bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil morphometrics applied to soil trenches in a contaminated site
Authors: Terribile Fabio , Vingiani Simona , Mileti Antonio , Langella Giuliano
Published: March 2020

In many contaminated sites and/or sites affected by a potentially toxic element (PTE) contamination, the spatial variability of soil contamination is a very complex issue.

This is because the history of contamination in a specific industrial site is often lost in time and with very different modifications occurring over time. It is even hidden in the case of illegal waste dumping, for which type, quantity and localization of contaminants are unknown. Thus it is not known in advance (i) the spatial distribution of contamination, (ii) the knowledge about how contaminants have been distributed over and beneath the soil, (iii) how far contaminants have been reworked during the life time of the contaminated site.

Despite these problems, it is self-evident that a detailed knowledge of the natural and the anthropogenic spatial variability of soil contamination and soil properties is of crucial importance in both site characterization and most importantly in site reclamation.

Here we claim that the analysis of soil trenches in combination with pXRF can strongly support the understanding about processes behind soil contaminant distribution and this information can then be used in the following study of contaminated site characterization.

This contribution focuses on how to acquire detailed knowledge of the spatial distribution of contamination in an agricultural area of southern Italy, 6 ha of farmland confiscated by the Italian Judiciary due to past illegal burial of industrial tannery wastes causing potential contamination by Cr, Zn and heavy hydrocarbons (C>12). After indirect geophysical and radiometric (i.e. soil gamma ray emissions) prospections, 8 sites for soil profiles and trenches (10 x 1.7 m wide) digging were identified.

Over these trenches both morphological (i.e. colour, structure, plant roots, etc.) and elemental total content analysis (Olympus p-XRF) were performed. This analysis enable to identify three type of soil contaminant deposition which affected to various degree the Ap, Bw and C horizons of the investigated Silandic Andosol. The highest Cr and Zn content was found in the B horizon, where levels of 25000 ppm were measured in soil-pockets of muddy-grey materials, very likely hosting the original processing residues.
Thermodynamic constraints on the size distributions of tropical convective clouds.
Authors: Garrett Timothy , Krueger Steven , Glenn Ian , Ferlay Nicolas
Published: March 2020

Parameterizations for sub-grid cloud dynamics are commonly developed by using fine scale modeling or measurements to explicitly resolve the mechanistic details of clouds to the best extent possible, and then to formulating these behaviors cloud state for use within a coarser grid. A second is to invoke physical intuition and some very general theoretical principles from equilibrium statistical thermodynamics. This second approach is quite widely used elsewhere in the atmospheric sciences: for example to explain the heat capacity of air, blackbody radiation, or even the density profile or air in the atmosphere. Here we describe how entrainment and detrainment across cloud perimeters is limited by the amount of available air and the range of moist static energy in the atmosphere, and that constrains cloud perimeter distributions to a power law with a -1 exponent along saturated isentropes and to a Boltzmann distribution across saturated isentropes. Further, the total cloud perimeter in a cloud domain is directly tied to the buoyancy frequency with respect to a moist adiabatic in the column. These simple results are shown to be reproduced within a complex dynamic simulation of a tropical convective cloud field, the Giga-LES, and in passive satellite observations of cloud 3D structures. The suggestion is that statistical properties of tropical cloud structures can be inferred from the bulk thermodynamic structure of the atmosphere rather than much more computationally expensive dynamic simulations.
The more they enjoy it, the better they learn it !
Authors: Bozdoğan Tuğba
Published: March 2020

                                               Overcome Misconceptions and Provide Permanent Learning   

      As being an elementary science teacher for over ten years, I have observed that students learn best when they are active and enjoy when they like the topic. However, I have also observed that they can easily forget what they have learnt or can learn in the wrong way. I try to organize my lessons in the way that provide permanent learning or prevent misconceptions. For example, in order to teach concept of balanced and unbalanced forces and teaching the properties of force I usually let my students play tug of war outside of classroom, then they argue the size of the force and the direction of the force and the results. Similarly, in order to teach the topic calculation of average velocity, I also let my students to discover velocity outside of classroom, in this activity, the students gather data as a class from a person running at different rates on a school garden or football field and then they calculate the average velocity of their friends and create a distance versus time graph with data they collected. Moreover, in other to teach the basics of the kinetic molecular theory: properties of solids, liquids and gases, I let my students animate matter’s particles that are constantly in motion in company with the music which goes  from slow to upbeat music. In addition it can be hard to teach to my students the motion of the Sun, Earth and the Moon the relationship between the three and in particular to show eclipses. In order to make this concept understandable for them, they build a “Tellurion” that is model of The Earth, the Sun and the Moon as a long term project.

 As a result, at the end of all these activities, students can learn easily, permanently and also enjoy. While doing such as activities I try to catch the misconceptions and correct them as possible as I can do. I’m planning to demonstrate in my poster such examples of activities and my students’ reactions to them and share with my colleagues from other countries as well as, I planning to ask for alternatives ways in such topics they use in their lessons.
How to differentiate nighttime transpiration and water recharge in nocturnal sap flow?
Authors: Chen Zuosinan , Zhang Zhiqiang , Chen Lixin
Published: March 2020

Nocturnal sap flow (Qn) affect not only forest carbon and water budgets but also their responses to climate change as it consists of two ecohydrological and ecophysiological significant components: nighttime transpiration and water recharge. A vapor pressure deficit (VPD) based sap flow partitioning method has been developed to estimate nighttime transpiration, which is normally quantified through the discretely measured nighttime stomatal conductance, from the widely and continuously measured sap flow. However, given the increasing knowledge of Qn mechanisms, whether Qn could be partitioning simply by VPD and whether this method is valid in semi-arid regions remain unclear. We measured sap flow of Pinus tabuliformis and Acer truncatum in a middle-aged and a young monoculture forest stand, respectively, in a semi-arid mountainous area of northern China. We found the influence of VPD on Qn conditioned by soil moisture. Meanwhile, a considerable impact of wind speed on Qn was observed. In the stands with relatively dry soils, both increased and decreased soil moisture promoted Qn, which might be due to enhanced nighttime water recharge for two distinct purposes, i.e., capacitance refilling and avoiding hydraulic failures. For these three environmental factors (i.e., VPD, wind speed, and soil moisture) that have been considered most in previous studies, their total effect explained less than 55% of the Qn variations. This study highlights that physiological influences of VPD on nighttime stomatal water loss were uncertain. Furthermore, it suggests that there could exist considerable nighttime water loss induced by wind, possible region-specific patterns of nighttime water recharge, and limited concurrent environmental controls on Qn. Our findings are helpful to improve the VPD-based sap flow partitioning method to differentiate nighttime transpiration and water recharge.
Explicating potential soil development of reclaimed farmlands using the molecular ecological network analysis in mining disturbed area, East China
Authors: Chen Fu , Ma Jing
Published: March 2020

Understanding the interactions among different soil microbial species and how they responded to reclamation is essential to ecological restoration and the land development. In this study, we investigated the bacterial distribution in different reclamation sites and constructed molecular ecological networks to reveal the interactions among soil bacterial communities along the reclamation timeline. The relationship between the microbial network module and environmental factors were also analyzed. Bacterial community diversity and composition changed dramatically along the reclamation timeline. PCA and NMDS analysis showed the microbial distribution patterns varied along the reclamation years. Additionally, based on the network profile, phyla Acidobacteria, Planctomycetes and Proteobacteria were distinguished as the key microbial populations in most reclamation sites. Moreover, different network structures were significantly correlated with different soil properties, such as pH value, soil organic matter, soil dehydrogenase and urease activity, which implied that microbial network interactions might influence the soil ecological functions. The variation of the network complexity along the reclamation years revealed that the microbial development and the persistent agricultural utilization promoted the land development of the reclaimed soil in disturbed mining area. Overall, our findings could provide some information of how microorganisms changed along the increasing reclamation time, and how they responded to reclamation activity by regulating their interactions in different ecosystems.
Geoarchaeological evidence of multiple climatic and anthropic triggers driving the breakdown of the Terramare civilization (Bronze Age, Northern Italy)
Authors: Zerboni Andrea , Mercuri Anna Maria , Florenzano Assunta , Clò Eleonora , Zanchetta Giovanni , Regattieri Eleonora , Isola Ilaria , Brandolini Filippo , Cremaschi Mauro
Published: March 2020

The Terramare civilization included hundreds of banked and moated villages, located in the alluvial plain of the Po River of northern Italy, and developed between the Middle and the Recent Bronze Ages (XVI-XII cent. BC). This civilization lasted for over 500 years, collapsing at around 1150 years BC, in a period marked by a great societal disruptionin the Mediterranean area. The timing and modalities of the collapse of the Terramare Bronze Age culture are widely debated, and a combined geoarchaeological and palaeoclimatic investigation – the SUCCESSO-TERRA Project –is shading new light on this enigma. The Terramare economy was based upon cereal farming, herding, and metallurgy; settlements were also sustained by a well-developed system for the management of water and abundant wood resources. They also established a wide network of commercial exchange between continental Europe and the Mediterranean region.The SUCCESSO-TERRA Project investigated two main Bronze Age sites in Northern Italy:(i) the Terramara Santa Rosa di Poviglio, and (ii) the San Michele di Valestra site, which is a coeval settlement outside the Terramare territory, but in the adjoining Apennine range. Human occupation at San Michele di Valestra persisted after the Terramare crisis and the site was settled with continuity throughout the whole Bronze Ages, up to the Iron Age. The combined geoarchaeological, palaeoclimatic, and archaeobotanical investigation on different archaeological sites and on independent archives for climatic proxies (offsite cores and speleothems) highlights the existence of both climatic and anthropic critical factors triggering a dramatic shift of the landuse of the Terramare civilization. The overexploitation of natural resources became excessive in the late period of the Terramare trajectory, when also a climatic change occurred. A fresh speleothem record for the same region suggests the occurrence of a short-lived period of climatic instability followed by a marked peak of aridity. The unfavourable concomitance between human overgrazing and climatic-triggered environmental pressure, amplified the on-going societal crisis, likely leading to the breakdown of the Terramare civilization in the turn of a generation.
Monitoring of suspended sediment load and Sediment Sources in a Karst Plateau Catchment of Southwest China.
Authors: Peng Tao , Cheng Qianyun , Cao Le
Published: March 2020

The development of karst landforms in southwest China has resulted in surface and underground dual hydrogeological structure. The characteristics of the mechanism of soil erosion and its environmental effects are different from those in non-karst regions. This study aims to monitor sediment load and identify the main sediment source in a typical karst plateau agroforestry catchment, to estimate the relative contribution rates of surface and underground river sediment sources. The results show that the annual sediment transport modulus in catchment is very low (5.1 Mg km-2 a-1) in this carbonate agroforestry catchment compare to deforestation 20 years ago (20 Mg km-2 a-1). Sediment Fluxes in the underground river and surface river account for 19.7% and 80.3% respectively. Soil leakage is an important way but not a main way of soil erosion in typical karst watershed. There is no obvious soil erosion on the hillsides (less than 1 Mg km-2 a-1), but the sediment sources results shows sediment sources of surface and underground river are different in 2017 and 2018, In 2017, it indicate that carbonate surface soil contributes 16.2% and 11.9% of the total suspended sediment to the surface and underground river respectively, and the clastic rock pieces are the primary source of both surface and underground river sediments, 79.5% and 60.8% respectively. Subsurface soil contributes a smaller fraction to the total sediment load, 4.3% to surface rivers and 27.3% to underground rivers. The 137Cs values for some suspended sediments in 2018 were outside the range all of the soil source samples, it attributed to re-mobilization of old sediment stored in karst underground conduits during the deforestation, and these “old sediments” could generate to the surface again when with the rainfall erosivity above 49 J·mm·m-2·h-1.
GOANA, a Global Ocean Atlas, Neutrally Averaged
Authors: Barker Paul , McDougall Trevor
Published: March 2020

Isopycnally averaged hydrographic data gives results that are significantly different to the standard method of averaging at constant depth. The act of averaging isopycnally ensures that water masses are neither created or destroyed.  We average using the weighted least squares quadratic (or LOESS) fitting method of Chelton and Schlax (1994) and Ridgway et al. (2002) along appropriately defined density surfaces.  This produces an gridded oceanographic atlas that is composed of the Fourier coefficients of the mean temporal trend, the strength of the semi-annual and seasonal cycle allowing the user to reconstruct a climatology at any temporal resolution. Initially we are producing an atlas consisting of Absolute Salinty and Conservative Temperature but in the future we aim to include nutrient data.
Groundwater Flow System in Tokyo Metropolitan Area, Japan: Focusing on Changes in the Last 60 Years
Authors: Nagano Kosuke , Tsujimura Maki , Suzuki Ryu , Asakura Hiroko , Tabe Kazunori
Published: March 2020

     In 1960s, the groundwater level dropped with serious land subsidence due to the excessive pumping of groundwater for economic development in Tokyo Metropolitan area, whereas the groundwater level has been recovered after 1990’s because of the strict groundwater use regulation by the government. A few studies have reported long-term changes in the groundwater including a groundwater level dropdown and the recovery in Southeast Asia, such as Ho Chi Minh City in Vietnam and Jakarta in Indonesia. However, there are not enough investigations to monitor the groundwater flow covering the water level dropdown and the recovery during more than 50 years at the megacities in Asia regions. Therefore, we investigated the change of groundwater flow system at the Tokyo Metropolitan area with a special concern on the lowland area where the impact of land subsidence was particularly large due to an excessive pumping in the 1960's.

     First, we observed a spatial distribution of hydraulic head and the chemical and stable isotopic compositions in the groundwater and the river water to understand a current groundwater flow system in the whole Tokyo area in 2019, in which the groundwater level is stable. Then, we compared those results with that monitored from 1960’s to 1990’s.

     Groundwater was sampled from May to October 2019 at multiple boreholes installed at whole of Tokyo area with the depths ranging from 5 m to 260 m, and the main inorganic dissolved ions, stable isotopes (δD, δ18O) and the dissolved gas (CFCs, SF6) were determined on all samples. The high Cl- concentration more than 500 mg/L is limited in the groundwater and the river water in the coastal area with the average distance of 6 km from the sea, whereas the contour line of 500 mg/L intruded inland area with the average distance of 15 km from the coastal line in 1965 and 12 km in 1971, then 8 km in 1994 (Institute of Civil Engineering of the Tokyo Metropolitan Government, 1996). The groundwater hydraulic head is -6 m (m.s.l) at the lowland area in 2019, whereas that was -58 m in 1965, -52 m in 1971, and - 14 m in 1994.

     The depleted stable isotopes and the higher solute concentrations are observed in the lowland in 2019. Also, SF6 is not detected in the groundwater at the low land area, whereas we observe the SF6 concentration ranging from 0.8 pptv to 78 pptv in the upland area. These suggest that the groundwater in the upland has an apparent age of approximately less than one year to 40 years, whereas the groundwater in the lowland is recharged with an age more than 80 years at the higher elevation.
Microphysical cloud parameters of optically thin clouds in the Arctic in summer 2017
Authors: Richter Philipp , Palm Mathias , Weinzierl Christine , Rowe Penny , Notholt Justus
Published: March 2020

As a precursor of the current MOSAiC campaign, the PASCAL campaign took place in summer 2017 around Svalbard [1]. In the scope of the project (AC)3, infrared radiation emitted by clouds was measured using a calibrated Fourier Transform Infrared Spectrometer (EM-FTIR). EM-FTIR can be used for different purposes, like the observation of trace gases or microphysical cloud parameters (MCP) like cloud optical depths and cloud effective droplet radii. In the observation of MCP, EM-FTIR can be used to measure optically thin clouds with very low amounts of liquid water paths below 30 gm-2, where microwave radiometer face problems because of their larger measuring uncertainty. 

The retrieval of the MCP is performed using the newly introduced retrieval code CLARRA [2]. CLARRA shows a high accuracy in the retrieval of MCP from low-level clouds, which were often observed during the measurements. 

The measurements were performed between June 2017 and August 2017 around Svalbard and include measurements of clouds over sea ice and open water. The spatial distribution of the MCP around Svalbard and a comparison to model results will be shown. This dataset can later serve as a reference for the question, how representative the measurements in Ny-Alesund on Spitzbergen are for the nearby arctic region.

[1] Wendisch et al., 2019: The Arctic Cloud Puzzle: Using ACLOUD/PASCAL Multi-Platform Observations to Unravel the Role of Clouds and Aerosol Particles in Arctic Amplification, Bull. Amer. Meteor. Soc., 100 (5), 841–871, doi:10.1175/BAMS-D-18-0072.1
[2] Rowe et al., 2019: Toward autonomous surface-based infrared remote sensing of polar clouds: retrievals of cloud optical and microphysical properties, Atmos. Meas. Tech., 12, 5071–5086, https://doi.org/10.5194/amt-12-5071-2019
Assessment on atmospheric parameters at co-location sites
Authors: Kitpracha Chaiyaporn , Balidakis Kyriakos , Heinkelmann Robert , Schuh Harald
Published: March 2020

Atmospheric ties are affected by the differences of atmospheric parameters of space geodetic techniques at co-location sites. Similar to local ties, they could be applied along with local ties for a combination of space geodetic techniques to improve the realization of terrestrial reference frames (TRF). Theoretically, atmospheric ties are affected by the height differences between antennas at the same site and meteorological conditions. Therefore, atmospheric ties could be determined by analytical equation based on meteorological information from in situ measurements or weather model. However, there is often a discrepancy between the expected zenith delay differences and those estimated from geodetic analysis, thus potentially degrading a combined atmospheric ties solution. In this study, we analyse the time series of zenith delays from co-located GNSS antennas at Wettzell (height differences below 3 meters), for 11 years (2008–2018). GNSS observations were analyzed with Bernese GNSS software version 5.2 with double-differencing technique and relative tropospheric delay and gradients were estimated with L1, L2, and the ionosphere-free (L3) linear combination thereof. Atmospheric ties were derived analytically employing meteorological data from Global Pressure and Temperature model 3 (GPT3) and ERA5 reanalysis, as well as corrections derived from ray tracing (Potsdam Mapping Functions, PMF). The comparison shows that zenith delay differences are dominated by equipment changes. The discrepancies between atmospheric ties and estimated zenith delay differences are frequency dependent, with the L1 solutions being the least biased. For these small vertical differences, seasonal signals are not significant for all frequencies.
Forecasting climate extremes to aid decisions on multi-week timescales
Authors: de Burgh-Day Catherine , Hudson Debbie , Alves Oscar , Griffiths Morwenna , Marshall Andrew , Young Griffith
Published: March 2020

Extreme events such as droughts, heat waves and floods can have significant and long lasting financial, infrastructural and environmental impacts. While probabilistic seasonal outlooks are commonplace, there are relatively few probabilistic outlooks available on multiweek timescales. Additionally, many services focus on the middle of the distribution of possible outcomes – e.g., forecasts of probability of above or below median, or probability of mean conditions exceeding some threshold. These do not encompass the types of extreme events that can be the most damaging, such as several consecutive days of extreme heat, unusually large numbers of cold days in a season, or an extended period where rainfall is in the lowest decile of historical years.

Advance warning of extreme events that impact particular industries enable managers to put in place response measures which can help to reduce their losses. This can involve:

Active responses which aim to reduce the severity of the impact. For example, losses in dairy production due to extreme heat can be mitigated by adjusting grazing rotations such that cows are in shadier paddocks during these events

Defensive responses which aim to account for any losses incurred due to an event. For example, the purchase of new farm equipment can be deferred if a forecast extreme event indicates a likely unavoidable financial loss in the near future

To meet this need, the Australian Bureau of Meteorology is developing a suite of forecast products communicating risk of extreme events using data from the Bureau’s new seasonal forecasting system ACCESS-S. Each prototype forecast product is trialed with external users through a webpage to assess usefulness and popularity.
Hybrid long-period volcanic events observed in off Nicobar region, the Andaman Sea from a passive OBS experiment
Authors: Aswini Karanam Kattil , Dewangan Pawan , Kamesh Raju Kattoju Achuta , Vadakkeyakath Yatheesh , Singha Pabitra , Reddy Ramakrushana , Arya Lalit
Published: March 2020

The off Nicobar region in the Andaman Sea is witnessing frequent earthquake swarms after December 2004 Tsunamigenic earthquake in January 2005, March and October 2014, November 2015 and April 2019. In this study, we present the geophysical evidence of active volcanism in the Off Nicobar back-arc region on 21st and 22nd March 2014 based on a passive Ocean Bottom Seismometer (OBS) experiment. We detected a series of hybrid earthquake events characterized by the onset of high–frequency signal (1-10 Hz) which is followed by a long period waveform of up to 600s having a range of 0.1-1 Hz. The waveforms appear to be emergent and lack the onset of a distinct S-phase. We also observed a very high frequency (10-40 Hz) hydro-acoustic phase in the coda of long-period events.  These hybrid events are considered to be volcano-tectonic (VT) events that may trigger magmatic activities in the Off Nicobar region. We have identified and located 141 high-frequency events on 21st and 22nd March 2014 using hypocent v.3.2 program and they are distributed along NW-SE direction aligning with the submarine volcanoes defining the volcanic arc as observed in the high-resolution bathymetry data. The fault plane solution of the major high-frequency events suggests strike-slip faulting with the strike, dip and rake values of 334°, 89° and 171°, respectively along the direction of the prevalent sliver strike-slip faulting in the Andaman back-arc region. We propose that the upward movement of magma is a plausible mechanism which can explain the frequent occurrence of earthquake swarms in the off Nicobar region. The stress generated from magma movement may initially trigger shallow VT events such as faulting or dike intrusions and later generate long period ringing associated with the resonance of the magma chamber. The shallow nature of the events also generates a hydroacoustic wave which is detected in the OBS experiment as the source region is in the SOFAR channel.
Spatial and statistical analysis of coherent vortical structures within a stress-driven free-surface turbulent shear flow
Authors: Chen Po-Chen , Tsai Wu-ting
Published: March 2020

The water surface under high wind condition is characterized by elongated high-speed streaks and randomly emerged low-speed streaks, which are attributed to underneath coherent vortical motions. These vortical structures within aqueous turbulent boundary layer plays a critical role in turbulent exchange, their characteristics and statistics are therefore of interest in this study. Direct numerical simulation of an aqueous turbulent flow bounded by a stress-driven flat free surface was performed. Simulation results of cases with high wind condition (surface friction velocity = 1.22 cm/s) as well as weak wind condition (surface friction velocity = 0.71 cm/s) are analyzed. To identify the underlying vortical structures, an indicator of swirling strength derived from local velocity-gradient tensor is adopted. A formal classification scheme, based on the topological geometry of the vortex core, is then applied to classify the identified structures. Surface layers with the two wind conditions reveal similar results in statistics and spatial distribution of vortical structures. Two types of characteristic vortices which induce the surface streaks are extracted, including quasi-streamwise vortex and reversed horseshoe vortex (head pointing upstream), most inclining at about 10 to 20 degrees. Quasi-streamwise vortices are the dominant structure, and both high- and low-speed streaks are fringed with such vortices; they adjoin the surface streaks as counter-rotating arrays in either staggered or side-by-side spatial arrangement. The length of quasi-streamwise vortices, however, are significantly shorter than the corresponding surface streaks, only 10% of the extracted quasi-streamwise vortices are longer than 150 wall units. Reversed horseshoe vortices, associated with downwelling motions and surface convergence, are located beneath the high-speed streaks. In contrast to the turbulent boundary layer next to a flat wall, typical forward horseshoe vortices (head pointing downstream) associated with upwelling motions are barely found within the free-surface turbulent shear flow.

This work was supported by the Taiwan Ministry of Science and Technology (MOST 107-2611-M-002 -014 -MY3).
Healthy synergies of carbon mitigation under climate policy in China
Authors: Zhao Jing , Wang Haikun
Published: March 2020

As the largest carbon emitter in the world, China shoulders weighty responsibility for carbon emission reduction. Recent evidence shows that carbon emission in China has the potential to peak ahead of schedule (2030). Analysis of both economic and environmental outcomes of the acceleration of carbon emission reduction will provide important implications for the better design and implementation of climate policies in China and other countries. However, there is a lack of research.

In this study, we focus on carbon emission paths and assess health impacts related to the synergistic emission reduction of atmospheric pollutants and conduct a cost-benefit assessment. We adopte the simulated emission of different Shared Socioeconomic Pathways and climate policy scenarios based on Global Change Assessment Model (GCAM) to quantify co-reduction of air pollution. Using the WRF-Chem chemical transport model and MEIC emission inventory, we simulate the change of air pollutant concentrations and calculate the related health benefit using the IER model and monetize it using the VSL model.

Our analysis shows that carbon emission in China could peak before 2030 in stringent climate policy. Meanwhile, cleaner developing pathways or stricter climate strategies can help to alleviate the pressure of carbon emission reduction. Climate policy will bring additional emission mitigations to atmospheric pollutants, especially for SO2, and NOx, but NH3 emission increases. Climate policies aimed at reducing carbon emissions will also bring different degrees of improvements in air quality and health benefits across China in 2030 and 2050, respectively.
Computational framework for discontinuity network characterization
Authors: Poulet Thomas , Kelka Ulrich , Westerlund Stefan , Peeters Luk
Published: March 2020

The topological and geometrical description of fault and fracture networks is an essential first step in any investigation of fractured or faulted media. The spatial arrangement, density, connectivity, and geometry of the discontinuities strongly impact the physical properties of the media such as resilience and permeability. Obtaining reliable metrics for characterizing fault and fracture networks is of interest for mining engineering, reservoir characterization, groundwater management, and studies on the regional fluid flow history. During large-scale studies, we mostly rely on two-dimensional lineaments obtained through structural mapping, outcrop analysis, or remote sensing. An efficient and widely applicable framework for discontinuity network characterization should therefore be based on the analysis of the frequently available two-dimensional data sets.

Here, we present an automated framework for efficient and robust characterization of the geometric and topologic parameters of discontinuity networks. The geometry of the lineaments is characterised based on orientation, length, and sinuosity. The underlying distribution of these parameters are determined, and representative probability density functions are reported. The connection between the geometric parameters is validated, e.g. correlation between orientation and length. The spatial arrangement is determined by classical line- and window-sampling, by assessing the fractal dimension, and via graph-based topology analysis.

In addition to the statistical analysis of lineament networks, we show how the graph data structure can be utilized for further characterization by linking it to raster data such as magnetic, gravimetric, or elevation. This procedure not only yields an additional means for lineament characterization but also allows users to assess dominant pathways based, for instance, on hydraulic gradients. We demonstrate the applicability of our algorithm on synthetic data sets and real-world case studies on mapped fault and fracture networks.

We finally show how our framework can also be utilized to design detailed numerical studies on the fluid flow properties of analysed networks by conditioning mesh refinement on the type and number of intersections. In addition, due to known scaling relationships our framework can help to determine appropriate parameters for the simulations. We provide examples of statistically parametrized fluid flow simulations in natural discontinuity networks and show the impact of conceptualizing the lineaments as conduits, barriers or conduit-barrier systems.
Grain size characteristics of surface aeolian sands in the downwind margin of modern Mu Us Sandland
Authors: Wang Zhongyuan , Wu Yongqiu
Published: March 2020

Desert (sandland) margin is the transition region from inner aeolian landforms  to other landforms outside, while it remains as an ambiguous conception in previous researches. Accurately delineating its boundary line and realizing the characteristics of the particle size distribution of surface aeolian sands in margin area can help us understand the formation of modern boundary of desert (sandland). In this research, the criteria of identification of the boundary were proposed and the boundary line was extracted quantitative. Then systematic analyses of grain size of aeolian sand in margin were conducted. Together with the morphologic type, activity and the geomorphological location of collected dunes, the factors controlled the particle-size distributions had also been analyzed. The results reveal the following: (1) There is notable difference in grain size characteristics of aeolian sand between inside and outside of Mu Us sandland. The outside samples are finer than inside. Additionally, the aeolian sand covering on loess is always more poorly sorted and with different grain size fraction composition. (2) The controlling factors on particle size distribution are different in different downwind margins. In southwest margin, the grain size characteristics of aeolian sand are influenced by time and degree of stabilization of sampled dune and locally topographic relief; From the estuary of Lu River to Yuxi River, sediment transport by wind is affected by topographic obstacles including both valley and loess gully. Meanwhile, the small dunefields in Loess Plateau outside of Mu Us sandland may originate from a local alluvial source; In northeast downwind margin, the grain size characteristics of aeolian sand covering on loess are determined by regional gully erosion after its deposition.
How much fire-derived carbon is transported vertically through the soil and what controls its mobility?
Authors: Schiedung Marcus , Bellè Severin-Luca , Coppola Alysha , Abiven Samuel
Published: March 2020

Wildfires produce a fire-derived carbon (C) residue known as pyrogenic carbon (PyC). This residue is one of the largest and most persistent terrestrial organic C pools with residence times over 1000 years. Large quantities of PyC can remain on the site where the fire occurs or can be transferred along the landscape and eventually enter the soil where it represents a major component of the total soil organic carbon (SOC). The drivers explaining the vertical PyC mobility in soils and the quantities it represents remain largely unknown, which limits our understanding of the fate of PyC in the terrestrial systems. Here, we used a manipulative soil column experimental approach in order to study the proportion of transportable PyC and its interaction with the soil mineral phase and non-fire-derived SOC during its vertical transport. To do this, we applied highly 13C-labelled ryegrass biochar (as a PyC proxy) on the upper layer of small soil columns (7 cm length, 2.5 cm diameter), and traced the fire-derived C in the soil and in the soluble fractions sequentially extracted during a percolation of 600 pore volumes under saturated conditions (equivalent to 18 years continues rainfall). We studied a combination of ranging soil texture (sandy loam and sand), SOC content (0.3-3.0%) and weathering state (age) of the ryegrass biochar (artificial oxidation with H2O2) to identify drivers controlling the vertical mobility of fire-derived C. We hypothesized that: i) Significant proportions of fire-derived C are transported through the soil column over the whole experimental period but decrease with time, ii) fire-derived C can be retained and stabilized within the soil column and influence the mobility of non-fire-derived SOC and iii) weathered fire-derived C is more mobile than fresh fire-derived C which may control its long-term fate in soils.
Influence of Different Data Fusion Methods on the Accuracy of Three-Dimensional Displacements Field
Authors: Guo Nannan
Published: March 2020

Combining multi-source data can improve the accuracy and the spatial resolution of the three-dimensional (3-D) displacements field. How to effectively integrate multi-source data to obtain high-precision and high spatial resolution 3-D displacements field is worthy of further study. The stochastic model and fusion model of integrating multi-source data affect the accuracy of data fusion. In this paper, based on the least squares method, the effects of different stochastic models and data fusion models on the 3-D displacements field’s accuracy are studied. The optimal method for estimating large-scale 3-D displacements field from integrated InSAR, leveling and GPS measurements is obtained. Then we realize the integrating InSAR, leveling and GPS measurements to obtain the high-precision 3-D displacements velocity field in Tianjin(China) from 2016 to 2018. The results are validated with GPS measurements at 6 independent stations, with the root mean squares (RMS) residuals of the discrepancies being 2.39mm/yr、2.54mm/yr and 2.83mm/yr in eastern, northern and vertical directions, respectively. By comparing different stochastic models, the 3-D displacements field obtained from multi-source data is optimized by the variance component estimation-least squares method, which is better than weighted least squares (WLS) method. By comparing different data fusion models, the accuracy of the horizontal displacements velocity is better than that of interpolated GPS results. The horizontal displacements component has a great influence on the vertical displacements velocity accuracy in the process of acquiring the 3-D displacements velocity by integrating InSAR, GPS and leveling measurements. This study provides a reference method for integrating multi-source data to obtain 3-D displacements field. This method effectively utilizes the advantages of GPS, InSAR and leveling measurements, and extends the limitations of single technical in describing surface-time scale applications. The 3-D displacements information with a large spatial scale and high spatial resolution provide a reliable data basis for studying the crustal movement and its dynamic mechanism.
Comparison of optical characteristics in non-red tide and red tide areas in the South Sea of Korea
Authors: Lee Eunkyung , Moon Jeong-Eon , Park Young-Je , Han Tai-Hyun
Published: March 2020

Red tide, which occurs off the southern coast of the Korean Peninsula, is a maritime phenomenon that usually occurs between June and September every year, mostly by Cochlodinium polykrikoides single species. There are very few studies using the analytical methods of the inherent and apparent optical properties for these red tide. Ahn et al.(2009) analyzed the inherent optical properties of 26 species of red tide organisms occurring off the southern coast of the Korean Peninsula. Kim et al.(2016) distinguished the optical characteristics for Cochlodinium polykrikoides using field data and Hydrolight simulator. Using these analytical methods, we will understand the ocean optical properties of red tide and use the remote sensing reflectance simulator in the future to produce the input data necessary for developing the red tide analysis technology based on machine learning. Therefore, in this study, as an initial analysis, we will compare the in-situ data of red tide and non-red tide waters off the southern coast of the Korean Peninsula in September 2014 and August 2017 to identify differences in the spectral form and compare the ability of the remote sensing reflectance spectrum with the field data using a remote sensing reflectance simulator.
Data assimilation system for estimating methane flows using satellite data
Authors: Platonova Marina
Published: March 2020

This work is devoted to the urgent task of assessing regional flows of greenhouse gases from the Earth's surface according to satellite observations. The article presents the practical and theoretical results of the first year of study in the PhD program, later they will be included in the final dissertation. Flows will be estimated based on the observational data assimilation system for a three-dimensional model of diffusive transport of gas components in the atmosphere (MOZART-4). Model for Ozone and Associated Chemical Indicators, Version 4 (MOZART-4) is an autonomous global model for the transport of chemicals in the atmosphere.

The development of a modern system for the assimilation of real satellite data for assessing greenhouse gas sources is currently a very important theoretical and practical area in science. The ensemble approach is relevant and has great potential for using both stochastic and variational methods. In the process of implementation, this is an order of magnitude simpler, since there are no cumbersome matrix calculations using the model.

To solve the problem of estimating methane flows, the parameter estimation problem was solved: an algorithm for data assimilation was developed; the Kalman filter with the transformation of the local ensemble was used as the basis for it. Using an example of a model problem, an algorithm for estimating the concentration of a passive impurity and a parameter is developed. The case was also considered when only one parameter can be estimated in the assimilation system. In this case it is considered that at the forecasting stage the parameter does not change, and the calculations in accordance with the transport model are included in the operator H, for example, as in Feng (2009,2017). H is the observation operator; transfers predicted values to observation points (and observed variables). For example, for satellite methane data, H includes:

a) interpolation to the observation point;

b) vertical averaging (using the middle core);

c) if the observation data is obtained from a large time interval, then the operator H also includes a forecast for the model in time.

Numerical experiments were carried out with model and real data. Using numerical experiments with the model, it was shown that a large problem (global) can be solved sequentially by subregion, independently in each subregion, which allowed the use of MPI and OpenMP.
Study on distribution features of faults based on gravity data in the Gulf of Mexico and its adjacent areas
Authors: Ma Jie , Wang Wanyin , Du Xiangdong , Cai Wenjie , Ji Xiaolin , Yang Min , Luo Xingang , Wang Dingding
Published: March 2020

In the study of Gulf of Mexico and its adjacent areas, the faults are kinds of important structures in the plate tectonics, oceanic-continental distribution and sedimentary basin structure. Based on the normalized vertical derivative of total horizontal derivative (NVDR-THDR) of Bouguer gravity anomaly and the minimum curvature field separation method, the distribution characteristics of the faults and the relating geological effects are studied. Because of the interaction between the plates, at the plate margin, the maximum values in the map of NVDR-THDR of Bouguer gravity anomaly are characterized by stable and continuous strikes. The maximum values in the map of NVDR-THDR of Bouguer gravity anomaly of intraplate region are macroscopically consistent and locally discontinuous. The faults in NWW and EW-NEE directions are mostly related to plate movement. In NE-NEE directions, arc faults are related to oceanic crust expansion. The faults in NE and NW are related to late Jurassic rift activities, or simply showing the boundaries of Yucatan and Chortis old landmass. The faults in nearly SN direction are less than that of we have talked above. In the Gulf of Mexico, there are four kinds of faults: the transition faults and mid-ocean ridge faults in the middle of central deep-sea area, the ocean-crust boundary faults in the north and south side of the central deep-sea area, the faults of thinning continental crust in the north and south of the Gulf of Mexico and the strike slip faults in the west of the Gulf of Mexico. Our research can contribute to regional geological researches and natural resources evaluations.
Analysis of Gust Characteristics and Forecast Correction for the 2022 Olympic and Paralympic Winter Games in Zhangjiakou
Authors: Li Jiarui , Dong Quan , Li Rong
Published: March 2020

In order to meet the high demand for advanced weather forecasts in the 2022 Olympic and Paralympic Winter Games, hourly wind observation data of some venues in Zhangjiakou City  is analyzed. Based on the specific gust characteristics in these venues, deviation of numerical weather prediction model is initially calculated to demonstrate the systematic bias of instantaneous wind speed forecasts derived from ECMWF. Additionally, a statistical down scaling method is further used by establishing the relationship between model forecasts and observation. Then independent samples are imported to the established equations to generate revised outputs. Tests show that the established equations have a better effect on forecasting the instantaneous wind speed than original model outputs and the corrected outputs have significantly better accuracy in predicting the instantaneous wind speed in the studied area.