bluuebunny/crossref_metadata_2025 huggingface dataset:
Global Sea Level Trend, Acceleration and Its Components over 1993-2
Authors: Wang Fengwei , Shen Yunzhong , Chen Qiujie , Geng Jianhua
Published: February 2023

A 24-year global mean barystatic sea level change from January 1993 to December 2016 is derived by the joint use of Tongji-LEO2021 and Tongji-Grace2018 monthly gravity field solutions, with which the global sea level budget is investigated together with altimetry, steric and four mass elements (glaciers, Greenland, Antarctica and land water storage). The derived global mean sea level changes from altimetry, steric and two Tongji solutions generally agree well with each other with three correlation coefficients all higher than 0.90. The results show that the linear trend of global mean sterodynamic sea level change is 2.85±0.30 mm/year from altimetry, close to 2.82±0.19 mm/year of barystatic (1.55±0.15 mm/year) plus steric (1.27±0.12 mm/year) and 2.94±0.13 mm/year of the sum mass contributions (1.67±0.06 mm/year) plus steric, whose misclosure ranges -0.09 to 0.03 mm/year. The acceleration of global mean barystatic sea level change is 0.139±0.019 mm/year2, which is mainly caused by four factors, 0.051±0.002 mm/year2 (~36.7%) by Greenland ice melting, 0.027±0.002 mm/year2 (~19.4%) by Antarctica ice melting, 0.027±0.001 mm/year2 (~19.4%) for other glaciers melting and 0.032±0.010 mm/year2 (~23.0%) for land water storage, respectively. The findings in this study suggested that the global sea level budget was closed from 1993 to 2016 based on altimetry, steric, Tongji solutions and mass elements data.
Investigation of Endocrine disruptor - PAEs and Carcinogenic - PAHs bound to ambient fine particulate matter over Northwest Indo-Gangetic Plain
Authors: Patnana Durga Prasad , Praphulla Chandra Boggarapu , Chaudhary Pooja , Sinha Baerbel , Sinha Vinayak
Published: February 2023

 Phthalic acid esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) are classified as priority pollutants by United States Environment Protection Agency (USEPA). Some of the PAEs and PAHs are considered as human carcinogens by International Agency for Research on Cancer (IARC). In the present study, an ultra-high performance liquid chromatography coupled to triple quadruple mass spectrometry (LC-MS QQQ) method was developed and validated for the simultaneous determination of PAEs and PAHs bound to ambient particulate matter. After the method validation, it was deployed for the quantification of PAEs and PAHs bound to PM2.5 collected at a sub urban site in the Northwest Indo-Gangetic Plain. The targeted PAEs in this study are dimethyl phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBP), di butyl phthalate (DBP), bis (2-ethyl hexyl) phthalate (DEHP), bis (2-ethylhexyl) adipate (DEHA), di-n-octyl phthalate (DNOP) and PAHs are benzo[a]anthracene (B[a]A), benzo[b]fluorenthene (B[b]F), benzo[k]fluorenthene (B[k]F), benzo[a]pyrene (B[a]P), dibenzo[ah]anthracene (D[ah]A), benzo[ghi]perylene (B[ghi]P), and indeno[1,2,3-cd]pyrene (IND). The measured concentrations of PAEs and PAHs are seasonally varied and the higher concentrations of PAEs were observed in summer and PAHs in winter. DEHP (17.94 ng m-3) and B[b]F (36.13 ng m-3) are the most abundant PAE and PAH measured at the sampling site. The concentrations of B[a]P (4.66 ng m-3; Group 1 carcinogen) exceeded the threshold limits (1 ng m-3) set by the National Ambient Air Quality Standards of India (NAAQS). Further, the incremental lifetime cancer risk due to inhalation exposure to DEHP and B[a]P were estimated for adults (0.3678 × 10-6 and 1.40 × 10-5 respectively) and children (0.8792 × 10-6 and 3.272 × 10-5 respectively). Also, the cancer risk associated with the inhalation exposure to B[a]P has exceeded the limits (1 ×10-3) set by USEPA at the measurement site.
Thin film flow: fluid transport via thin liquid films in slow porous media flows
Authors: Moura Marcel , Reis Paula , Schäfer Gerhard , Toussaint Renaud , Flekkøy Eirik Grude , Rikvold Per Arne , Måløy Knut Jørgen
Published: February 2023

The standard liquid transport processes in porous media happens through a network of interconnected pore bodies and pore throats (here called the primary network). When a non-wetting phase displaces a wetting phase from a porous sample (drainage), thin films of the wetting phase are bound to be left on the surface of the constituting grains (for example when air displaces water from a porous rock, thin films of water are left behind, covering the rock grains). Under certain conditions, isolated liquid films can eventually merge, forming a secondary network of interconnected films and capillary bridges (see red arrows in the figure) that can effectively enhance the overall connectivity of the medium and act as a new pathway for fluid transport. We have performed experiments using transparent networks with the objective of studying transport processes that are enhanced by film flow. Our setup allow us to directly visualize the secondary network in the sample and we have shown how fluid bodies that are not linked via the primary network can actually be connected via the secondary network. This connection has important consequences for processes such as the dispersion of pollutants in soils and the transport of nutrients to plants in arid regions.  ReferencesMoura, E. G. Flekkøy, K. J. Måløy, G. Schäfer and R. Toussaint, “Connectivity enhancement due to film flow in porous media,” Phys. Rev. Fluids 4, 094102 (2019).Moura, K. J. Måløy, E. G. Flekkøy, and R. Toussaint, “Intermittent dynamics of slow drainage experiments in porous media: Characterization under different boundary conditions,” Front. Phys. 7, 217 (2020).
Abrupt debris-flow mobilization in a hillslope experiment
Authors: Reid Mark , Ochiai Hirotaka
Published: February 2023

Debris-flow mobilization from shallow landsliding is widespread, can be deadly, and is the focus of warning systems worldwide. One challenge of forecasting is that some shallow landslides transform into rapid debris flows, whereas others do not. Although early warning systems can depend on forecasting this poorly understood transition, high-resolution hydrologic and deformation data from debris-flow mobilization events are rare. As part of the APERIF project (Ochiai et al., Landslides, 2004), we performed a field-scale artificial rainfall (sprinkling) experiment on a planar 33º natural hillslope near Mt. Kaba-san, Japan. Using 100-Hz sampling, we recorded synchronous subsurface pore-pressure response and ground-surface motion throughout the transition from slide (~1 m thick) to flow, including slow precursory deformation, abrupt rapid failure, and subsequent debris-flow motion down a small channel. The experiment began with ~6 hours of high-intensity sprinkling (at 78 mm/hr), which triggered motion of the slide in response to rising positive pore-water pressures. Continued sprinkling led to persistent slow motion of the slide for ~1 hour, until acceleration and abrupt failure. Our data revealed that during the several seconds of rapid failure, pore pressures dropped (indicative of soil dilation) then oscillated greatly in response to deformation, thereby enhancing liquefaction and flow. An abrupt transition from slow to fast motion in dilative soils can present a mechanical conundrum. Although loose, contractive soils may collapse and liquefy, many hillslope soils are dense and dilate in shear, thereby impeding motion. We explored slide behavior using a 1D model (Iverson, 2005) that fully couples slide motion and pore pressure with evolving shear-zone dilatancy, and utilized measured and estimated parameters from our hillslope experiment. Simulations demonstrated that dilative soils impede motion, as observed initially in our experiment. However, dilatant systems can evolve dynamically through persistent landslide motion driven by prolonged rainfall. When motion-inhibiting dilatant effects are exhausted, our analysis showed rapid acceleration during a swift drop and subsequent increase in pore pressures (within a few sec), as was also observed in the field experiment. This behavior provides a mechanism to mobilize debris flows from shallow landsides in dense hillslope soils. Our results suggest that although high-resolution monitoring might detect precursory motion, forecasting liquefaction and debris-flow genesis is still dependent on soil properties and transient hydrologic conditions.
Tracing metal footprints through global renewable power value chains
Authors: Fu Rao , Peng Kun , Wang Peng , Zhong Honglin , Liu Xi , Feng Kuishuang , Li Jiashuo
Published: February 2023

The globally booming renewable power industry has stimulated an unprecedented interest in metals as key infrastructure components. Many economies with different endowments and levels of technology participate in various production stages and cultivate value in global renewable power industry production networks, known as global renewable power value chains (RPVCs), complicating the identification of metal supply for the subsequent low-carbon power generation. Here, we use a value chain decomposition model to trace the metal footprints (MFs) and value-added of major global economies’ renewable power sectors. We found that the MFs of the global renewable power sector increased by 47% during 2005—2015. Developed economies occupy the high-end segments of RPVCs while allocating metal-intensive (but low value-added) production activities to less developed economies. The fast-growing demand for renewable power in developed economies is a major contributor to the embodied metal transfer increment within RPVCs, which is partly offset by the declining metal intensities in less developed economies. Therefore, it is urgent to establish a metal-efficient and green supply chain for upstream suppliers as well as downstream renewable power installers for transition in the power sector across the globe.
Chemistry-Weather Interacted Model System GRAPES_Meso5.1/CUACE CW V1.0: Development, Evaluation and Application in Better Haze/fog Prediction in China
Authors: Wang Hong
Published: February 2023

The Chinese Meteorology Administration chemistry model CUACE is online integrated into the mesoscale operational weather prediction (NWP) model (GRAPES_Meso5.1) and aerosol-cloud-radiation interaction is achieved to establish the first version (V1) of chemistry-weather (CW) interacted model GRAPES-Meso5.1/CUACE CW V1. The most polluted winter 2016-2017 is selected to study the meteorology impacts on haze/fog prediction, the impact of aerosol-radiation, aerosol-cloud and CW interaction (ARI, ACI, CWI) on haze/fog prediction and NWP. Single way model without CWI displays reasonable PM 2.5 and visibility prediction in general. However, modeled PM2.5 peaks are underestimated and visibility valleys are overestimated during haze/fog pollution, the underestimation of relative humidity (RH) contributes major to this misestimation; CWI model cut the negative bias of PM 2.5 peaks and the positive bias of visibility valleys. The improvement of 5km and 3km low visibility by CWI during severe haze/fog period is more obvious than that of 10 km, which just compensates for the largest deficiency in low visibility prediction related with severe haze/fog by single way model; The NWP including sea level pressures, relative humidity(RH), temperature, wind speed are also improved by CWI from surface to upper troposphere; ARI contributes larger to the predicted PM2.5 ,visibility and NWP improvement than that of ACI, their relative contributions varies with model vertical height and the overlapping condition of cloud and aerosols. Due to the joint contribution of RH and PM2.5, CWI’s improving on visibility is larger than PM2.5. This study illustrates the importance of including CWI in air quality prediction model.
Knowledge about Plant Coexistence during Vegetation Succession for Forest Management on the Loess Plateau, China
Authors: Tian Qilong , Zhang Xiaoping , Xu Xiaoming , Yi Haijie , He Jie , He Liang
Published: February 2023

Coexistence between species within plant communities is a key issue in the practice of revegetation, forest management, and biodiversity conservation. Vegetation restoration is critical to control soil erosion and improve the ecological environment on the Loess Plateau. Here, we investigate the interspecific relationships of dominant plants during natural vegetation succession on the Loess Plateau. The results suggest that, under the ecological process of environmental filtering, species within communities can reduce interspecific competition and promote species coexistence via spatial heterogeneity and temporal asynchronous differences. The ecological niche overlap index (Oik) significantly and positively correlated with the strength of interspecific associations. Most species pairs had weak competition and more stable interspecific relationships. The results of the χ2 test showed that 317 species pairs were positively associated and 118 were negatively associated. The community is in a positive succession process, and the interaction relationship between species tends to be neutral. We should enhance the protection of positively associated species and pay attention to negatively associated species during forest management. Results revealed that Boott and Lespedeza bicolor Turcz coexisted easily with other species for mutual benefit, which could help build artificial forestland of native species to improve the ecological function.
Flood frequency analysis integrated with unprecedented flood samples and mixed probability distribution
Authors: Ganapathy Abinesh , Hannah David M , Agarwal Ankit
Published: February 2023

Different flood-generating mechanisms are responsible for high flows in different catchments. This mixture of generating mechanisms could violate the homogeneity assumption of the extreme value distribution used often in flood frequency analysis. Thus, this study aims to classify flood samples into homogenous process-based groups and estimate the flood quantiles for different return periods. Furthermore, this study also deals with the sample inadequacy in the flood classification by pooling ensemble reforecast datasets based on the UNprecedented Simulated Extreme ENsemble (UNSEEN) approach. The Dresden gauge in the Elbe River is selected as the study site. Daily discharge data are extracted from the GRDC, and flood events are separated based on our proposed ‘Peak-identification flood separation algorithm’, which follows four steps: 1. Identification of peaks, i.e., points with a higher streamflow value than its prior and next values, 2. Pruning based on 90th percentile threshold value, 3. Application of independence criterion, 4. Identification of flood starting and ending position. After flood separation, hydrograph features-based flood grouping and ensemble data pooling are performed. We observe the difference in the distribution characteristics of the observed in comparison to the pooled datasets. A relative difference of 0.25 (cumecs/cumecs) is noticed for the 100-year return level between observed and pooled data. As our key contribution, we address the sample mixing problem using the flood classification technique and establish the importance of data pooling.
Empirical GNSS-derived terrestrial water storage-streamflow relationship in the Sierra Nevada ranges, California
Authors: Lau Nicholas , Knappe Ellen , Borsa Adrian
Published: February 2023

One of the most dynamic components of Earth surface mass variability is the constant global redistribution of terrestrial water storage (TWS) across temporal scales of hours to decades. Mass loading and unloading from TWS changes induce instantaneous elastic deformation of the solid earth, producing predominantly vertical transient displacements that are observable by geodetic methods. The global expansion of Global Navigation Satellite Systems (GNSS) networks during the last decade have provided new opportunities of directly estimating changes in TWS at high spatial and temporal resolutions. While contemporary GNSS studies have demonstrated the ability to map regional-scale water storage variability, incorporating these geodetic TWS estimates with in-situ hydrologic measurements can provide further insights on the physical mechanisms underlying the terrestrial water cycle. In this study, we investigate the potential of using GNSS-derived TWS estimates to infer individual watershed condition along California’s Sierra Nevada, a major water source for urban and agricultural use. Utilizing the dense GNSS network in the western United States, we invert vertical displacements for TWS change at subbasin scale spatial resolution (USGS HUC-8). Joint analysis of our TWS estimates and stream gauge data shows contrasting seasonal behaviours in the northern and southern Sierra Nevada. The snow-dominated southern section exhibits a significant time lag between maximum storage and maximum baseflow from March to May, indicating wet-season decoupling between surface storage and the subsurface reservoirs that drive baseflow. In contrast, the northern section exhibits little to no lag, indicative of persistent surface-to-subsurface coupling, consistent with the higher rain-to-snow ratio in the north. Furthermore, we demonstrate that GNSS-derived TWS estimates can be used to infer watershed antecedent storage conditions, in which interannual variability in summer storage (dry season) influences streamflow recession behaviours during early precipitation season. Continued development of GNSS-based water storage estimates and future assimilation with hydrologic models should provide additional understanding of the water budget and hillslope hydrology in the Sierra Nevada.
Influence of the Asthenosphere on Earth Dynamics and Evolution
Authors: Richards Mark , Cathles Lawrence , Fjeldskaar Willy , Lenardic Adrian , Romanowicz Barbara , Seales Johnny
Published: February 2023

The existence of a thin, weak asthenospheric layer beneath Earth’s lithospheric plates is consistent with existing geological and geophysical constraints, including Pleistocene glacio-isostatic adjustment, modeling of gravity anomalies, studies of seismic anisotropy, and post-seismic rebound. Mantle convection models suggest that a pronounced weak zone beneath the upper thermal boundary layer (lithosphere) may be essential to the plate tectonic style of convection found on Earth. The asthenosphere is likely related to partial melting and the presence of water in the sub-lithospheric mantle, further implying that the long-term evolution of the Earth, including the apparently early onset and persistence of plate tectonics, may be controlled by thermal regulation and volatile recycling that maintain a geotherm that approaches the wet mantle solidus at asthenospheric depths.
Mapping of Soils Salinity with Landsat 8 OLI Imagery and Random Forest Algorithm
Authors: Zhang Teng , Wang Zhongjing , Tang Yingfu , Shi Yujia
Published: February 2023

Soil salinity mapping is essential for sustainable land development and water resources management. In situ sampling is time-consuming, laborious, and restricted by geographical conditions. Therefore, an efficient and accurate model is necessary to monitor and assess the spatio-temporal dynamic salinization at regional a scale. In this study, Shule River Basin (SLRB) is taken as an example to develop the soil salinity mapping model based on Landsat 8 OLI images using random forest (RF) algorithms. A series of extended soil salinity indexes (ESSIs) were generated by combining any two, three, or four spectral bands were combined in expressions that include one or more of the arithmetic operations: addition, subtraction, multiplication, division, square and rooting form. The features selected from ESSIs outperformed the features selected from soil salinity indexes (SSIs) used in references. The best selected indexes are (B7^2-B5^2)^0.5, (B4^2+B5^2-B6^2)^0.5, (B1*B5-B4*B6/(B1*B5+B4*B6))^0.5,(B2*B6-B3*B7/( B2*B6+B3*B7))^0.5. In addition, three partition sampling methods of the training set and validation set for long-tail distribution problems are compared. The results showed that the resampling method considering the long-tail distribution performs better than systematic resampling and random k-fold cross-validation. The regional soil salinity mapping results showed that most areas are seriously salt-affected in the whole basin, especially along the river and the southeast mountainous area, where the soil salinity classes are highly and even over-extremely saline. This study could have implications for agricultural schemes planning and salinization control.
Assessing soil degradation status in croplands: insights from the variations in soil particulate organic carbon fraction
Authors: Ma Jiamin , Shi Pu
Published: February 2023

Intensified soil use and management practices have led to serious soil degradation in the world’s croplands, compromising their ability to provide food and ecosystem services. Under the United Nations Sustainable Development Goals framework, “change in soil C stock” has been adopted as a key indicator to assess the degree and extent of cropland degradation. Among the underlying drivers that can cause soil C losses, reduced inputs of organic substrates, tillage-induced soil structural destabilization and erosion-associated lateral matter transfer are regarded as key processes that not only diminish the bulk C content, but also alter the soil C composition of functionally distinct fractions.In this study, we attempt to analyze the relationship between soil degradation and soil C dynamics from a "beyond bulk” perspective. We selected two study sites, one in Northeast China and one in the Belgian Loam Belt, that share similar bulk soil C content, soil texture and parent materials, but contrasting degrees of soil degradation at regional scale. We will present results on (i) the response of soil aggregate stability, as a measure of soil degradation, to varying bulk C content, as well as to particulate and mineral-associated organic C fractions; (ii) how varied organic inputs and soil erosion intensity could affect the fraction of soil particulate organic carbon that has important control over the level of aggregate stability.
Plasma-Sheet Bubble Identification Using Muitivariate Time Series Classification
Authors: Xuedong Feng , Jian Yang
Published: February 2023

Abstract: Plasma-sheet bubbles play a major role in the process of magnetotail particle injections. They are defined as fast flows with reduced plasma density or pressure accompanied by magnetic field dipolarization. Typically, we can detect these bubbles from in-situ observations, but subjective uncertainty needs human verification. In this study, we combine three different methods including MINImally RandOm Convolutional KErnel Transform (MINIROCKET), 1D and 2D convolution neural network (CNN) to identify bubbles. The imbalanced training dataset consists of bubble and non-bubble events with a ratio of 1:40 from year 2007 to 2020. The results indicate that the accuracy of the all three models is around 99%, and the precision and recall rates of all three models are above 80% in both the validation and test datasets. The three methods are combined with the intersection set as the minimum set of predictions and the union set as the maximum set. The methods greatly reduce the number of false positives. To identify bubbles in the observations of year 2021, our neural network model is found to be comparably good to the traditional criterial and manual inspections. Using joint machine learning forecasting methods, we can easily and automatically identify bubbles without a priori knowledge like a domain expert.Keywords: plasma-sheet bubble, multivariate time series classification, sample imbalanced, image identification
Probabilistic mapping of co-seismic landslide hazard in Uttarakhand state (India)
Authors: Gupta Kunal , Satyam Neelima
Published: February 2023

Probabilistic mapping methods are receiving more attention in the field of landslide susceptibility assessment due to their ability to incorporate the spatial and temporal uncertainties linked to the variability of hydrological, seismological, geological, geotechnical, and geomorphological parameters. Studies on the probabilistic seismic landslide hazard are necessary for Uttarakhand state (India) due to its high seismic activity. Therefore, the present research presents a probabilistic methodology to model the uncertainties associated with modified Newmark’s model, which considers the shear strength parameters of rock joints for the static factor of safety computations. By using statistical distributions to describe these values, the uncertainties pertaining to the input parameters were taken into consideration. The Monte Carlo approach was used to simulate several probability density functions pixel-by-pixel, and the simulation results were carried over into the computation. As a result, when converting the obtained numbers into probabilistic hazard maps, there were no restrictions on the mathematical symmetry or complexity of the underlying distributions. The likelihood of seismically induced slope deformation surpassing a threshold of 5 cm was computed for each pixel and presented in terms of the hazard map. The Greater and Middle Himalayas had high probability values, highlighting the potential of earthquake-induced landslides in this area. Finally, the landslide inventory from the 1999 Chamoli earthquake was used to validate the results. The produced seismic landslide hazard map will provide local governments and infrastructure planners with a tool for assessing the danger of a seismic landslide for land use planning and applying suitable mitigation measures to limit the losses.
Interannual variability of the meridional overturning circulation in the subpolar North Atlantic
Authors: Fu Yao , Lozier M. Susan
Published: February 2023

Variability of the Atlantic Meridional Overturning Circulation (MOC) has drawn extensive attention due to the MOC’s impact on global heat and freshwater redistribution. The Overturning in the Subpolar North Atlantic Program (OSNAP) array, consisting of an OSNAP West section covering the Labrador Sea and an OSNAP East section covering the eastern subpolar basins (Irminger and Iceland Basins), has continuously observed the MOC and meridional heat and freshwater transports since 2014. The OSNAP observations have contributed substantially to the understanding of the mean state and sub-seasonal to seasonal variability of the subpolar MOC. In this study, we present the latest OSNAP observational results and investigate interannual variability of the subpolar MOC with respect to water mass transformation and formation in the Labrador Sea and eastern subpolar basins. We detail the differences between formation and transformation in each of these basins and discuss their relationships to overturning on monthly and interannual time scales. Finally, we explore the mechanism(s) responsible for these differences.
El Niño Southern Oscillation influence over the Orinoco low-level jet variability
Authors: Builes Alejandro , Yepes Johanna , Salas Hernán D.
Published: February 2023

We studied the most active season of the Orinoco Low-Level jet (OLLJ), December-January-February (DJF), during the El Niño-Southern Oscillation canonical phases, El Niño and La Niña. In particular, we studied the occurrence days of the jet in each month, wind speed, moisture transport and precipitation over northern south America. In terms of the occurrence of the OLLJ, during El Niño in January, the jet exhibits its highest reduction with changes up to 24% in the eastern Colombian plains. On the contrary, during La Niña, the jet exhibits an increase between 6–16% in the frequency of occurrence mainly located in the eastern Colombian plains and the border between Colombia, Ecuador and Peru. Although the diurnal cycle of the OLLJ windspeed remains unaltered during the ENSO phases the maximum decrease (increase) up to -2m/s (up to 1 m/s) during El Niño (La Niña). Regarding moisture transport there is a gradual reduction during the season in both ENSO phases reaching up to 18 gm-1 kgm-1 during El Niño, and the precipitation also shows a reduction of around 5 mm/day. In conclusion, during DJF at the ENSO canonical phases the OLLJ shows changes in its occurrence along the jet corridor, and the region experiences changes in both moisture transport and precipitation.
Site response and liquefaction hazard analysis in Ramsar city, North of Iran
Authors: Shabani Elham
Published: February 2023

Liquefaction hazard analysis is critical to the safety and cost-effectiveness of structures. Ramsar, the westernmost city of northern Iran's Mazandaran province, borders the Caspian Sea to the north. Since the soil strata of the Ramsar region are predominantly composed of low-grade sand and the groundwater is at low depths, it is highly vulnerable to liquefaction. Understanding how sedimentary basins react to seismic energy generated by earthquakes is a major concern for seismic hazard assessment and risk analysis. The primary purpose of this study is to determine the distribution of the natural frequency value, the amplification factor value and the soil vulnerability index. These were carried out as indicators for potential liquefaction sites in the city of Ramsar based on measurements of seismic ambient noise or microtremors. In this regard, ambient seismic noise was collected at 100 stations in the Ramsar region by Nanometrics Trillium40s intermediate sensors. Data are processed using the horizontal-to-vertical spectral ratio (HVSR) method provided by Nakamura (1989). Based on the results, the vulnerability index Kg is determined, which can be used as a parameter for calculating the region's liquefaction potential. Huang and Tseng (2002) suggested that the HVSR of microtremor data can be a good alternative indicator of the liquefaction potential of an area. It is revealed by previous researchers that improving the accuracy of geology and geomorphology-based liquefaction susceptibility map is accomplished by supplementing it with subsurface data (e.g., SPT, CPT, shear wave velocity data). The results of this study show that with the use of seismic ambient noise, the accuracy of the assessment of liquefaction susceptibility and zonation improves substantially.
Data-guided exploration of streamflow generation mechanism: A global-scale analysis
Authors: Sharif Hamed , Ameli Ali
Published: February 2023

Identifying a catchment’s streamflow generation mechanisms could inform the hydrologic functioning of the catchment, and how the catchment responds to the changes in climate and land-use. This study focuses on identifying the dominant streamflow generation mechanism and its drivers at more than 2,000 natural catchments located in North and South America, Europe, and Oceania. First, in a given catchment, we use a suite of diagnostic tools to infer the relative contribution of different streamflow generation mechanisms from precipitation and streamflow observations and simulated time series of subsurface storage. Then, in a large sample hydrology framework, we explore the major physical and climatic drivers of streamflow generation mechanisms. In this study, we made progress in differentiation among, seemingly similar, but naturally different subsurface mechanisms of streamflow generation (e.g., subsurface stormflow, transmissivity feedback, groundwater flow) as well as in identifying the drivers of these mechanisms. Our study extracts generalizable process understanding by combining conventional hydrologic science tools with modern data learning techniques.
Global Ionospheric Total Electron Content Completion with a GAN-based Deep Learning Framework
Authors: Liu Yang , Yang Kunlin
Published: February 2023

    The ionosphere serves as a critical medium for radio signal propagation in outer space. A good morphology of the global TEC distribution is very useful for both ionospheric studies and their relative applications. In this work, a deep learning framework was constructed for better spatial estimation in ionospheric TEC. Both the DCGAN and WGAN-GP were considered, and their performances were evaluated with spatial completion for a regional TEC. The performances were evaluated using the correlation coefficient, RMSE, and MAE. Moreover, the IAAC rapid products were used to make comparisons. The results show that both the DCGAN and WGAN-GP outperformed the IAAC CORG rapid products. The spatial TEC estimation clearly goes well with the solar activity trend. The RMSE differences had a maximum of 0.5035 TECu between the results of 2009 and 2014 for the DCGAN and a maximum of 0.9096 TECu between the results of 2009 and 2014 for the WGAN-GP. Similarly, the MAE differences had a maximum of 0.2606 TECu between the results of 2009 and 2014 for DCGAN and a maximum of 0.3683 TECu between the results of 2009 and 2014 for WGAN-GP. The performances of the CORG, DCGAN, and WGAN-GP were also verified for two selected strong geomagnetic storms in 2014 and 2017. The maximum RMSEs were 1.8354 TECu and 2.2437 TECu for the DCGAN and WGAN-GP in the geomagnetic storm on February 18, 2014, respectively, and the maximum RMSEs were 1.3282 TECu and 1.4814 TECu in the geomagnetic storm on September 7, 2017. The GAN-based framework can extract the detailed features of spatial TEC daily morphologies and the responses during geomagnetic storms. It shows that the GAN-based framework can extract the detailed features of the spatial TEC responses to geomagnetic storms. Further investigation can be conducted to improve the generator and discriminator architecture of the GAN-based framework for better and higher spatial descriptions of TEC morphology.
Changes in global wind patterns since the late 1700s from American whaling ship logbooks and reanalyses
Authors: Ummenhofer Caroline , Walker Timothy , Münch Bastian , Sander Neele , George Tyson , Miah Milon
Published: February 2023

Maritime weather data contained in U.S. whaling ship logbooks are used to assess historical changes in global wind patterns. We focus on unexploited caches of archival documentation, namely U.S. whaling logbooks of voyages spanning the period 1785 to 1910 from New England archives housed by the New Bedford Whaling Museum, Nantucket Historical Association, and Providence Public Library. The logbooks, often covering multi-year voyages around the globe, contain systematic weather observations (e.g., wind strength/direction, sea state, precipitation) at daily to sub-daily temporal resolution. The qualitative, descriptive wind recordings are quantified and compared with reanalysis products where applicable. They are also employed to help address contemporary questions in climate science, such as long-term shifts in position and strength of the Southern Hemisphere westerlies since the late 1700s, changes in characteristics of the subtropical high pressure systems (e.g., Azores High, Mascarene High) and associated circulation regimes in the 19th century, as well as changes in South Asian monsoon characteristics.The historical records provide an important long-term context for changing maritime wind patterns in remote ocean regions lacking high-quality observational records. The project is predicated on historical climate data rescue and recovery through the extraction of data from under-utilised archived documentation, and advocating and facilitating the digitisation of such materials.
Ecological Restoration Declined the Rainstorm—Flood Relationship for past 40 years on Chinese Loess Plateau
Authors: An Zefeng , Zhang Xiaoping , He Liang , Yi Haijie , He Jie , Sun Weinan , Geng Wenliang , Wang Haojia , Wang Yicheng , Zhang Yujie , Yu Kaiyang
Published: February 2023

The Loess Plateau has been experiencing large-scale ecological construction over the past  40 years. The watershed of Zhou River (1334 km2 ) in the core land of the Loess Plateau was chosen as a case study to understand the impact of land use and cover change on the relationship between rainstorm and flood. The land use of the watershed in 1985, 2000 and 2015 was extracted from corresponding Landsat images and the series of event data from 1980 to 2019 of rainfall and runoff were collected from seven rain measuring stations and one gauging station (774 km2) distributed in the watershed. he different magnitude of rainstorm-flood was classified to investigate its responses of ecological restoration by mathematical statistics method. The results showed that the land use conversions were mainly from cropland to forest and grassland, and from grassland to woodland in the time. The proportion of forest and grassland increased from 60.5% in 1985 to 72.1% in 2000 and reached as 85.3% in 2015. While in the meantime, the rainstorm frequency and magnitude of quantity had no obvious trend, however, the annual maximum flood peak discharge in the watershed showed a significantly downward trend, and a change point occurred in 2003. Also the flood magnitude and frequency decreased significantly. Under the same peak discharge, the flooding lag time and runoff coefficient showed an obviously increasing trend compared to that before 2003. And after 2003, most of the floods turned to be once every two years (peak discharge of 169 m3/s) after that year. For floods greater than 10 year-return period, the runoff coefficient is mainly affected by forest land increasing, and the contribution rate is 0~78%. For floods less than 10 year-return period, the runoff coefficient is mainly affected both by the increase of forest land and grassland area, and their contribution rates are 0~57% and 11%~65%, respectively. Outcomes from this study are helpful to understand the shifts of the hydrological process with ecological restoration and assist the sustainable catchment management and land use planning on the Loess Plateau. 
Plant growth strategy determines the magnitude and direction of drought-induced changes in root exudates in subtropical forests
Authors: Zhou Xuhui , Jiang Zheng , Fu Yuling
Published: February 2023

Root exudates are an important pathway for plant-microbial interactions and are highly sensitive to climate change. However, how extreme drought affects root exudate and its components, as well as species-specific difference in response magnitude and direction, are poorly understood. In this study, root exudation rates of total carbon (C) and its components (e.g., sugar, organic acid, and amino acid) were measured under the control and drought treatments (i.e., 70% throughfall reduction) by in situ collection of four tree species with different growth rates in a subtropical forest. We also quantified soil properties, root morphological traits, and mycorrhizal infection rates to examine the driving factors underlying variations in root exudation. Our results showed that drought significantly decreased root exudation rates of total C, sugar, and amino acid by 17.8%, 30.8%, and 35.0%, respectively, but increased root exudation rate of organic acid by 38.6%. These changes were largely associated with drought-induced changes in tree growth rates, root morphological traits, and mycorrhizal infection rates. Specifically, trees with relatively high growth rates were more responsive to drought for root exudation rates compared to those with relatively low growth rates, which were closely related to root morphological traits and mycorrhizal infection rates. These findings highlight the importance of plant growth strategy in mediating drought-induced changes in root exudation rates. The trade-offs between root exudation rates, root morphological traits, and mycorrhizal symbioses in response to drought could be incorporated into land surface models to improve the prediction of climate change impacts on rhizosphere C dynamics in forest ecosystems. 
On the representation of small-scale soil biophysical features for large-scale applications
Authors: Bonetti Sara , Or Dani
Published: February 2023

In light of the complex interactions of multiple biotic and abiotic processes acting at different spatio-temporal scales and the high spatial variability in their biophysical features, our ability to describe catchment dynamics is still limited. Such a limitation stems, on one side, from the mismatch of scales between key small-scale processes and their current parameterization and the large scales of many modeling applications, and, on the other, from the challenge of considering the spatial configurations in an explicit manner. As a motivating example, we will discuss here the issue of representing the effect of biologically-induced soil structure in the parameterization of soil hydraulic properties (SHPs) for large scale applications. Currently available parameterizations based on soil pedotransfer functions (PTFs) do not account for the effects of soil structure, thus limiting their applicability in vegetated areas in which macropores are expected to significantly increase soil saturated hydraulic conductivity. Considering the strong links between vegetation and soil structure, we propose a systematic approach for incorporating structural effects on PTF-derived SHPs. We will show that, under certain soil and climatic conditions, small scale soil structure features prominently alter the hydrologic response emerging at larger scales and that upscaled parameterizations must explicitly consider the spatial variability of soil and vegetation attributes. Lastly, opportunities in the representation of multiple small‐scale ecohydrological processes for regional and global applications will be discussed. Progress on this front is key for establishing more complete causal links between landscape attributes and heterogeneities in physical properties, thus providing a mechanistic strategy for model parameterization and process description across scales and a path forward for more reliable large-scale modeling under future scenarios.
Study on the change of spawning habitat suitability of four major Chinese carps in the lower reaches of the dam
Authors: Yu Bowen , Zhang Peng , Chen Li , Chen Fan , Lv Zehao , Niu Jingyi
Published: February 2023

The Yichang-Chenglingji reach is important spawning ground for the Four Major Chinese Carps (FMCC) in the Yangtze River, which once accounted for 42.7% of the total spawning quantity in the Yangtze River basin. The impoundment of Three Gorges Reservoirs as well as other reservoirs in the upper reach have changed the flow and sediment regimes in the study reach. On the one hand, the flow regimes in the spawning ground during the spawning period is changed. On the other hand, the reduction of sediment concentration has greatly increased the water unsaturation, causing the morphological response of the spawning ground like riverbed erosion and scouring. These changes have potential impacts on the habitat suitability of the spawning ground for domestic fish. In this paper, based on the measured cross section topographic data of the studied reach and the spawning amount data of FMCC in typical years, the habitat simulation model including one-dimensional hydrodynamic model and habitat model based on fuzzy logic is created. The factors of water level fluctuation and flow velocity which profoundly influence the spawning activity of the FMCC are considered, the Weighted Usable Area (WUA), which can reflect the suitability of the habitat, is calculated, and the impact of flow discharge, water level fluctuation (reflected by variation of discharge ΔQ), and channel erosion on the WUA of FMCC during spawning period is compared. The results show that both the discharge and the variation of discharge significantly affect the suitability of the habitat. In general, the WUA basically increases first and then decreases with increasing discharge, and there is an optimal ΔQ value under different discharges, and the optimal ΔQ increases with the increase of discharge. During the years from 2003 to 2018, the Yichang-Chenglingji reach witnessed significant erosion, and the volume of bankful channel increased by 17.9%. According to the calculation results of the habitat model, the channel erosion did not change the general relationship between discharge,ΔQ and WUA curve, but it would affect the value of WUA, mainly manifested in the reduction of WUA, of which the maximum impact was about 6%, and the impact mainly occurred when the flow submerges the floodplain. In general, discharge, variation of discharge and channel erosion will all affect WUA, so in the future, on the one hand, it is necessary to pay attention to the impact of reservoir operation on spawning of domestic fish, and create flow and flow process suitable for spawning; on the other hand, it is also important to seek measures to alleviate the reduced habitat suitability caused by channel erosion.
Comparison of Deterministic and Probabilistic framework for Vs30 estimation in data scarce region: a case study for Southern Bihar, India.
Authors: Srivastava Mudit , Sharma Mukat Lal
Published: February 2023

Time-averaged shear-wave velocity in the topmost 30 meters of soil (Vs30) is a broadly accepted tool employed for site characterization. Adoption of Vs30 in the development of region-specific ground motion prediction equations and seismic design provisions marked it as a global parameter for local-site effect studies. Challenges arise in tectonically complex regions where an evaluation of Vs30 requires great exertion including mobility of equipment and manpower. Over the period, where researchers are still engaged in studying the effects and limitations of Vs30 at a location of interest, during the years various proxies have arrived for Vs30 estimation. Also, the selection of proxy depends upon the existing prior information about the region and its relationship with measured Vs30 values. Data scarce region requires interpolation techniques to address extensive geographical area with limited attainable datasets. Various deterministic (Inverse distance weighing, spline, etc.)  and probabilistic (kriging formats) interpolation techniques are widely used for robust estimation. In this study, an attempt has been made for a reliable region-specific selection of interpolation techniques. 35 Vs30 measurements are used as primary data and the topographic-slope proxy-based Vs30 model by U.S. Geological Survey is used as secondary data. Quantitative assessment acknowledges the existence, and validity which provides an understanding of the merits and flaws of interpolation techniques. The applicability of IDW, kriging and Bayesian scheme for sturdy estimation of Vs30 with focus on Southern Bihar region is examined for seismic response studies providing paramount importance to hazard and risk mitigation.Keywords: Vs30, Topographic-slope Proxy, IDW, Kriging, Bayesian Scheme.
Inelastic compaction and failure mode of Bleurswiller sandstone under true triaxial compression
Authors: Meng Fanbao , Shi Lu , Hall Stephen , Baud Patrick , Wong Teng-fong
Published: February 2023

Previous investigations of the compressive failure of porous rocks under true triaxial compression have focused on the brittle faulting regime. These studies have underscored the dependence of the peak stress state on the interplay of the three principal stresses. In comparison, there is a paucity of systematic investigations of ductile failure under true triaxial compression. In this study we selected Bleurswiller sandstone, which has been extensively investigated in relation to the brittle-ductile transition under conventional triaxial compression at room temperature. Experiments were conducted in Wuhan on water-saturated samples with the size of 100mm×50mm×50mm at the minimum and intermediate principal stresses ranging up to 70 MPa and 170 MPa, respectively. Previous conventional tests have shown that the initial yield points of Bleurswiller sandstone fall on a linear cap relating the differential and mean stresses. Our new data show that initial yielding under true triaxial loading at a fixed Lode angle is also characterized by a Mises effective shear stress that decreases linearly with increasing mean stress, in agreement with the prediction of an elastic-plastic pore collapse model. Subsequent yielding was manifested by various degrees of strain hardening, that would culminate in a spectrum of failure modes (high-angle shear bands, conjugate shear bands, compaction bands, distributed cataclastic flow). The 3D complexity and geometric attributes of these failure modes have been characterized by X-ray CT imaging of the failed samples.   