bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphodynamics of Lowland River Networks Modeled as Simple Binary Trees
Authors: Parker Gary , Zhang Li
Published: March 2022

River networks are ubiquitous in nature. The example of the Amazon River, South America, is shown below.

Typically, channel branches farther upstream tend to be steeper than branches farther downstream. Here we explain this tendency via a simple model of lowland sand-bed stream networks. Any given downstream branch bifurcates into two branches upstream, here each assumed to have discharges equal to half of the downstream branch. . Each branch satisfies (at bankfull flow) a relation each for flow resistance, sand transport and sediment mobility Shields number. We show that if the transport rate of sand increases downstream in proportion to the water discharge, the river slope must be the same everywhere, so that the long profile following any path shows no upward concavity. When the sand load increases downstream at a lower rate than the water discharge, on the other hand, upward concavity is manifested. The bifurcations are allowed to continue upstream until a specified drainage density is reached. The inverse of drainage density scales the distance from any channel to the nearest ridge; at an appropriately low value, it is assumed that sediment can be delivered to the nearest stream solely through overland processes. We use the above conditions to determine the extent of the spatial network, and also the spatial variation of network denudation rate.

 
Changes in AE similarity track fault kinematics during laboratory earthquakes
Authors: Marty Samson , A. Affinito Raphael , Wood Clay , Marone Chris , Shokouhi Parisa , Rivière Jacques
Published: March 2022

It is now recognized that acoustic emissions (AEs) generated during stick-slip frictional sliding (i.e., lab earthquakes) can be considered as microearthquakes. Over the past decades, many laboratory AE studies have addressed issues related to the physics of earthquakes such as fault nucleation and growth in brittle rocks, frequency magnitude statistics of earthquakes, laboratory earthquake precursors and, more recently, laboratory earthquake prediction based on machine learning techniques. Here, we conduct double direct shear experiments on samples of Westerly granite under applied normal loads of 5-15 MPa and with shearing rates of 1-100 μm/s. We use template matching and other cross correlation techniques to study the evolution of AE similarity during the laboratory seismic cycle. The aim of this study is to connect changes in AE similarity to fault stress-loading and kinematics. AE similarity is derived from the correlation matrices of AE catalogs and is found to vary primarily with fault slip velocity. AE similarity is, on average, constant at slow speed (fault slip velocity <= 10 mm/s) and drops as fault slip velocity increases. Our observations show that AE similarity follows a power law of fault slip velocity. Based on previous experimental and theoretical works, we suggest that AE similarity reflects the evolution of fault contact area. One interpretation of our results is that a simple metric such as AE similarity carries relevant information about fault kinematics and fault structural properties that may be used for forecasting and prediction of failure.
Evaluating Direct and Semi Direct Effect of Aerosol on Subseasonal Prediction Using a Coupled UFS Model with and without Prognostic Aerosols
Authors: Sun Shan , Grell Georg , Zhang Li , Henderson Judy , Yang Fanglin , Huang Anning
Published: March 2022

The interactions between aerosols, radiation and clouds are one of the key climate  uncertainties despite recent improvements in observational systems and model complexity. Here we investigate the impacts of aerosol direct and semi-direct effects on subseasonal predictions using NOAA’s coupled Unified Forecast System (UFS) – specifically, the coupled atmosphere (FV3), ocean (MOM6), and sea ice (CICE6) model combined with the GOCART aerosol component based on the GEFS-Aerosols model. We perform experiments with 32-day long integrations initialized in May and September from 2003 to 2019. Two more parallel sets of experiments are carried out as well, using either modeled climatological aerosol concentrations or zero aerosol concentration in lieu of GOCART. We found in the multi-year simulations, the estimated aerosol optical depth from the UFS-GOCART model is in good agreement with the satellite observations. The radiative forcing of the total aerosol direct effect shows negative, while the impact on precipitation is not obvious. In addition, the UFS using the modeled climatological aerosol concentrations is able to capture most of the radiative forcing seen in the UFS-GOCART experiments. This suggests a possible alternative of replacing the costly chemistry module with the modeled aerosol concentration climatology in the subseasonal applications. 
Sea Spray Generation Function in Major Tropical Cyclones
Authors: Soloviev Alexander , Vanderplow Breanna , Lukas Roger , Haus Brian , Sumi Muhammad , Ginis Isaac
Published: March 2022

Sea spray is a factor in thermodynamics, intensity, and intensification of tropical cyclones. However, the sea spray generation function under major tropical cyclone conditions is still virtually unknown and the scatter of data between different field experiments is significant. In this work we have conducted a computational fluid dynamics experiment using the approach that has been partially verified with data from the air-sea interaction facility SUSTAIN. In the computational model, the sea spray generation function has been studied using the Volume of Fluid (VOF) method. This method is enhanced with a Volume of Fluid to Discrete Phase transition model (VOF to DPM). Due to dynamic remeshing, VOF to DPM resolves spray particles ranging in size from tens of micrometers to a few millimeters (spume). The water particles that satisfy the condition of asphericity are converted into Lagrangian particles involved in a two-way interaction with the airflow. The size distribution of non-spherical spray particles is represented by the equivalent radii calculated from the particle mass. The sea spray generation function has been calculated for category 1, 3, and 5 tropical cyclones. A comparison with the data available from literature for a category 1 tropical cyclone shows that our sea spray generation function is close to those found by Zhao et al. (2006) and Troitskaya et al. (2018) for the radius range of spume. Our sea spray generation function results in the spray-induced stress exceeding the interfacial wind stress at approximately 60 m/s wind speed. Connection of spray-induced enthalpy flux to the sea spray generation function is more complicated due to the suspension and evaporation of small-size particles in the turbulent boundary layer (Richter’s and Peng 2019 effect of negative feedback).

 
Rill flow velocity affected by the subsurface water flow depth of purple soil in Southwest China
Authors: Tao Tingting , Chen Shiqi , Chen Xiaoyan
Published: March 2022

    Subsurface water flow above the weakly permeable soil layer commonly occurs on purple soil slopes. However, it remains difficult to quantify the effect of subsurface water flow on the surface flow velocity. Laboratory experiments were performed to measure the rill flow velocity on purple soil slopes containing a subsurface water flow layer with the electrolyte tracer method considering 3 subsurface water flow depths (SWFDs: 5, 10, and 15 cm), 3 flow rates (FRs: 2, 4, and 8 L min-1), and 4 slope gradients (SGs: 5°, 10°, 15°, and 20°). As a result, the pulse boundary model fit the electrolyte transport processes very well under the different SWFDs. The measured rill flow velocities were 0.202 to 0.610 m s-1 under the various SWFDs. Stepwise regression results presented the positive dependence of the flow velocity on FR and SG but a negative dependence on SWFD. SWFD had notable effects on the rill flow velocity. Decreasing the SWFD from 15 to 5 cm increased the flow velocity. Moreover, the flow velocities under the 10- and 15-cm SWFDs were 89% and 86%, respectively, of that under the 5-cm SWFD. The flow velocity under the 5-, 10- and 15-cm SWFDs was decreased to 89%, 80%, and 77%, respectively, of that on saturated soil slopes. The results will enhance the understanding of rill flow hydrological processes under SWFD impact.
Effects of changing precipitation pattern on stream water chemistry at a forested catchment in the Russian Far East 
Authors: Zhigacheva Ekaterina S. , Sase Hiroyuki , Ohizumi Tsuyoshi , Nakata Makoto , Gromov Sergey A.
Published: March 2022

Acidification of the environment is still an important problem in the Russian Far East. Since the number of studies related to acidification is limited, the monitoring at the Primorskaya, one of the EANET sites, is of interest. The Primorskaya site has a set of continuous monitoring data on air, precipitation, and stream water (SW). The site is located within the watershed of the Komarovka River.

While emissions of major acidifying agents have started decreasing in the Russia Far East and neighboring countries (e.g., China, Korean Peninsula, and Japan), the SW pH has been decreasing continuously alongside increases in concentrations of sulfate and nitrate for the observation period at the Komarovka River. Deposition trends also do not follow the major emission tendencies completely. To understand the mechanism of SW acidification, we tried to estimate the influences of meteorological variability and atmospheric-deposition seasonality on the SW discharge of the Komarovka River. The monitoring data for the period 2005 - 2020 is presented in the study.

Two major climatic seasons can be distinguished at the Komarovka river catchment: the cold season (from October to March) with low precipitation, and the warm season (from April to September) when the major amount of precipitation falls. Although concentrations of major acidifying agents, such as sulfate and nitrate, in precipitation are usually higher in the cold season, the deposition fluxes are higher in the warm season due to the difference in precipitation amounts. While the annual precipitation amount did not show a clear trend, the contribution of precipitation during the warm season was tended to be increased since the early 2010s. Accordingly, the deposition fluxes of sulfate and nitrate were tended to be increasing in the warm season. Similarly, the recent SW fluxes of sulfate and nitrate have become higher in the warm season. It is suggested that the change in precipitation pattern influenced atmospheric deposition and SW fluxes, resulting in SW acidification (Zhigacheva et al. submitted).

Besides the fluxes, SW concentrations in each sampling month showed specific trends, although the SW samples were taken only five times per year according to the hydrological regime: low water in February and November, snow melting period in April, summer low water in June, and high flow in September. Moving weighted mean concentrations of nitrate show an increasing trend at every hydrological phase except for September. Sulfate and calcium concentrations are more stable. We will discuss the effects of hydrological and biological processes on the seasonality and trends of SW chemistry.
On the value of thermal infrared remote sensing for water and land management
Authors: Anderson Martha , Yang Yun , Xue Jie , Knipper Kyle , Yang Yang , Gao Feng , Hain Christopher , Holmes Thomas , Kustas William , Fischer Milan , Trnk Mirek
Published: March 2022

Thermal infrared (TIR) and visible/near-infrared (VNIR) surface reflectance imagery from remote sensing can be effectively combined in surface energy balance models to map evapotranspiration (ET) and vegetation stress, with broad applications in agriculture, forestry, and water resource management. Particularly valuable are ET retrievals at medium resolution (100 m or finer), resolving scales at which water and land are actively managed over much of the Earth’s surface. At this scale, TIR and VNIR data in the Landsat archive provide a 40-year and growing global record of coupled land and water use change.  In this presentation we will discuss the unique information content conveyed by the land-surface temperature signal regarding the surface moisture status and vegetation health. We will explore applications for field-scale temperature and ET retrievals in promoting sustainable water use, forest health, and regenerative agricultural practices. Widespread and routine generation of ET data at this scale has been enabled by cloud computing technologies, with the OpenET ensemble modeling platform as an example of collaborative geospatial information development.  Looking forward, integration of Landsat with new sources of medium-resolution TIR imagery (e.g., ECOSTRESS, LSTM, TRISHNA, SBG, Landsat-Next, and Hydrosat), as well as all-sky microwave-based temperature retrievals, will improve our ability to detect rapid changes in water use and availability – a key factor in real-time decision making.
Representative models and energy and material efficiency strategies for residential buildings in urban India
Authors: Iyer Aishwarya , Aly Etman Mohamed , Hertwich Edgar , Rao Narasimha
Published: March 2022

40% of global energy demand can be attributed to buildings, and 75% of this share is contributed by residential buildings. Developing countries are expected to be the hotspot for future growth in residential energy demand, as many of them expect significant growth in population and urbanization. For instance, 75% of the residential floorspace expected to exist in India in 2030 remained to be constructed in 2015. Thus, a lot of the new energy demand from residential buildings can still be controlled and mitigated. As the country expected to have the largest population in the world by 2025, India has a responsibility to grow sustainably, in a way that aids global climate change mitigation goals. Studying the residential building sector in India thus is a necessary step towards achieving these goals.

Indian residential buildings are diverse, and include informal slums,  low-quality formal buildings, mid-rise formal buildings, and high-rise skyscrapers. Global models for energy efficiency in the residential sector usually consider only one type of building from developing countries, the formal (cement-concrete) type. They create a generalized model, based on the assumption that appliances and thermal comfort standards are the same in most countries. These generalizations do not consider the diverse types of buildings, appliances and thermal comfort standards in India, or any developing country.

This project presents a life-cycle assessment representing all residential building types in India - formal, semi-formal and informal. The semi-formal typology is hitherto missing from building energy modeling literature.  We include and model embodied phase and use-phases separately. The embodied phase study helps understand the energy demand and material demand from the building materials and construction. In the use-phase study, we create detailed models of all residential building typologies, and simulate cooling energy demand results for the city of Mumbai. We study building clusters, to account for the heat transfer and shading effects from the crowded urban environment in India. We also model realistic cooling appliances commonly used in Indian households, like fans and water-based coolers, in addition to air conditioners, and more representative cooling behaviour.

For the first time in this Indian residential life-cycle assessment study, we define three representative typologies for Indian residential buildings. We study clusters and model real appliances used in these homes. We explore some simple material efficiency and energy efficiency strategies through different envelopes, appliances and usage. The goal of this study is to create a preliminary model of what buildings in India are like, and understand how their life-cycle energy demands differ, and some simple options to reduce this demand.
Interstellar Probe: A Mission to the Heliospheric Boundary and Interstellar Medium to Understand our Home in the Galaxy
Authors: Brandt Pontus ,   The Interstellar Probe Study Team
Published: March 2022

For the past 60, 000 years our Sun and its protective heliosphere have been plowing through the Local Interstellar Cloud (LIC), but is now in a historic transition region towards the G-cloud that could have dramatic consequences for the global heliospheric structure. An Interstellar Probe mission to the Very Local Interstellar Medium (VLISM) would bring new scientific discoveries of the mechanisms upholding our vast heliosphere and directly sample the Local Interstellar Clouds to allow us, not only to understand the current dynamics and shielding, but also how the heliosphere responded in the past and how it will respond in the new interstellar environment. An international team of scientists and experts have now completed a NASA-funded study led by The Johns Hopkins University Applied Physics Laboratory (APL) to develop pragmatic example mission concepts for an Interstellar Probe with a nominal design lifetime of 50 years. The team has analyzed dozens of launch configurations and demonstrated that asymptotic speeds in excess of 7.5 Astronomical Units (AU) per year can be achieved using existing or near-term propulsion stages with a powered or passive Jupiter Gravity Assist (JGA). These speeds are more than twice that of the fastest escaping man-made spacecraft to date, which is Voyager 1 currently at 3.59 AU/year. An Interstellar Probe would therefore reach the Termination Shock (TS) in less than 12 years and cross the Heliopause into the VLISM after about 16 years from launch.

In this presentation we provide an overview of the study, the science mission concept, discuss the compelling discoveries that await, and the associated example science payload, measurements and operations ensuring a historic data return that would push the boundaries of space exploration by going where no one has gone before.
Constraining middle and upper atmospheric variables by assimilating measurements from infrasound propagation
Authors: Amezcua Javier , Näsholm Sven Peter , Vera-Rodriguez Ismael
Published: March 2022

When an infrasound wave travels through the atmosphere, it is affected by the atmospheric variables it encounters (e.g. temperature and winds) in its path. When the wave is detected, the integrated effect of these variables along the trajectory of the wave affects measured quantities such as apparent velocity, backazimuth angle and travel time.  

Data assimilation combines background atmospheric information with observations to get a better estimate (analysis) of atmospheric variables. In this work, we use the ensemble Kalman filter --with the 10-member ERA-5 reanalysis as background-- to assimilate integrated infrasound observations from the Hukkakero explosions detected by the ARCES array. This process helps get better estimates of atmospheric variables, specially in the stratosphere and lower mesosphere. For each explosion, this process has three steps: (i) the mapping of each of the 10 atmospheric profiles into observation space using the Infra-GA wave propagation model, (ii) the application of the filer equations in observation space, and (c) the mapping back to the space of model variables. The results of these experiments are compared to the Copernicus Artic Regional Reanalysis Service.

 

 

 
The early-phase growth of ULF waves in the ion foreshock observed in a hybrid-Vlasov simulation
Authors: Zhang Kun , Dorfman Seth , Turc Lucile , Ganse Urs , Shi Chen , Palmroth Minna
Published: March 2022

Large-amplitude ULF waves are usually observed in the foreshock region ahead of quasi-parallel shocks and their generation is driven by the backstreaming ions. In the early phase of the wave growth, the waves are growing with time and traveling in space simultaneously. Therefore, it is very difficult to observe the wave growth properly using single-point measurements such as single spacecraft observations, because the spatial and temporal variations cannot be decoupled. This has also brought difficulties into understanding the detailed physical connection between the foreshock ion properties and the wave properties. In comparison, it is more straightforward to study this problem in global simulations, as simulation results are available everywhere in the foreshock at all times. Here we perform detailed analysis of the ULF wave growth and its relationship with the ion distribution using a Vlasiator simulation (a hybrid-Vlasov code). We calculate the phase speed of the ULF waves and observe the wave growth in the wave frame continuously. We show that the growth rate of the ULF waves decreases with time due to the decrease in beam velocity and the scatter of the ion distribution. And we compare the calculated growth rate with the dispersion relation solved by LEOPARD (a dispersion solver with arbitrary ion distribution input) based on the corresponding ion distribution obtained from the simulation results, and we will discuss the related physical mechanisms such as the ion-ion beam instability when the wave growth can be explained by ion distribution and discuss possible reasons when there is any discrepancy.
Global distribution and climatological temperature sensitivity of soil organic matter fractions differ between observations and models 
Authors: Georgiou Katerina , Wieder William R. , Abramoff Rose Z. , Koven Charles D. , Riley William J. , Ahlström Anders , Bouskill Nicholas J. , Hartman Melannie , Pellegrini Adam , Pierson Derek , Sulman Benjamin , Slessarev Eric , Zhu Qing , Pett-Ridge Jennifer , Jackson Robert B.
Published: March 2022

Soils contain the largest actively-cycling terrestrial carbon pool, which is itself composed of chemically heterogeneous and measurable pools that vary in their persistence. Fundamental uncertainties in terrestrial carbon-climate feedbacks still depend on the timing, sign, and magnitude of the response of soil carbon, and its underlying pools, to environmental change. However, model comparisons typically focus on benchmarking only bulk soil carbon stocks and climatological temperature sensitivities. Underlying microbial and mineral-associated pools, and their response to global change, have received increasing attention among empirical studies, yet data limitations still hinder benchmarking of these pools and processes in models at ecosystem- to global-scales. Here we examined the distribution of carbon within particulate and mineral-associated fractions across an ensemble of global soil biogeochemical models, and compared model estimates to a global database of soil fractions. We found that, while bulk soil carbon stocks were seemingly comparable in magnitude and geographic distribution across the models and observations, the spread in underlying pools was much more pronounced. Indeed, the ensemble of models varied nearly 6-fold in the proportion of carbon in mineral-associated fractions, and the majority of models greatly underestimated mineral-associated carbon stocks compared to the observations. Latitudinal differences between the models resulted in divergent pool-specific climatological temperature sensitivities, with implications on projections to global change scenarios. Our study elucidates key structural and theoretical differences between models that drive divergent soil carbon projections, and clearly highlights the need to benchmark underlying carbon pools, in addition to bulk soil carbon stocks.
The influence of slurry viscosity on the resistance characteristics of debris flow
Authors: Wang Xi'an , Chen Jiangang , Fei Gaogao , Wang Jinshui
Published: March 2022

The slurry viscosity has significant influence on the movement of debris flow by affecting the resistance characteristics of the debris flow. Slurry viscosity affects several dimensionless parameters that characterize the debris flow regime, such as Bagnold number, Darcy number, and Reynolds number. Slurry viscosity also affects dimensionless parameters that characterize the scale of the debris flow. Manning’s roughness coefficient is an important parameter to characterize the resistance of debris flow. However, the values ​​of these dimensionless parameters related to slurry viscosity in natural gullies and its influence on roughness coefficients are still unclear. Through the analysis of the observation data of Jiangjia Ravine debris flow in Dongchuan, Yunnan Province, China, this study studied the value range of dimensionless numbers related to slurry viscosity and the relationship between debris flow roughness coefficient and slurry viscosity. The results showed that the roughness coefficient of debris flow gradually increased with an increase in the slurry viscosity. Slurry viscosity enhanced resistance in the macroscopic sense. The calculation formula of roughness coefficient considering slurry viscosity improved the precision in calculating the roughness coefficient of debris flow with high slurry viscosity. The research results can provide a reference for choosing slurry viscosity in the small model tests, and provide new method for the calculation of debris flow roughness coefficient in engineering practice.
Tracking slow-moving landslides over large regions using open-access standardized InSAR products produced by the Advanced Rapid Imaging and Analysis (ARIA) Center for Natural Hazards project
Authors: Handwerger Alexander , Fielding Eric , Sangha Simran , Bekaert David
Published: March 2022

Slow-moving landslides are hydrologically driven and respond to changes in precipitation over daily to decadal timescales. Open-access satellite InSAR data products, which are becoming increasingly common, can be used to investigate landslides (and other ground surface deformation) over large regions. Here we use standardized open-access satellite radar interferometry data processed by the Advanced Rapid Imaging and Analysis (ARIA) team at NASA’s Jet Propulsion Laboratory to identify 247 active landslides in California, USA. These landslides occur in both wet and dry climates and span more than ~2 m/yr in mean annual rainfall. We quantify the sensitivity of 38 landslides to changes in rainfall, including a drought and extreme rainfall that occurred in California between 2015 and 2020. Despite the large differences in climate, we found these landslides exhibited surprisingly similar behaviors and hydrologic sensitivity, which was characterized by faster (slower) than normal velocities during wetter (drier) than normal years. Our study documents the first application of open-access standardized InSAR products from ARIA to identify and monitor landslides across large regions. Due to the large volume of open-access InSAR data that is currently available, and will continue to increase with time, especially with the upcoming launch of the NASA-ISRO SAR (NISAR) satellite, standardized InSAR products will become one of the primary ways to deliver InSAR data to the broader scientific community. Thus, it is important to continue to explore new approaches to analyze these InSAR products for scientific research.
Chronostratigraphy of Larsen blue ice, East Antarctica, and a tentative reconstruction of surface temperature and accumulation rate during the last deglaciation
Authors: Lee Giyoon , Ahn Jinho , Ju Hyeontae , Ritterbusch Florian , Oyabu Ikumi , Buizert Christo , Kim Songyi , Moon Jangil , Ghosh Sambit , Kawamura Kenji , Lu Zheng-Tian , Hong Sangbum , Han Chang Hee , Hur Soon Do , Jiang Wei , Yang Guo-Min
Published: March 2022

Ice coring in blue ice areas (BIAs) serves as an alternative to deep ice core drilling, allowing collection of large-sized old ice samples in a cost-effective way because old ice samples are outcropped to the surface. However, the stratigraphy in many blue ice areas can be complicated due to complex ice flows. Based on ice layers defined by dust bands and ground penetration radar (GPR) surveys, we show that Larsen BIA has a surface transect of ice with an undisturbed horizontal stratigraphy from mid- to downstream side ice. However, the upstream ice exhibits a potential repetition of ages on scales of tens of meters. Correlating δ18Oice, δ18Oatm, and CH­4 records of Larsen ice with existing ice core records indicates that the analyzed gas age and ice age ranges between 9.2–23.4 ka BP and 5.6–24.7 ka BP, respectively. Radiometric 81Kr dating of one of the cores confirms the estimated gas ages within uncertainty. A tentative reconstruction based on a simple analytical framework suggests a warming of 15 ± 5 ℃ during the last deglaciation that we attribute to the retreat of the Ross Ice Shelf, and an increase in snow accumulation by a factor of 1.7–4.6 that we attribute to the increased penetration of snow-bearing storms. Exact estimation of the original deposition site and updated ice ages may enhance the tentative climate reconstructions in future studies. Our study shows that BIAs in Northern Victoria Land may contribute to obtain high-quality paleoclimate proxy records through the last deglaciation.
Using tracheidogram analysis in xylogenesis kinetics: abilities and prospects.
Authors: Zharkov Mikhail , Belokopytova Liliana , Babushkina Elena , Vaganov Eugene , Shishov Vladimir
Published: March 2022

In the work, a simple hypothesis was tested: whether treats of anatomical tree-ring structure of conifer (i.e. tracheidograms of rings) can be used for reconstruction of seasonal growth kinetics. Using the example of two sharply different growing seasons during which the seasonal growth of annual rings was measured with periodic sampling and dividing the forming annual ring into zones (cambium, enlargement zone, cell wall thickening zone and zone of matured tracheids) and the final tracheidograms, a simple scheme of recalculating the variability of radial cell size into cumulative and differential cell production curves was proposed. Statistical analysis of both correspondences and discrepancies between simulated and observed data shows the prospects of the proposed approach which can be testified for longer seasonal observations.
Detecting China's urban built-up areas expansion over the last decade based on the deep learning through NPP-VIIRS images
Authors: Bai Maoyang
Published: March 2022

Abstract： Accurate spatial extent changes in urban built-up areas are essential for detecting urbanization, analyzing the drivers of urban development and the impact of urbanization on the environment. In recent years, nighttime light images have been widely used for urban built-up areas extraction, but traditional extraction methods need to be improved in terms of accuracy and automation. In this experiment, a U-Net model was built and trained with the NPP-VIIRS and MOD13A1 data in 2020. We used the optimal tuning model to inverse the spatial extent of built-up areas in China from 2012 to 2021. Through this model, we analyzed the changing trend of built-up areas in China from 2012 to 2021. The results showed that U-Net outperformed random forest (RF) and support vector machine (SVM), with an overall model accuracy (OA) of 0.9969 and mIOU of 0.7342. Built-up areas growth rate is higher in the south and northwest, but the largest growth areas are still concentrated in the east and southeast, which is consistent with China's economic development and urbanization process. This experiment produced a method to extract China's urban built-up areas effectively and rapidly, which provides some reference value for China's urbanization.
Feedback attribution to dry heatwaves over East Asia
Authors: Seo Ye-Won , Ha Kyung-Ja , Park Tae-Won
Published: March 2022

Summer heatwave events have exhibited increasing trends, with sudden increases occurring since the early 2000s over northeastern China and along the northern boundary of Mongolia. However, the mechanism behind heatwaves remains unexplored. To quantitatively examine the feedback attribution of concurrent events related to surface temperature anomalies, the coupled atmosphere–surface climate feedback-response analysis method based on the total energy balance within the atmosphere–surface column was applied. The results demonstrate that the contributions of the latent heat flux and surface dynamic processes served as positive feedback for surface warming by reducing the heat release from the surface to the atmosphere because of deficient soil moisture based on dry conditions. Cloud feedback also led to warm temperature anomalies through increasing solar insolation caused by decreasing cloud amounts associated with anomalous high-pressure systems. In contrast, the sensible heat flux played a role in reducing the warm temperature anomalies by the emission of heat from the surface. Atmospheric dynamic feedback led to cold anomalies. The influence of ozone, surface albedo, and water vapor processes is very weak. This study provides a better understanding of combined extreme climate events in the context of radiative and dynamic feedback processes.
Generating conversations on geoethical education through arts-integrated research
Authors: Johnstone Sandra
Published: March 2022

The applications of geoscience knowledge to complex interdisciplinary socioenvironmental challenges, including climate change and sustainability, are broadly acknowledged. The ways we educate geoscience professionals to make ethical decisions in how geological knowledge is applied to these existential challenges can have profound impacts on the Earth system. Proponents of improving ethical applications of geoscience knowledge and ethical decision-making for geoscientists have identified post-secondary educational settings as essential sites of exposure to geoethical thinking. However, discussions of geoethical pedagogy may not address the ways geoscience knowledge production continues to further exacerbate these problems. Post-secondary geoscience educators, with little ethical or interdisciplinary training themselves, may be ill-equipped to navigate the potentially uncomfortable norm-challenging classroom conversations that can arise.

This research applies arts-integrated methodologies to analyze events from my professional roles a geologist and reflections from my current position as a post-secondary geoscience educator, working in a Canadian context. Results of this work offered counter-perspectives to some of the normalized narratives about professional roles of geoscientists, especially: 1) Geoscientists as environmental stewards, 2) Geoscientists as providers of raw materials essential to society, and 3) Geoscientists on a journey of scientific discovery. Questioning these stories proved to be uncomfortable, opening conversations in which both students and educators may feel implicated in ongoing harms. Proposals to improve geoethical education for post-secondary geoscience students may need to better account for the challenging experiences that arise for both students and teachers as difficult knowledge is engaged in the classroom.

Here, visual art is used as a tool to bring together perspectives across dissonant knowledge paradigms, and in the process to open up new questions about geoethical education. Though arts-integration is common in educational research, this methodology remains extremely rare for research focused on post-secondary technoscientific training. I contend that this novel application offers the opportunity to open up different conversations about both ethical applications of geoscience knowledge and the challenges of geoethical training.
Dependence of GIA-induced gravity change in Antarctica on viscoelastic Earth structure
Authors: Irie Yoshiya , Okuno Jun'ichi , Ishiwa Takeshige , Doi Koichiro , Fukuda Yoichi
Published: March 2022

The Antarctic ice mass loss is accelerating due to recent global warming. Changes in Antarctic ice mass have been observed as the gravity change by GRACE (Gravity Recovery and Climate Experiment) satellites. However, the gravity signal includes both the component of the ice mass change and the component of the solid Earth response to surface mass change (Glacial Isostatic Adjustment, GIA). Evaluating the GIA-induced gravity change requires viscoelastic Earth structure and ice history from the last deglaciation.

Antarctica is characterized by lateral heterogeneity of seismic velocity structure. West Antarctica shows relatively low seismic velocities, suggesting low viscosity regions in the upper mantle. On the other hand, East Antarctica shows relatively high seismic velocities, suggesting thick lithosphere. Here we examine the sensitivities of GIA-induced gravity change in Antarctica to upper mantle viscosity and lithosphere thickness using spherically symmetric Earth models.

Results indicate that the gravity field change depends on both the upper mantle viscosity profile and the lithosphere thickness. In particular, the long-wavelength gravity field changes become dominant in the adoption of viscoelastic models with a low viscosity layer beneath the elastic lithosphere. The same trend is also shown in the adoption of viscoelastic models with a thick lithosphere, and there is a trade-off between the structure of the low viscosity layer and the thickness of the lithosphere. This trade-off may reduce the effect of the lateral variations in Earth structure beneath Antarctica on the estimate of Antarctic ice sheet mass change.
Soil Conservation Service Underpins Sustainable Development Goals
Authors: Yin Caichun , Zhao Wenwu , Pereira Paulo
Published: March 2022

Soil conservation service (SCS), one of the vital ecosystem services, represents the ecosystem’s capacity to conserve soil and control erosion. Achieving the Sustainable Development Goals (SDGs) requires multidisciplinary efforts in which SCS plays a key role. However, the coupling analysis of SCS and the SDGs is lacking. We analysed SCS’s contribution to the SDGs by a case study in China and a global expert questionnaire and explored systematic strategies to improve SCS implementation. The results showed that i) SCS ensures the SDG achievement by mitigating soil erosion; ii) SCS showed a significant and positive relationship (coef. = 0.41, p < 0.01) with SDG 15 (Life on land) in China. Moreover, SCS supports multiple SDGs by regulating ecological processes, producing food and products, and providing social and cultural values. More than 50% of respondents recognised that SCS benefits SDG 15, SDG 13 (Climate Action), and SDG 6 (Clean water and sanitation). Finally, to be goal-oriented, we presented an SDG-holistic guiding framework to promote SCS for the SDG achievement, thus harnessing the SCS’s roles in social, economic, and eco-environmental sustainability. Altogether, our work highlights the associations between the SDGs and SCS, which is key to recognising the contribution of soils and ESs to sustainable development.
Future changes in monsoon duration and precipitation using CMIP6 
Authors: Moon Suyeon , Ha Kyung-Ja
Published: March 2022

Future change in summertime rainfall under a warmer climate will impact the lives of more than two-thirds of the world’s population. However, the future changes in the duration of the rainy season affected by regional characteristics are not yet entirely understood. We try to understand changes in the length of the rainy season as well as the amounts of the future summertime precipitation, and the related processes over regional monsoon domains using phase six of the Coupled Model Intercomparison Project archive. Projections reveal extensions of the rainy season over the most of monsoon domains, except over the American monsoon. Enhancing the precipitation in the future climate has various increasing rates depending on the subregional monsoon, and it is mainly affected by changes in thermodynamic factors. This study promotes awareness for the risk of unforeseen future situations by showing regional changes in precipitation according to future scenarios.

 
Effects of viscosity on internal wave focusing by an oscillating torus. 
Authors: Shmakova Natalia , Voisin Bruno , Sommeria Joel , Flor Jan-Bert
Published: March 2022

An experimental study of the focused internal waves generated by a horizontally oscillating torus in a linearly stratified fluid is presented for a large range of Stokes numbers from 100 to 6000. For low Stokes number the waves are unimodal, i.e. in each propagation direction they diffuse to form a single wave beam, after their emission at the critical locations where the wave rays are tangential to the torus boundary. In that regime, the waves amplify in amplitude in a single focal zone. With increasing Stokes number the waves become bimodal, forming dual wave beams in each propagation direction and focusing in four zones of amplitude amplification.

Comparison of the experimental results at small oscillation amplitude with an original linear theory gives excellent agreement over the entire Stokes number range. As the oscillation amplitude increases the wave amplitude saturates in the focal zone. This saturation only appears at large oscillation amplitude for low Stokes number and is present already at moderate oscillation amplitude for high Stokes number.

Fourier analysis reveals triadic interactions of the fundamental wave with two subharmonic waves owing to focusing. This triadic resonance is visible only at large oscillation amplitude when viscous effects are high, i.e. for low Stokes number, but with increasing Stokes number it manifests itself at smaller oscillation amplitude. For high Stokes numbers, above 1800, and large oscillation amplitudes, greater than or equal to the minor radius of the torus, wave turbulence is observed.

The Stokes drift, calculated theoretically, appears as the key to understand the generation of vertical mean flow in the focal zone. At low and moderate Stokes numbers the mean flow is almost exactly opposed by the Stokes drift, while for higher Stokes numbers perturbations of this flow start to appear with time, possibly due to the generation of subharmonics.
Desertification assessment using ecosystem resistance and resilience in drylands
Authors: sasaki Ryo , Fujimaki Haruyuki , Yanagawa Aki
Published: March 2022

Desertification has been estimated by various perspectives such as meteorology and geography. Desertification indicates the changing of the vegetation and the ecosystem function. However, the evaluation of the desertified area in terms of ecosystem function is not fully understood. Therefore, we calculated the time series fluctuation of desertification using the ecosystem function index (resistance and resilience). We used MODIS satellite-based Normalized Difference Vegetation Index (NDVI) and short-term Standardized Precipitation Evapotranspiration Index (SPEI) data. Resistance and resilience calculated from NDVI. We estimate desertification by resistance and resilience during drought period. The results show trends of fluctuation of resistance and resilience, which indicates a condition of desert areas.
Interfacial Tension of CO2-Water Under Conditions for High-Temperature Geothermal Systems: Prediction and Investigation by Molecular Dynamics Simulation
Authors: Shiga Masashige , Morishita Tetsuya , Sorai Masao
Published: March 2022

For several decades, research on CCUS (carbon capture, storage, and utilization) have been extensively carried out to achieve substantial reduction of the amount of CO2 emitted into the atmosphere and effective resource development. In recent years, high temperature reservoirs have recently been considered as a target for CO2 injection. This aims at development of unconventional geothermal resources and CO2 mineralization.

Since the value of CO2-water interfacial tension is a fundamental property of fluid behavior in CO2-water-rock systems, many studies have been reported on CO2-water interfacial tension. However, the temperature of the geothermal reservoir in the above-mentioned technology may be up to 300 ℃, which is much higher than typical conditions for CCUS. It is not easy to perform measurements under such high temperature conditions, and no experimental data have been reported in existing studies.

Therefore, in this study, we performed molecular dynamics simulations to estimate the interfacial tension up to 300 ℃, and also studied the detailed properties such as density and dynamics.
Climatic and anthropogenic drivers of river intermittence in Poland
Authors: Rutkowska Agnieszka , Osuch Marzena , Żelazny Mirosław , Banasik Kazimierz , Klimek Mariusz
Published: March 2022

Studies on river intermittence are pivotal in water management because water scarcity impacts, apart from the catchment itself, also neighbouring catchments and water reservoirs.

River intermittence was noticed recently in Poland in small and mid-sized catchments. The objective of the study was to answer questions about whether drying showed an increasing tendency, what might be the drivers of the tendency, and how could anthropogenic activity affect the catchment reaction to drought conditions. The total number of zero-flow days and the maximum length of zero-flow events were analysed at the annual and seasonal scale in terms of metrics of intermittence, temporal trend, association with climatic conditions, and the link with anthropogenic pressure. The Standardised Precipitation Evapotranspiration Index (SPEI) was used in identifying the association between intermittence and the climatic drivers such as precipitation and temperature. Statistical methods, namely the circular statistics, the Spearman correlation coefficient, the Mann-Kendall test for monotonic trend, and the Cucconi and the Lepage tests for step trend were applied in the study.

An increasing trend in the total number of zero-flow days and the maximum length of zero-flow events, as well as the negative correlation with the SPEI was detected in two catchments with natural flow regime. The increasing evapotranspiration was identified there as the possible driver of intermittence because the SPEI often showed a decreasing trend in summer months. In the catchment under strong anthropogenic pressure, the zero-flow occurrence resulted from climatological reasons as well as from the operation of the open-cast brown coal mines. The anthropogenic activity enhanced the reaction of the catchment to drought conditions. Some inhomogeneities in discharges were also detected downstream from the location of the dry river bed because of water transfers from the mine. The catchment response to drought conditions was reflected in the pattern of intermittence for natural catchments and for the catchment under strong anthropogenic pressure.

The pattern of intermittence in the form of circular diagram can serve as an indicator of the degree of anthropogenic influence on runoff conditions.