bluuebunny/crossref_metadata_2025 huggingface dataset:
Post Wildfire Debris Flow and Flood Analysis of the September 2020 Badger Fire in the Trapper Creek and Rock Creek Watersheds, Idaho, USA.
Authors: Turnbull Stephen , Pradhan Nawa , Floyd Ian
Published: March 2021

There are several different infiltration, overland flow routing, and channel routing schemes that can be used in conjunction with recommended hydrodynamic and infiltration parameter values, which are found within the literature, to provide critical flooding assessments for stakeholders and decision makers.  We focus on post wildfire debris flow and flood analysis in two tributaries of the Snake River in Idaho, Trapper Creek and Rock Creek.  The Badger Fire started on September 12, 2020 in the Sawtooth National Forest in Idaho, USA, and burned sub-alpine fir, lodgepole pine, juniper, mountain brush and grass communities, in the upper part of both the Trapper Creek and Rock Creek watersheds.  Trapper Creek has a U.S. Geological Gaging station, and there are two snow gaging sites available.   The biggest concern for flooding and debris flow is the result of a wintertime rain-on-snow event, which resulted in the largest storm in the gaging record period.    

To estimate runoff in ungaged stream locations, existing process-based hydrodynamic models can be applied in a distributed form to solve the governing equations for mass, momentum and energy in a spatially explicit way. The purpose of this study is to predict potentially inundated land areas as a result of a rain-on-snow event, using the data in the gages basin to provide flood analysis information for both the gaged (Trapper Creek) and ungaged watershed (Rock Creek).  Rain-on-snow events are rainfall events that occur on the snowpack and frozen ground, resulting in a larger magnitude and volume of streamflow.  To predict these flows, Gridded Surface Subsurface Hydrologic Analysis (GSSHA) watershed models are prepared and calibrated to simulate rain-on-snow events in both watersheds.  The runoff generated from a two dimensional overland flow grid is transferred over land with a finite volume numerical method into a one dimensional channel network.  The channel network also uses a finite volume method.    The consistency in the identified range of the parametric values and their physical applicability make GSSHA an ideal candidate for this study, as the model equations provide a methods to evaluate a rain-on-snow event.
Monitoring and Modelling of ionospheric disturbances by means of GRACE, GOCE and Swarm in-situ observations
Authors: Schmidt Michael , Goss Andreas , Erdogan Eren
Published: March 2021

The main objective of the ESA-funded project COSTO (Contribution of Swarm data to the prompt detection of Tsunamis and other natural hazards) is to better characterize, understand and discover coupling processes and interactions between the ionosphere, the lower atmosphere and the Earth’s surface as well as sea level vertical displacements. Together with our project partners from the University of Warmia and Mazury (UWM), the National Observatory of Athens (NOA) and the Universitat Politecnica de Catalunya (UPC) we focus in COSTO to tsunamis that are the result of earthquakes (EQ), volcano eruptions or landslides.

In the scope of COSTO a roadmap was developed to detect the vertical and horizontal propagation of Travelling Ionospheric Disturbances (TID) in the observations of Low Earth Orbiting (LEO) satellites. Under the assumption that the TIDs triggered by tsunamis behave in approximately the same way for different EQ / tsunami events, this roadmap can be applied also to other events. In this regard, the Tohoku-Oki EQ in 2011 and the Chile EQ in 2015 were studied in detail. The aim of investigating these events is to detect the TIDs in the near vicinity of the propagating tsunami. Thereby, given tsunami propagation models serve as a rough orientation to determine the moments in time and positions for which there is co-location with selected LEO satellites/missions, namely GRACE, GOCE and Swarm. GOCE with an altitude of around 280km and the GRACE satellites with an altitude of around 450km flew over the region where the Tohoku-Oki tsunami was located, about 2.5 hours after the EQ. Using wavelet transform, similar signatures with periods of 10-30 seconds could be detected in the top-side STEC observations of GOCE as well as in the Ka-band observations of GRACE at the time of the overflight. These signatures can be related to the gravity wave originating from the tsunami. Similar signatures were detected in the signals from the GRACE Ka-band observations and in the Swarm Langmuir Probe measurements at an altitude of 450 km for the 2015 Chile tsunami. These roadmap studies provided the first opportunity to observe the vertical and horizontal tsunami induced gravity waves in the ionosphere.
Advancing Scientific Research and Education at the FLB Reiche Zeche underground mine in Freiberg - Germany
Authors: Garcia-del-Real Jose , Müller Toni , Mischo Helmut , Lay Vera , Buske Stefan
Published: March 2021

The shaft at Reiche Zeche mine provides direct access to the research and training underground mine of the reputed TU Bergakademie Freiberg, where advanced scientific research and practical education is executed for more than 100 years now.

Since 1919, the former ore mine is used for educating and training of miners, engineers and mine surveyors by the TU Bergakademie Freiberg. Drifts and tunnels of the mine stretch over several kilometres at depths down to 230 m. Today, the Reiche Zeche mine plays a major role in mining research and related activities including various research institutes and industrial partners. Several underground test facilities and laboratories are in use and play a key role in university education. A variety of local (15 institutes of TU Bergakademie Freiberg) and external partners (30 from 26 countries) are actively shaping research and education in the mine.

Real-world applications and cutting-edge technologies are tested in a stimulating environment underground, helping to improve competitiveness, leadership, creativity and critical thinking of researchers, companies and stakeholders.

Most recent research projects provide innovative solutions in way different fields. Robotics, smart mining, geophysical monitoring, a blasting chamber used for material science research, and also new mining technologies such as biohydrometallurgical mining for the winning of metals from ores, tailings and recycling material are only a small sample of the Reiche Zeche´s advanced innovation areas.

At Reiche Zeche mine, an efficient research and innovation environment is provided. It includes high quality underground spaces, cutting-edge methodology, state-of-the art labs, high-quality staff, resources and services to industries, talented individuals, leading researchers and teams from six continents, who truly want to make a real positive difference in the Society, contributing therefore, to sustainable optimisation for the raw materials value chain.

We are actively contributing to the European Underground Laboratories (EUL) network, forming an efficient platform for future, innovative research and business activities in underground laboratories. We are always open for collaboration with interested researchers and related stakeholders.
Stability of clay buffer systems in the conditions of deep geological disposal of radioactive waste in the presence of microorganisms
Authors: Abramova Elena , Safonov Alexey , Artemyev Grigoriy , Popova Nadezhda , Boldyrev Kirill
Published: March 2021

Clay minerals are the main promising materials for engineering safety barriers in the disposal of radioactive waste in geological formations. Clays have high chemical stability, good sorption properties, and low diffusion coefficients. Bentonite clays combine the most optimal properties - high swelling pressure, low diffusion coefficients. At the moment, there is no unified international concept of the clay barrier density and its composition. Also, the parameters of the influence of biogenic processes on the properties of clay materials have not been correctly determined. It is planned to use of bentonite barrier between the metal container and the external environment in the design of the supercontainer for the new disposal of radioactive waste in the Nizhnekanskiy gneiss massif.

Within the studies of microbiological processes in the Yeniseisky disposal site, big attention will be paid to clay barriers as sources of biogenic elements in the system and microflora and organic and inorganic carbon.

Special attention will be paid to thermophilic microorganisms characterized by high growth rates and high levels of metabolic processes, which, along with the extreme impact of radioactive waste (temperature, gas release) on a site in the mountain range, can lead to the destruction of safety barriers.

Based on the data of phylogenetic analysis of the 16S rRNA gene sequences in clay materials, which are planned to be used as a barrier material, bacteria of the fermentative type of metabolism, capable of forming biogenic gases and organic acids, sulfate-reducing microflora, and a wide variety of microorganisms of the iron cycle were found. We investigating the processes under conditions corresponding to both the internal and external conditions of the clay barrier. As a result of our studies, in model experiments, the effect of microflora activation by radiolysis products, carbon steel corrosion products, hydrogen, and carbon dioxide was found. A thermophilic microbiota was found in samples with bentonite clays of the Khakass and Dinosaur deposits cultivated at temperatures of 50, 70, 90° C. High content of aluminum and silicon amorphous oxide phases was found in the liquid phase after cultivation, and an increase in bioleaching was observed with increasing temperature. Screening of biocidal additives was performed to suppress microbial activity, primarily sulfate reduction. The most effective, thermally stable biocide with prolonged action was polyhexamethylguanidine at a concentration of 0.5 wt. %.
Improving Soil Health through Climate-smart Agriculture in Sub-Saharan Africa – The Essential Role of Farmers’ Knowledge
Authors: Eze Samuel , Dougill Andrew , Banwart Steven , Sallu Susannah , Mgohele Rashid , Senkoro Catherine , Smith Harriet , Tripathi Hemant
Published: March 2021

Soil health is key to building resilience into agricultural and food systems in sub-Saharan Africa (SSA), where climate change presents a major challenge and unsustainable land management practices have exacerbated land degradation. A suite of interventions labelled climate-smart agriculture (CSA) such as conservation agriculture (cover cropping, mulching, crop rotation, intercropping, minimum/zero tillage, crop residue management), soil and water conservation (contour planting, terraces and bunds, planting pits, and irrigation) and agroforestry are promoted in SSA to improve soil health but adoption among smallholder farmers remains low. A strong evidence base on the impacts of CSA interventions on soil health in different agro-ecosystems in SSA is lacking. This contributes to weak policies and institutional support as well as conflicting messages that farmers receive about CSA impacts, which limit their adoption and lead to disadoption. Farmers’ knowledge of their soils influences their land management decisions and is an important factor in the uptake of CSA interventions. Using a multi-method approach that combines conventional soil testing and farmers’ visual techniques, we examined the impacts of soil and water conservation techniques on soil health indicators in the East Usambara Mountains of Tanzania. The link between farmers’ soil knowledge and their land management decisions was also explored in a wider review of lessons from the African Highlands. Farmers’ observed changes in selected soil health indicators, which influenced their land management decisions did not always match results of conventional soil testing, highlighting the need for integrating farmers’ observational techniques and conventional soil testing for a more targeted and comprehensive assessment of soil health. A hybrid approach to soil assessment is outlined that could foster greater uptake of sustainable land management practices including CSA by farmers in SSA and should be proactively pursued by soil scientists to ensure that their efforts translate to actions by land managers.
Generalization of Vegetation Indices for Monitoring the Terrestrial Biosphere
Authors: Camps-Valls Gustau , Campos-Taberner Manuel , Moreno-Martinez Alvaro , Walther Sophia , Duveiller Grégory , Cescatti Alessandro , Mahecha Miguel , Muñoz-Marí Jordi , Garcı́a-Haro Francisco Javier , Guanter Luis , Gamon John , Jung Martin , Reichstein Markus , Running Steven W.
Published: March 2021

Vegetation indices are the most widely used tool in remote sensing and multispectral imaging applications. This paper introduces a nonlinear generalization of the broad family of vegetation indices based on spectral band differences and ratios. The presented indices exploit all higher-order relations of the involved spectral channels, are easy to derive and use, and give some insight on problem complexity. The framework is illustrated to generalize the widely adopted Normalized Difference Vegetation Index (NDVI). Its nonlinear generalization named, kernel NDVI (kNDVI), largely improves performance over NDVI and the recent NIRv in monitoring key vegetation parameters, showing much higher correlation with independent products, such as the MODIS leaf area index (LAI), flux tower gross primary productivity (GPP), and GOME-2 sun-induced fluorescence. The family of indices constitutes a valuable choice for many applications that require spatially explicit and time-resolved analysis of Earth observation data.

 Reference: "A Unified Vegetation Index for Quantifying the Terrestrial Biosphere", Gustau Camps-Valls, Manuel Campos-Taberner, Álvaro Moreno-Martı́nez, Sophia Walther, Grégory Duveiller, Alessandro Cescatti, Miguel Mahecha, Jordi Muñoz-Marı́, Francisco Javier Garcı́a-Haro, Luis Guanter, John Gamon, Martin Jung, Markus Reichstein, Steven W. Running. Science Advances, in press,  2021
A waterline method to derive intertidal bathymetry from multispectral satellite images and its application to hydrodynamic modelling
Authors: Costa Wagner , Bryan Karin , Coco Giovanni
Published: March 2021

Bathymetric data are a key parameter to assess shallow-water hydrodynamic processes. In-situ surveys provide high data quality; however, surveys are expensive and cover a limited spatial extent. To fill this gap, over recent years, the Satellite Derived Bathymetry (SDB) techniques have been developed. The present work aims to elaborate a technique to estimate bathymetric data from satellite images for intertidal zones. The method applied in this work is composed of 6 steps: (1) image querying and pre-processing is done through Google Earth Engine application (API) using Copernicus Sentinel 2A and B, product type 2A. (2) Identification of the intertidal zone for the study area by temporal variability of the Normalized Difference Water Index (NDWI). (3) Recognition of the waterline in each image by the use of an adaptive threshold technique; and assignment of the elevation for each detected waterline based on local observed tide heights. (4) Validation of the estimated bathymetry by comparison with LiDAR measurements. (5) Implementation of a SDB correction: numerical and/or statistical and, (6) assessment of the validity of SDB for hydrodynamic modelling. The SDB technique was applied to 4 different estuaries in New Zealand: Maketu, Ohiwa, Whitianga and Tauranga Harbour showing similar or better estimations in comparison to previous works using optical or synthetic aperture radar (SAR). For Tauranga Harbour, results from the statistical and dynamical corrections showed that the major error source is due to the image optical properties and environmental conditions when the image was acquired (35%). However, the tidal propagation can significantly decrease the SDB accuracy (13%). Finally, the use of the SDB in numerical simulations does not present huge differences in the predicted waterlevels in comparison to the use of survey bathymetry, showing that SDB could be potentially used for coastal flooding simulations.  
Radio and X-ray Observations of Short-lived Episodes of Electron Acceleration in a Solar Microflare   
Authors: Sharma Rohit , Battaglia Marina , Luo Yingjie , Chen Bin , Yu Sijie
Published: March 2021

Solar flares release enormous magnetic energy into the corona, producing the heating of ambient plasma and acceleration of particles. The flaring process is complex and often shows multiple spatially separated temporal individual episodes of energy releases, which can be hard to resolve based on the instrument capability. We analysed the multi-wavelength imaging and spectroscopy observations of multiple electron acceleration episodes during a GOES B1.7-class two-ribbon flare observed simultaneously with the Karl G. Jansky Very Large Array (VLA) at 1--2 GHz, the Reuven Ramatay High Energy Solar Spectroscopic Imager (RHESSI) in X-rays, and the Solar Dynamics Observatory in extreme ultraviolet (EUV).
We observed a total of six radio bursts. First three bursts were co-temporal, but not co-spatial nonthermal X-ray source and represent multiple electron acceleration episodes. We model the radio spectra by optically thick gyrosynchrotron emission and estimate the magnetic field strength and nonthermal electron spectral parameters in each acceleration episode. We note that the nonthermal parameters derived from X-rays differ considerably from the nonthermal parameters inferred from the radio and originates in the lower corona. Although co-temporal, our multi-wavelength analysis shows that different electron populations produce multiple acceleration episodes in radio and X-rays wavelengths. 
Geomorphic response and paleohydrology of a debris flow event in the upper Ganga River basin, NW Himalaya
Authors: Devrani Rahul , Kumar Rohit
Published: March 2021

Debris flow events are recognized as one of the most prominent mechanisms for landscape evolution in the Himalayan river basins. Triggered by cloud bursts, glacial and landslide lake outburst floods; debris flows can erode, transport and deposit vast amount of sediments with profound landscape changes. The Himalayan river basins frequently experience such debris flow events during the monsoon. However, only a few morphological and hydrological studies are available for such events. Hence, we studied a high-magnitude, low-frequency debris flow event in the Asiganga River basin (a headwater tributary of the Ganga River) on 3rd August 2012.

In the present study, we (i) computed landscape change during the event and (ii) calculated the paleohydrology of the event. The pre and post geomorphic mapping is carried out using satellite imageries (Google Earth), field data, and published literature to analyze landscape modification/change. The paleohydrology of the event is calculated using dimensions of 440 mobilized stream boulders at 11 locations in the Asiganga River basin. Our results suggest that the Asiganaga River’s reaches encountered sediment deposition and erosion on a massive scale; especially in the lower terrace levels. Channel shifting and widening was also a dominating geomorphic response, and it occurred in different magnitude along the course of the Asiganga River. A significant alteration trend is observed in sediment bars, especially in the reaches, which were exceedingly influenced by morphological and hydraulic parameters. The peak discharge is calculated using D95, D90, D85, and D80 of the mobilized stream boulders. Overall, the calculated highest peak discharge is around 4500 m3s-1. Interestingly, the peak discharge from D90 yielded the value of 2661 m3s-1 , and it corresponds with the peak discharge (i.e., 2665 m3s-1 ) measured using an instrument based previous study. 

In the Himalayan River basins, documentation of such debris flow events is crucial. Such studies will provide a unique database to study river sensitivity towards future debris flow events.
Distributed modeling of runoff and soil erosion in vegetated slopes with man-made mountain tracks
Authors: Cuomo Sabatino , Moscariello Mariagiovanna
Published: March 2021

Mountain tracks and slope cuts are important sources of runoff and sediment transport in a watershed. Some slope instabilities are also observed nearby mountain roads and tracks. Most of the current literature points out as relevant the modifications of the slope topography, and the concentration of runoff at the bends of the trackways. However, quantitative analysis of runoff generation and sediment delivery are still uncommon. Moreover, the role of vegetation removal or modification along/nearby tracks is not addressed. A physically-based distributed modelling of water runoff, soil erosion and deposition on a natural slope is performed considering the impacts of a mountain track, either in terms slope topography modifications or for the infiltration-runoff patterns. The erosion scenarios for a 30° steep slope are computed with different rainstorms and initial soil suction considered. The numerical analyses provide a comprehensive set of erosion scenarios. Particularly, the numerical results outline the bend of the mountain roads as a major confluence path for water runoff, consistently with the in-situ evidences. The highest loss of soil is found besides and downslope the bends. Very unfavorable combinations of vegetation removal and change in slope topography may finally lead to extensive rill erosions and/or shallow slope failures.
Magnetic field turbulence studies aboard the China Seismo-Electromagnetic Satellite and related ground based phenomena
Authors: Schwingenschuh Konrad , Magnes Werner , Shen Xuhui , Wang Jindong , Cheng Bingjun , Zhou Bin , Pollinger Andreas , Hagen Christian , Lammegger Roland , Ellmeier Michaela , Schirninger Christoph , Eichelberger Hans U. , Boudjada Mohammed Y. , Besser Bruno P. , Delva Magda , Jernej Irmgard , Aydogar Özer
Published: March 2021

With a new type of a scalar magnetometer, the Coupled Dark State Magnetometer (CDSM) aboard the China Seismo-Electromagnetic Satellite (CSES) mission, we observed magnetic field fluctuations in the period mid July 2018 until mid November 2018. 
The measurement range of the CDSM is from 1000 nT up to 100000 nT and the accuracy 0.19 nT (1), the operational performance is discussed in (2). We are using 1 Hz data in the latitude range -65 degree to +65 degree, CSES has an altitude of approx. 507 km in Sun synchronous polar configuration with 97.4 degree inclination. 
We analyzed the total magnetic field turbulence by converting the time series into thermodynamic parameters, e.g. entropy, finally these results have been compared with ground based seismic and volcanic events.

Ref:
(1) Pollinger, A., et al.: Coupled dark state magnetometer for the China Seismo-Electromagnetic Satellite, Measurement Science and Technology, 29, 9, 2018. https://doi.org/10.1088/1361-6501/aacde4
(2) Pollinger, A., et al.: In-orbit results of the Coupled Dark State Magnetometer aboard the China Seismo-Electromagnetic Satellite, Geosci. Instrum. Method. Data Syst., 9, 275–291, 2020. https://doi.org/10.5194/gi-9-275-2020
Deformational characteristics of thermally treated sandstone from an underground coalmine fire region, India
Authors: Tripathi Adarsh , Gupta Noopur , Singh Ashok Kumar , Rai Nachiketa , Pain Anindya
Published: March 2021

The Jharia region of lower Gondwana in India is one of the largest Underground Coalmine Fires (UCF) affected coalfield in the world. The UCF induced small scale as well as large-scale surface fracturing often creates the life-threatening conditions to coal miners and local surroundings. So, there is a need to understand the thermomechanical behaviour of coal measures rocks to predict the land disturbances in thermo-environmental conditions. It will provide an insight into the UCF induced subsidence mechanism and its preventive measures. The Jharia coal field predominantly consists of sandstone (75-80% by volume) and rest is composed of coal, shale and carbonaceous shale. The present study focuses on thermo-mechanical behaviour of Barakar sandstone (BS) under elevated temperatures. The cores of BS sample were prepared according to the ISRM standards. Further, samples were grouped and thermally treated in temperature range of 25°C, 100°C, 150°C, 300°C, 400°C, 500°C, 600 °C, 700°C and 800°C at a heating rate of 5°C/min for 24 hours in furnace.  Then, these thermally treated BS samples were subjected to laboratory test for stress-strain characteristics. In the process of deformational characteristics evaluation, effect of mineralogical changes and mode of fracture pattern were also studied at the mentioned elevated temperature. Based on the obtained results, the deformational behaviour of thermally treated BS specimens can be grouped into three zones, viz., zone 1 (25-300°C), zone 2 (300-500°C) and zone 3 (500-800°C). In zone 1, the characteristics of the stress-strain curve is similar to those under air dried sandstone specimen. However, small increment in stiffness were observed upto 300°C. The stress-strain curves in this zone shows dominantly brittle fracturing. The increment in stiffness may be related to evaporation of pore water that increases the cohesion between the mineral grains resulting higher stiffness value. In zone 2, the deformation pattern again shows brittle fracturing with continuous decrement in stiffness. The reduction in stiffness may be related to thermally induced porosity and increased microcrack density. In zone 3, the stress strain curve is observed to be concave upward. It indicates the pseudo-ductile behaviour of the thermally treated BS specimens. The observed results suggest a typical behaviour of deformation pattern under UCF induced rock fracturing which may be useful in predicting the land subsidence in UCF affected areas. Present research outcome may be used to design the support measures to reduce the associated hazards.
LamaH: Large-sample Data for Hydrology in Central Europe
Authors: Klingler Christoph , Herrnegger Mathew , Kratzert Frederik , Schulz Karsten
Published: March 2021

Open large-sample datasets are important for various reasons: i) they enable large-sample analyses, ii) they democratize access to data, iii) they enable large-sample comparative studies and foster reproducibility, and iv) they are a key driver for recent developments of machine-learning based modelling approaches.

Recently, various large-sample datasets have been released (e.g. different country-specific CAMELS datasets), however, all of them contain only data of individual catchments distributed across entire countries and not connected river networks.

Here, we present LamaH, a new dataset covering all of Austria and the foreign upstream areas of the Danube, spanning a total of 170.000 km² in 9 different countries with discharge observations for 882 gauges. The dataset also includes 15 different meteorological time series, derived from ERA5-Land, for two different basin delineations: First, corresponding to the entire upstream area of a particular gauge, and second, corresponding only to the area between a particular gauge and its upstream gauges. The time series data for both, meteorological and discharge data, is included in hourly and daily resolution and covers a period of over 35 years (with some exceptions in discharge data for a couple of gauges).

Sticking closely to the CAMELS datasets, LamaH also contains more than 60 catchment attributes, derived for both types of basin delineations. The attributes include climatic, hydrological and vegetation indices, land cover information, as well as soil, geological and topographical properties. Additionally, the runoff gauges are classified by over 20 different attributes, including information about human impact and indicators for data quality and completeness. Lastly, LamaH also contains attributes for the river network itself, like gauge topology, stream length and the slope between two sequential gauges.

Given the scope of LamaH, we hope that this dataset will serve as a solid database for further investigations in various tasks of hydrology. The extent of data combined with the interconnected river network and the high temporal resolution of the time series might reveal deeper insights into water transfer and storage with appropriate methods of modelling.
Carbon release from tropical forest soils informed by soil chemistry, fertility, and carbon quality derived from geochemistry of the parent material 
Authors: Bukombe Benjamin , Fiener Peter , Hoyt Alison M. , Doetterl Sebastian
Published: March 2021

Tropical forest soils are a vital component of the global carbon (C) cycle and their response to environmental change will determine future atmospheric carbon dioxides (CO2). For example, increasing biomass productivity in tropical forests suggests a potential sink for C. However, its storage and stability are driven by factors acting from small to large scale. For tropical Africa, these factors are not well known and documented.  Predicting tropical soil C dynamics ultimately depends on our understanding and the ability to determine the primary environmental controls on soil organic carbon content and respiration.

Here, using samples collected along strong geochemical gradients in the East African Rift Valley, we demonstrate how soil chemistry and soil fertility, derived from the geochemical composition of soil parent material, can drive soil respiration even in deeply weathered soils. 

To address the drivers of soil respiration, we incubated soils from three regions with contrasting geochemistry (mafic, felsic, and mixed sedimentary). For three soil depths, we measured the potential maximum heterotrophic respiration as well as the radiocarbon isotopic signature (Δ14C) of the bulk soil and respired CO2 under stable environmental conditions. 

We found that soil microbial communities were able to mineralize C from fossil as well as other poor quality C sources under laboratory conditions representative of tropical topsoils. Despite similarities in terms of climate, vegetation, and the size of soil C stocks, soil respiration showed distinct patterns with soil depth and parent material geochemistry. Our study shows that soil fertility conditions are the main determinant of C stability in tropical forest soils. Further, in the presence of organic carbon sources of poor quality or the presence of strong mineral-related C stabilization, microorganisms tend to discriminate against these sources in favor of more accessible forms of soil organic matter as energy sources, resulting in a slower rate of C cycling. 

Our results demonstrate that even in deeply weathered tropical soils, parent material has a long-lasting effect on soil chemistry that can influence and control microbial activity, the size of subsoil C stocks, and the turnover of C in soil. Soil parent material and its lasting control on soil chemistry need to be taken into account to understand and predict C stabilization and rates of C cycling in tropical forest soils. 
Understanding intrinsic ocean variability by suppressing regional stochastic variability
Authors: Shen Mao-Lin , Keenlyside Noel , Chiu Ping-Gin
Published: March 2021

Intrinsic ocean variability is essential for climate prediction because it is less sensitive to stochastic process, but it is very difficult to be identified due to internal climate variability. Here we use regional interactive ensemble applied on ocean-atmosphere interface (RIE-OA) to suppress atmosphere stochastic variability and to reveal intrinsic variability as well as to understand climate dynamic across multiple timescales. Five atmosphere general circulation models (AGCM) are coupled to an ocean general circulation model (OGCM) over the North Atlantic basin (20oN to Denmark Strait and Greenland-Scotland ridge). The OGCM interacts with fluxes from a selected AGCM globally except over the North Atlantic basin where the OGCM interacts with the ensemble averaged fluxes from the five AGCMs. The five AGCMs, on the other hand, feel the same ocean states. Hence, the atmosphere stochastic variability impacting the ocean is one-fifth weaker than stand-alone configuration (control case). This leads to reduction of the local climate variability, such as Atlantic Multidecadal Variability, but should not reduce intrinsic variability. Comparing control cases and RIE-OA case, we found the intrinsic ocean variability, a narrow-banded low-frequency (about 8 to 20 years) signal over the North Atlantic Subtropical Gyre, is not influenced by the weakened stochastic variability. More details will be discussed.
Land Subsidence Detection in Jakarta Province Using Sentinel-1A Satellite Imagery
Authors: Situmorang David , Endrani Arhatin Risti , Lumban-Gaol Jonson , Meisnnehr Devyan
Published: March 2021

The land surface in DKI Jakarta Province is thought to have experienced relatively continuous subsidence because of natural processes and man-made activities. This research was carried out to evaluate the rate of land subsidence in Jakarta Province. The data used in this study are two pairs of Sentinel-1A level 1 Single Looking Complex (SLC) images which were acquired in 2019 and 2020. The data was processed using the DInSAR method to examine the rate of land subsidence.  The results show that the land subsidence rate in Jakarta Province during the 2019-2020 period varies from 1.8 cm to -10.7 cm/year. From 2019 to 2020, the average land subsidence in the City of North Jakarta is around –4.9 cm/year, East Jakarta is around –2.5 cm/year, West Jakarta is around –4.8 cm/year, Central Jakarta is around –3.1 cm/year, and South Jakarta about –2.8 cm/year. Land subsidence occurs mostly in coastal areas and near estuaries caused by the nature of alluvial deposition materials. It has caused damages to road infrastructure in several regions of Jakarta Province, such as Mutiara Beach, West Cengkareng, and Pademangan.

 

Keywords: coastal areas, DInSAR, land subsidence, satellite imagery, Sentinel-1A
Physicochemical processes in the main river of Mexico using geochemical models
Authors: Olea-Olea Selene , Alcocer Javier , Oseguera Luis A.
Published: March 2021

The Usumacinta River is the most extensive tropical fluvial system in North America and the principal river in Mexico and the tenth of North America. Diverse and growing anthropogenic activities (land-use change, agriculture, and urban development) modify water quality. However, to separate natural (e.g., geology) from anthropic factors responsible for this system characteristics, we looked to evaluate geological environment’s influence on the river’s water quality.

Water and sediment samples were collected along the mainstem and principal tributaries in the rainy and the dry seasons (2017-2018). We analyzed the major ionic composition in water and metals in sediments. We applied inverse and evaporation models (PHREEQC code) to reveal the physicochemical reactions taking place in the river.

The inverse models in the middle basin in both seasons showed the influence of ion-exchange between Ca and K, dissolution of dolomite, and precipitation of kaolinite and calcite, whereas in the lower basin in the rainy season suggested the chemical composition is controlled by ion-exchange among Ca, Na and K, dissolution of dolomite, halite, plagioclase, and feldspar and precipitation of calcite, gypsum, and kaolinite. In addition, the evaporation models in the dry season in the lower basin demonstrate the dominant process taking place is the precipitation of calcite, dolomite, gypsum, halite, and kaolinite.

We found that Cr and Ni are the most abundant metals in the sediments along the river. The geological environment in the basin suggests that the volcanic rocks with felsic minerals could be the source of Ni, whereas sedimentary rocks such as shales and clays could be the source of Cr.

The use of geochemical models in river systems is of great relevance to understanding the presence of major ions concentrations in water and their seasonal and spatial variations, as well the physicochemical processes (i.e., ion-exchange, dissolution, precipitation, redox reactions, and so on) that allow associating or discard the presence of metals.
Magnetic DNA-based microparticle as a hydrological tracer in river-water tracing experiments
Authors: van Rhijn Fay , Tang Yuchen , Foppen Jan Willem , Bogaard Thom A.
Published: March 2021

Recently an new microparticle tracer has been developed for investigating in stream-mass transport: a silica coated synthetic-DNA-tagged microparticles with a superparamagnetic core (SiDNAMag). SiDNAMag particles can be easily recovered by magnetic separation, with high DNA signal amplification by Quantitative Polymerase Chain Reaction (qPCR). However, with the presence of natural colloids, particulate matter and river bed sediments, SiDNAMag are likely to undergo complex interaction processes besides dispersion and advection. Moreover, little has been known for the possible sink sources of SiDNAMag tracer mass loss during transport in river waters.

In this research the focus is on investigating the transport behaviour of the SiDNAMag particle as a potential hydrological tracer. The behaviour of the SiDNAMag particles will be compared to those of solute tracers (NaCl) and silica microparticles in terms of breakthrough curves and mass recoveries, by performing open channel injection experiments in laboratory environment. The resulting breakthrough curves will be interpreted with a 1-D advection and dispersion model. Possible interactions and mass loss will be examined by performing batch and injection experiments in different river water types with the presence of river bottom sediments.
3rd model intercomparison projects of atmospheric dispersion model for 137Cs emitted from Fukushima Daiichi Nuclear Power Plant, and application of MIPs' results for usage in an emergency
Authors: Yamazawa Hiromi , Sato Yousuke , Sekiyama Tsuyoshi , Kajino Mizuo , Fang Sheng , Quérel Arnaud , Quélo Denis , Kondo Hiroaki , Terada Hiroaki , Kadowaki Masanao , Takigawa Masayuki , Morino Yu , Uchida Junya , Goto Daisuke , Nakamura Masataka , Kiriyama Yusaku
Published: March 2021

The 3rd model intercomparison project (MIP) of atmospheric dispersion model targeting on 137Cs emitted from the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011 was conducted (Sato et al. 2020). Nine models participated in the 3rd MIP. All participated models used the identical source term of Katata et al. (2015) and the identical meteorological data (Sekiyama and Kajino, 2020) as in the previous MIP (i.e., 2nd MIP Sato et al. 2018), but finer horizontal grid resolution (1 km) than that of 2nd MIP (3 km) was used for understanding the behavior of atmospheric 137Cs measured in the vicinity of FDNPP. Results of the models elucidated that, as in the 2nd MIP, most of the observed high atmospheric 137Cs concentrations (plumes) were reasonably well simulated by the models, and the good performance of some models cancelled a bad performance of some models when used as an ensemble, which highlights the advantage of the multimodel ensemble. The analyses also indicated that the use of the finer grid resolution (1 km) improved the meteorological field in the vicinity of FNDPP. As a consequence, the atmospheric 137Cs measured near FDNPP was more reasonably reproduced in 3rd MIP than 2nd MIP.

As well as the evaluation of the performance of the model, we examined the usefulness of the results of atmospheric dispersion simulation in an emergency base on the results of 2nd and 3rd MIPs. For the analyses we defined the worst situation as that plume is observed but the model does not simulate it. The analyses reported that the worst situation happened in only 3% of the total calculation period by using the multimodel ensemble, even if the absolute value of the simulated 137Cs in each model was different in the range of factor 3-6. The analyses also indicated that from six to eight models are required for making most of the advantages of the multimodel ensemble.
Simulating the formation and decay of supraglacial lakes in South-West Greenland
Authors: Gantayat Prateek , Leeson Amber , Lea James , Gourmelen Noel , Fettweis Xavier
Published: March 2021

The dynamics of the Greenland Ice Sheet (GrIS) is greatly affected by surface meltwater that is routed from the surface to the bed, for example when a supraglacial lake (SGL) drains. The South-West Greenland Ice Sheet (SWGrIS) has an abundance of such lakes that form and decay over every hydrological year. In case a crevasse is opened up underneath an SGL, the lake water is likely to drain via the crevasse into the ice-sheet’s bed. This in turn influences the ice sheet motion by increasing the lubrication at the ice-sheet’s base. SGLs may also either drain laterally via a supra-glacial meltwater channel or the water they contain can stay put throughout the hydrological year, refreezing in the winter. These processes may affect the ice rheology in addition to influencing ice flow. While simulating the future evolution of the GrIS, it is thus important to account for processes associated with the evolution of SGLs. Until now, however, none of the existing ice sheet models have fully accounted for these processes, in part because no hydrological model yet includes them all. Here we propose a new process-based hydrological model for the SWGrIS which fully accounts for the evolution of  SGLs. The model consists of four units. The first is a surface water routing unit where the daily-generated surface meltwater is routed assuming steepest decent into the surface depressions forming SGLs. The second unit uses principles of Linear Elastic Fracture Mechanics (LEFM) to deal with the scenario where an SGL drains into the bed through an underlying crevasse. The third deals with the SGL drainage event that occurs when a surface meltwater channel gets incised though the ice sheet’s surface due to erosion from the SGL’s overflowing meltwater i.e. channel incision. Finally, the fourth unit simulates the freezing/unfreezing of SGLs by calculating the energy balance at the SGL’s surface. Using this model forced by Modèle Atmosphérique Régionale (MAR) derived daily surface melt-water values we quantify a) the amount and location of surface meltwater injection to the ice-sheet’s bed via moulins or crevasses and ,b) the meltwater that is either  retained in SGL or drained overland via meltwater channels and stored elsewhere over the period 2011-2020, in the Leverett glacier catchment. In the future, we plan to integrate this hydrological model with the sophisticated state-of-the-art BISICLES ice sheet model.
Analysing Temporal Effects on Classification of SAR and Optical Images
Authors: Polat Ahmet Batuhan , Akcay Ozgun , Balik Sanli Fusun
Published: March 2021

Obtaining high accuracy in land cover classification is a non-trivial problem in geosciences for monitoring urban and rural areas. In this study, different classification algorithms were tested with different types of data, and besides the effects of seasonal changes on these classification algorithms and the evaluation of the data used are investigated. In addition, the effect of increasing classification training samples on classification accuracy has been revealed as a result of the study. Sentinel-1 Synthetic Aperture Radar (SAR) images and Sentinel-2 multispectral optical images were used as datasets. Object-based approach was used for the classification of various fused image combinations. The classification algorithms Support Vector Machines (SVM), Random Forest (RF) and K-Nearest Neighborhood (kNN) methods were used for this process. In addition, Normalized Difference Vegetation Index (NDVI) was examined separately to define the exact contribution to the classification accuracy.  As a result, the overall accuracies were compared by classifying the fused data generated by combining optical and SAR images. It has been determined that the increase in the number of training samples improve the classification accuracy. Moreover, it was determined that the object-based classification obtained from single SAR imagery produced the lowest classification accuracy among the used different dataset combinations in this study. In addition, it has been shown that NDVI data does not increase the accuracy of the classification in the winter season as the trees shed their leaves due to climate conditions.
Evapotranspiration flux dynamics in a changing climate
Authors: Radolinski Jesse , Tissink Maud , Bahn Michael
Published: March 2021

Global change in the Anthropocene will impose various combinations of warming, atmospheric CO2 levels , and moisture availability on terrestrial ecosystems. A warming climate may increase vapor pressure gradients near plant and soil evaporation fronts driving higher rates of evapotranspiration (ET), whereas atmospheric CO2 enrichment (eCO2) can trigger stomatal closure, suppressing transpiration. Our best depiction of future water resources comes from controlled climate-manipulation experiments; however, climate change factors (e.g., eCO2, warming, and drought) are primarily studied in isolation, limiting the scope of inference. Here we use a series of chamber measurements taken throughout the 2020 growing season to quantify the individual and combined effects of elevated atmospheric CO2 (+300 ppm), warming (+ 3°C) and recurrent drought on evapotranspiration and plant water use in a mountain grassland. Though water use efficiency (WUE) was nearly identical between “future” (+300 ppm CO2 and 3°C) and “current” (ambient conditions) systems during drought simulations, the future plots maintained a 2-3 fold higher WUE with the twice the inter-measurement variance during the post-drought recovery period. The isotopic signatures of droughted plots were generally isotopically depleted compared to their non-drought counterparts at peak drought, and the future drought systems had 20 ‰ lighter bulk ET δ2H compared to plots receiving warming alone. Altogether these preliminary results suggest that 1) drought under a future warmer climate and eCO2 may drive grassland ecosystems to conserve water; 2) when warmed, mountain grasslands may preferentially return recently fallen precipitation to the atmosphere, whereas 3) drought can induce preferential withdrawal of older water storage. Future work will include the use of StorAge Selection (SAS) modeling to characterize the preference of water residence time to atmospheric fluxes under a changing climate.
MMS observations of electron firehose fluctuations in the magnetic reconnection outflow
Authors: Cozzani Giulia , Khotyaintsev Yuri , Graham Daniel , André Mats
Published: March 2021

Plasma waves and instabilities driven by temperature anisotropies are known to play a significant role in plasma dynamics, scattering the particles and affecting particle heating and energy conversion between the electromagnetic fields and the particles. Among these instabilities, the electron firehose instability is driven by electron temperature anisotropy Te, > Te,perp (with respect to the background magnetic field) and produce nonpropagating oblique modes. 

Magnetic reconnection is characterized by regions of enhanced temperature anisotropy that could drive instabilities - including the electron firehose instability - affecting the particle dynamics and the energy conversion of the process. Yet, the electron firehose instability and its role in the reconnection process is still rather unexplored, especially with in situ measurements. 

We report MMS observations of electron firehose fluctuations observed in the exhaust region of a reconnection site in the magnetotail. The fluctuations are observed in the Earthward outflow relatively close (less than 2 di distance) to the electron diffusion region (EDR). While the characteristics of the fluctuations are compatible with oblique electron firehose fluctuations, the associated firehose instability threshold is not exceeded in the interval where the fluctuations are observed. However, the threshold is exceeded in the EDR. The wave analysis in the EDR suggests that the firehose instability could be active at the reconnection site. We suggest that the firehose fluctuations observed in the outflow region may have been originated at the EDR, where the electron temperature anisotropy exceeds the threshold values, and then advected in the outflow region.