Period Of Accumulation Research Articles

Structural and tectonic conditions for the development of the Bering Sea sedimentary basin

Introduction. In order to characterize the oil and gas potential of any area under exploration, its structural and tectonic evolution should be studied. In this paper, a structural and tectonic modelling of the Bering Sea is carried out.Aim. To identify the structural and tectonic characteristics of the Bering Sea by interpreting the results obtained during a geodynamic analysis of sedimentary basin formation, based on the tectonic and geodynamic paleoreconstructions and sedimentary basin modelling of the Bering Sea.Materials and methods. A structural and tectonic modelling of the Bering Sea sedimentary basins was carried out using contemporary methods of basin analysis and numerical geological modelling (PetroMod software, Schlumberger). Three-dimensional time-spatial structural-tectonic models of the Bering Sea were formed using the bottom structural maps of Pliocene-Quaternary deposits, near the Lower Miocene and Oligocene tops and along the acoustic basement bottom. Maps were digitalized and converted to grids (with a 500-m step), in which the discrepancies (intersections) were removed taking into account the available geological and geophysical data (seismogeological sections). The contemporary surface of sedimentary basins was constructed by the connection of bathymetric and topographic maps. The beginning and end time of sedimentary accumulation periods was determined in accordance with the international stratigraphic scale.Results. The performed study identified the sufficiently continuous development areas of the oceanic or suboceanic crust of deep-water (back-arc) basins, aged from the Upper Jurassic-Cretaceous to the Cenozoic and repeatedly affected by the subsequent phases of the tectonic and magmatic activation; development belts of the Cretaceous-Cenozoic block-magmatic basement of island arcs, locally including reformed basement blocks of an older, Paleozoic or Cimmerian, consolidation; extensive depth-differentiated alpine/newest (syn-oceanic) shelf platforms, occassionally partially destroyed due to the latest destruction, including blocks or large blocks of Pre-Cambrian or Paleozoic relatively rigid massifs in the structure of their base.Conclusion. The modelling results indicate the deeply submerged West Anadyr, East Anadyr and Central Anadyr basins to be possible depocentres with their own hydrocarbon generation centres.

Interpolation of rainfall observations during extreme rainfall events in complex mountainous terrain

AbstractThe representation of rainfall in space is important for hydrological modelling. Accurate estimation of rainfall is particularly challenging in mountainous regions where observations are often sparse relative to the spatial variability of rainfall. In these regions, orographic processes lead to complex patterns of rainfall enhancement and rain shadow depletion. This study testsNatural Neighbour Interpolation (NNI),ordinary kriging (OK)andordinary cokriging (CK), to determine ifCKimproves rainfall interpolation during three extreme rainfall events. Three different elevation indices were considered as secondary variables forCK. Preliminary analysis using long‐term annual average rainfall totals, including additional high elevation rainfall observations, showed thatCKwith an effective elevation index (a directionally smoothed elevation, corrected for degree of ‘orographic processing’ and shifted to account for ‘wind‐drift’ of rainfall) as a secondary variable performed better thanNNIandOKwith an overall improvement of around 40%. Using rainfall totals for long‐term wind direction and wind speed rainfall classes,CKperformance was variable but provided an improvement of approximately 15% for wind direction classeswithoutan easterly wind component. For 15‐min timesteps during extreme rainfall events, there were comparatively small differences (cross‐validation usingRMSE) between interpolation methods, partly attributed to having only relatively low elevation rainfall observations, providing weak constraint. Using cross‐validation andmean biasdid, however, show an improvement for both high and low elevation observation classes. Importantly, cross‐variogram estimation provided differing cross‐validation results when estimated for different rainfall accumulation periods: 15‐min, hourly, daily and long‐term. Variograms and cross variograms estimated at a 15‐min timestep frequency were robust for many timesteps, but were difficult to fit automatically for others. Variograms estimated from longer periods were more reliably estimated, but tended to have lower variance and cross‐variance and longer correlation ranges producing a smoother interpolated rainfall field. Given the weak cross‐validation constraint, care must be taken in identifying the most appropriate method and variogram estimation period.

Estimation of sugar content in sugar beet root based on UAV multi-sensor data

Sugar beet (Beta vulgaris L.) is the second largest sugar source crop in the world. Sugar content in its beetroot is an important quality index of sugar beet. Rapid and accurate estimation of sugar content in beetroot is helpful to high-throughput phenotype and genotype breeding. The purpose of the current study is to explore the potential of UAV-based multimodal remote sensing data in sugar content estimation. Multimodal data were collected by different UAV-platform carried with RGB, multi-spectral, thermal infrared, hyperspectral and LiDAR. Spectral, structure and thermal features of canopy were extracted from different sensor combinations to estimate sugar content during sugar accumulation period of beetroot by using Partial Least Squares Regression (PLSR), Bayesian Ridge Regression (BRR) and Support Vector Regression (SVR). The main results are as follows: (i) In estimating sugar content, published vegetation indices (PBI, NDVI, TCARI, etc.) calculated from hyperspectral as spectral features outperformed these of multispectral. Structure features calculated from LiDAR outperformed those from RGB. (ii) Eight newly developed vegetation indices presented better performance than published vegetation indices. Among them (R730-R734)/(R730 + R734) index using two bands and (R694-R714)/(R710-R714) using three bands presented the best performance. (iii) Multimodal data combination from different sensors improved estimation accuracy of sugar content than data from individual sensors. PLSR based multimodal data from LiDAR, hyperspectral, thermal infrared sensor presented the best accuracy with R2 = 0.64 and relative root mean square error (rRMSE) = 7.2 %. These results showed that UAV-based canopy features from multimodal data can be used to quickly and accurately obtain sugar content of beetroot. This study provides a basic reference for estimating bioactive substances in roots of root tuber crops based on multimodal canopy remote sensing data.

Infant Exposure to PCBs and PBDEs Revealed by Hair and Human Milk Analysis: Evaluation of Hair as an Alternative Biomatrix.

Human hair, as an emerging biological monitoring matrix, has begun to be used in various human exposure studies, but little research has been done on persistent organic pollutants (POPs), especially for the body burden of POPs in infants. In this study, 36 breast-fed infants in Shanghai were recruited for a study to determine their exposure to POPs, including 12 dioxin-like polychlorinated biphenyls (dl-PCBs), 6 indicator PCBs, and 8 polybrominated diphenyl ethers (PBDEs) in the inner layer (internal) and outer layer (external) of infant hair and human milk. The similarity or difference of the POP distribution pattern or concentration among these matrices was investigated, and only weak correlations (r < 0.4) were observed between the POP concentration in human milk and infant hair (internal or external). POPs in human milk have a different profile than those in infant hair, while they have stable concentration ratios (0.58-2.72), similar distribution patterns, fine Spearman's rank correlations, and tangled principal component analysis (PCA) plots in each POP family between external and internal hair samples. The result suggested that POPs in internal hair can be easily affected by those in external hair, but POPs in human milk seem to have little contribution to the POP profile in internal hair. Although infant hair cannot reflect the POPs from diet or from body burden, it can be an ideal biomatrix that estimates infant exposure to POPs from exogenous sources like house dust when considering the similar pattern of POPs and their proper accumulation period in hair.

Oil and gas accumulation periods and charging path of continental lake basin: A case study of the Chang 9-Chang 10 oil reservoir in the Yanchang formation in the Ordos Basin

The Chang 9-Chang 10 Formation in the Ordos Basin has been explored intensively in recent years. However, the accumulation timing and migration paths of the oil in the formation reservoir are still unclear. This study uses reservoir geochemistry and software basin modeling to study the hydrocarbon accumulation periods of the oil-bearing sandstones in four wells in different areas of the basin. The results show that the principal oil charging period of the Chang 9-Chang10 formation was from 100 Ma – 130 Ma. The Chang 10 oil reservoirs in the Shanbei area and the Chang 9 oil reservoirs in the Jiyuan and Longdong areas experienced a single oil charging period. However, the Chang 9 oil reservoirs in the central lake area experienced two oil charging periods, from 190 Ma – 210 Ma and from 100 Ma – 130 Ma. The relative abundances of 1,8-/2,7-Dimethylcarbazole and PSNs/Ens carbazole indicate that there are hydrocarbon charging points in the source rocks of the Chang 7 formation in the Jiyuan area, and charging points of Chang 9 source rocks in the Shanbei area. Chang 9 crude oil in the Longdong area shows the characteristics of long distance migration. This study improves understanding of the hydrocarbon accumulation process in the Chang 9-Chang 10 oil reservoirs, which will inform and support future oil and gas exploration in the area.

Ultrafast laser ablation of copper with GHz bursts: A numerical study on the effects of repetition rate, pulse number and burst fluence on ablation efficiency and heat-affected zone

Ultrafast laser burst ablation (ULBA) with high repetition rates up to GHz has emerged as a promising method for improving ablation efficiency and reducing heat-affected zone (HAZ). However, the effects of different laser parameters are not well understood. This article presents a numerical study by an improved two-temperature model on the influences of repetition rate, pulse number and burst fluence on ablation efficiency and HAZ in ULBA of copper. Due to thermal accumulation, increasing the repetition rate enhances the maximum ablation efficiency, by over 150% at 3456 MHz. Interestingly, large pulse numbers also assist this effect by extending the period of thermal accumulation. However, if the burst fluence is too low, increased pulse numbers will reduce the ablation efficiency due to insufficient pulse fluences. Burst duration and fluence are determined to have the greatest impact on HAZ thickness. To minimize HAZ, the burst duration needs to be short, by raising repetition rates or reducing pulse numbers, to decrease the thermal diffusion time. The dependences of ablation optimum and threshold fluences on pulse numbers and repetition rates are analyzed and summarized in simple formulae. This study unveils the impacts of laser parameters in ULBA and provides guidelines for ablation efficiency and HAZ optimization.

Long term analysis of N2O emission from partial nitritation anammox process under oxygen limitation

Partial nitritation with anammox (PNA) process was achieved during 300 days to investigate the fate of N2O and NO. N2O emission factor increased from 0.4 ± 0.1 % up to 6.1 ± 0.3 % during intensification phase of 5 months and progressively stabilized at 2.0 ± 0.1 % after 10 months without any significant emission of NO. The emission of N2O correlated with the ammonium consumption rate and the oxygen transfer rate. Experiment carried out in anoxic condition suggested that heterotrophic denitrification poorly contributed. Measurements of δ15N, δ18O and SP of N2O demonstrated that its production resulted from the reduction of nitrite. The stimulating effect of nitrite on N2O production was demonstrated with specific tests and observed during transient nitrite accumulation periods. This study highlighted the importance of nitrite and oxygen transfer rate control for future control strategies aiming to mitigate N2O emission in PNA system.

МЕТОДИ ВИЗНАЧЕННЯ КОЕФІЦІЄНТА ВОЛОГОПРОВІДНОСТІ ҐРУНТІВ ЗЕМЛЯНОГО ПОЛОТНА

Introduction. All periods of moistening of the road structure constitute a single regular cycle of moisture movement in it due to the influence of natural factors. For the final selection of the construction of the subgrade and road pavement, the values of density, humidity and frost heaving of the soil in the annual cycle should be established. To forecast these values, it is necessary to determine the amount of moisture entering the soil from precipitation falling on the surface of the roadway and roadsides during periods of seasonal moisture accumulation. This makes it possible to develop high-quality measures that improve the water-thermal regime of the soils of the subgrade, to model its construction taking into account the properties of the soil, to increase durability by increasing the degree of soil density and reducing the harmful effects of moisture infiltration. Problem Statement. Coefficient of soil moisture conductivity of soil is obtained by the existing method I.A. Zolotar. According to the international standard ISO 17892-11:2019 (E), there are different values as well as different units of measurement, which creates significant problems for their further practical use. Therefore, there are a number of urgent problems regarding the adaptation of existing methods for determining moisture accumulation during the annual cycle to European standards for measuring the coefficient of moisture conductivity of soils of the subgrade. Purpose. The purpose of this work is to carry out analysis of the existing methods of determination of soil moisture conductivity coefficient for calculation of seasonal moisture accumulation in the subgrade. Materials and methods. Methods of determination of the coefficient of moisture conductivity, in particular The Method I.A. Zolotar, are used mainly in the countries of the post-Soviet space. At the same time, in the European Union countries, the determination of the coefficient of moisture is regulated by the international standard ISO 17892-11:2019 (E), according to which the coefficient of moisture is determined depending on the conditions of carrying of the experiment. In the educational and scientific laboratory of the department of transport construction and property management of the National Transport University, a series of studies was conducted using equipment for testing moisture conductivity under conditions of constant pressure. Results. Based on the obtained results of experimental studies carried out in the research laboratory of the National Transport University, the coefficient of moisture conductivity of sandy soil was determined according to the international standard ISO 17892-11:2019 (E) and a comparison was made with the coefficient of moisture conductivity calculated according to the method of I.A. Zolotar. Conclusions. On the basis of the obtained results of experimental studies according to the European approach to determining the coefficient of electrical conductivity of soils of the subgrade, the method of calculating seasonal moisture accumulation will be improved. This will make it possible to move away from outdated Soviet methods, to solve a number of issues important for the practice of design, construction, restoration, reconstruction and operation of roads: to assess the suitability of local soils for the arrangement of the subgrade; determine its structural parameters; to establish calculated values of strength and deformation characteristics of the soil.

Accumulation mechanism and model of coal measure derived oil and gas in the deep reservoir of Huanghua Depression, Bohai Bay Basin, China

Hydrocarbon accumulation in coal measure strata is consist of several types which includes intra-source accumulation and adjusted accumulation, particularly in basins that had experienced multi-stage tectonic activities. The mechanism governing this accumulation is extremely complex. Using the Paleozoic petroleum system in the Huanghua Depression as an example, the mechanism of hydrocarbon accumulation in deep reservoirs can be revealed by means of core observation, geochemistry testing of coal measure source rock, thin section observation, fluid inclusions testing, and profile analysis of typical reservoirs, combined with the burial and thermal history of strata. Based on the regional tectonic, the mechanism of hydrocarbon accumulation in coal measures is defined and the accumulation model was established. The results show that the Paleozoic petroleum system in the Huanghua Depression has three different types of source-reservoir-cap assemblages: under-source, intra-source, and above-source assemblage. Regional tectonic evolution controlled the hydrocarbon generation process of source rocks, showing the hydrocarbon generation characteristics of “oil in the early stage and gas in the late stage.” The Middle Cretaceous is the first of two periods of hydrocarbon accumulation, during which stage occurred in low-maturity oil and a small amount of natural gas were mainly stored in intergranular pores and dissolution pores. The tectonic uplift in the Late Cretaceous caused the destruction of the ancient reservoir. The second accumulation stage occurred in the Middle Paleogene to the present. A large amount of natural gas and high maturity oil were mostly stored in dissolution pores and structural fractures. The hydrocarbon accumulation in Huanghua Depression was simultaneously regulated by reservoir reformation, tectonic activities, and source rock maturation. Based on the foregoing understanding, the hydrocarbon accumulation model of “oil and gas transfer station” in coal measures is put forward, that is, oil and gas are first accumulated in intra-source or near-source reservoirs, and are then adjusted from this “oil and gas transfer station” to other areas as a result of tectonic activity.

Оценка влияния орошения на экологическое состояние серо-коричневых почв Гянджа-Казахского массива

The article presents the results of a study of irrigated gray-brown soils of the Ganja-Kazakh massif, the reasons for changes in individual soil properties associated with the characteristics of specific soil-hydrogeological conditions. It was pointed out that irrigation of gray-brown soils with low mineralized slightly alkaline waters leads to a change in the qualitative composition of salts, an increase in the content of absorbed sodium and its activity. There is also a tendency towards dehumidification of irrigated soils and deterioration of their agrophysical properties. To eliminate the negative effects of irrigation, it is necessary to systematically, comprehensively regulate soil processes and regimes. Thus, during irrigation for 50–60 years, the main properties of gray-brown soils that determine its fertility deteriorated. However, a negative effect of irrigation water with a mineralization of 1.25–2.50 on the salt regime of the soil was noted. Optimization of the reclamation state of soils, prevention of salinization and increase of fertility is promoted by modern agrotechnical measures in combination with an optimal irrigation regime (68–78% HB), as well as with improving the quality of irrigation water by reducing its discharge from irrigated fields and the use of chemical meliorants. Since irrigation of gray-brown soils with mineralized waters was carried out on small areas until recently and, as a rule, was not accompanied by a general increase in the groundwater level, secondary salinization of soils is noted locally in the lowered relief elements. In the main irrigation area for most systems, the period of active salt accumulation observed in the first 3–5 years after the start of irrigation stabilizes at the level of 0.12–0.25% in arable horizons and 0.26–0.32% in sub-arable horizons, and they do not leave the gradation of unsalted. Based on the conducted research, generalization and analysis of the literature data, a systematics of changes on gray-brown soils occurring during irrigation was carried out.

Reliability of road pavement constructions reinforced by geosynthetic materials

Existing experience of unpaved road constructions reinforced by geogrids is described in the article, amended by own practical experience of reinforcement usage in unpaved road constructions. The Object of the research is reinforced and non-reinforced unpaved road constructions. The Purpose of the research is to determine influence of unpaved constructions reinforcement by rigid geogrids on overall bearing capacity and its deviation. The Methods of the research are field bearing capacity dynamic testing and statistic data analysis. The article is a long-term study generalization of unpaved road constructions with grained layers reinforced by rigid geogrids. The study was performed within the period of 2017-2019, and it covers both the construction and operation stages within the period of moisture accumulation and during the drainage period. The results of the study can be used for design and calculation for road constructions by geogrids and geotextile. Forecast assumptions about the object of the research are expansion of the experimental base, taking into account different test methods, different reinforcing materials and different construction conditions.

Determining the gas accumulation period using fluid inclusion observations: Xiang Zhong Basin, China

Abstract There are a large number of natural gas shows in the Upper Paleozoic of the central Hunan Basin. However, the hydrocarbon accumulation process was complicated due to the strong tectonic reformation in this area. A study of the natural gas accumulation period is of significance for determining gas accumulation models. In this research, the fluid inclusion samples were tested, the fluid inclusion occurrence characteristics, uniform temperature data, and reservoir evolution were analyzed, and four diagenetic periods and four diagenetic periods and three hydrocarbon accumulation periods were identified. (i) For the syntaxial stage, the filling is dark and nonluminous, and the fluid captured by the overgrowing cement around the particles is mainly seawater; (ii) for the (Early) Mesogenetic burial stage, the calcite cement grows around the particles or micritic calcite matrix, and the fluid captured is mainly brine; (iii) for (Late) Mesogenetic burial stage, two sets of decomposed fissures developed in massive calcite colloids with non-luminous gas-rich hydrocarbon inclusions within the crystals; and (iv) for Telogenetic burial stage, weakly fluorescent pure gaseous hydrocarbon inclusions are developed in luminescent calcite veins. The result indicates that the organic inclusions in the Lower Carboniferous of the central Hunan Basin are dominated by weakly fluorescent and nonfluorescent rich gas inclusions and pure gas-phase inclusions, with three stages of hydrocarbon filling. By integrating the average homogenization temperatures on burial curves, the three charging orders correspond to 260–250 Ma during the Late Permian, 249–245 Ma during the Early Triassic, and 208–170 Ma during the Late Triassic. Dense reservoir characteristics reveal deep basin gas reservoir in deep basin.

Hydrological Response to Meteorological Droughts in the Guadalquivir River Basin, Southern Iberian Peninsula

Drought is an extreme phenomenon that will likely increase in frequency and severity in the current context of climate change. As such, it must be studied to improve the decision-making process in affected areas. As a semi-arid zone, the Guadalquivir River basin, located in the southern Iberian Peninsula, is an interesting area to perform this study. The relationship between meteorological and hydrological droughts is studied using drought indices with data from 1980 to 2012. The chosen indices are the Standardized Streamflow Index (SSI) and the Standardized Precipitation Evapotranspiration Index (SPEI). Their correlations are calculated, based on SPEI accumulation periods, and these values are analyzed with a principal component analysis to find spatial patterns in drought behavior inside the basin. This analysis was performed for the continuous series and also for monthly series, to account for seasonal changes. It has been found that the relationship of drought types occurs at different time scales depending mainly on orography and catchment area. Two main patterns were found. Generally, for low altitudes and small catchment areas, accumulation periods are shorter indicating that hydrological system in this area respond rapidly to meteorological conditions. In mountainous parts of the basin, longer accumulation periods have a stronger influence due to effects such as snowmelt.

Satellite observed spatiotemporal variability of snow cover and snow phenology over high mountain Asia from 2002 to 2021

Accurate understanding the spatiotemporal variability of snow cover and snow phenology over High Mountain Asia (HMA) is of great interest because of their vital impacts on the hydrological processes, global climate system and regional water resource management. This study investigates the spatiotemporal variability of snow-covered extent (SCE), snow-covered days (SCD), snow onset date (SOD), snow end date (SED) and snow duration days (SDD) of HMA using the daily cloud-free Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover products from the hydrological year 2002 to 2020. The vertical difference of the effect of elevation on snow phenology and the response of snow phenology to climate change are explored. The results indicate that the monthly SCE over the whole HMA exhibited a slight decreasing in most months over the study period. The variability of snow cover and snow phenology over the whole HMA generally showed decreased SCD (significant decrease accounts for 15.73%), delayed SOD (significant delay accounts for 14.35%), advanced SED (significant advance accounts for 15.46%) and shortened SDD (significant shorten accounts for 16.01%). It is worth noting that the snow cover in the West Himalaya was enhancing with its increased SCE, increased SCD and lengthened SDD. There is an elevation dependence of snow phenology changes over HMA with the high-altitude mountain ranges generally having a higher SCD, earlier SOD, later SED and longer SDD than low altitude areas. The air temperature of snow accumulation period is the dominant factor affecting the interannual variation of SOD, and the air temperature of snow melt period is the dominant factor affecting the interannual variation of SED. The increase of air temperature leads to the delayed SOD, advanced SED and shortened SDD.

Accumulation and Elimination of Cadmium by the Nile Tilapia (Oreochromis niloticus) in differing Temperatures and Responses of Oxidative Stress Biomarkers.

The aims of this study were to investigate the accumulation (15 days) and elimination (15 and 30 days) of cadmium (Cd) in the liver, gill, kidney and muscle of Oreochromis niloticus following exposures to different concentrations (1 and 2mg/L) of Cd at different water temperatures (20, 25, 30 oC). Additionally, responses of oxidative stress biomarkers (superoxide dismutase, SOD; catalase CAT; glutathione peroxidase, GPx and malondialdehyde, MDA) of the liver were determined following Cd exposures. In accumulation period, Cd levels increased significantly in all the tissues at all temperatures and tissue accumulation order was kidney > liver > gill. All tissues, except the muscle, accumulated Cd in relation to exposure concentrations and water temperatures. There was no measurable level of Cd accumulation in the muscle, except in fish exposed to 2mg Cd/L at 30 oC. Likewise, elimination of Cd from the tissues also increased in depends on periods and water temperatures. The order of Cd elimination from the tissues was gill > liver > kidney. The oxidative stress biomarkers also responded to both Cd exposure and temperature increases. The activities of antioxidant enzymes such as SOD, CAT, GPx and MDA levels in the liver increased in relation to increases in Cd concentrations and water temperatures.

Sub-hourly resolution quality control of rain-gauge data significantly improves regional sub-daily return level estimates.

This research demonstrates how the use of high-resolution rain-gauge data for quality control (QC) significantly changes extreme rainfall estimates, with implications in scientific, meteorological and engineering applications. Current open QC algorithms only consider data at hourly or daily accumulations. Here we present the first open QC algorithm utilising sub-hourly rain-gauge data from official networks at a national, multi-decade scale. We use data from 1,301 rain-gauges in Great Britain (GB) to develop a threshold-based methodology for sub-hourly QC that can be used to complement existing, freely available hourly QC methods by developing an algorithm for sub-hourly QC that uses monthly thresholds for 1 hr, 15 min and 1 min rainfall totals. We then evaluated the effect of combining these QC procedures on rainfall distributions using graphical and statistical methods, with an emphasis on extreme value analysis. We demonstrate that the additional information in sub-hourly rainfall allows our new QC to remove spuriously large values undetected by existing methods which generate errors in extreme rainfall estimates. This results in statistically significant differences between extreme rainfall estimates for 15 min and 1 hr accumulations, with smaller differences found for 6 and 24 hr totals. We also find that extremes in the distributions of 15 min and 1 hr rainfall accumulations tend to grow more rapidly with return period than for longer accumulation periods. We observe similarities between the shape parameter populations for 15 min and 1 hr rainfall accumulations, suggesting that hourly records may be used to improve shape parameter estimates for extreme sub-hourly rainfall in GB. Sub-hourly QC moderates unrealistically large return level estimates for short-duration rainfall, with beneficial impacts on data required for the design of urban drainage infrastructure and the validation of high-resolution climate models.

A satellite lightning observation operator for storm-scale numerical weather prediction

Abstract. This study aims at simulating satellite-measured lightning observations with numerical weather prediction (NWP) system variables. A total of eight parameters, calculated with the AROME-France NWP system variables, were selected from a literature review to be used as proxies for satellite lightning observations. Two different proxy types emerged from this literature review: microphysical and dynamical proxies. Here, we investigate which ones are best related to satellite lightning and calibrate an empirical relationship between the best parameters and lightning data. To obtain those relationships, we fit machine learning regression models to our data. In this study, pseudo flash extent accumulation (FEA) observations are used because no actual geostationary lightning observations are available yet over France, and non-geostationary satellite lightning data represent a sample that is too small for our study. The performances of each proxy and machine learning regression model are evaluated by computing fractions skill scores (FSSs) with respect to observed FEA and proxy-based FEA. The present study suggests that microphysical proxies are more suited than the dynamical ones to model satellite lightning observations with the AROME-France NWP system. The performances of multivariate regression models are also evaluated by combining several proxies after a feature selection based on a principal component analysis and a proxy correlation study, but no proxy combination yielded better results than microphysical proxies alone. Finally, different accumulation periods of the FEA had little influence, i.e. similar FSS, on the regression model's ability to reproduce the observed FEA. In future studies, the microphysical-based relationship will be used as an observation operator to perform satellite lightning data assimilation in storm-scale NWP systems and applied to NWP forecasts to simulate satellite lightning data.

Determination of Silicon Accumulation in Non-Bt Cotton (Gossypium hirsutum) Plants and Its Impact on Fecundity and Biology of Whitefly (Bemisia tabaci) under Controlled Conditions

Considering the resistance development-potential of whitefly (Bemisia tabaci) against control tactics with limited action mechanisms, the present study investigated the accumulation of two different silicon (Si) sources (SiO2 and K2SiO3) in cotton plants. The tested dose rates (0, 200, and 400 mg/L) of both Si sources were applied directly to the soil or through foliar application on cotton leaves. Moreover, a laboratory bioassay was also conducted to evaluate the performance of applied Si sources against the oviposition preference and biology of B. tabaci. A significantly higher Si accumulation, reduction in oviposition preference, and prolonged developmental period of all nymphs and total life cycle of B. tabaci was observed in the case of foliar-applied silicon. Similarly, among Si sources, a significant decline in the number of oviposited eggs and delay in the developmental period of B. tabaci was observed in the case of SiO2, followed by K2SiO3. Moreover, cotton plants subjected to SiO2 treatments possessed higher Si contents in their leaves than K2SiO3 treated plants. The results further revealed that both Si sources showed promising results at their higher concentrations regarding the tested parameters of Si accumulation, fecundity, and developmental period of B. tabaci. Our results strongly suggest that among emerging pest control strategies in cotton plants lies the use of foliar application of Si, which can also be incorporated in different integrated pest management programs due to its safety for humans and beneficial insect fauna.

Seismic Scattering Property Changes Correlate With Ground Deformation at Suwanosejima Volcano, Japan

AbstractContinuous estimation of changes in seismic velocity and seismic scattering property by passive interferometry using seismic ambient noise is a promising tool for monitoring volcanoes. To improve the usefulness of this method, it is necessary not only to detect subsurface structural changes but also to quantitatively compare the estimated changes in seismic wave velocity and seismic wave scattering property with other observations, such as ground deformation. We applied passive interferometry to continuous seismic records from the Suwanosejima volcano, Japan, recorded between April 2017 and December 2021. We detected repeated significant waveform decorrelations in seismic ambient noise cross‐correlation functions (CCFs), indicating changes in seismic scattering property in the shallow areas of the volcano. These decorrelations were observed from 2 weeks to a few days before the increase in the number of explosions, suggesting that seismic scattering properties changed significantly during that period. We found that the timing of the decorrelation in seismic ambient noise CCFs and tilt changes related to magma accumulation and injection beneath Suwanosejima were well synchronized. The high correlation between the amounts of decorrelation and the tilt change during the magma accumulation period possibly suggests that a large volume of accumulated magma caused great changes in the scattering property. These results provide a significant first step toward a quantitative comparison of the amount of changes in the scattering property with the amount of magma accumulation beneath volcanoes.

Genesis and Accumulation Period of CO2 Gas Reservoir in Hailar Basin

Gas reservoirs with high CO2 have been found in several wells in the Hailar Basin. In this paper, a composition analysis, stable carbon isotope analysis, and a rare gas helium isotope 3He/4He and argon isotope 40Ar/36Ar analysis were carried out. These comprehensive analyses show that the CO2 in the Hailar Basin is inorganic-origin gas, which generally has the characteristics of crust–mantle-mixed CO2, and the fraction of helium of mantle source can reach 15.12~18.76%. There are various types of CO2 gas reservoirs. CO2 gas mainly comes from deep crust. The distribution of gas reservoirs is mainly controlled by deep faults and volcanic rocks, as well as by reservoir properties and preservation conditions. Magmatic rocks provide gas source conditions for the formation of inorganic CO2 reservoirs. Deep–large faults provide the main migration channels for CO2 gas. The sandy conglomerate and bedrock weathering crust of the Nantun Formation and the Tongbomiao Formation provide favorable reservoir spaces for the formation of CO2 gas reservoirs. The combination of volcanic rock mass and deep–large faults creates a favorable area for CO2 gas accumulation. The age of magmatic intrusion and the homogenization temperature of oil–gas inclusions in Dawsonite-bearing sandstone indicate that 120 Ma in the Early Cretaceous was the initial gas generation period of the CO2 reservoir and that oil and gas were injected into the reservoir in large quantities in 122~88 Ma. This period is the peak period of magmatic activity in Northeast China, as well as when the crust of Northeast China greatly changed. A large-scale CO2 injection period occurred in 100~80 Ma, slightly later than the large-scale injection period of the oil and gas. Since the Cenozoic, the structure has been reversed, and the gas reservoir has been adjusted.