney, E.B., Hossner, L.R., Arnold, J,G. 2010. Modification to the New Soil Extractant H3A-1: A Multinutrient Extractant. Communications in Soil Science and Plant Analysis, 41:1513-1523.
Overview of conventional hydrocarbon resources in the North Sea Basin – harmonization of assessments, cross-border play mapping and new concepts
Authors: Nelskamp Susanne , Steward Margaret , Schovsbo Niels , Ladage Stefan , Peeters Stefan , Britze Peter
Published: March 2020

A cross-border assessment study looking at selected hydrocarbon systems is conducted as part of the EU Horizon 2020 GeoERA project (GARAH H2020 grant #731166 lead by GEUS). Within this project the geological surveys of the Netherlands (TNO), Germany (BGR), the United Kingdom (BGS) and Denmark (GEUS) are working together to create an overview of hydrocarbon resources and potential plays in the North Sea Basin. The project will harmonize the available resource assessments, and take a closer look at the play systems and potential new concepts. The focus of the work is on resolving border issues and identifying play concepts that are successful in one country but are underexplored in others. Potential risk factors related to subsurface exploration and production as well as options for multiple use of the subsurface will also be included in the overview. The results of the project will be published in report and GIS format and made available to legislators as well as the public.

Other parts of the project include the assessment of unconventional hydrocarbon plays (see Schovsbo et al. this conference), detailed basin and petroleum system modelling of a case study area in the Danish-German-Dutch offshore area (Lutz et al. this conference) and a pan-European database for gas hydrates (Léon et al. this conference).