bluuebunny/crossref_metadata_2025 huggingface dataset:
Key trends and opportunities in water footprints of crop production
Authors: Mialyk Oleksandr , Booij Martijn J. , Hogeboom Rick J. , Berger Markus
Published: February 2023

Crops consume the majority of green and blue water worldwide which, in many areas, affects water availability and state of ecosystems. Hence, it is important to understand the recent dynamics in crop water footprints (WF, m3 t-1). Here, we analyse the global WF of more than 150 crops during 1990–2019 simulated with a global gridded crop model ACEA at 5 x 5 arc minute resolution. Our results indicate the overall decreasing trends in unit WF across all crop groups. However, these reductions are insufficient to curb the increase in total water consumption, which is mostly driven by the growing demand for oil crops. The WF dynamics vary among regions due to a combination of multiple environmental and socio-economic factors. Thus, it is possible to identify key challenges and opportunities in WFs of crop production. Addressing them may benefit water and food security while making the global food system more sustainable.
Horizontal and vertical slab tearing as different stages of a self-sustaining process developing in a non-collisional setting with oblique subduction
Authors: Koptev Alexander , Andrić-Tomašević Nevena , Maiti Giridas , Gerya Taras , Ehlers Todd
Published: February 2023

Slab break-off is usually referred to as an early collisional process driven primarily by the slowing of the subduction rate as negatively buoyant oceanic lithosphere detaches from positively buoyant continental lithosphere that is attempting to subduct. In this context, slab tearing (or slab break-off propagation) is traditionally attributed to continental corner dynamics, when the subducting plate first detaches in the area of continental collision and then the slab window opens toward the adjacent segment of the convergence boundary, where ocean-continent subduction continues. Another important process, previously thought to be independent of slab break-off and horizontal slab tearing, is a fragmentation of the subducting slab along vertical planes perpendicular to the convergence direction. Previous numerical studies have linked this vertical slab tearing to pre-existing weakness within the subducting plate and/or abruptly changing convergence rates along the trench.In our study, we use a 3D thermo-mechanical numerical approach to study slab tearing in a non-collisional geodynamic context. The effects of subduction obliquity angle, age of oceanic slab, and partitioning of boundary velocities have been investigated. We show, for the first time, that horizontal and vertical slab tearing are different stages of the same process, which can develop in a self-sustained manner in a non-collisional environment of oblique ocean-continent subduction. Even with an initially absolutely homogeneous oceanic plate and laterally unchanging and temporally constant boundary velocities, the obliquity of the active margin appears to be a sufficient factor to trigger complex system evolution, which includes the transition from horizontal to vertical slab tearing along with additional processes such as retreat and rotation of the trench, decoupling of the overriding and downgoing plates by upwelling asthenosphere in the mantle wedge (also termed “delamination”), initiation of new subduction, and formation of a transform fault.Our results show striking similarities with several features – such as trench curvature, subduction zone segmentation, magmatic production, lithospheric stress/deformation fields, and associated topographic changes – observed in many subduction zones (e.g., Marianas, New Hebrides, Mexico, Calabrian).
Eyes in the sky to the rescue - Monitoring the impact of armed conflict on cultivated land using satellite imagery in Tigray, Ethiopia.
Authors: Weldegebriel Liya , Lobell David , Negash Emnet , Nyssen Jan
Published: February 2023

On November 4th, 2020 a deadly civil war broke out in Tigray, Ethiopia displacing close to 2 million people internally and more than 48,000 refugees in neighboring Sudan by August 2021[1]. Given agriculture is the livelihood of millions of people in Tigray, evaluation of the conflict’s impact on cultivated land and the consequent crop production is critical for government and non-government disaster relief institutions. Unfortunately, such evaluation is extremely challenging as the conflict is characterized by communication blackout leaving the region without access to cellphone or internet.In this study, we used Sentinel-2 and Planet satellite imagery data to map loss of well cultivated land in 2021 due to the war. We developed multiple cultivation detection criteria based on the peak and falling limb characteristics of Normalized Difference Vegetation Index (NDVI) time series, validated using limited field observations of fallow and cultivated plots from the wet season in 2021 and 2022. We employed object detection machine learning model to identify harvest piles as an additional parameter to detect farming activity.Our predicted change in cultivation map from 2019/20 to 2021 showed that the density of conflict incidents was positively correlated to the mean net loss of well cultivated land with R2 of 0.7 in Tigray highlands (elevation > 1200 m). Sub-regions with high estimated net loss of cultivated land due to abandonment of reported internally displaced people also resulted in high predicted loss of well cultivated land using NDVI based criteria in our study. In the absence of extensive in situ data, we demonstrate how satellite imagery along with good understanding of local farming practices can provide timely and useful information to assist humanitarian management efforts in times of crisis and recovery phase.[1] Annys, Sofie, Tim Vanden Bempt, Emnet Negash, Lars De Sloover, Robin Ghekiere, Kiara Haegeman, Daan Temmerman, and Jan Nyssen. Tigray: Atlas of the Humanitarian Situation (version 2.2). Zenodo, 2021. https://doi.org/10.5281/zenodo.5805687.
Modelling the impacts of policy, climate and socioeconomic change on water security in China
Authors: Gao Danyang , Chen Albert S. , Memon Fayyaz Ali
Published: February 2023

The management of water resource in China has been under pressures due to rapid socioeconomic growth that escalates the demands in food, energy and domestic sectors, which rely on reliable water provision. Together with climate change, water security is expected to face greater uncertainty in the future. To support sustainable water resource management, this study established a system dynamic model to investigate the impacts of policy, socioeconomic and climate change on water security in China during 2025 to 2100. Five policy options related to carbon neutrality and water management, three socioeconomic and climate scenarios (SSP1-RCP2.6, SSP2-RCP4.5 and SSP5-RCP8.5) were considered. The results show that water demand and water resource will both be greater in the future. Under BAU, water demand will reach 514, 544 and 717 km3 while water resource will increase to 989, 992 and 1032 km3 in 2086-2100 under SSP1-RCP2.6, SSP2-RCP4.5 and SSP5-RCP8.5, respectively. Future water demand for food sector is expected to decrease slightly and then increase under SSP1-RCP2.6, while it shows continuous increase under SSP2-RCP4.5 and SSP5-RCP8.5 due to the changes of planted area, livestock and temperature. Water demand for domestic sector will decrease under three SSP-RCPs because the population will reach a peak around 2030 and then decrease with time. Water demand for energy is expected to decrease under SSP1-RCP2.6 while it will increase under other SSP-RCPs because of more energy demand under SSP2-RCP4.5 and SSP5-RCP8.5. China may face low water security pressure without policy intervention in the future especially under SSP5-RCP8.5. The analysis shows that bioenergy-oriented agriculture cannot mitigate water scarcity risks in China, while low-carbon agriculture strategies can potentially ensure water safety under carbon neutral goal. Water scarcity can be averted if we follow the development path of SSP1-RCP2.6 as well as apply interventions on water management combining with carbon neutral policies that focus on low-carbon agriculture and supplemented by low fossil energy.
Study on the relationship between geometrical features and permeabilities of fracture networks based on the spring hydrographs
Authors: Chen Yuan , Shu Longcang , Wang Zhe , Niu Shuyao , Ling Zihan
Published: February 2023

Identifying the hydraulic properties of fracture networks is important for groundwater management of karst aquifers which are composed of fractured rocks and cavernous conduits. Although much research has been done on the geometrical characteristics and flow calculation of discrete fracture networks, further exploration on the relativity between them is still needed. This study aims to quantitatively analyze the relationship between different geometrical features and permeabilities of fracture networks based on the spring hydrographs, which can intuitively reflect the flow velocity of karstic medium system.We simulated rainfall-discharge processes of a karst area with different distributions of random fracture networks using a numerical model developed based on a laboratory experiment. The results of plenty of simulation show that the total length of fracture networks and relative density of fractures are most related to the peak values of spring discharge with the Pearson correlation coefficients of over 0.8, indicating that these two geometrical parameters can reflect the permeability of random fracture networks best, followed by the fractal dimension and number of intersection points. However, the connectivity of fracture networks also depends on whether there is one or more fractures that go through the entire study area, which greatly promote water movement and solute transport in the fractured rocks. Another factor that impacts the permeability of fracture networks is uniformity of distribution of fractures, in that a drastic propagation that occurs in a small area with clusters of fractures could not represent the overall permeability of fracture networks. Additionally, the surrounding rock matrix with ultralow hydraulic conductivity has a positive and significant impact on the water transmission capacity of fracture networks, showing that the strong water blocking effect of matrix pushes the groundwater movement towards fractures with high delivery capacity.  This study utilized the spring hydrographs to evaluate the permeability of fracture networks for convenience compared to the calculation of equivalent permeability coefficient, while the latter is more accurate and representative. The above findings can enhance the understanding of properties of fracture networks, benefit targeted observations of detailed structures of fractured rocks and then improve the efficiency of groundwater management in karst areas.  
High-resolution mapping of nitrogen oxides emissions in US large cities from TROPOMI retrievals of tropospheric nitrogen dioxide columns
Authors: Liu Fei , Beirle Steffen , Joiner Joanna , Choi Sungyeon , Tao Zhining , Knowland K. Emma , Smith Steven , Tong Daniel Q. , Wagner Thomas
Published: February 2023

We map high-resolution nitrogen oxides (NOx) emissions in US cities from the retrieved TROPOspheric Monitoring Instrument (TROPOMI) tropospheric nitrogen dioxide (NO2) columns. A new database of gridded emissions at a horizontal spatial resolution of 0.05°×0.05° has been developed using our newly-developed CTM-Independent SATellite-derived Emission estimation Algorithm for Mixed-sources (MISATEAM). We validate the accuracy of MISATEAM using synthetic NO2 observations derived from the NASA-Unified Weather Research and Forecasting (NU-WRF) model at a horizontal spatial resolution of 4 km × 4 km. The validation results demonstrate the excellent agreement between the inferred emissions magnitudes and the NU-WRF given ones with a correlation coefficient (R) of 0.99 and a normalized mean bias (NMB) of -0.08. They also show a consistent spatial pattern with R of 0.88 ± 0.06 for all investigated cities when comparing inferred and given emissions at grid level. The TROPOMI-based database derived in this study includes annual emission maps for 39 US large cities from 2018 to 2021. While there is a good agreement with national emission inventory (NEI) in general, there are noticeable differences in spatial pattern in some cases. The satellite-derived spatiotemporal patterns of NOx emissions complement information difficult to capture in the conventional emission inventories compiled with “bottom-up” methods by suggesting the misallocation of emissions and/or missing sources. We expect to extend the database globally and also include estimates based on NO2 observations from OMI to provide a longer time record. The method could also be applied to data from future geostationary satellites, such as Geostationary Environment Monitoring Spectrometer (GEMS) or the Tropospheric Emissions: Monitoring Pollution (TEMPO) instrument, to provide diurnal variations in NOx emissions.
The CEDAS (building CEnsus for seismic Damage Assessment) project: citizen science to increase risk awareness
Authors: Scaini Chiara , Peresan Antonella , Barnaba Carla
Published: February 2023

Citizen science has proven very useful to increase awareness and preparedness of societies prone to disaster risk. The active involvement of citizens is also strongly envisaged by strategic documents related to disaster risk reduction (e.g. SENDAI Framework, United Nations Global Assessment Report). Here, we describe the CEDAS (building CEnsus for seismic Damage ASsessment) project, which involved high-school students in citizen science activities related to seismic risk reduction. In particular, students collected data on building characteristics (e.g. height, material) near to their homes using their phone or personal computer. Prior to data collection students were trained on risk-related concepts (hazard, exposure and vulnerability) with specific focus on buildings exposure the area where the activity was carried out (northeastern Italy). CEDAS was implemented in 2021 and 2022 involving approximately 320 students who collected more than 6000 building forms. The CEDAS project is not only data collection: students also analyzed the data and compared the exposure parameters in different areas. Finally, the interpreted the results with the help of teachers and researchers. CEDAS has demonstrated its potential for collecting exposure data in seismic-prone areas and/or include characteristics useful for multi-hazard and multi-risk assessment. However, its generalization requires the adaptation of the training material to the specific context. This presentation will support the discussion on CEDAS based on active involvement of participants. Attendants will have the opportunity to test the CEDAS approach for selected buildings. Pictures of the building front and aerial view, together with a street view, will be displayed on the screen. The active involvement of participants will support the discussion both on technical (e.g. parameters to be prioritized during the collection) and communication (e.g. citizens engagement and training) aspects. The discussion will also cover future developments of CEDAS, in particular in relation to risk awareness and preparedness (e.g. definition of impact assessment metrics).
Near road urban air pollution due to vehicular traffic: Effect of real-world driving conditions and vehicle composition
Authors: Debbarma Sohana , Lal Bajrang , Phuleria Harish C.
Published: February 2023

Rapid economic growth with ongoing urbanization trends has led to exponential growth in global transport demand, especially in Asia. The growing vehicle population in India is one of the major contributors to congestion and air pollution causing related health and climate risks in urban areas. In this study, we assessed the impact of motor vehicles on near-road air pollution using roadway tunnel and roadside measurements under real-world traffic conditions based on speed, type of roads, vehicle types (LDV: light duty vehicles, HDDV: heavy-duty diesel vehicles), and fuel composition (gasoline and diesel vehicles). Portable real-time and gravimetric instruments were used to measure emissions from high-speed urban traffic (at Freeway tunnel: all LDV fleet), low-speed creeping traffic (at LBS road: 5% HDDVs and rest LDV fleet), and idling traffic (at Mulund toll plaza: 8% HDDVs and rest LDV fleet) in Mumbai city, and high-speed inter-city traffic (at Kamshet-I tunnel on Mumbai-Pune expressway: 20% HDDV and 80% LDV), covering both peak and off-peak traffic hours. A very small fraction of electric vehicles was also observed in the fleet at LBS road and Toll plaza. Simultaneous measurements were also carried out at an urban background location in Powai, Mumbai. All measured gaseous (CO2, CO, NO2, and VOCs) and particulate (PM2.5 and BC) pollutants at the roadsides and the tunnels were 1.2 to 3.8 times higher than in the background. Total fine carbonaceous species, comprising of elemental carbon (EC) and organic carbon (OC) accounted for up to 47%(±5%) of total PM2.5, highest in the inter-city traffic which could be attributed to its high HDDV and super-emitter fraction followed by the urban idling traffic which had significant HDDV fraction. The OC/EC ratio was 1.8 (± 0.3), highest in the high-speed urban traffic with all light-duty vehicles (LDV) fleet, and the higher HDDV fraction in the inter-city traffic attributed to the low OC/EC ratio of 0.7 (±0.4).  The water-soluble organic carbon (WSOC) fraction that affects aerosol hygroscopicity accounted for up to 70% of the total OC. WSOC was found highest during the afternoon period at the roadsides as well as the background site indicating the contribution of other sources, including photochemical processes. Our study finds that while the near-road emission levels are inevitably higher due to the significant contribution from on-road vehicles, the emission profiles vary significantly depending on the vehicle and fuel composition. Higher HDDV fraction and super-emitters in the fleet contributed to 2.8 folds of higher EC concentrations.  These findings can help in making informed policy decisions towards urban vehicle emission control and monitoring by focusing on targeted vehicles that are polluting disproportionately more than the rest of the vehicles.
The importance of wave chronology in wave schematization for morphodynamic modeling in coastal zones
Authors: Aragón Marta , Martín-Llanes Guillermo , Zarzuelo Carmen , López-Ruiz Alejandro , Ortega-Sánchez Miguel
Published: February 2023

Over the years, a relevant percentage of the population migrate towards coastal areas and nearby. In Spain, nowadays almost 40% of the population is settled close to the coast, and this value increases in summertime. Therefore, these areas have a great social, environmental and economic pressure. Besides their inherent value, both sea level rise and an increase in the frequency and intensity of extreme events are expected over the coming years induced by climate change. According to the last AR6 IPCC Report (2022), natural and anthropised coastal areas will still be at severe risk of erosion and flooding. Therefore, the understanding and modeling of the long-term morphodynamics of near-shore areas with some certainty is crucial for adaptation and mitigation. Even though the study of coastal morphodynamics has evolved during the last decades, a great computational effort in modelling the effects of the different drivers is still required, particularly to analyze the effects of wave climate on near-shore morphodynamics. On account of the above-mentioned, different wave climate schematization techniques have been developed and applied during the last years: Synthetic Wave Events, SWE, Categorized Wave Classes, CWC, or Seasonal Averaged Wave Events, SAWE. Although with all these techniques shorter but morphodynamically equivalent wave climate time series are obtained, the storm chronology is not always preserved. In this research we aim to analyze the relative importance of maintaining (or not) the wave chronology in efficient morphodynamic simulations. For that, we will run the different existing methods in an idealised numerical model and will present a new type of wave schematization technique, called “Storm Preservation Schematization” (SPS) in which storm chronology is preserved and a variable morphological acceleration factor (morfac) is used, accelerating the morphodynamics changes only during the time intervals between extreme events. Eventually, lowering the computational effort in numerical models will lead to a better understanding of the present and future dynamics of coastal environments. In order to get a more realistic geometry, the initial conditions used for the comparative simulations between schematization techniques are obtained after a one-year simulation with realistic climate information in an idealised bathymetry. Both the initial simulation and those for the comparative analysis are performed with the Delft3D model. Initial results after analyzing the final morphologies obtained with each methodology indicate that the new approach for wave schematization (SPS) provide more realistic results when compared to the existing methods, highlighting the importance of keeping the real duration of the storms. Detailed results will be presented at the congress.
Can soil and plant health, and ecosystem services, be improved via reclamation efforts in heavy metal-contaminated alluvial mine tailings deposits?
Authors: Ippolito Jim , Li Liping , Banet Travis
Published: February 2023

The Leadville Mining District in central Colorado, USA began in 1860, extracting over $2 billion USD (current value) in precious metals over its 140 year history.  Unfortunately, mining operations and pyritic deposits contributed to metals contamination in surface/ground waters, ultimately decimating parts of the food chain.  Some sediments contained > 30,000 ppm available Zn; subsequently, sites were devoid of vegetation leading to enhanced erosional losses.  The location was deemed a US EPA Superfund site in 1983.  In 1998, a study was initiated to prove that alluvial mine tailings’ acid-generating potential can be reduced via lime application (224 Mg ha-1), and the addition of biosolids (224 Mg ha-1) in conjunction with native seed mixes could help reclaim these locations. In 2019, we revisited Leadville to access reclamation success on soil health, plant metal accumulation, and the potential positive or negative long-term environmental effects.  Four transects were located on-site, corresponding to past locations that contained varying heavy metal concentrations yet with ~ the same soil pH.  Five soil samples (to 15 cm) were collected along each transect; all plants were collected within a 1-m quadrant next to each soil sampling location.  Five additional soil samples were collected on-site in areas represented by seeps, where no plants were growing and soil surface metal salt precipitates were present.  We utilized the Soil Management Assessment Framework (SMAF) to ascertain changes in soil health between on-site locations, and overlaid this data with plant metal concentration data.  We found that soil organic C, aggregate stability, bulk density, microbial biomass C, pH, EC, and extractable P and K were indicative of soil reclamation success.  Unfortunately, SMAF does not ascertain differences in bioavailable heavy metals, which were still elevated at locations across the site, leading to excessive plant heavy metal accumulation even though plants did not show toxicity symptoms. However, the presence of plants has helped stabilize these alluvial mine tailings, protecting them from loss via water erosion, leading to improved ecosystem function and services. We anticipate this work leading towards a framework to ascertain soil-plant health on heavy metal contamination mine lands globally.
Increase in Arctic amplification and high-latitude marine extremes in the 21st century as obtained from high-resolution modelling
Authors: Gou Ruijian , Lohmann Gerrit , Wu Lixin
Published: February 2023

The Arctic is warming at a rate faster than any other oceans, a phenomenon known as Arctic amplification that has widespread impact on the global climate. In contrast, the Southern Ocean (SO) and Antarctica have been cooling over the past decades. The projection of these regions under global warming has a non-negligible model spread. Here we show that under a strong warming scenario from 1950 to 2100, comparing a cutting-edge high-resolution climate model to a low-resolution model version, the increase of Arctic amplification is 3 °C more and the SO and Antarctica warming is 2°C less. Previously ice-covered Arctic Ocean will exhibit greater SST variability under future global warming. This is due to an increased SST increase in summer due to sea ice retreat. Extreme warming events in the Arctic and SO, known as marine heat waves (MHW) that influence the ecology, are largely unknown. We find that the MHWs in the Arctic and SO are twice as strong in the high-resolution model version, where the increasing intensity of MHWs in the Arctic corresponds to strong decline (<-6% per decade) of sea ice. In both the high-resolution and low-resolution models, the duration of MHWs in the Arctic and SO shows a declining trend under global warming. The much stronger MHWs in the high-resolution model could be caused by two orders of magnitude more ocean turbulent energy. For example, the spatial patterns of SO MHW intensity correspond to the pattern of SO EKE. We conclude that the Arctic amplification and MHWs at high latitudes might be underestimated by the current generation of climate models with low resolution, and the SO and Antarctica warming might be overestimated. Our eddy- and storm-resolving model is expected to open new frontiers on how the system responds to human activities in a high CO2 world by evaluating the impact on past and future climate and environmental extremes.
Cotransport of PFOA with Different Electrically Charged Plastic Particles in Saturated Porous Media
Authors: Rong Haifeng , Tong Meiping
Published: February 2023

The wide application of industrial and consumer product leads to the ubiquitous presence of PFOA (an anionic surfactant) in natural environments. PFOA could interact with microplastics (one emerging pollutants abundant in environments) and the transport of both PFOA and microplastics thus might be altered. The cotransport behaviors of PFOA with micron-sized plastic particles (MPs) with different surface charge (both negative and positive surface charge) in porous media in both 10 and 50 mM NaCl solutions were investigated in present study. Both types of MPs (negatively charged carboxylate-modified MPs (CMPs) and positively charged amine-modified MPs (AMPs)) could adsorb PFOA onto MPs surfaces which decreased PFOA transport with MPs co-present in suspensions under both solution conditions examined. PFOA had diverse impact on the transport behaviors of CMPs and AMPs. Specifically, PFOA decreased the transport of CMPs, while increased the transport of AMPs when PFOA was copresent in suspensions. The mechanisms driving to the changed transport of two types of MPs induced by PFOA were found to be different. The decreased electrostatic repulsion of CMPs due to the adsorption of PFOA onto CMPs surfaces led to the decreased transport of CMPs when PFOA was copresent. The increased electrostatic repulsion due to the adsorption of PFOA onto AMPs surfaces as well as the steric repulsion induced by suspended PFOA caused the enhanced AMPs transport with PFOA in solutions. The results of this study show that when PFOA and microplastics are copresent in natural environments, their interaction with each other will alter their transport behaviors in porous media, and the alteration is highly correlated with the surface charge of MPs.
Interpretable Machine Learning Procedure Unravels Hidden Interplanetary Drivers of the Low Latitude Dayside Magnetopause
Authors: Li Sheng , Sun Yang-Yi
Published: February 2023

Interplanetary parameters such as solar wind and interplanetary magnetic fields (IMF) drive the shape and size of the magnetopause jointly, which has complex relationships. In this study, we proposed an interpretable machine learning procedure to disentangle the influences of interplanetary parameters on the magnetopause standoff distance (MSD) and sort their importance in the MSD simulation. A magnetopause crossings database from the THEMIS satellites and interplanetary parameters from OMNI during the period of 2007-2016 are utilized to construct machine learning magnetopause models. SHapley Additive exPlanations (SHAP) is the basis of the interpretable procedure, which introduces interpretability and makes the machine learning magnetopause model to be a “white box”. The solar wind dynamic pressure and IMF BZ are widely considered the top two important parameters that drive the MSD. However, the interpretable procedure suggests that the IMF magnitude (i.e. strength of the IMF) leads BZ as the second most important interplanetary driver. This ranking result is unexpected, and it implies that the role of IMF magnitude is underestimated although magnetic pressure, which is a function of the IMF magnitude was considered in previous studies. The examination of disentangled effects of interplanetary parameters reveals that the combined influence of the IMF magnitude and BZ can cause an MSD sag near BZ = 5 nT. This is for the first time we conduct the interpretable concept into the machine learning model in the study of the magnetosphere.
Irreversible changes in surface temperature and precipitation to CO2 forcing
Authors: Kim Soong-Ki , Shin Jongsoo , An Soon-Il , Kim Hyo-Jeong , Im Nari , Xie Shang-Ping , Kug Jong-Seong , Yeh Sang-Wook
Published: February 2023

Anthropogenic global warming by carbon dioxide emissions may cause irreversible changes in a wide range of climate variables. A comprehensive understanding of this hysteresis effect and its regional patterns is, however, lacking. Here, we use the Community Earth System Model version 1.2 with a CO2 removal scenario to show that surface temperature and precipitation exhibit globally widespread irreversible changes. To explore the climate hysteresis and reversibility on a regional scale, we develop a novel method that quantifies their spatial patterns. Our experiments project that 89% and 58% of the global area experiences irreversible changes in surface temperature and precipitation, respectively. Strong irreversible response of surface temperature is found in the Arctic, Southern Ocean, and North Atlantic Ocean and of precipitation in the global monsoon regions, tropical Pacific, and the Himalayas. The identified global land hotspots of irreversible changes can indicate elevated risks of negative impacts on developing countries.
Seasonal and diurnal variations of carbon dioxide and energy fluxes over three land cover types of Nepal
Authors: Joshi Bharat Badayar , Ma Yaoming , Wang Binbin
Published: February 2023

This study examines the seasonal and diurnal variations of carbon dioxide and energy fluxes over three land cover types of Nepal by using the eddy covariance method from March to November 2016. The surface energy balance closures were moderate with values of about 56%, 61%, and 64% closure at Kirtipur, Simara, and Tarahara sites respectively. The monthly average values of net radiation flux and latent heat flux peaked in August at Kirtipur and Tarahara sites where as in June at the Simara site respectively. The maximum monthly average measured sensible heat flux was 37 W m−2, 43.6 W m−2, and 36.3 W m−2 in April for all the sites whereas soil heat flux was 5.1 W m−2 and 2.9 W m−2 in April for Kirtipur and Simara sites and 6.2 W m−2 in June for the Tarahara site. The magnitude of the diurnal peak of net ecosystem CO2 exchange (NEE) reached up to 11.04 μmol m−2 s−1 atKirtipur, 15.04 μmol m−2 s−1 at Simara, and 10.44 μmol m−2 s−1 at Tarahara sites respectively. Among the three study sites, the ecosystem at the Kirtipur site was a good carbon source; the ecosystems at Simara and Tarahara sites were low and had good carbon sinks in the growing season. In addition, all three different land cover ecosystem were carbon sources when accounted for during the measurement period.
Mapping Retrogressive Thaw Slumps Using Satellite Data With Deep Learning
Authors: Yang Yili , M. Rogers Brendan , Fiske Greg , Watts Jennifer , Potter Stefano , Windholz Tiffany , Mullen Andrew , Nitze Ingmar , Natali Sue
Published: February 2023

Retrogressive thaw slumps (RTS) are thermokarst features in ice-rich hillslope permafrost terrain and can cause dynamic changes to the landscape. Their occurrence in the Arctic has become increasingly frequent. RTS can significantly impact permafrost stability and generate substantial carbon emissions. Understanding the spatial distribution of RTS is critical to understanding and modelling global warming factors from permafrost thaw. Mapping RTS using conventional Earth observation approaches is challenging due to the highly dynamic nature and often small scale of RTS in the Arctic. In this study, we trained deep neural network models to map RTS across several landscapes in Siberia and Canada. Convolutional neural networks were trained with 965 RTS features, where 509 were from the Yamal and Gydan peninsulas in Siberia, and 456 from six other pan-Arctic regions including Canada and Northeastern Siberia. We used 4-m Maxar commercial imagery as the base map, 10-m NDVI derived from Sentinel-2 as the vegetation feature and 2-m ArcticDEM as the elevation feature. The best-performing model reached a validation Intersection over Union (IoU) score of 0.74 and a test IoU score of 0.71. Compared to past efforts to map RTS features, this represents one of the best-performing models and generalises well for mapping RTS in different permafrost regions, representing a critical step towards pan-Arctic deployment. Our experiments shed light on the impact of within-class and between-class variances of RTS in different regions on the model performance and provided critical implications for our follow-up study. We propose this method as an effective, accurate and computationally undemanding approach for RTS mapping.
A synthetic ambient-noise data set fortime-lapsed monitoring
Authors: Nunes Sérgio , Mohammadigheymasi Hamzeh , Tavakolizadeh Nasrin , Garcia Nuno
Published: February 2023

Synthetic simulation of seismic wave propagation is a fundamental way to evaluate the accuracy and performance of signal processing methods developed for application to real seismic datasets. Various research papers have introduced state-of-the-art synthetic active and passive seismic datasets to implement this critical step. However, a versatile seismic data set for ambient noise is still missing in the literature. In this study, we conducted synthetic simulations by leveraging the noise simulation modules of SPECFEM3D Cartesian open-source codes. The simulation is carried out for the geometries of station pairs of the YB Cavola Broadband Dense Array temporary network installed in 2004 through the village of Cavola, northern Apennine, Italy. This is a dense array (8m separation one way and10m the other way) installed on an active landslide through the village of Cavola, northern Apennines, Italy. By considering a fixed crustal velocity model reported for this region, a noise correlation seismogram is computed for each station pair by implementing three processing steps: 1) simulation for generating wavefields, 2) simulation for ensemble forward wavefields, and 3) simulation for ensemble adjoint wavefields and sensitivity kernels. The generated cross-correlation seismograms are post-processed, detrended, and decimated by a factor of 2 to obtain a dataset with a sampling rate of 0.01sec. Then the traces are rotated to the transverse-radial-vertical coordinate system making 3-component data for each station pair. To make the simulation more realistic, the data is contaminated by Gaussian noise (bandpass-filtered in the range of [0.02, 100] Hz) to give a Signal to Noise Ratio (SNR) of 10. The generated dataset provides one epoch of a synthetic time-lapsed ambient noise dataset as a reference for evaluating time-lapsed processing algorithms. This research contributes to the ALLAB project.
 
The authors would like to thank the support of the Instituto de Telecomunicaçõe. This work is funded by FCT/MCTES through national funds.
Improving the Accessibility of Borehole Geophysics: A Cost-Efficient, Highly Modifiable Borehole Tilt Sensor
Authors: Lee Ian , Hawley Robert , Collins David , Elliott Joshua
Published: February 2023

We present a cost-efficient borehole tilt sensor that was developed by our group at Dartmouth College to study ice deformation on Jarvis Glacier in Alaska. We first detail the entire sensor development, deployment, and data collection process, along with showcasing successful use cases of our sensors on Jarvis and other glaciers both by our and other geophysical research groups. For our Jarvis work, we installed our tilt sensor system in two boreholes drilled close to the lateral shear margin of Jarvis Glacier and successfully collected over 16 months of uninterrupted borehole deformation data in a harsh polythermal glacial environment. The data included gravity and magnetic measurements that tracked the orientation of the sensors in the borehole as ice flows, and we used the resultant kinematic measurements to compute borehole deformation that provided insights into the ice flow dynamics on polythermal glaciers. Our tilt sensors can house many types of sensors to accommodate different scientific needs (e.g., temperature, pressure, electrical conductivity), and can be adapted for the different glacial thermal regimes and conditions like Athabasca Glacier in Canada, which is a temperate glacier in contrast to Jarvis’ polythermal regime. There remains a high knowledge and financial barrier to entry for borehole geophysics research for both development and procurement of a tilt sensor system, and our goal is to lower this barrier by supporting production efforts of our tilt sensor system for both research and educational needs. With our established sensor development plan and demonstrated success in the field, our group has collaborated with Polar Research Equipment (PRE), a Dartmouth alumni-founded company specializing in the development of polar research tools, to serve as a commercial resource to help support polar researchers during the development and/or production of an effective and cost-efficient (~80% cheaper than commercial versions) tilt sensor and its associated systems.
Winter jet stream wind speed changes in the eastern North Atlantic
Authors: Tenenbaum Joel , Williams Paul
Published: February 2023

We have published [ https://doi.org/10.1002/qj.4342 ] recent results on winter jet stream wind speed changes in the eastern North Atlantic: there is no change for the past 40 years but a statistically significant increase for the past roughly 20 years (2002-2020).  The increase shows up in both the Global Aircraft Data Set (GADS) observations from flight data recorders and the ERA5 reanalysis.  The wind speeds seem to track the North Atlantic Oscillation (NAO).  We can consider four possibilities: ( 1 ) synoptic fluctuation; ( 2 ) improved aircraft routing, though inconsistent with NAO correlations; ( 3 ) greater number of automated aircraft observations; ( 4 ) actual secular change in the polar jet exit region of the atmosphere.  This type of study must deal with subtleties of North Atlantic track system that includes aircraft step climbs.  We will present newer results on the secular increase in automated aircraft observations and the effects of including more recent Northern Hemisphere winters (2021 through, possibly, 2023).
Contrasting inﬂuences of biogeophysical and biogeochemical impacts of historical land use on global economic inequality
Authors: Liu Shu , Wang Yong , Zhang Guang , Wei Linyi , Wang Bin , Yu Le
Published: February 2023

Climate change has significant implications for macro-economic growth. The impacts of greenhouse gases and anthropogenic aerosols on economies via altered annual mean temperature (AMT) have been studied. However, the economic impact of land-use and land-cover change (LULCC) is still unknown because it has both biogeochemical and biogeophysical impacts on temperature and the latter differs in latitudes and disturbed land surface types. In this work, based on multi-model simulations from the Coupled Model Intercomparison Project Phase 6, contrasting influences of biogeochemical and biogeophysical impacts of historical (1850–2014) LULCC on economies are found. Their combined effects on AMT result in warming in most countries, which harms developing economies in warm climates but benefits developed economies in cold climates. Thus, global economic inequality is increased. Besides the increased AMT by the combined effects, day-to-day temperature variability is enhanced in developing economies but reduced in developed economies, which further deteriorates global economic inequality.
Spatiotemporal changes in communities of snow-ice microbes living on Gulkana Glacier, Alaska
Authors: Ono Masato , Takeuchi Nozomu , Tsushima Akane , Onuma Yukihiko , Kobayashi Kino , Seto Daiki , Usuba Suzunosuke , Konishi Fuki , Uetake Jun
Published: February 2023

Snow-ice microbes, which adapted to harsh conditions such as low temperature and high dose of UV, inhabit the cryospheric environments. They cause unique phenomena represented by colored snow and ice occurring with blooms of snow and glacier ice algae, and cryoconite holes formed by filamentous cyanobacteria with inorganic matter. These phenomena also darken glacial surface and have a significant effect on the albedo of snow and ice. It is important to understand factors controlling the abundance of all microbes including consumers of algae and cyanobacteria (tardigrades and rotifers) for evaluating the collective influence of biological communities on albedo (biological albedo reduction: BAR). However, most studies have focused only on each taxon (algae, cyanobacteria, fungi or heterotrophic bacteria), and there is a lack of information on whole microbial communities. In this study, we aimed to describe spatiotemporal changes of microbial communities, and discuss the process of their growth and the factors determining their distribution.          The fieldworks were carried out from June to September of 2022 on Gulkana Glacier in the Alaska Range, Alaska. Three different types of samples (snow, bare-ice, cryoconite) were collected spatially at maximum 51 points across the glacier. Microscopic observation and analysis of Chlorophyll a concentration, which is a proxy for the total abundance of snow and glacier ice algae, revealed that the algae were most abundant around the snow line and that their maximum occurred in the end of July (1.0 × 103 μg/m2) and in the middle of August (7.8 × 103 μg/m2) on the snow and ice surfaces, respectively. Their distribution in the ice area showed a similar spatial pattern throughout the season, higher abundance in the upper right side and lower in the left side. Consumers of algae (tardigrades and rotifers) were found only in the upper parts of the glacier. These results suggest that each microbial species on the glacier have different distribution and that their growth is associated with local characteristics such as microtopography of the glacier surfaces. In this presentation, we will show more data of spatial distribution of chemical composition, total impurities, and concentration of each microbe in all three surface types and discuss the factors of their growth and distribution.  
The slowdown tends to be greater for stronger tropical cyclones
Authors: Sun Yuan , Zhong Wei , He Hongrang , Yao Yao
Published: February 2023

Understanding the impact of climate change on tropical cyclones (TCs) has become a hot topic. The slowdown of TC translation speed contributes greatly to the locally accumulated TC damage. While the recent observational evidence shows that TC translation speed has decreased globally by 10% since the mid-twentieth century, the robustness of the trend is questioned by other studies as effects of changes in observational capability can strongly affect the global trend. Moreover, none of the published studies considered dependence of TC slowdown on TC intensity. This is the caveat of these analyses as the effect of TC slowdown is closely related to TC intensity. Here, we investigate the relationship between TC translation speed trend and TC intensity, and reveal possible reasons for the trend. We show that the global slowing trend without weak TC moments (≤ 17 m s-1) is about double of that with weak TC moments in a recent study. This is because the slowing trend is dominated by strong TCs’ trend. Stronger (weaker) TCs tend to be controlled more by upper-level (lower-level) steering flow, and the calculated trend of upper-level steering flow is much larger than that of lower-level steering flow. This may be an important reason for the large difference between the slowing trend without weak TC moments and that with weak TC moments. Furthermore, the changes of TC tracks (including inter-basin trend and latitudinal shift), which are partly attributed to data inhomogeneity, make a much larger contribution to the slowing trend, compared with the weakening of tropical circulation, which is related to anthropogenic warming.
Spatial Assessment of Asbestos Mine Remediation Effect Using Airborne Hyperspectral Imaging System
Authors: Jeong Yongsik , Yu Jaehyung , Wang Lei , Kim Hyun-Cheol
Published: February 2023

This work investigated an abandoned asbestos mine (AAM) remediation project in CA, US. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) hyperspectral data were used to assess the mine treatment effect. The distribution of AAM and restored area were evaluated before and after remediating based on the spectral analysis and model for indicating naturally occurring asbestos (NOA) and encapsulation (remediation). We developed NOA, host rock, and encapsulation indices by binary logistic regression modeling using hyperspectral bands. The detection models statistically selected visible-near infrared (VNIR) regions rather than shortwave infrared (SWIR) ranges. The models-based classification accuracy was approximately 84%. Notably, the detection accuracy of non-treated and treated areas was increased to about 90% excluding the host rock index. The NOA and encapsulation indices showed that they can be efficiently applied to asbestos occurrence/remediation. The remote sensing data revealed that the whole AAM area was increased by ~5% by the remediation process, and the restoration activity reduced asbestos exposure by ~32%. This work would be contributed to providing an intuitive and realistic-spatial understanding of the planning and managing remediation project.
Estimation of 3-D hydraulic conductivity tensor for a granitic rock mass near the low and intermediate level radioactive waste disposal site in Korea
Authors: Um Jeong-Gi , Bae Junbong
Published: February 2023

A workflow is presented to estimate the size of a representative elementary volume and 3-D hydraulic conductivity tensor based on the discrete fracture network (DFN) fluid flow analysis through the case study performed for a granitic rock mass near the low and intermediate level radioactive waste disposal site in southeastern Korea. Intensity and size of joints were calibrated using the first invariant of fracture tensor for the 2-D DFN of the study area. Effective hydraulic apertures were obtained by analyzing the results of field packer tests. The representative elementary volume of the 2-D DFN was determined to be 20m square by investigating the variations in the directional hydraulic conductivity for blocks of different sizes. The directional hydraulic conductivities calculated from the 2-D DFN exhibited strong anisotropy related to hydraulic behaviors of the study area. The 3-D hydraulic conductivity tensor for the fractured rock mass of the study area was estimated from the directional block conductivities of the 2-D DFN blocks generated for various directions in 3-D. The orientations of the principal components of the 3-D hydraulic conductivity tensor were found to be identical to those of the delineated joint sets in the study area.