bluuebunny/crossref_metadata_2025 huggingface dataset:
ULF waves in the foreshock formed by the radial IMF: their effect on solar wind sheath-like deflection
Authors: Gutynska Olga , Urbář Jaroslav , Šafránková Jana , Němeček Zdeněk
Published: March 2020

Particle reflection at the bow shock provides a source of free energy to drive local instabilities and turbulence within the foreshock. A variety of low-frequency fluctuations (up to 16 mHz) results from the interactions of back-streaming ions with the incoming solar wind flow. We report observations of low-frequency magnetosonic waves observed during intervals of a radial interplanetary magnetic field in the foreshock. A case study of simultaneous dual THEMIS spacecraft observations of asymmetrical fluctuations in Vy is complemented by a statistical study of similar solar wind deflections in the foreshock.  Our moment calculations do not include the reflected particles as well as heavier ions, revealed the modulation of a solar wind core and deflection of the solar wind in the foreshock. This effect decreases with the distance from the bow shock. We conclude that large asymmetrical Vy velocity component fluctuations are typical for the foreshock formed by the radial IMF. The asymmetry of fluctuations changes the mean direction of the incoming solar wind flow within the foreshock leading to preconditioning prior to its encounter with the bow shock.
Illuminating the speed of sand – quantifying sediment transport using optically stimulated luminescence
Authors: Mey Jürgen , Schwanghart Wolfgang , de Boer Anna-Maartje , Reimann Tony
Published: March 2020

Sediment burial dating using optically stimulated luminescence (OSL) is a well-established tool in geochronology. Yet, an important prerequisite for its successful application is that the OSL signal is sufficiently reset prior to deposition. However, subaqueous bleaching conditions are vastly understudied, for example the effect of turbidity and sediment mixing on luminescence bleaching rates is only poorly established. The possibility that slow bleaching rates may dominate in certain transport conditions led to the concept that OSL could be used to derive sediment transport histories. The feasibility of this concept is still to be demonstrated and experimental setups to be tested. Our contribution to this scientific challenge involves subaquatic bleaching experiments, in which we suspend saturated coastal sand of Miocene age in a circular flume and illuminate for discrete time intervals with natural light. We further record the in-situ energy flux density received by the suspended grains in the UV-NIR frequency range by using a broadband spectrometer with a submersible probe.

Our analysis includes pre-profiling of each sample following a polymineral multiple signal protocol (Reimann et al., 2015), in which we simultaneously measured the quartz dominated blue stimulated luminescence signal at 125°C (BSL-125) and the K-feldspar dominated post-infrared infrared stimulated luminescence signal at 155°C (pIRIR-155). Preliminary results from the flume experiments show that the bleaching rates are indeed slow, differ for both signals and that the pIRIR155 seem to bleach faster than the BSL125. Besides the good prospects of acquiring a new tool for quantifying sediment transport, these results might have potentially far-reaching implications regarding the preferred target mineral for OSL dating in fluvial settings.  
IERS Rapid Service/Prediction Center Use of Atmospheric and Ocean Angular Momentum for Earth Orientation
Authors: Stamatakos Nicholas , Salstein David , McCarthy Dennis
Published: March 2020

The accuracy of near real-time estimates and short-term predictions of Earth orientation parameters (EOPs) can be enhanced by the use of Atmospheric Angular Momentum (AAM) and Ocean Angular Momentum (OAM) information, by accounting for the global conservation of angular momentum in the Earth system. The US Navy analysis and forecast scheme is named the Navy Earth System Prediction Capability (NAVY ESPC)  and is comprised of the Navy Global Environmental Model (NAVGEM) atmospheric and Hybrid Coordinate Ocean Model (HYCOM) ocean systems (along with ice forecasts). GOFS is being improved continually, and the resultant motion and mass fields are potentially useful for operational Earth orientation applications.  Consistency between the NAVGEM and HYCOM fields is required for calculations of the total angular momentum of the combined system of geophysical fluids. However, they might not include land-based Hydrological Angular Momentum functions (HAM) and the additional amount due to sea-level variability, the Sea-Level Angular Momentum (SLAM), both of which may be accounted for separately. We investigate various combination and optimal estimation processes using these data series, in conjunction with existing EOP observations to improve accuracy and robustness of short-term EOP predictions. Results are compared with those from other fluid models, particularly from those of the GeoForschungsZentrum (GFZ), the German Research Center for Geosciences. We also estimate power spectral density as a measure of error, for NAVGEM and HYCOM-based AAM/OAM series and similar series from other centers, comparing them to equivalent measures calculated from Earth orientation parameters.
Identification of the surface traces of historical earthquakes: one example from the southeast margin of the Tibetan Plateau
Authors: Han Zhujun , Dong Shaopeng , Guo Peng
Published: March 2020

The surface traces of historical earthquakes on the optical images are easily obscured by dense vegetation. Fortunately, the vegetation can be filtered and removed mostly or completely from LiDAR-derived cloud point data. We incorporate tectono-geomorphic interpretations of optical image, digital elevation model (DEM)-derived hillshades, contour maps, and field observations of tectono-geomorphic features and trenches to identify surface traces created by a historical earthquake. Based on DEM data, we used LaDiCaoz_v2_1 and 3D_Fault_Offsets to quantify offsets of tectonically displaced geomorphic markers. These approaches help us to recover an Mw7.5 historical earthquake at the southeast margin of the Tibetan Plateau, but the seismogenic fault had been considered as a weakly active fault and the magnitude of this earthquake was cited as M6.8 in the catalog of Chinese historic strong earthquakes from BC 2300 to AD 1911.
The role of surface air temperature over the east Asia on the early and late Indian Summer Monsoon Onset over Kerala
Authors: Choudhury Devanil , Nath Debashis , Chen Wen
Published: March 2020

We investigated the physical mechanism for late Indian Summer Monsoon onset over Kerala
(MOK). 14 early and 9 late onset years are selected based on the criteria when the onset is 5 days or
more prior and after normal onset date (i.e 1 st June according to India Meteorological Department)
respectively. Then, we perform composite analyses of mean May monthly and daily evolution during
early and late onset years to examine the differences in monsoon circulation features prior to the MOK.
We find that advection of Surface Air Temperature (SAT) from the northern to the southern China and
the eastern Tibetan Plateau (TP) plays an important role to modulate the MOK processes. In the late
onset years, more low-level jet (LLJ) from the Bay of Bengal (BOB) divert towards the east Asia before
the onset, which is due to an extension of the low sea level pressure and high SAT over the east Asia
(eastern TP, east-central China). This strengthens the low-level convergence and upper level divergence
over the eastern TP and southern China. As a result, a significant amount of moisture from the BOB
is transported towards the eastern TP and southern China. Thereby, a comparatively weaker LLJ and
deficit low-level moisture supply over the eastern BOB maintain the key roles in modulating the MOK
processes.
Chemical composition and characterization of aerosols off Namibia: results from the AEROCLO-sA project
Authors: Formenti Paola , Klopper Danitza , Chevaillier Servanne , D’Anna Barbara , Desboeufs Karine , Doussin Jean-François , Feron Anaïs , Giorio Chiara , Mallet Marc Daniel , Mirande-Brét Cécile , Monod Anne , Namwoonde Andreas , Triquet Sylvain , Piketh Stuart
Published: March 2020

The western coast of southern Africa off Namibia is characterized by a semi-permanent and widespread stratocumulus (Sc) cloud deck, very frequent coastal fog, and the oceanic northern Benguela upwelling system (nBUS). It is also the crossroad of large quantities of natural and anthropogenic aerosols of distant and local origins (biogenic, anthropogenic, biomass burning, sea salt and mineral dust) from continental and marine sources, with significant differences in terms of physico-chemical and optical properties, water affinity, scale and height of transport, which are not well represented in climate models.

In this presentation we will illustrate the results of the first extensive chemical and microphysical characterisation of aerosol particles in the area that has been conducted since 2016 at  the coastal Henties Bay experimental site (22°6’ S, 14°17’ E) in the framework of the AErosol, RadiatiOn and CLOuds in southern Africa (AEROCLO-sA) and the Atmospheric Research in the Southern Africa and Indian Ocean (ARSAIO) projects.

Synergetic filter sampling and online measurements provide examples of the numerous new particle formation in link with marine biogenic emissions and the apportionment of maritime sulfate aerosols, including their biogenic component.
Rethinking the production and consumption on the transition
Authors: Ruohomaa Heikki , Salminen Vesa , Pöykkä Tapani
Published: March 2020

Abstract. The new opportunities offered by technologies have caused societies to break through towards the fourth industrial transformation. It will change the whole society and its structures alongside the business and the transition process is still speeding. The world is also facing big megatrends like global warming, urbanization, digitalization, new revolutionary technologies.

Like the industrial revolutions before, the whole paradigm of society is changing, and it will happen also in the fourth industrial revolution, so there is a need to think how we should take a step towards to the new paradigm, so that we could be able to response to future challenges on sustainable way.

The fourth industrial revolution (4IR) technologies like sensor, IoT-platforms, artificial intelligence etc., give new possibilities to develop new, more efficient, more sustainable and more customer driven supply chain, prolong the lifetime of products and create new services and business models and this way reduce the use of materials of energy. There is also an argument to rethink the source of raw material, and in which extent the cities itself could be seen the source of needed materials and energy, by using new technology.

The move towards new ICT based technologies will happen unexpected fast, including exponential growth of data. That is the reason, why it is essential to understand the challenges of change and have a strategic view, identify the key elements and see the new opportunities in all levels of society development.

Circular Economy has been very much a hot topic in many discussions, but there has been quite little discussion about reengineering the value chains and production based on circular economy principles by using the new opportunities on 4IR technologies not only in production but also in creating service, which change the need/thinking of ownership and build new business models. In addition to this, the elements to improve business environment by local or national authorities and legislators.

Finland has is as a goal to develop to one of the leading countries in circular economy, In Finland, Forssa region is considered to be one of the most advanced region in bio-based circular economy.

In this article has been described the development of regional industrial symbiosis in order to have competitive of business and future development.
Mid- to- late Holocene hydroclimatic changes on the Chinese Loess Plateau: evidence from n-alkanes from the sediments of Tianchi Lake
Authors: Zhou Aifeng
Published: March 2020

We have reconstructed the history of mid-late Holocene paleohydrological changes in the Chinese Loess Plateau using n-alkane data from a sediment core in Tianchi Lake. We used Paq (the proportion of aquatic macrophytes to the total plant community) to reflect changes in lake water level, with a higher abundance of submerged macrophytes indicating a lower water level and vice versa. The Paq -based hydrological reconstruction agrees with various other lines of evidence, including ACL (average chain length), CPI (carbon preference index), C/N ratio and the n-alkane molecular distribution of the sediments in Tianchi Lake. The results reveal that the lake water level was relatively high during 5.7 to 3.2 ka BP, and decreased gradually thereafter. Our paleohydrological reconstruction is consistent with existing paleoclimate reconstructions from the Loess Plateau, which suggest a humid mid-Holocene, but is asynchronous with paleoclimatic records from central China which indicate an arid mid-Holocene. Overall, our results confirm that the intensity of the rainfall delivered by the EASM (East Asian summer monsoon) is an important factor in affecting paleohydrological changes in the region and can be considered as further evidence for the development of a spatially asynchronous “northern China drought and southern China flood” precipitation pattern during the Holocene.
Source apportionment of soil-contamination in Baotou City (Northwestern China) based on a combined magnetic and geochemical approach
Authors: Wang Bo , Xia Dunsheng , Jia Jia
Published: March 2020

We studied the magnetic properties and trace element concentrations (Cr, Cu, Fe, Mn, Pb, Ti, V, Zn) of urban topsoils from 111 urban sites in a large REE-Nb-Fe mining and smelting city, Baotou, Inner Mongolia, China. The results show that pseudo-single domain and multi-domain magnetite dominates the magnetic properties of the soil samples, and the magnetic concentration parameters show a large positive anomaly near the Baotou iron and steel works. The average contents of all trace metals exceeded their background level in soils in Inner Mongolia, except for Pb. The spatial distribution and correlation analysis show that magnetic parameters related to the magnetite concentration and Cr, Fe, Mn, Ti, V and Zn show similar trends of variation. In addition, the results of PCA show that Fe, Ti, and V are highly correlated with the magnetic particles derived from the Baotou iron and steel works, tailing dam, chromium plant, and cement plant. In contrast, Cr, Mn, Pb and Zn are derived from both the steel plant and traffic pollution. Using a PMF model, three potential pollution sources are identified: industrial pollution, including the steel works, tailing dam, cement plant and chromium plant, are reflected by χlf, χARM, SIRM and SOFT, and they account for 71.2%; traffic pollution is reflected by Pb and Zn and accounts for 9.0%; and natural sources, reflected by χfd%, χARM/χ, χARM/SIRM, HARD%, S-300, S-100 and Ti, contribute 19.8%. The results are potentially useful for developing control measures for reducing trace metal contamination in soils in Baotou city, and in addition we conclude that a combined magnetic approach and geochemical approach is an effective means for qualitative and quantitative sources apportionment of urban surface soil pollution.
Interactions between liming and availability of C and P regulate nitrogen transformations and denitrifying potential in an acidic arable soil
Authors: Liang Zhi , Abalos Diego , Elsgaard Lars
Published: March 2020

Liming to increase pH of acidic soils is a common agricultural practice to optimize crop yields, which also modulates greenhouse gas emissions from soils. In particular, soil pH has been identified as a primary regulator of denitrification pathways with enhanced ratio of nitrous oxide (N2O) to dinitrogen (N2) emissions (i.e., enhanced N2O/N2 ratio) at lower soil pH. Therefore liming could represent a potential management option to mitigate soil N2O emissions. However, changes in soil pH have pervasive effects on general microbial activity and on soil properties, including transformations of carbon (C) and bioavailability of phosphorus (P), with a feedback on microbial processes. Thus, the eventual net effects of liming on microbially derived N2O emissions may be complex. The aim of this study was to discern the interaction between liming (soil pH), and availability of C and P in regulating N2O emissions from acidic fertilized agroecosystems. Using coarse sandy soils from a long-term liming field experiment, N2O/N2 ratios from denitrifying enzyme activity was shown to be strongly affected by liming, i.e., with gradually decreasing ratios at increasing soil pH. Although liming acidic soil (pH, 3.6) to almost neutral (pH, 6.4) favored the reduction of N2O to N2, it also enhanced the overall denitrification rate, which eventually resulted in the highest N2O emission from moderately limed treatments (pH, 4.7). Interactions between P availability and denitrification (and N2O emission) occurred, where P addition generally increased cumulative N2O emissions with strongest effect at the moderately limed soil. Mechanistic hypotheses for this effect are discussed. Overall, our results suggest that a critical liming rate should be pursued which may lead to substantial mitigation of N2O emissions from acidic arable soil.
Cave wall-rock alteration as an indicator of hypogene speleogenesis
Authors: Spötl Christoph , Dublyanky Yuri , Koltai Gabriella , Plan Lukas
Published: March 2020

Recent years have seen an increasing number of studies suggesting that hypogene processes are more important in the origin of cave systems than previously thought. Recognizing such hypogene caves has important implications for e.g. paleohydrology and has been primarily based on morphological criteria, which to some degree are subjective and difficult to quantify. Apart from caves containing coarsely crystalline spar backed by evidence of elevated paleotemperatures based on isotopes and/or fluid-inclusion data, there are no well-established physico-chemical tools to validate a hypogene model for a given cave.

In a systematic approach we have studied a number of cave systems showing morphological features diagnostic of upwelling fluids, and examined the composition of the rock immediately behind the cave wall using small-diameter drill cores. We commonly observed two features in this wall rock: (1) an increase in porosity (partly later occluded by carbonate cement) and (2) a change in the rock colour (bleaching of initially grey rock, or reddening). We also identified dedolomitisation of the dolomite host rock, which may locally lead to the formation of boxwork. The most diagnostic feature, however, is a systematic shift in the carbon and/or oxygen isotopic composition along wall rock drill cores. None of these petrographic and geochemical features were observed in wall-rock cores of epigene caves, opening the door to use this approach in order to identify, and in some cases quantify, paleo-water-rock interactions associated with hypogene speleogenesis.
Random objective surface-wave waveform inversion
Authors: Pan Yudi , Gao Lingli , Bohlen Thomas
Published: March 2020

The full-waveform inversion (FWI) of surface waves, including both Rayleigh and Love waves, is becoming increasingly popular for near-surface characterizations. Due to the high nonlinearity of the objective function and a huge amount of data, FWI may converge towards a local minimum and is usually computationally expensive. To overcome these problems, we reformulate FWI under a multi-objective framework and propose a random objective waveform inversion (ROWI) method for surface-wave characterization. We use three objective functions: the classical least-squares (l2) waveform difference, the envelope difference, and the difference in the FK spectra. At each iteration, we randomly choose one shot and randomly assign one of the three objective functions to this shot. We only update the model with one iteration using a preconditioned steepest descent algorithm to optimize the currently assigned objective function. Therefore, ROWI has high freedom in exploring the model and objective spaces.
We use a synthetic example to compare the performance of ROWI with conventional FWI approaches. ROWI converges to better result compared to the conventional FWI approaches, while some of the conventional FWI approaches are trapped at local minima and fail to reconstruct reasonable results. We also apply ROWI to a field data acquired in Rheinstetten, Germany. The main geological feature, a refilled trench, is successfully reconstructed in the ROWI result. The reliability of the ROWI result is also proven by a migrated GPR profile. Overall, both synthetic and field-data examples show that ROWI is computationally more efficient, less dependent on the initial model, and more robust compared to conventional FWI approaches.
Exhumed vs active geothermal systems: faults controlling ore deposits in Las Minas area as a key for the deep exploration in the Los Humeros geothermal field (Mexico)
Authors: Liotta Domenico , Agostini Alessandro , Bastesen Eivind , Bianco Caterina , Boschi Chiara , Braschi Eleonora , Brogi Andrea , Caggianelli Alfredo , Garduno Victor Hugo , Gonzalez Partida Eduardo , Morelli Guia , Olvera-Garcia Emmanuel , Ruggieri Giovanni , Torabi Anita , Ventruti Gennaro , Wheeler Walter , Zucchi Martina
Published: March 2020

The investigation of the deep geothermal systems is a challenging task in active geothermal systems. In order to decrease the mining risk, the study of the analogue exhumed systems sheds light on the relationships between fluid circulation and geological structures through the analyses of faults and ore deposits distributions. In the Las Minas area (Central Mexico), ore deposits are quite diffuse at the boundary between crystalline and sedimentary rocks and in fault zones. This is a consequence of the interaction between cooling of Miocene felsic magmas, hydrothermal fluids and coeval fault activity. We investigated the role of the faults in channeling the hydrothermal fluids by fieldwork and analysis of fractures at outcrops. The field mapping was carried out at 1:10000 scale (60 km2). When possible, kinematic data on recent fault planes influencing the permeability and geothermal fluid paths were collected. This includes information on the main structural trends and the orientation of the intermediate kinematic axis.The evolution and origin of the hydrothermal fluids circulating in the exhumed geothermal system of Las Minas area (Central Mexico) were investigated by i) structural and minero-petrographic studies and, ii) fluid inclusion and isotope analyses carried out on skarn and hydrothermal alteration minerals.Two families of faults have been recognized, NNW-SSE and SW-NE oriented, respectively. The SW-NE trending faults often controlled the emplacement of dykes, indicating that the magmatic fluid was channeled and driven by the faults induced permeability. Their activity is at least encompassed between Miocene and Quaternary. The kinematic relation between these two fault systems could be explained in a extensional framework, assuming that the NNW-SSE fault system acted as transfer faults. Fluid inclusions recorded the circulation of: 1) high-temperature (up to 650°C), high-salinity (up to 60 wt.% NaCl equiv.) fluid of magmatic origin; 2) high-temperature (470-650°C) aqueous-carbonic fluid produced during fluid-rock interaction with carbonate basement rocks and 3) relatively low-salinity (up to 2 wt.% NaCl equiv.) fluid of meteoric origin. A general evolution from high- to low-temperature fluid circulation characterized the geothermal system.
Installation of blue-green solutions at large scale to mitigate pluvial floods
Authors: Cristiano Elena , Farris Stefano , Deidda Roberto , Viola Francesco
Published: March 2020

 The growth of urbanization and the intensification of extreme rainfall events, that has characterized the last century, are leading to an increase of pluvial floods, which are becoming a significant problem in many cities. Among the different solutions proposed and developed to mitigate flood risk in urban areas, green roofs and rainwater harvesting systems have been deeply investigated to reduce the runoff contribution generated from rooftops. These tools have been largely studied at small scale, analysing the flood reduction that can be achieved from one single building or in a small neighbourhood, without considering the large-scale effects. In this work, the potential impact of the installation of green-blue solutions on all the rooftops of a city is evaluated, assuming to place green roofs on flat roofs and rainwater harvesting systems on sloped ones. We investigated nine cities from 5 different countries (Canada, Haiti, United Kingdom, Italy and New Zealand), representing different climatological and geomorphological characteristics. The behaviour of the blue-green solution was estimated with the help of a conceptual lumped ecohydrological model and the mass conservation, using rainfall and temperature time series as climatological input to derive the discharge reduction for different scenarios. Due to the high percentage of sloped roofs in most of the investigated locations, the cost-efficiency analysis highlights that the large-scale installation of rainwater harvesting tanks enables to achieve higher mitigation capacity than green roofs at lower cost. Green roofs, however, present many additional benefits (such as biodiversity contribution, thermal insulation for buildings, pollution reduction and increase of aesthetic added value) that need to be evaluated by urban planners and policy makers. The best achievable performance is given by the coupled system of rainwater harvesting tanks and intensive green roofs: for extreme rainfall events this solution guarantees a discharge reduction up to 20% in most of the cities.
Seafloor sediment supply of nutrient silicon on the Greenland margin
Authors: Ng Hong Chin , Cassarino Lucie , Pickering Rebecca , Woodward Malcolm , Hammond Samantha , Hendry Katharine
Published: March 2020

The biogeochemical cycling of nutrient silicon (Si) in the northern high latitudes has received increasing attention over recent years. This is in large part due to the discovery of silicon limitation of diatoms over seasonal timescales, the potential role of melting glaciers in supplying a significant amount of this nutrient to the coastal ocean, and the rapid environmental changes the polar ocean is experiencing as a result of global climate warming. However, our understanding of the nutrient Si in the polar ocean is severely restricted by the lack of knowledge of the benthic Si cycling and its controlling processes, which is due to the limited number of seafloor observations in the region. In this study, we address this knowledge gap through the acquisition of sediment pore water profiles and the execution of incubation experiments on sediment cores collected from the Greenland continental margin and the Labrador Sea.

Our results indicate a net (benthic) flux of dissolved silica (DSi) out of the sediment into the overlying seawater at the study sites. A new global compilation also reveals that benthic Si flux observed at our marginal sites are substantially higher than in the open ocean. This is likely because benthic flux in the open ocean is solely maintained by molecular diffusion along a concentration gradient, while there are additional processes: pore water advection and rapid dissolution of certain siliceous sponge groups, and other reactive silica phases, that contribute to the elevated benthic Si flux on the Greenland margin. This finding has important implications for existing evaluations of oceanic Si budgets, which have not accounted for any processes other than diffusion in the global estimation of benthic Si flux. Our results also suggest that strong benthic Si flux observed on the Greenland margin, combined with wind-driven coastal upwelling, could be a significant source of this nutrient to both the diverse (benthic) sponge communities and (planktonic) diatom productivity in the region. The magnitude of this benthic cycling could potentially rival the other continental inputs of Si in the northern high latitudes, as the first estimation of total benthic Si flux from the western Greenland shelf alone (0.04–0.27 Tmol year-1) is in the same order of magnitude as the total Si export from Greenland Ice Sheet (0.2 Tmol year-1) and the pan-Arctic rivers (0.35 Tmol year-1) respectively.
Biogenic safety of clay barrier materials for radioactive waste repository database
Authors: Safonov Alexey , Popova Nadezhda , Spirina Elena , Abramova Elena , Philippova Nadezhda , Jarkova Victoria , Boldyrev Kirill
Published: March 2020

Clay minerals are widely used as materials for construction of engineered barriers for nuclear waste and spent fuel repositories all over the world due to perfect isolation properties and high sorption capacity. Unwanted microbiological processes that occur in geological repository can cause deterioration of clay barrier materials, which may significantly affect long-term safety of the repository. It is important to note that such unwanted processes could be caused both by native microbial population and bacteria brought in from outside during the construction of the repository.

This paper aims to develop a general concept that could be used to prove the risk of unwanted microbial processes’ occurrence in clay materials.  

Some features of mineral composition of clay materials, including the content of iron, sulphur, phosphorus, organic and mineral carbon, provide the basis for the concept. The ratios of free mono- and di-valent cations present in the solution (Na-K-Ca-Mg) are also taken into account. Another approach presumes microflora composition analysis by means of high-efficient 16S rRNA sequencing method. In addition, the results of several tests dedicated to microbial communities’ stimulation are discussed. These include tests on hydrogen or organic substance addition as electron donors with subsequent standard tests on metabolic activity evaluation, MTT test and respiration assessment of microbial population, which is represented by both planktonic cells and cells incorporated into biofilms. The developed concept was used to assess clay materials found in Russian Federation that could potentially be used to construct engineered safety barriers. These data formed the basis for the formation of a database of microbial safety of engineering barrier materials for radioactive waste storage.
Critical area prioritization for river basin planning and management under future scenarios using SWAT model
Authors: Pandey Ashish , Kc Bishal , Kalura Praveen , Chowdary Vemuri Mutthya
Published: March 2020

Suitable and practicable best management practices (BMPs) are needed to develop effective and efficient watershed management under future climate change scenarios. Tons river basin is an agricultural-based watershed having a great significance to the States of Madhya Pradesh and Uttar Pradesh. Identification of critical erosion prone areas of the Tons River basin and implementation of BMPs for the future scenarios (2030-2050) using RCP 4.5 and RCP 8.5 scenarios is the main aim of this study. In this study, the Soil and Water Assessment Tool (SWAT) model was calibrated and validated for simulation of runoff and sediment yield using the Sequential Uncertainty Fitting (SUFI-2) technique. The values of coefficient of determination (R2), Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS) and RMSE-observations standard deviation ratio (RSR) were 0.71, 0.70, -8.3 and 0.54 respectively during the calibration period whereas in validation the values were 0.72, 0.71, -3.9 and 0.56 respectively. Thus, the SWAT model can be employed in the Tons river basin of India for critical area prioritization and river basin planning and management under future scenarios.
Joint inversion of the lithospheric density struture in the North China Craton based on GOCE satellite gravity gradient data and surface gravity data
Authors: Tian Yu , Wang Yong
Published: March 2020

The North China Craton (NCC) is one of the oldest cratons in the world. Currently, the destruction mechanism and geodynamics of the NCC still remain controversial. All of the proposed views regarding the issues involve studying the internal density structure of the NCC lithosphere. Gravity field data are one of the most important data in regard to investigating the lithospheric density structure, the gravity gradient data and the gravity data possess their own advantages. Given the inconsistency of the on orbit GOCE satellite gravity gradient and surface gravity observation plane height, also effects of the initial density model upon of the inversion results, the joint inversion of gravity gradient and gravity are divided into two integrated processes. By using the preconditioned conjugate gradient (PCG) inversion algorithm, the density data are calculated using the preprocessed remaining gravity anomaly data. The newly obtained high resolution density data are then used as the initial density model, which can be served as the constraints for the subsequent gravity gradient inversion. Downward continuation, terrain correction, interface undulation correction and long wavelength correction are performed for the four gravity gradient tensor data(Txx，Txz，Tyy，Tzz)of the Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite,  after which the remaining gravity gradient anomaly data(T'xx，T'xz，T'yy，T'zz) are used as the new observation quantity. Finally, the ultimate lithospheric density distribution within the depth range of 0–180 km in the NCC is obtained using the same PCG algorithm.
Retrieval of High Spatial Resolution Aerosol Optical Depth from Chinese gAofen Data for Australian bushfire
Authors: Xue Yong
Published: March 2020

Aerosol optical depth (AOD) is an important factor to estimate the effect of aerosol on light, and an accurate retrieval of it can make great contribution to monitor atmosphere. Therefore, retrieval of AOD has been a frontier topic and attracted much attention from researchers at home and abroad. However, the spatial resolution of AOD, based on Moderate-resolution Imaging Spectroradiometer (MODIS), is low, and hard to meet the needs of regional air quality fine monitoring. In 2018, China launched Gaofen-6 satellite, which set up a network with Gaofen-1 enabling two-day revisited observations in China's land area, improving the scale and timeliness of remote sensing data acquisition and making up for the shortcomings of lacking multi-spectral satellite with medium and high spatial resolution. Along with advancement of the Earth Observation System and the launch of high-resolution satellites, it is of profound significance to give full play to the active role of high-scoring satellites, in monitoring atmospheric environmental elements such as atmospheric aerosols and particulate matter concentrations, and achieve high-resolution retrieval of AOD through Gaofen satellites.

In this paper the data of Gaofen-6 and Gaofen-1 was used to retrieve the AOD. based on the Synergetic Retrieval of Aerosol Properties (SRAP) algorithm. This algorithm can retrieve the surface reflectance and AOD synchronously through constructing a closed equation based on double star observations. It can be applied to various types of surface reflectance which extends the coverage of the retrieval of AOD inversion effectively. Experimental data includes the satellite data of New South Wales and eastern Queensland on November 21, 2019, which have been suffered from unprecedented large-scale forest fires for over 2 months. The retrieval of AOD during the time with the satellite data is benefit for the prevention and monitoring of forest fire. The experimental results are compared with the AERONET ground observation data for preliminary validation. The correlation coefficient is about 0.7. The experimental results show that the method have higher accuracy, and further validation work is continuing.
Reconstructing Past Indian Summer Monsoon Productivity and Stratification During the Late Pliocene and Early Pleistocene
Authors: Gray Emmeline , Anand Pallavi , Bolton Clara , Murayama Masafumi , Badger Marcus
Published: March 2020

The South Asian or Indian Summer Monsoon (ISM) brings seasonal winds and rains to the Indian subcontinent and affects billions of people.  It is likely that the global monsoon will strengthen in a 1.5 °C warming scenario (IPCC special report (2018)), however our ability to predict ISM behaviour in the future is restricted due to lack of understanding of its behaviour under varying climatic conditions before instrumental records began.  Thus, reconstructing the palaeo-monsoon using proxies gives insight into past and potentially future controls on the ISM.  We present new data covering the interval ~5 to ~2 million years ago (Ma), during the Pliocene and early Pleistocene when the long-term Cenozoic cooling trend culminated in intense northern hemisphere glaciations from 2.7 Ma.  At this time, global temperatures are suggested to have been 2-3 °C warmer than today and atmospheric CO2 was over 400 ppm (similar to today). 

This study focuses on sediments from Site U1443 ( 5°N, 90°E), drilled during International Ocean Discovery Program (IODP) Expedition 353 in the Bay of Bengal (BoB) for the Pliocene – early Pleistocene.  We present X-ray fluorescence (XRF)-derived bulk sediment geochemical data and suggest that erosional flux (terrigenous elements/total counts) as well as productivity (Br/Cl) varied in response to runoff strength, precipitation, and wind stress at the study site to reconstruct ISM variability.  Additionally, new nannofossil assemblage and morphometric data, collected using the automated system SYRACO, are used to reconstruct BoB stratification and productivity and thereby assess ISM dynamics.  A new benthic oxygen isotope-based age model will allow us to place the Site U1443 records into the context of existing climate and monsoon records and evaluate ISM response due to external and internal climate forcing factors.
Static Stability Associated with Southern Hemisphere Blocking Onsets
Authors: Dong Li , Colucci Stephen
Published: March 2020

The horizontal and temporal variation of static stability prior to blocking onset is characterized through composite analysis of blocking events in the Southern Hemisphere. It is found that a local minimum of static stability in the upper troposphere and on the tropopause is achieved over the block-onset region when blocking onset takes place. From the perspective of isentropic potential vorticity, blocking onset is accompanied by extratropical tropopause elevation and a local low isentropic potential vorticity anomaly that is formed right under the elevated tropopause. This low isentropic potential vorticity anomaly is coincident with a local minimum of static stability over the block-onset region. In addition, based on static stability budget analysis, it revealed that the decrease of static stability in the upper troposphere and on the tropopuase prior to blocking onset is attributable to horizontal advection of low static stability from subtropics to midlatitude as well as the stretching effect associated with upper-level convergence, with the horizontal advection forcing being the primary contributor. On the other hand, the vertical advection of static stability tends to oppose the decreasing static stability through advecting more stable air downward such that it stabilizes the local air over the block-onset region. Furthermore, the indirect and direct effect of latent heat to the local change of static stability over the block-onset region are also discussed, respectively.
Dynamics and energetics of nonlinear internal wave around a double-canyon system
Authors: Li Qun
Published: March 2020

The continental shelf/slope northeastern Taiwan is a ‘hotspot’ of nonlinear internal wave (NLIW). The complex spatial pattern of NLIW indicates the complexity of the source and the background conditions. In this talk, we investigated the dynamic and energetics of the internal tide (IT) and NLIW around this region based on a 3D high resolution nonhydrostatic numerical model. Special attention is paid on the role of two main topographic features-the Mien-Hua Canyon and the North Mien-Hua Canyon, which are the energetic sources for ITs and NLIW.

The complex IT field is excited by the double-Canyon system and the rotary tidal current. ITs from different sources and formation time interference with each other further strengthen the complexity. The area-integrated energy flux divergence (the area-integrated dissipation rate) is ~0.45GW (~0.28GW) and ~0.26 GW (~0.17 GW) over the Mien-Hua Canyon and the North Mien-Hua Canyon, respectively. Along with the energetic internal tides, large-amplitude NLIW and trains are also generated over the continental shelf and slope region. The amplitude of the NLIW can reach to about 30 m on the continental slope with a water depth of 130 m and shows similar spatial complexity, which is consistent with in situ and satellite observations. Further analysis shows that the dominant generation mechanism of the NLIW belongs to the mixed tidal-lee wave regime. In addition, the dynamic processes can be significantly modulated by the Kuroshio. With the present of Kuroshio, the energy flux of the M2 internal tide shows a distinct gyre pattern and strengthens over the double canyon system, which is more close to the mooring observations and previous study.
Do CMIP5 emergent constraints on the large scale atmospheric circulation work to constrain CMIP6 projections?
Authors: Simpson Isla , Davenport Fances , Al Fahad Abdullah , Lehner Flavio
Published: March 2020

Accurate future projections of the climate system are hindered by a number of sources of uncertainty: forcing uncertainty, internal variability and model structural uncertainty. An ``Emergent constraint'' is a technique that has been devised to reduce projection uncertainties arising from the model structural component. It consists of a statistical relationship (across a model ensemble) between a model’s representation of some aspect of the present day climate and its future projected climate change. This relationship can then be used to imply the future projected change, given the observed value of that present-day aspect. However, in order for the emergent constraint to be considered robust it must: (a) be accompanied by a physical mechanism and (b) be robust to out-of-sample testing.

 

In prior Coupled Model Intercomparison Projects (CMIP), in particular CMIP5, a number of emergent constraints on the large scale atmospheric circulation were proposed, with implications for regional hydroclimate change. These include: (1) a relationship between a model’s climatological jet latitude and its future projected poleward shift in the Southern Hemisphere; (2) a relationship between a model’s future projected wintertime circulation and hydroclimate change over North America and its climatological representation of stationary waves in the North Pacific; and (3) a relationship between a model’s future projected precipitation change over California and its representation of the relationship between ENSO and California precipitation. Constraints (2) and (3) actually imply opposite constraints on California precipitation changes for the real world, which speaks to the need for a deeper understanding of these emergent constraints and a comprehensive assessment of their robustness.

 

While the CMIP6 archive does not represent a true ``out-of-sample’’ test of CMIP5 emergent constraints, it does provide us with a new dataset composed of new and/or more advanced models in which to assess their robustness. This presentation will review the proposed emergent constraints on the large-scale atmospheric circulation and assess whether or not they are robust across both the CMIP5 and CMIP6 ensembles. Their potential for constraining regional hydroclimate projections will also be discussed.

 
MPDATA method for non–uniform mesh
Authors: Yuan Xinpeng
Published: March 2020

 

MPDATA method for non–uniform mesh

 

Xinpeng Yuan

State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences,China 

Meteorological Administration, Beijing 100081, China 

 

Keyword: Atmospheric dynamics, MPDATA, non–uniform mesh, precision

Abstract: MPDATA[1,2]（multidimensional positive deﬁnite advection transport algorithm） is proposed by Piotr K. Smolarkiewicz in 1983. This method is used to efficiently solve the advection transport problem of non-negative thermodynamic variables (such as liquid water or water vapor) in the atmospheric dynamics model. This method has been proved to be an effective numerical solution to the advection transport problem for uniform meshes. However, since there is no uniform mesh division on the sphere, the traditional MPDATA method is faced with the incompatibility problem for the non-uniform and quasi-uniform meshing of the sphere, resulting in the numerical algorithm failing to reach the designed second-order accuracy. Firstly, this paper analyzes the insufficiency of traditional MPDATA methods for non-uniform grids. That is, the incompatibility of the first-order numerical scheme and the approximation of boundary derivative.Then the MPDATA method suitable for non-uniform grid is proposed. According to the characteristics of non-uniform grid and the characteristics of well-balance[3] central grid point algorithm, the MPDATA method suitable for 1-d and 2-d complex grid structure is designed. The consistency and positivity of the algorithm are proved by mathematical analysis. Finally, the theoretical proof is verified by numerical simulation.

 

Reference

[1] Smolarkiewicz P. A Simple Positive Definite Advection Scheme with Small Implicit Diffusion[J]. Monthly Weather Review. 1983.

[2] Smolarkiewicz P K, Szmelter J. MPDATA: An edge-based unstructured-grid formulation[J]. Journal of Computational Physics. 2005, 206(2): 624-649.

[3] Kurganov A, Levy D. Central-Upwind Schemes for the Saint-Venant System[J]. ESAIM: Mathematical Modelling and Numerical Analysis. 2002, 36(3): 397-425.

 
Investigating the impacts of coal-fired power plants on ambient PM2.5 by a combination of chemical transport model and receptor model
Authors: Chen Xi , Yang Ting , Wang Zifa , He Litao
Published: March 2020

Aiming at evaluating the impact of coal-fired power plants on urban air quality and human health, a one-month intensive observation campaign was conducted in a typical polluted city located in “2+26” city cluster in China North Plain in December 2017. The observation results illustrated that coal-fired plant can increase the PM2.5 concentration by ~5% on monthly average in city scale. The impacts differed under various diffusion conditions. A three-dimensional Nested Air Quality Perdition Model (NAQPMS) with source apportionment was employed to reveal the impacts. The results indicated that the power plant had the greatest effect on regional air quality during severe pollution period while it was ignorable during the excellent dissipation period under the robust wind. PM2.5 contributed by the power plant was below 150 m, 100 km far away, and about 5 μg m-3 during light pollution period. When it came to accumulation period, the plume reached 500 m height, diffused to downwind area about 100 km away within half a day, and with a maximum contribution of 40 μg m-3 to PM2.5. The affected area extended further to 250 km in severe pollution period and the contribution to PM2.5 was at least 10 μg m-3 in different distances. The affected height was up to about 500 m with more than 10 μg m-3 PM2.5 mainly constrained below 150 meters. Overall, regional integrated control strategies should be taken for power plants in “2+26” city cluster during pollution episodes to further improve the air quality.