bluuebunny/crossref_metadata_2025 huggingface dataset:
Machine learning-enabled quantification of segmentation uncertainty of X-Ray CT image-based analysis for vegetated soils
Authors: Jiang Zhenliang , Leung Anthony , Liu Jianbin
Published: February 2023

Segmentation of X-ray computed tomography (CT) images of four-phase unsaturated rooted soils is challenging yet a crucial step for conducting the subsequent image-based analysis (IBA) for various properties, for instance, volume fraction of each phase, morphologies of pore and roots, pore fluid distributions and some engineering properties such as hydraulic conductivity. The accuracy and efficiency of phase segmentation have been widely investigated, but the segmentation uncertainty (SU), which is a measure of reproductivity or reliability, on IBA and how the uncertainty propagates at different stages of IBA have rarely been studied for rooted soils. In this study, we developed a machine learning (ML)-based technique, called the percentile-based segmentation method, to perform phase segmentation of CT images and quantify the uncertainty and propagation of phase segmentation at different stages of IBA. Two indicators were used: relative value (RE), which has been used in the literature and SU magnification factor (SU-MF), which is newly proposed in this study. X-ray CT images of soil samples with different particle sizes and cultivated with different plant species were taken by a micro-X-ray CT scanner. The images were then segmented using the proposed ML method. In the presentation, a detailed case study and sensitive analysis (e.g., different number of phases, plant species, sampling resolution, and simulation methods) will be presented. We will show that root volume is susceptible to SU yet has a marginal influence on CT-IBA as its fraction is relatively small compared to other phases. However, the volume of soil grains is less SU-sensitive, which could lead to a significant change in the IBA. Root architectures could substantially influence the SU. Increasing the segmentation percentile improves the reliability, but the accuracy reduces at the same time. Moreover, we will show that the newly proposed indicator, SU-MF, can reasonably reflect the SU propagation behaviour. Therefore, SU could significantly impact the CT-IBA of rooted soils, and SU propagation is phase- and parameter-dependent. The explored quantification and propagation of SU provide novel and practical perspectives for increasing the measurement reliability of the X-ray CT-IBA of rooted soils.
Analyzing the behavioural changes of various fluvial geomorphological parameters using multi-temporal satellite images for the Godavari River, India
Authors: Prashanth Thallam , Ganguly Sayantan
Published: February 2023

Fluvial geomorphology is the study of various landforms while analyzing the changes that are happening on the earth surface due to climate change and anthropogenic activities. Fluvial geomorphological parameters change due to natural processes like erosion, transportation, and deposition of sediments. It also changes due to manmade activities such as the construction of dams, canals, irrigation projects, etc. In this regard, the present study aims to analyze the changes in various fluvial geomorphological parameters of the Godavari River basin such as sinuosity index, braiding index, channel length index, channel count index, etc. using the Landsat images at a frequency of every 2 years from 2000 to 2022, along the length of the channel in the Godavari River, India. The second objective of this study is to perform a river bank stability analysis by using the Automatic Water Extraction Index (AWEI) at different time scales. Thirdly, we aim to quantify length, areal and relief parameters using ALOS PALSAR Digital Elevation Model (DEM) for different sub-basins of the Godavari. Due to the changes in the geomorphology, cross-section of the river is altered; the silt content increases near the hydraulic structures, the velocity of the water changes, the sinuosity (meandering) increases and it tends to the formation of oxbow lakes. This analysis helps to investigate the performance of the sub-basins of Godavari River and how much sensitive they are to erosion. An economical river bank stabilization technique can be suggested based on the rate of river bank shift and type of soil information obtained from Food and Agricultural Organization.
Impacts of Observation Forward Operator on Infrared Radiance Data Assimilation with Fine Model Resolutions
Authors: Lei Lili
Published: February 2023

All-sky radiance assimilation often has non-Gaussian observation error distributions, which can be exacerbated by high model spatial resolutions due to better resolved nonlinear physical processes. For ensemble Kalman filters, observation ensemble perturbations can be approximated by linearized observation operator (LinHx) that uses the observation operator Jacobian of ensemble mean rather than full observation operator (FullHx). The impact of observation operator on infrared radiance data assimilation is examined here by assimilating synthetic radiance observations from channel 1025 of GIIRS with increased model spatial resolutions from 7.5 km to 300 m. A tropical cyclone is used, while the findings are expected to be generally applied. Compared to FullHx, LinHx provides larger magnitudes of correlations and stronger corrections around observation locations, especially when all-sky radiances are assimilated at fine model resolutions. For assimilating clear-sky radiances with increasing model resolutions, LinHx has smaller errors and improved vortex intensity and structure than FullHx. But when all-sky radiances are assimilated, FullHx has advantages over LinHx. Thus for regimes with more linearity, LinHx provides stronger correlations and imposes more corrections than FullHx; but for regimes with more nonlinearity, LinHx provides detrimental non-Gaussian prior error distributions in observation space, unrealistic correlations and overestimated corrections, compared to FullHx.
Physical property characterization of deep core sediments in the southeastern shelf (Korea strait) of Korea
Authors: Kim Gil Young , Park Kiju , Hong Seok-Hwi , Lee Gwang Soo , Yoo Dong Geun , Kim Seong-Pil
Published: February 2023

The deep core samples (site name: 21ESDP-203, drilled depth: 200.3m) collected from the southeastern shelf (Korea strait) of Korea were used to characterize physical property with sedimentary depth. Laboratory analysis (i.e., velocity and physical properties) was conducted on core samples. The physical property data were readily classified in good agreement with the lithological units alternating sandy mud and muddy sand with sedimentary depth. Based on compressional wave velocity data, the geoacoustic units are divided by 11 units with sedimentary depth. In particular, the upper sediments above 15 meter are characterized by high compressional wave velocity (greater than 1700 m/s) and high wet bulk density (∼2.2g/cm3 in maximum). Whereas, the porosity is very low (25% in minimum). This is due to the abundance of sandy sediments in this interval. The shear wave velocities of sediments are calculated from the compressional wave velocity and the effect of burial depth (Hamilton, 1980). The range of shear wave velocity is from 267 to 1345 m/s. However, most of data are less than 400 m/s. The velocity ratio (Vp/Vs) and the velocity gradient with sedimentary depth are calculated and estimated. The patterns are slightly different from those of Hamilton (1980). These results suggest that the physical properties are not only controlled by lithology and compaction caused by dewatering with burial depth, but also by different sedimentary environment after deposition. 
Sedimentary characteristics of abandoned-channel deposits in shallow tidal environments
Authors: Tognin Davide , Puppin Alice , D'Alpaos Andrea , Ghinassi Massimiliano , Finotello Alvise
Published: February 2023

Tidal channel networks control tide propagation and, therefore, fluxes of water, sediment, nutrients, and particulate matter in wetlands and low-lying coastal areas. Furthermore, tightly linked wetland-channel systems deliver multiple ecosystem services, among which blue carbon sequestration is critically important. While carbon fluxes associated with both vertical and lateral dynamics of salt marshes have been extensively studied, the role of tidal channel abandonment still needs to be further investigated. Reduced flow velocities promote rapid particle settling within abandoned channels thus rapidly storing large volumes of inorganic and organic sediment, both from autochthonous and allochthonous sources. Hence, a better understanding of the processes that lead to the abandonment of active tidal channels and the characterization of the related sedimentary deposits are critical steps to assess their potential sequestration capacity and storage of blue carbon.Towards this aim, here we investigate the sedimentary features and the related depositional processes in abandoned tidal channels by analyzing several undisturbed sediment cores retrieved in the microtidal Venice Lagoon, Italy. Cores were cut longitudinally and photographed for classical sedimentary facies analysis and description of the main sedimentary units. In each core, soil subsamples were taken every 5 cm and were prepared for different laboratory analyses. Organic matter content was estimated as the difference in weight before and after the Loss-On-Ignition (LOI), while organic carbon was directly measured using an elemental analyzer.The deposits accumulated during the abandonment phase and the related infill volumes were identified thanks to sedimentary facies analyses. The combination of the infill volume and organic carbon content allowed us to estimate the carbon stock potential of abandoned channels. Preliminary results show that, although the organic matter content in abandoned channel deposits is lower than that of the surrounding salt marshes, high infill rates make the carbon accumulation rate comparable between these different depositional systems. Moreover, the analysis shows that there is a very high spatial variability in sedimentary features of abandoned channel deposits, which needs to be taken into account to assess the potential of abandoned tidal channels as carbon sinks.
Flood Risk Assessment for Single-Family Home in A Zone
Authors: Al Assi Ayat , Mostafiz Rubayet Bin , Friedland Carol J. , Rohli Robert V , Rahim Md Adilur
Published: February 2023

In the United States, the Federal Emergency Management Agency (FEMA) delineates 100-year flood zones (special flood hazard area (SFHA) in the U.S.A.) to define flood risks and insurance rates. Quantifying flood risk in the SFHA which is the area of high risk of flooding is vital for individual, communities, and decision makers to minimize flood consequences. Flood risk is assessed as the product of the probability of flooding and the consequences associated with its occurrence. The unavailability of the modeled flood depth data for 100- year return period or for all return periods in most of SFHA’s areas make quantifying flood risk is challenging. This research develops a systematic approach that generates a synthetic flood parameter to quantify flood risk in A Zone- portion of the SFHA in which the potential base flood wave height is between 0.0 and 3.0 feet. The synthetic flood hazard parameters are generated in 100-year floodplain considering different flooding scenarios, and the flood risk is quantified in terms of average annual loss (AAL) at 100-year flood elevation (E100), and with an additional elevation above E100 for single-family home with different attribute located in A Zone. The results reveal that the AAL for single-family home (i.e., one vs. two-plus stories, with vs. without basement), at E100  and located in A Zone ranging of 0.27–0.98 percent of replacement cost value. The methodology and results generated in this research will benefit homeowners, engineers, surveyors, and community planners in enhancing resilience to the flood hazard in A Zone.
Examination of the performance of viaduct with pile groups underoblique-slip fault creeping: a case study in Chegualin Fault, Taiwan
Authors: Liu Yu-Liang , Lin Cheng-Han , Lin Ming-Lang
Published: February 2023

    Since the 1999 Chi-Chi Earthquake, earthquake engineering has devoted much effort to the issues of fault rupture-engineering structure interaction in Taiwan. So far, the Central Geology Survey of Taiwan has announced 36 active faults. Due to natural terrain conditions, linear traffic structures are difficult to avoid crossing the fault zone. However, the current design code rarely considers the effects of long-term fault creeping displacement in the assessment of structural performance. This study aims to develop a numerical-based performance examination approach for the viaduct with pile group foundations subjected to long-term fault offset. The area where the High-Speed Rail of Taiwan crosses the Chegualin Fault was selected as the case study. Remote-sensing survey and structural monitoring both indicated that the viaduct has been offset by approximately 30 cm due to fault creeping since 2006. The ratio between right-lateral and uplift movements is approximately 7:1. This study adopted coupled FDM-DEM technique as the numerical tool, and first validated its performance by physical sandbox tests. We used non-cohesive soil as the overburden material and polyethylene hollow foam tube as the foundation piles. Several key factors, including the Riedel shear bands, fault extended distance, tri-shear zone, pile cap deformation, were compared between numerical and sandbox models. Next, full-scale numerical modeling was calibrated based on in-situ structural monitoring data. The comparison of bridge pier displacement shows approximately 80% agreement between simulation and monitoring data. We found that the deformation of piles was dominated by the location of the fault tip. Simulation shows that the maximum rigid-body rotation of the pile cap will occur close to the fault tip. The cap of each pile group exhibits differential rotations and displacements behaviors, resulting significant superstructure distress. Based on the simulation, the performance of the High-Speed Rail in the study area was expected to fail meeting the current design code of Taiwan after 50 years. 
First results of the Chinese Ha Solar Explorer - CHASE mission
Authors: Li Chuan , Fang Cheng , Ding Mingde , Chen Pengfei , Li Zhen
Published: February 2023

The Chinese Hα Solar Explorer (CHASE) was successfully launched on 14 October 2021 as the first solar space mission of China National Space Administration (CNSA). The scientific payload of the CHASE satellite is the Hα Imaging Spectrograph (HIS). The CHASE/HIS acquires seeing-free spectroscopic observations of the whole solar disk at three spectral lines of Si I (6560.6 Å), Hα (6562.8 Å) and Fe I (6569.2 Å) which are formed at different heights of the photosphere and chromosphere. A full-Sun scanning takes only 46 seconds, with a spectral sampling of 0.024 Å and a spatial resolution of 1.2 arcsec. Since its launch and in-orbit calibrations, the performance of the CHASE mission is excellent and meets the pre-launch expectations. The FITS formatted science data are now available to the community through the Solar Science Data Center of Nanjing University (SSDC-NJU, https://ssdc.nju.edu.cn). Here we introduce the CHASE science data and the calibration procedures. The first series of scientific studies of the CHASE mission are also presented.
The Optimal Initial Condition of MJO Development
Authors: Chang Chun-Hao , Tseng Kai-Chih
Published: February 2023

Madden-Julian Oscillation (MJO), an intraseasonal oscillation over the equatorial Indian ocean and Pacific, has profound impacts around the globe. Its extended-range life cycle (20-90 days) makes it the most important predictability source on subseasonal-to-seasonal timescales. While the mechanisms responsible for MJO's life cycle have been well  explored through the frameworks of moisture modes, and tropical wave dynamics, the mechanisms of initiation remain unsolved. By using linear inverse modeling (LIM) and incorporating different frameworks, this study investigates the processes resulting in MJO convection initiation. It is suggested that multi-scale interactions play a vital role in intraseasonal convection initiation over the Indian ocean. On intraseasonal timescales, the remnant of former MJO can create an environment favoring the convection development for the next event through modulating the prevailing circulations and moisture state (e.g., moisture advection). On shorter timescales (< 20 days), the optimal initial condition arises from the synoptic convergence/divergence of moisture flux, and the upper troposphere instability. 
Constraining fluid-rock alteration and temperature history using multi-mineral argon spectra and conjoint T–t-Δ inversion
Authors: Wu Yoli , Forster Marnie , Fraser Geoff , Kelsey David , Lister Gordon
Published: February 2023

Metamorphic rocks record the imprint of the tectonic processes that shaped the lithosphere and record the effects of their journey through time and space. The record can be interrogated by using a number of different geochronological techniques. The 40Ar/39Ar geochronology method is particular useful when it comes to extracting information from the major rock-forming minerals such as mica and feldspar, commonly filling the temporal gap between the ages obtained by U–Pb dating of accessory minerals and the application of low-temperature thermochronometers. Here we present a case study illustrating a novel and innovative way to investigate metamorphic processes across tectonic settings and geologic time, involving metamorphic petrology, geochronology, geochemistry, numerical modelling and tectonics.The method involves quantitative modelling of 40Ar/39Ar age spectrum morphologies, constrained by conjointly using information from white mica, biotite and potassium feldspar from a single Proterozoic gneiss. Temperature-controlled step-heating diffusion experiments provide estimates of the relevant diffusion parameters using Multi-Domain Diffusion (MDD) models to invert Arrhenius data. Computer modelling and simulation then allows the production of admissible temperature-time paths for all three minerals used in this study, allowing the identification of previously unrecognised episodes of mineral growth and/or periods of cryptic metasomatism. In this way, 40Ar/39Ar geochronology enables estimates for the timing of a sequence of mineral growth events and the veriation of ambient temperature through time.Two examples are provided from Palaeoproterozoic gneisses from northern Australia. Typically, the morphology of each age spectrum (for biotite, white mica, and potassium feldspar) required a minimal two-component microstructure to explain the mixing pattern. In each mineral, a MDD model is needed to explain the pattern of gas release during furnace step-heating. Estimates of the diffusion parameters using the Arrhenius data allow the inference that both phengite-poorer muscovite and phengite-richer muscovite existed in the white mica aliquot. Quantitative modelling of the age spectrum morphology allowed constraints to be placed on possible temperature-time-growth (T-t-Δ) paths followed by the rock sample in the natural environment, spanning a duration of more than a billion years.
From Dissemination to Participation – A Creative Approach to Geoscience Communication
Authors: Illingworth Sam
Published: February 2023

Science communication exists on a spectrum: from dissemination to dialogue. While participation is likely to be the most effective way of helping to truly diversify science, there is still a need for geoscience communication initiatives that exist across this spectrum. In this Katia and Maurice Krafft Award lecture I will present an overview of my research into using poetry and games as facilitatory media to help disseminate knowledge, develop dialogue between scientists and non-scientists, and engender participation amongst diverse publics, including those audiences that have previously been marginalised by the geosciences.By presenting a series of case studies, published works, and works in progress, I aim to demonstrate how this creative approach can help to address a lack of diversity in the geosciences. This lack of diversity should be paramount to anyone who is involved in either the geosciences or geoscience communication, not only because it is ethically the ‘right thing’ to do, but because ultimately greater diversity results in better science.In addition to my own research, I will also explore how the work that we are doing with the EGU journal Geoscience Communication is supporting others in developing innovative and effective research and practice in this space, and how this in turn is helping to provide greater recognition for science communication in the geosciences.
Wildfire Fuel Characterization in Subtropical Ecosystems Using Ground-Based SLAM LiDAR
Authors: Strattman Katherine , Kaplan Jed O. , Maeda Eduardo Eiji
Published: February 2023

In Hong Kong’s sub-tropical ecosystems, anthropogenic wildfires burn 5% of the territory’s natural areas every year. With projected climate change including warmer temperatures in the winter dry season, wildfires in Hong Kong may increase in frequency and intensity in the future. Increased wildfire would threaten biodiversity, water resources, reduce carbon storage, and hinder ongoing efforts to restore and rehabilitate forests. To better understand wildfire behavior and project how future climate change could affect wildfire occurrence in Hong Kong it is essential to understand the characteristics of wildfire fuels in local ecosystems. However, no information on wildfire fuels in Hong Kong is currently available.  

Here we aim to characterize wildfire fuels in Hong Kong to develop “fuel models” for the typical Hong Kong vegetation communities of grassland, shrubland, and forest. These fuel models describe wildfire fuels in terms of five derived metrics: fuel load, surface area to volume ratio, fuel bed depth, packing ratio, and bulk density. A fuel model describes how fire will behave in an ecosystem and is an important input for wildfire modeling. 

We developed fuel models for Hong Kong using ground-based Simultaneous Location and Mapping Light Detection and Ranging (SLAM LiDAR). During the winter dry season of 2022-2023, we surveyed grassland, shrubland, and forest plots at Kadoorie Farm and Botanical Gardens, New Territories, Hong Kong with an Emesent Hovermap ST SLAM LiDAR scanner. Fuel models were developed using a voxelization approach by dividing the LiDAR point clouds into uniform voxels, in which the different fuel metrics were estimated. We used field-based measurements to assess the accuracy of the LiDAR-derived wildfire fuel characteristics. Our results demonstrate the potential for SLAM LiDAR to make fast, accurate, and non-destructive characterization of wildfire fuels. The fuel models we developed will be essential for wildfire modeling, land management, and potentially for operational firefighting activities including resource allocation.
A review of the application of the scaling approach for geological interpretation  
Authors: Dimri Vijay Prasad , Ganguli Shib S.
Published: February 2023

Sources of geophysical anomalies, such as density, susceptibility, conductivity, reflectivity, etc., are not always random as we often adopt, but follow a scaling/fractal distribution. The application of fractal and scaling approaches in Earth science is widespread. Potential field theory has also been studied in the frame of fractals or scaling laws and found to be worthwhile in inferring the physical properties of the subsurface. Here, an attempt is made to discuss the in-depth review of the application of the fractal/scaling approach for qualitative and quantitative interpretation of complex sources of interest. The implications of this study will be beneficial for readers to understand the gaps in sub-surface source characterization with examples in a potential field data application.
Circulation aspects associated with heat wave events over Iraq
Authors: Al-Shamarti Hasanain , Birner Thomas , Rupp Philip
Published: February 2023

Heat waves lead to increased mortality due to heat exhaustion and heatstroke, wildfire, reduced agricultural yields, increased energy demand, economic predicaments and other societal issues. Heat wave events over the Middle-East have received far less attention compared to events elsewhere. Here, we provide a comprehensive characterization of heat wave events over Iraq, covering the period 1980-2019.We use ERA5 reanalysis data for Northern summer (June-July-August) to identify heat waves in daily maximum 2-m temperature (Tmax) data and study them using composite analyses and clustering. We define a heat wave event if the Tmax anomaly exceeds the 90th percentile over three consecutive days, provided this threshold exceedance covers at least 50% of our target area.The composite-mean evolution of daily Tmax anomalies demonstrates that our heat waves typically strengthen gradually over the week preceding the central day with a sharp decline in strength at positive lags, reaching an average maximum anomaly of ~3.7 K at the central day. We find the heat waves to extend from the Arabian peninsula northward across Iraq toward southwestern Russia. Clustering of all heat wave events reveals two dominant flow anomaly patterns that roughly distinguish early from late summer events.The first cluster (early summer events) is associated with anomalous anticyclonic flow associated with a quasi-stationary upper-level high pressure system to the north-east of Iraq precisely over Caspian sea. This anomalous anticyclonic flow is embedded in a Rossby wave train that initially propagates along the north Atlantic wave-guide, then further equatorward along the North African-Asian jet just before the central day. Our composite-mean evolution for this first cluster further shows mid-tropospheric subsidence over the Zagros mountains, i.e., upstream of our heat wave target area. Downslope Foehn winds appear to enhance the heat wave over Iraq.In contrast, the second cluster is primarily composed of late-summer events and shows strong anomalies in the Shamal winds - a pronounced low-level north-westerly jet along the western edge of the Zagros mountains. During these late summer heat wave events the Shamal jet is substantially weakened or even reversed, transporting warm air from the Persian gulf into the target region.  
A Study on Fine Particle Emission Characteristics in Dangjin Port Using High Resolution Scanning LiDAR
Authors: Lee Yuseon , Kim Jaewon , Noh Youngmin
Published: February 2023

As emissions from ships and marine sources account for a high proportion of fine particle emissions, interest in air pollutants generated in port areas and the need to prepare countermeasures are increasing. For port air pollutants, it is necessary to consider substances emitted from ships and various emission sources from the yard around ports. This study uses a scanning LiDAR system capable of observing PM10 and PM2.5 in a radius of up to 5 km at a high resolution of 30 m horizontally and left and right to check high-concentration pollutants generated around Dangjin Port(36.985476°N, 126.745613°E) in real time and corresponding substances tried to distinguish. The scanning LiDAR used in this study provides the Ångström exponent calculated from the extinction coefficient at both wavelengths of 1064 and 532 nm and the depolarization ratio at 532 nm. First, the Ångström exponent can confirm information about the particle size. In addition, the depolarization ratio is a parameter representing information on the asphericity of particles. It provides information on the classification of aerosol types depending on whether the particles are spherical or non-spherical. The concentration of fine particle generated was identified using the extinction coefficient, and the kind of particle was determined using the Ångström exponent and the depolarization ratio. The primary source of fine particle in the vicinity of Dangjin Port was an industrial complex, such as a steel mill located on the west side of Dangjin Port, and fine particle was also generated from the port's coal yard and moving ships. The diffusion direction of fine particle was closely related to the wind direction. The type of fine particle confirmed by a low Ångström exponent between 0 and 1 and a high depolarization ratio degree between 0.1 and 0.2 was confirmed as non-spherical scattering dust. Through this study, it was confirmed that it was possible to identify the generation and movement of fine particle in a wide area and to distinguish the types of particles using scanning lidar.AcknowledgementThis work was supported by the “Graduate school of Particulate matter specialization.” of Korea Environment Industry & Technology Institute grant funded by the Ministry of Environment. Republic of Korea.
Shallow and Deep Circulations in the Tropical Atmosphere
Authors: Singh Martin
Published: February 2023

The vertical structure of large-scale tropical circulations is determined by their complex coupling with both deep and shallow convection. This is reflected in our theoretical frameworks for understanding the tropical precipitation distribution, which consist of “deep” theories that focus on overturning circulations that extend throughout the depth of the troposphere and “shallow” theories that focus on low-level convergence driven by boundary-layer pressure gradients. While both types of theories suggest links between low-level thermodynamic fields and the precipitation distribution, shallow theories highlight the importance of the distribution of surface temperature, while deep theories additionally highlight the importance of the low-level humidity. Here we use idealised cloud-permitting simulations to elucidate the physical factors that control the vertical structure of tropical circulations. We first demonstrate how the influence of convective entrainment on the lapse rate can act to change the vertical structure of deep tropical circulations, with implications for the behaviour of precipitation in the current and future climate. We further investigate the interaction between deep and shallow tropical circulations  by simulating an idealised overturning circulation over varying surface conditions. By independently varying the sea-surface temperature and moisture availability, the low-level temperature and moisture distributions are manipulated such that the predictions of “deep" and “shallow" theories of the circulation may be distinguished. The results provide insight into the relative roles of oceanic SST gradients and land-ocean contrasts in determining the climatological precipitation distribution in the tropics.
A force-balance MEMS gravimeter with area-changed capacitors for transducing and actuating
Authors: Li Fangzheng , Gao Le , Cai Bingyang , Wu Wenjie , Tu Liang-Cheng
Published: February 2023

The measurements of gravity have been widely applied to earthquake monitoring, resource exploration and identification of natural voids. Traditional gravimeters, restricted by the exorbitant price and bulk, are hardly to be utilized in newly developed applications such as AUV-borne gravimetry and the multi-pixels gravimetry. Fortunately, this is changing with the development of portable MEMS gravimeters.Here, we have already developed a relative MEMS gravimeter with a quasi-zero stiffness spring-mass system and an arrayed area-changed capacitor for displacement transducing and actuating. This quasi-zero stiffness spring-mass system transfers the acceleration variation to the displacement of the proof-mass with high sensitivity. The displacement is then detected by the arrayed area-changed capacitor. The spring-mass system was installed inside a vacuum chamber for reducing the thermal noise and environmental disturbances. However, the response time of the gravimeter was enlarged when operating in open-loop mode dues to the decreased air damping. Therefore, a force-balance system is utilized in a MEMS gravimeter to improve the response time and the measurement range. This paper proposes an area-changed capacitors for transducing the displacement and balancing the inertial force on the proof-mass. As no additional structures are required on the MEMS chip, the design of the force-balance system is beneficial to simplifying the fabricating process and avoiding additional noise sources.We calibrated our MEMS gravimeter statically in our cave lab. After linear correction of the drift, the output of the MEMS agrees well with the theoretical earth tide with a coefficient of association of 0.92. The self-noise is evaluated to be 1 μGal/√Hz, which is one of the most sensitive MEMS-based gravimeter reported. In addition, the response time of the MEMS gravimeter was calibrated to be 0.2 s in close-loop mode, which is 2000 times faster than that in open-loop mode. This will promote improved accessibility of mobile gravity measurements at an affordable cost.
Negative Effects of Ecological Restoration on Slope Stability in Chinese Yellow River basin
Authors: Liu Xiao , Lan Hengxing , Li Langping
Published: February 2023

Abstract: With the implementation of the large-scale “Grain for Green” program, vegetation in the Chinese Loess Plateau (CLP) has been remarkably restored, which is believed to in turn have significantly mitigated soil erosion in the Yellow River basin (YRB). However, various local-scale evidences suggest that plants may also promote slope failures; whether the large-scale ecological restoration in the YRB has posed negative effects on slope stability, remains an open question. Here, we inspect the effects of ecological restoration on slope stability in the YRB by quantitatively correlating the distribution of landslides with the variation of vegetation cover. We pick out those landslides located in areas with increasing vegetation continuous fields (VCF), and group them into eight major spatial clusters. We find that, landslide clusters with higher increasing gradients of VCF generally have higher proportions of active landslides, revealing that ecological restoration has posed negative effects on slope stability in the YRB. We then clarify that, soil moisture is "U-shaped" correlated with the negative effect intense index (NEII) of ecological restoration on slope stability, and a specific threshold of soil moisture correlate a minimum NEII. Finally, we demonstrate that, the ecological restoration of more than 20 years in the YRB has caused widespread increasing but fluctuation of soil moisture and evaporative stress factor and induced negative effects on loess strength and slope stability in the CLP. We show that, in areas with limited water-source, excessive revegetation will damage soil strength and reduce soil resistance because its water-consumption will exceed its water-conservation. This contribution suggests that, ecological restoration should be restrained to a sensible extent for effective soil-water conservations and landslide hazard mitigations, especially in arid and semi-arid areas like the CLP.
Modeling nitryl chloride and its source and effect on gaseous and aerosol chemistry
Authors: Kim Hyeonmmin , Park Rokjin , Jeong Jean , Kim Saewung , Jeong Daun , Fu Xiao , Cho Seogju
Published: February 2023

Nitryl chloride (ClNO2) has been reported as a critical species of chlorine chemistry. Its chemistry interrupts a nighttime sink of NOX and emits chlorine radical (Cl•) in the daytime, consequently altering gaseous and aerosol chemistry. Recent field studies have also measured considerable concentrations of ClNO2 in South Korea under the influences of natural and anthropogenic chlorine sources. However, the impacts of ClNO2 chemistry on air quality in South Korea have yet to be evaluated. We validate simulated ClNO2 and its chemistry in South Korea using observations and a 3-D chemical transport model (CTM) during the Korea-United States Air Quality field study. We implemented the latest Chinese and Korean anthropogenic chlorine emissions in the model. We found that the model reproduces the observed spatial and temporal variations of ClNO2, including its local and transboundary transport and precursors. We found that ClNO2 chemistry results in a more efficient conversion of NO to NO2 at night and daytime acceleration of the NOX-O3 cycle. It results in an increase of O3 (1.1%), NOX (3.1%), OH (2.0%), HO2 (0.8%), and Cl• (507.8%) and a decrease of TNO3(HNO3 + aerosol nitrate, 1.7%) on the campaign mean basis.
Analysis of the hydrological conditions based on hydrological model in a data-scarce basin: A case study in the Yongding River Basin
Authors: Yang Yiyang , Cai Siyu
Published: February 2023

The hydrological conditions are key factors in ensuring the health of water ecosystems. The lack of runoff data constrains the assessment of the basin's evolutionary pattern of the eco-hydrological conditions. The Yongding River Basin (YDRB) is a typical water-scarce basin in northern China, where the changing environment has led to widespread water scarcity and ecosystem degradation problems. In response to the shortage of information at the upper reaches of the YDRB at the Xiangshuibao gauging station, this study adopted a distributed hydrological model, WetSpa, to simulate the daily runoff data in this station from 1960 to 2019. Then, Indicators of Hydrologic Alteration (IHA) was used to identify the most ecologically relevant hydrological indicators (ERHIs) and further determine the "true" eco-hydrological variation point in the basin. Finally, the evolution rule of the eco-hydrological conditions in the basin was analyzed and the overall hydrological alteration degree of the Xiangshuibao Section was determined. The results showed that the rising rate, decline rate, annual maximum 1-day flow, annual minimum 1-day flow, annual maximum flow occurrence time, and July flow were the ERHIs. The variation period was from 1980 to 1986. Except for the annual maximum 1-day flow and decline rate were moderate variation indicators, all others were low variation indicators. The overall hydrological variability of the Xiangshuibao section was low. The results of this study were intended to provide a reference for ecological management construction in the YDRB and other similar areas.
Stereoscopic Development Adjustment Mode for Enhanced Oil Recovery in Mature Multi-Layer Oilfield
Authors: Lai Lingbin , Zou Cunyou , Jiang Zhibin , Su Haibin , Zhang Xuyang , Li Songlin , Zhang Hualing
Published: February 2023

After a long period of water flooding development, oilfields will enter the production stage of "high water cut, high recovery degree, and low oil recovery rate". On the one hand, due to the displacement effect of the water injection, some oil layers already reached the water flooding limit. On the other hand, due to the effect of reservoir heterogeneity, dominant seepage channels, and imperfect injection-production well pattern, some oil layers are enriched with a large amount of remaining oil. Unbalanced production of reservoirs and difficulty in development and adjustment are common problems in mature oilfields. Mature multi-layer oilfields generally develop many sets of oil-bearing layers vertically. After a long water injection period, the water-flood law and the remaining oil distribution are complex, and the production of different well patterns or strata varies greatly. Through strata and well pattern reorganization, combined with the evaluation results of water flooding adjustment potential, some reservoir engineers and researchers established a stereoscopic development adjustment mode for enhanced oil recovery in mature multi-layer oilfields. This paper summarizes the main technologies of stereoscopic development adjustment mode for enhanced oil recovery in mature multi-layer oilfields. The main technologies of stereoscopic development adjustment mode include research on the remaining oil distribution, evaluation of water flooding adjustment potential, selection of tertiary oil recovery methods, reorganization of strata and well pattern, and optimization of timing from water flooding to tertiary oil recovery, etc. For strata with low water flooding adjustment potential, the tertiary oil recovery well pattern is reorganized and tertiary oil recovery is adopted to improve oil recovery. For strata with large water flooding adjustment potential, the water drive well pattern is reorganized and water flooding development is used to excavate the remaining oil. As for strata with general water flooding adjustment potential, the tertiary oil recovery well pattern is reorganized and water flooding development is used to excavate the remaining oil first, and then transfer to tertiary oil recovery at the proper time. The stereoscopic development adjustment mode is applied to test block K of Q reservoir which is a mature multi-layer oilfield. After stereoscopic development adjustment, the development effect of test block K meliorates. It is estimated that the EOR will be increased by more than 8% after stereoscopic development adjustment in test block K.
Can we account for the “missing” phosphorus in simulated low phosphorus agricultural systems?
Authors: Davies Jennifer , Janes-Bassett Victoria , Blackwell Martin , Burgess Andrew , Davies Jessica , Haygarth Philip
Published: February 2023

Long term total phosphorus (P) concentration, inorganic P and / or organic P concentration in agricultural soils is not commonly measured. As a consequence, computer-based models, that have been developed to predict P responses to changing management practices, are typically tested against soil “agronomically available” P data (as measured by tests such as; Olsen-P, Morgan’s-P, Mehlich-3, etc.) and those that do test against total P are limited to a few agricultural experimental sites across the world. While there is some correlation with total soil P, the term “available P” is arguably a functional concept, influenced by a large number of biotic and abiotic factors, rather than a direct soil measurement. This highlights a developmental gap in P modelling which could help to further unlock our understanding of P biogeochemical cycling when used in conjunction with contemporary empirical P research. 

Investigating P cycling in agricultural systems using the computer-based model N14CP has demonstrated that the model can predict carbon and nitrogen cycling and crop yields well for systems receiving abundant fertiliser. However, in systems where there is no P applied, predicted yield responses are greatly underestimated, with “missing” P input concentrations equivalent to annual fertiliser application rates. To date, the testing of N14CP has not included the P pools due to a lack of soil total P and/or soil organic P data from long-term field trials. Using recent total, organic and inorganic phosphate concentrations in the topsoil and yield data from two contrasting long-term field trial sites in the UK and the USA, this research will test P outputs and modelled yields from N14CP. It is hypothesised that the model will underestimate soil P concentrations, and crop yield, in the absence of P fertiliser inputs. This study will then apply changes to the mode model inputs, outputs and control processes to investigate whether these are sufficient to supply the crops and soil with the “missing” P. 

Understanding this source of “missing” P in N14CP will not only be useful for developing our understanding of P processes in computer-based models but could also further understanding of P processes linked to P draw-down in agricultural systems that have a history of high legacy P concentrations. 
AtmoRep: Large Scale Representation Learning for Atmospheric Data
Authors: Lessig Christian , Luise Ilaria , Schultz Martin
Published: February 2023

The AtmoRep project asks if one can train one neural network that represents and describes all atmospheric dynamics. AtmoRep’s ambition is hence to demonstrate that the concept of large-scale representation learning, whose principle feasibility and potential was established by large language models such as GPT-3, is also applicable to scientific data and in particular to atmospheric dynamics. The project is enabled by the large amounts of atmospheric observations that have been made in the past as well as advances on neural network architectures and self-supervised learning that allow for effective training on petabytes of data. Eventually, we aim to train on all of the ERA5 reanalysis and, furthermore, fine tune on observational data such as satellite measurements to move beyond the limits of reanalyses.We will present the theoretical formulation of AtmoRep as an approximate representation for the atmosphere as a stochastic dynamical system. We will also detail our transformer-based network architecture and the training protocol for self-supervised learning so that unlabelled data such as reanalyses, simulation outputs and observations can be employed for training and re-fining the network. Results will be presented for the performance of AtmoRep for downscaling, precipitation forecasting, the prediction of tropical convection initialization, and for model correction. Furthermore, we also demonstrate that AtmoRep has substantial zero-short skill, i.e., it is capable to perform well on tasks it was not trained for. Zero- and few-shot performance (or in context learning) is one of the hallmarks of large-scale representation learning and to our knowledge has never been demonstrated in the geosciences.
Ionospheric Plasma Depletions at Mars: MAVEN Observations of In-situ Plasma and Wave properties
Authors: Basuvaraj Praveen , Němec František , Regoli Leonardo , Fowler Christopher , Němeček Zdeněk , Šafránková Jana
Published: February 2023

Since September 2014, NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has been measuring the in-situ ionospheric constituents of Mars. Recently, MAVEN detected the presence of large-scale plasma depletions (at least ten-fold) within the Martian ionosphere, also known as Plasma Depletion Events (PDEs). Geometrically, the Martian PDEs appear to be bubble-like plasma structures. Although the origin and formation of PDEs are not entirely understood, they are known to occur primarily on the nightside and in regions with stronger crustal magnetic fields.In this study, we analyze the variation of magnetic field magnitude and direction and electric field power (2–100 Hz) associated with PDEs. We show that, in most cases, the magnetic fields do not considerably change within the plasma-depleted region. Conversely, the low-frequency electric field wave power is enhanced by up to two orders of magnitude at the peak depletion. Both ions and electrons within PDEs are highly magnetized. We present possible formation mechanisms of PDEs supported by recent findings.