bluuebunny/crossref_metadata_2025 huggingface dataset:
The Potential Role of Modified Electron Acoustic Wave in Auroral Electron Acceleration
Authors: Shi Run
Published: March 2024

Results from a 1D kinetic simulation, for the first time, reveal the important role of modified electron acoustic wave (MEAW) in auroral electron acceleration. Parallel electric fields, generated due to the mode coupling between kinetic Alfven waves (KAWs) and MEAWs in the transition region from the magnetosphere and the ionosphere, can be sustained by continuous energy input carried by Alfven waves from the magnetosphere. Under the incidence of long-period Alfven waves carrying upward field-aligned currents, a parallel potential drop can be formed in the transition region, leading to mono-energetic electron acceleration. Such a mechanism provides a possible link between shear Alfven waves and the mesoscale mono-energetic auroral electron acceleration.
Numerical Modeling of Fluid and Heat Flow in the Southern North Sea
Authors: Orta Deniz , Düşünür Doğan Doğa
Published: March 2024

Understanding fluid flow and temperature distribution in geothermal potential fields is of utmost importance as it provides valuable insights into the mechanisms governing these fields. Extensive research has been conducted worldwide, employing geological, geophysical, and hydrothermal modeling techniques, to investigate geothermal fluid and heat flow patterns. This paper focuses on studying a geothermal potential area located in the southern North Sea to analyze fluid and heat flow characteristics and their temporal variations in the region. A comprehensive approach was adopted, combining geophysical data with modeling results. The marine seismic data obtained from the southern North Sea were utilized to identify faults, fluid flow features, and geological units, forming the basis of a hydrogeophysical model. To investigate this phenomenon further, numerical modeling was performed using ANSYS FLUENT, a finite volume-based Computational Fluid Dynamics (CFD) software. The model incorporated the geometry of the studied field derived from the seismic section, along with the physical and hydraulic properties of the medium. Thermal and physical rock properties were obtained from previous research. As the numerical simulation progresses over time, the expected results include the temperature distribution/fluid flow patterns and the factors controlling them. The models will provide novel perspectives on the geothermal potential in the southern North Sea, offering insights into the fluid and heat flow characteristics of the region.
Carbon export in the land-to-ocean aquatic continuum (LOAC) of China
Authors: Ran Lishan , Chen Shuai , Yang Qianqian
Published: March 2024

It has long been recognized that terrestrial ecosystems are not isolated from other earth systems with all the absorbed carbon being permanently sequestered on land. Inland water systems (e.g., streams, rivers, lakes, and reservoirs) are an important component of the global carbon cycle, functioning as active reactors that transport and transform large quantities of terrestrially derived carbon. Strong interactions between terrestrial ecosystems and inland waters indicate that a portion of the carbon sequestered on land by vegetation can be transported to the ocean through inland waters, the land-to-ocean aquatic continuum (LOAC). Therefore, the transport, transformation, and redistribution of terrestrial carbon along this continuum will change the land carbon sink strength. A comprehensive understanding of the magnitude and significance of carbon transfer in the LOAC in modulating the net landscape carbon balance is of paramount importance for an accurate assessment of carbon budget. In this work, we systematically examined the carbon transport in the LOAC of the entire China, including carbon export into the ocean, carbon burial within inland waters, and carbon emissions into the atmosphere. Our results show that the flux of carbon transported into the ocean and buried within Chinese inland waters was 40-45 Tg C yr-1 and 10-15 Tg C yr-1, respectively. In addition, the flux of carbon emissions (as CO2 and CH4) from Chinese inland waters was in the range of 100-105 Tg C yr-1. The total carbon flux entering Chinese inland waters was estimated at 150-160 Tg C yr-1 with carbon emissions being the largest transport pathway (63-70% of the total). Compared with the simultaneous terrestrial carbon sink in China, this terrestrial-aquatic carbon export could offset China’s terrestrial carbon sink capacity by up to 25%. Our results highlight that the terrestrial-aquatic carbon export must be integrated into future national-scale carbon budgets.
Detemination of Airborne Microplastics using LC-MS/MS
Authors: Chandra B Praphulla , Patnana Durga Prasad , Tripathi Prashanth
Published: March 2024

In recent times, microplastics (MPs) pollution has become a growing concern across the globe. MPs are easily transferred and ubiquitously found in ambient air. These MPs in the air can act as carriers for several toxic pollutants and exposure to MPs could lead to pulmonary diseases in humans. Polyethylene terephthalate (PET) is one of the most abundant airborne MPs in the ambient environements and nylon 66 is one of the most abundant MPs found in microenvironments. However, there are no studies reported for the quantification of airborne PET and nylon 66 microplastics present in inhalable fraction of ambient fine particulate matter. This study describes the methods optimized for the quantification of PET microplastics and nylon 66 microplastics bound to aiborne PM2.5 using LC-MS/MS. Teflon and Quartz fiber filters were tested for extraction efficiency in measuring the mass concentrations of airborne PET MPs and nylon 66 MPs. Teflon filters have shown good recovery (80 % – 120 %) compared to Quartz filters. Using the optimized methods, a pilot study was carried out at Delhi, the National Capital of India and Mohali, a suburban city in Northwest Indo-Gangetic Plain (NWIGP) for the determination of mass concentrations of PET MPs present in airborne inhalable fraction of ambient PM2.5 and a pilot study was carried out to measure the mass concentrations of nylon 66 microplastics present in the inhalable fraction of particulate matter collected in a shopping complex. Observed maximum mass concentrations of PET MPs in airborne PM2.5 at Delhi and Mohali are 135.2 ng m-3 and 158.0 ng m-3, respectively. The observed mass concentrations of nylon 66 MPs in the microenvironment in this study are in the range of 0.30 ng m-3 to 4.37 ng m-3.
Warmer Antarctic summers in the last two decades linked to earlier stratospheric final warming occurrences
Authors: Choi Hyesun , Kwon Hataek , Kim Seong-Joong , Kim Baek-Min
Published: March 2024

We proposed a link between the interannual and decadal variability in Antarctic surface climate during the austral summertime (December-January) and the timing of stratospheric final warming (SFW) occurrences. This connection is based on 44 years of reanalysis data and in-situ observation spanning from 1979 to 2023. Positive surface pressure anomalies over Antarctica, associated with an earlier occurrence of SFW, develop through stratosphere-troposphere downward coupling, which leads to a warmer surface in Antarctica, except for  the Antarctic Peninsula where a cooler surface is observed. On the contrary, the surface pressure and temperature anomalies associated with the later occurrence of SFW exhibit almost opposite or weaker behaviors. Congruence analyses support that a trend towards earlier SFW occurrences can explain the pause of the cooling trend or a slight reversal into the warming trend of the interior Antarctic surface through strengthening anti-cyclonic surface circulation since the 2000s. The resulting surface temperature responses can leave imprints on sea-ice concentration trends in the high-latitude Southern Hemisphere, displaying the dipole anomalies with an increase and a decrease of sea ice over the Antarctic Peninsula and northern Ross Sea, respectively.
Importance of Age of Convective Clouds for Explosive Ice Crystal Number Growth via Secondary Ice Production
Authors: Waman Deepak , Patade Sachin , Jadav Arti , Phillips Vaughan , Hoose Corinna
Published: March 2024

In many aircraft studies of natural convective clouds (CCs), it has long been observed that at subzero levels warmer than –38oC, the number concentrations of ice particles exceed the number concentration of available active ice nuclei particles (INPs). This suggests that following initial primary ice formation via INP activity at these levels in CCs, there must be some natural mechanisms present to enhance the number concentration of ice crystals, known as secondary ice production (SIP) mechanisms. SIP may form 1) during riming of supercooled cloud droplets between –3 and –8oC (Hallett-Mossop [HM] process), and during 2) fragmentation of freezing raindrops, 3) ice-ice collision, and 4) sublimation of ice particles. However, the relative importance of these SIP processes may differ for differing cloudy conditions.The present study discusses the importance of the age of the simulated CCs in their lifecycle to determine which SIP process is active. The degree of enhancement in the number concentrations of ice crystals due to SIP activity is defined using the term called ‘ice enhancement’ (IE) ratio. A line of CCs observed during the MC3E campaign in 2011 over Oklahoma, USA was simulated using the WRF-based Aerosol-Cloud (AC) model for a 3D mesoscale domain. AC initiates primary ice by predicting the INP activity of solid aerosol particles such as mineral dust, black carbon, and biological particles. Furthermore, AC forms secondary ice from the SIP processes mentioned above. The simulated microphysical characteristics of the MC3E clouds agree well with the coincident aircraft, ground-based, and satellite observations, with errors of ±30%.It is predicted that for relatively young developing CCs, with their tops warmer than –15oC, the HM process and raindrop-freezing fragmentation dominate the overall ice enhancement, creating an IE ratio as high as 104. As the cloud goes through its lifecycle, becoming mature, fragmentation in ice-ice collision becomes prolific, forming IE ratios of about 103, both in updraft and downdraft regions. While it is weak (IE ratios < 10) in the updraft regions, fragmentation in sublimation is predicted to create IE ratios of up to about 102.
On the climate impacts of four different Great Green Wall scenarios on the northern Africa and the Atlantic Tropical Cyclones variability.
Authors: Ingrosso Roberto , Pausata Francesco SR
Published: March 2024

The Great Green Wall (GGW) is a multibillion-dollar African initiative to combat desertification in the Sahel by restoring 100 million hectares of degraded land. The idea of a physical green wall of trees has now been developed into the implementation of scattered green zones throughout arid areas, providing sustainable reforestation, revegetation, and land management. In West Africa, the most important climate feature is the West African Monsoon (WAM), which brings rainfall over the Sahel during the Northern Hemisphere summer. Climate dynamics associated with WAM changes could also play a role on the Atlantic Tropical Cyclones (ATCs) formation and variability. The potential climate impacts of the most recent GGW plan on northern Africa and tropical Atlantic have not yet been adequately evaluated, raising concerns about unforeseen climate ramifications that could affect stability in northern Africa and impact on the ATC variability. Here, we use a high-resolution (~13 km) regional climate model to evaluate the climate impacts of four GGW scenarios with varying vegetation densities under two extreme emission pathways (low and high). Higher vegetation density GGW scenarios under both emission pathways show enhanced rainfall, reduced drought lengths and decreased summer temperatures beyond the GGW region relative to the cases with no GGW. However, all GGW scenarios show more extreme hot days and heat indices in the pre-monsoonal season. Furthermore, in spite of a strong variation in the African Easterly Waves activity, no significant changes are found in terms of ATCs frequency, intensity, meridional motion and translation speed over the North Atlantic area. Small changes in the TC densities are found in front of the cost of West Africa,  in the eastern side of the Main Development Region. These findings highlight the GGW's contrasting climatic effects, emphasizing the need for comprehensive assessments in shaping future policies. 
How the treatment of sea surface temperature affects the water cycle in EURO-CORDEX simulations
Authors: Da Silva Lopes Francis , Schindelegger Michael
Published: March 2024

Regional climate models (RCMs) over Europe often exhibit wet precipitation biases, primarily attributed to excess oceanic evaporation across time scales. One likely source for such wet biases are therefore imperfections in the models’ lower boundary condition (LBC) over the ocean, as realized by time-evolving sea surface temperature (SST) fields. SST data from atmospheric reanalyses (e.g., ERA5) are commonly adopted in RCMs, but ambiguity exists about the exact SST variable in these products (e.g., foundation or skin temperature) and the manner with which they represent the diurnal cycle and spatial gradients. Here we explore these questions with a ~12-km setup of ICON-CLM (Icosahedral Nonhydrostatic Model in Limited-Area Mode) over the EURO-CORDEX domain, run repeatedly for 6 years with various SST datasets. We use ERA5-based daily SST and skin temperature and hourly upper-layer SST drawn from our own global ocean simulations with FESOM2 (Finite Element Sea-Ice Ocean Model) at ~10-km node spacing in the eastern North Atlantic. Specifically, prescribing the FESOM2 SST fields in ICON-CLM both with and without spatial smoothing allows us to examine the effects of oceanic eddies and fronts on precipitation characteristics onshore. Preliminary results from 7 months of integration with ICON-CLM suggest that the choice of the SST data appreciably impacts latent heat fluxes, moisture transport onto land, and cumulative continental precipitation, generally in areas of pronounced moisture recycling. “Mind your SST” is therefore the advice we can give to ongoing dynamical downscaling efforts aimed at modeling future precipitation changes over land.
Development and sensitivity analysis of a tool to generate synthetic urban drainage models globally
Authors: Dobson Barnaby , Jovanovic Tijana , Chegini Taher
Published: March 2024

Continual improvements in the quality, coverage, and accessibility of global geospatial datasets now mean that it is feasible to derive hydraulically plausible urban drainage networks and simulation models of these networks in cities worldwide. Privacy concerns, coupled with the cost and uncertainties in developing traditional network models, have fuelled the demand for such synthetic alternatives. We present SWMManywhere, which can create a hydraulically plausible Storm Water Management Model (SWMM) simulation model for a city using only the boundary coordinates of the target area. The datasets used in SWMManywhere are global, although their quality varies from country to country. We assess the utility of a SWMManywhere model by comparing pluvial flooding, in-pipe flows, and drainage network outflows in known networks. A previously unexplored difficulty with the use of synthetic network generation in urban environments is delineating the network’s boundaries when there are multiple and competing plausible outfalls, which is typical of most large cities. By using a sensitivity analysis approach, we explore how changing parameters associated with the network topology and boundaries can alter simulations. Assessing the uncertainty in our method helps to understand whether synthetically generated network models can produce meaningful simulations in their presumed most common use case: a dense urban environment where little is known about the network’s boundaries or outfalls.  
Long-term trend and variability in surface temperatures over Emilia-Romagna from 1962 to 2022
Authors: Sabatani Davide , Pavan Valentina , Antolini Gabriele , Grazzini Federico
Published: March 2024

Scientific interest is increasingly drawn towards regional meteorological extremes, given their impacts on populations, infrastructure, and ecosystems. These extremes are shaped by a complex interaction between internal variability and long-term trends. The aim of the present work is to evaluate changes in high-frequency variability and the influence of long-term trends on the occurrences of extremes, with a focus on surface temperatures over the period from 1962 to 2022 in Emilia-Romagna, a region of Northern Italy. Daily data of 2m air temperatures averaged over the region are retrieved from ERACLITO, a high-resolution climate analysis. The distributions of daily temperature anomalies show a general broadening in 1992-2022 with respect to 1962-1991. This is true for maximum, minimum, and mean daily surface temperatures, especially during the summer and spring seasons. A significant warming trend of 0.37 °C/decade is detected in annual mean surface temperatures over the period considered. The observed frequency of record-breaking annual temperature events is compared to a hypothetical stationary climate distribution and a theoretical derivation that accounts for changes in trends and variability.  During the last decade, the theoretical count of extreme events is 1.26, which yields a likelihood of 86% that this is owed to the trend rather than interannual variability. Idealized experiments demonstrate that the expected occurrences of record-breaking events in future decades depend on the warming rate rather than the warming level. Finally, an analysis performed at seasonal level shows that the majority (minority) of record  events are occurring in the summer (spring) seasons.
Evidence for the formation of recalcitrant carboxyl-rich alicyclic molecules (CRAM) in an organic soil profile
Authors: Gamage Jeewan , Longstaffe James , Thevathasan Naresh , Al-Abdul-Wahid Sameer , Voroney Paul , Gillespie Adam
Published: March 2024

Recalcitrant soil organic matter (rSOM) plays a pivotal role in global carbon (C) sequestration within soil ecosystems, yet its formation remains enigmatic due to limited insights into its molecular composition and synthesis processes. Specifically, carboxyl-rich alicyclic molecules (CRAM) are recognized for their thermodynamic stability owing to their distinctive molecular structure and hydrophobic properties. In this study, we investigate the presence and transformation of CRAM structures within an organic soil profile employing 1D and 2D 1H nuclear magnetic resonance (NMR) spectroscopy. We conducted organic matter extraction from distinct soil horizons from a soil profile at the Muck Research Station in Kettleby, Canada, utilizing acetonitrile (ACN) and n-hexane (HEX) as organic solvents. ACN effectively extracts condensed structures with O/C ratios exceeding 0.5, while hexane selectively targets lipid-like compounds with low O/C ratios (<0.1). The ACN and HEX solvents are known to represent rSOM components reliably. Notably, all samples exhibited a broad resonance assigned as CRAM with more resolved spectra from the Cg horizon, observed in the 1D 1H NMR. Transformation of CRAM in the Cg and Oh horizons towards increased aliphatic characteristics at the expense of functionalized protons was evident. Further analysis involved 1H-13C HSQC NMR spectroscopy, identifying five major spectral regions: Region I (δH: 0.5–1.5 ppm and δC: 10–30 ppm, associated with purely aliphatic groups), Region II (ca. δH: 1.5–3.5 ppm and δC: 30–45 ppm, linked to CRAM), Region III (ca. δH: 3.0–4.0 ppm and δC: 50–65 ppm, characterized by aromatic methoxyl groups indicating ethers and esters), Region IV (ca. δH: 3.25–4.5 ppm and δC: 65–80 ppm, associated with carbohydrates), and Region V (ca. δH: 6.25–7.5 ppm and δC: 115–135 ppm, representing aromatic structures). Significantly, CRAM components in the Cg horizon displayed distinct compositions from those derived in the upper horizons, suggesting microbial reworking and radical-assisted synthesis of biomolecules or precursors contributing to CRAM formation within the soil profile. Overall, the HSQC cross-peak positioning in all samples exhibited closer similarities to dissolved organic matter (DOM) of microbial origin rather than plant-derived DOM. In the lower Cg horizon, we observed a greater diversity of aliphatic and carbohydrate cross-peaks, highlighting both a higher degree of newly produced organic moieties and the potential for early diagenetic rSOM formation within the soil profile. These findings underscore the substantial role of CRAM in long-term carbon sequestration within soils.
Impacts of land use and climate change on montane forest ecosystem services in Africa
Authors: Abera Temesgen Alemayehu , Maeda Eduardo , Heiskanen Janne , Muhammed Mohammed , Bhandari Netra , Hailu Binyam , Pellikka Petri , Nauss Thomas , Zeuss Dirk
Published: March 2024

Tropical montane cloud forest ecosystems contain some of the world's biodiversity hotspots and provide essential ecosystem services, including high quality freshwater and microclimate buffering against climate extremes. The microclimate buffering service provides microrefugia that allow species to persist under climate change, while the ability of montane forests to intercept cloud water from the atmosphere maintains freshwater availability. However, with increasing pressure from anthropogenic land use and climate change, the stability of montane forests to provide such ecosystem services remains unresolved. In this study, we investigated the impacts of deforestation and climate change on the cloud water interception capacity of montane forests in Africa over the last two decades. We predicted 2-m air and dew point temperature using satellite and in situ observations and ensemble machine learning. In addition, we estimated local warming due to deforestation and tested the 'lifting cloud base height' hypothesis attributed to deforestation and climate change separately. Our preliminary results show that 18% of montane forests in Africa were lost between 2003 and 2022, and deforestation increased the air temperature and lifted the cloud base height stronger than climate change. Deforestation weakened the cloud water interception capacity of montane forests in Africa. Overall, this study sheds light on the impacts of montane deforestation on local climate and water supply, which may have far-reaching implications for montane forest biodiversity and ecosystem service provision in Africa. This work is part of the MOFESD (montane forest ecosystem service dynamics in Africa) postdoctoral project funded by Alexander von Humboldt Foundation.
Co-drivers of air pollutant and CO2 emissions from on-road transportation in China 2010-202
Authors: Qi Zhulin , Zheng Yixuan , Feng Yueyi , Chen Chuchu , Lei Yu , Xue Wenbo , Xu Yanling , Liu Zeyuan , Ni Xiufeng , Zhang Qingyu , Yan Gang , Wang Jinnan
Published: March 2024

The sustained growth in on-road transportation demand poses an increasing challenge for countries in mitigating air pollution and addressing climate change. Revealing how varying socioeconomic and policy factors have contributed to synergies or trade-offs between CO2 and air pollution emissions is crucial for effectively co-controlling carbon-pollution emissions. Here, based on detailed air pollution and CO2 emission inventories from China’s on-road transportation over 2010-2020 and the Logarithmic Mean Divisia index (LMDI) analysis, we explore the on-road synergetic evolution trends among pollution and CO2 emissions and identify the co-drivers influencing carbon-pollution co-emissions. We find that the estimated sectoral emissions of VOCs, NOx, PM2.5, and CO declined by 49.9%, 25.9%, 75.2%, and 63.5%, respectively, while CO2 emissions increased by 46.1% in China over 2010-2020. The vehicle-type-specific analysis further highlights the crucial role of light-duty passenger vehicles and heavy-duty trucks in simultaneously improving air quality and mitigating CO2 emissions, given their synergies in emission growth of VOCs-CO2 and NOx-CO2, respectively. The driver analysis indicates that socioeconomic growth and rising transportation demand are major co-drivers of carbon-pollution emission growth, while the implementation of control policies, particularly advances in emission efficiency, can facilitate co-reductions. Specifically, in the passenger subsector, advances in emission efficiency and changes in travel behavior are identified as the most efficient co-drivers for synergistic emission reduction. The gradual proliferation of new energy vehicles also provides additional synergistic reductions. In the freight subsector, improved freight economic efficiency and optimized freight transport structure are identified as other two co-drivers of synergistic emission reduction. Regional disparities further emphasize the need for policy refinement, including reducing dependency on fuel vehicles in the passenger subsector and prioritizing co-reduction strategies in high-emission provinces in the freight subsector. Overall, our study confirms the effectiveness of China’s on-road control policies and provides valuable insights for future policy makers in China and other similarly positioned developing countries seeking to reduce CO2 and air pollutant emissions simultaneously.
Cumulative absolute absement for magnitude determination in earthquake early warning system using low-cost sensors
Authors: Wu Yih-Min
Published: March 2024

Through the utilization of P-Alert network data from Taiwan, this study endeavors to estimate earthquake magnitude (Mcaa) using the cumulative absolute absement (CAA) methodology across varying window lengths after the arrival of P-wave. It is differentiated that even the proximity of the nearest 12 stations to the epicenter results in robust magnitude estimations. Notably, the standard deviation between the estimated Mcaa and the moment magnitude (Mw) using 12 stations decreases with the increase in window length and is found minimum for 5s window length. For 3s window the variation between Mcaa and Mw is found ±0.385, whereas, for 5s window it is ±0.313. Consequently, the estimation of Mcaa remains reliable. The magnitude Mpd is alternatively deduced from Pd, utilizing the closest 12 stations situated near the epicenter. The standard deviation of the order of ±0.412 is observed between the estimated Mpd and Mw for 3s window, whereas for 5s window it is ±0.281. A difference is observed using Mpdand Mcaafor comparison with Mw. The standard deviation error decreases for Mcaaand Mpd with increase in window length. While Mpd performs better under a 5s window scenario, it tends to underestimate the magnitude of an earthquake with a magnitude of Mw 7.0. On the other hand, CAA surpasses Pd in magnitude estimation, though with a slightly higher standard deviation compared to Mcaa. As a result, Mcaa is considered a more reliable magnitude indicator.
Improved classification of explosive moment tensors using elliptical distribution functions on the hypersphere
Authors: Hoggard Mark , Scealy Janice , Delbridge Brent
Published: March 2024

Discrimination of underground explosions from naturally occurring earthquakes and other anthropogenic sources is one of the fundamental challenges of nuclear explosion monitoring. In an operational setting, the number of events that can be thoroughly investigated by analysts is limited by available resources. The capability to rapidly screen out events that can be robustly identified as not being explosions is, therefore, of great potential benefit. Nevertheless, possible mis-classification of explosions as earthquakes currently limits the use of screening methods for verification of test-ban treaties. Moment tensors provide a physics-based classification tool for the characterisation of different seismic sources and have enabled the advent of new techniques for discriminating between earthquakes and explosions. Following normalisation and projection of their six-degree vectors onto the hypersphere, existing screening approaches use spherically symmetric metrics to determine whether any new moment tensor may have been an explosion. Here, we show that populations of moment tensors for both earthquakes and explosions are anisotropically distributed on the hypersphere. Distributions possessing elliptical symmetry, such as the scaled von Mises-Fisher distribution, therefore provide a better description of these populations than the existing spherically symmetric models. We describe a method that uses these elliptical distributions in combination with a Bayesian classifier to achieve successful classification rates of 99% for explosions and 98% for earthquakes using existing catalogues of events from the western United States. Application of the method to the 2006–2017 nuclear tests in the Democratic People's Republic of Korea yields 100% identification rates. The approach provides a means to rapidly assess the likelihood of an event being an explosion and can be built into monitoring workflows that rely on simultaneously assessing multiple different discrimination metrics.
Thermo-mechanical models on the missing forearc basement in Taiwan
Authors: Chen Chih-Hsin , Tan Eh , Hung Shu-Huei , Lee Yuan-Hsi
Published: March 2024

Taiwan is located at the edge of the Eurasian plate and borders the Philippine Sea plate. The Philippine Sea plate is moving northwestward at a speed of 70 to 80 mm/yr and is converging with the Eurasian plate, forming the Luzon arc and the Taiwan orogenic belt. However, in the middle section of the Taiwan orogenic belt, the Luzon arc is directly adjacent to the edge of the Eurasian continental margin, and the forearc basement is missing. This phenomenon of missing forearc basement is also widely observed in similar plate convergence zones. Previous studies have suggested that this forearc basement has subducted between the Philippine Sea plate and the Eurasian plate. In order to explore the mechanism of forearc basement subduction, we used thermal-mechanical coupled numerical simulations combined with geological data to simulate the dynamic mechanism of forearc basement subduction in the middle section of the Taiwan orogenic belt. The simulation results show that when the subducting plate transitions from oceanic crust to continental crust, the continental crust has a lower density and is not easily subducted. The huge mass formed by the orogeny blocks the Philippine Sea plate from moving northwestward, causing the forearc crust to bend concavely and form a forearc basin. The basin begins to accumulate a large amount of sedimentary material. Later, the center of the basin breaks to form the Longitudinal Valley fault, the island arc to the east of the basin thrusts over the forearc basement, pushing the basin sediment to uplift rapidly, and finally the forearc basement subducts below the Philippine Sea plate. This model explains the mechanism for the missing forearc basement, the timing of the formation of the Longitudinal Valley fault, and the dramatic up and down movements recorded in the sedimentary rocks of the Coastal Mountains. It also explains the spatial pattern of the surface heatflow.
Temporal and spatial varieties of future wave climate under the scenario of climate change
Authors: Fan Yang-Ming
Published: March 2024

Examining the wave climate under climate change scenarios requires a concurrent analysis of both historical and predicted future wave data. This involves using historical wave data to understand seasonal fluctuations and long-term trends, while also utilizing future wave data to predict waves under diverse climate change scenarios. This information is pivotal for evaluating forthcoming risks and formulating strategies for climate change adaptation. This study employs historical wind field data, including ERA5 reanalysis data and CWB/WRF analysis field data, as well as wind field data from the CMIP6 dataset under the SSP5-8.5 extremely high emission scenario. These data are used to drive the WAVEWATCH III wave model for simulating waves. This study initially compared the simulated wave data from the WAVEWATCH III wave model with one year of observed wave data from met-ocean buoys. The results confirmed the high credibility of the simulated waves. Subsequently, extensive data simulations are conducted, encompassing historical wave data (1975-2022) and projected wave data for the future (2025-2100).This study delves into the long-term temporal variations in wave height in Taiwanese waters and the differential regional trends in spatial changes. Regarding temporal changes, the wave heights are averaged year by year, and then linear regression is performed in units of years. The slope of the regression equation indicates the long-term linear trend of wave height in Taiwanese waters over the years, revealing an increasing trend from the past to the future. Regarding spatial changes, the average wave height at each grid point is calculated, and linear regression is applied to determine the long-term trends in wave height at each grid point from the past to the future. The findings unveil a positive growth trend in Taiwanese waters. Furthermore, Taiwanese watersexperience distinct weather patterns in each season, such as the influence of the northeasterly monsoon in winter and typhoons or southwestern winds in summer. This study further explores the differences and variations of wave during spring (March to May), summer (June to August), autumn (September to November), and winter (December to February of the following year). The analysis results indicate negative growth trends in spring and summer, and positive growth trends are observed in autumn and winter, indicating a noticeable increase in wave height in Taiwanese waters during autumn and winter under the influence of climate change.
Extracting 3-dimensional co-seismic displacement using InSAR techniques
Authors: Sidorov-Biryukov Dmitry , Đurić Dragana
Published: March 2024

Synthetic-aperture radar (SAR) has emerged as a dependable data source across various disciplines, particularly in geophysics. Its utility extends to applications such as fault zones assessment, surface rupture extent estimation, and evaluation of potential infrastructure damage. A key advantage of SAR data in remote sensing for seismology lies in its reliability, as it operates independently of the day/night cycle and weather conditions within the designated area of interest. This characteristic enhances its efficacy in providing consistent and uninterrupted observations for seismic monitoring and analysis. This study proposes a slightly modified methodology for extracting three-dimensional movements of the terrain by leveraging ascending and descending synthetic-aperture radar (SAR) images acquired both pre- and post-event. The approach aims to contribute to a more comprehensive understanding of geophysical dynamics by analyzing SAR data in both orbital configurations, providing insights into the spatial and temporal aspects of co-seismic deformation. A seismic event investigation was conducted, focusing on the magnitude 6.9 earthquake that occurred in Indonesia on August 5, 2018. This seismic event was attributed to a shallow thrust fault located on or near the Flores Back Arc Thrust. The study utilized Sentinel-1 data for Differential Interferometric Synthetic Aperture Radar (DInSAR) processing and phase unwrapping, employing conventional procedures. The three-dimensional displacement extraction method was applied to the processed data, and the resulting image underwent a comprehensive analysis. The findings reveal a maximum displacement of 0.35 meters in the north-south direction, 0.125 meters in the east-west direction, and an uplift of approximately 0.68 meters.
3-D Intrinsic Attenuation Tomography of La Palma island (Canary Islands) using Ambient Seismic Noise
Authors: Cabrera-Pérez Iván , D'Auria Luca , Soubestre Jean , del Pezzo Edoardo , Prudencio Janire , Ibáñez Jesús M. , Jiménez María , Padilla Germán D. , Barrancos José , Pérez Nemesio M.
Published: March 2024

Seismic attenuation plays a vital role in geothermal exploration due to its direct association with the fluid content of reservoirs. In this study, we obtained the first attenuation model of La Palma island (Canary Islands) for geothermal exploration, applying a novel local-scale ambient noise attenuation tomography technique. Data from 44 seismic stations underwent meticulous processing. The initial stages involved preprocessing ambient noise data via standard normalization techniques, bandpass filtering and cross-correlation to retrieve the Empirical Green's functions (EGFs). For each EGF we retrieve the intrinsic attenuation  across various frequencies using the lapse-time dependence method, in which intrinsic attenuation is measured as a function of the coda window length for different onsets of the ambient-noise cross-correlation coda (Calvet and Margerin, 2013). Subsequently, 2-D spatial intrinsic attenuation maps for different frequencies were generated through linear inversion using sensitivity kernels (Del Pezzo and Ibáñez, 2020). Finally, we inverted the 2-D spatial intrinsic attenuation maps to derive 1-D depth profiles of intrinsic attenuation. The results unveiled distinct high-attenuation anomalies which releveled a possible hydrothermal zone  beneath the southern part of La Palma island. Comparative analyses with previous resistivity studies (Di Paolo et al., 2020), S-wave velocity research (Cabrera-Pérez et al., 2023), and density models (Montesinos et al., 2023) further corroborated these findings, underscoring the significance of ambient noise attenuation tomography in geothermal exploration.References:Cabrera-Pérez, I. et al. Geothermal and structural features of La Palma island (Canary Islands) imaged by ambient noise tomography. Sci. Reports 13, 12892 (2023)Calvet, M. & Margerin, L. Lapse-time dependence of coda q: Anisotropic multiple scattering models and application to the pyrenees. Bull. Seismol. Soc. Am. 103, 1993–2010 (2013).Del Pezzo, E. & Ibáñez, J. M. Seismic coda-waves imaging based on sensitivity kernels calculated using an heuristic approach. Geosciences 10, 304 (2020).Di Paolo, F. et al. La Palma island (Spain) geothermal system revealed by 3D magnetotelluric data inversion. Sci. reports 10, 1–8, DOI: 10.1038/s41598-020-75001-z (2020).Montesinos, F. G. et al. Insights into the magmatic feeding system of the 2021 eruption at Cumbre Vieja (La Palma, Canary Islands) inferred from gravity data modeling. Remote. Sens. 15, 1936 (2023)
Spatio-temporal climate fingerprint in palaeoclimate data vs models
Authors: Skiba Vanessa , Dolman Andrew , Hébert Raphaël , McPartland Mara , Laepple Thomas
Published: March 2024

Knowledge on natural climate variability is pivotal for making future climate projections. Previous studies demonstrated that centennial to millennial temperature variability is lacking in climate model simulations and that this bias is spatially heterogeneous. Various mechanisms have been proposed that might be important to modulate this low-frequency variability such as the ocean circulation, the meridional temperature gradient or external forcing and climate sensitivity to that forcing, but the evidence to identify the main driver(s) is still debated. Here, we provide preliminary insights on the respective importance of those mechanisms in driving long-term climate variability by investigating spatial patterns of low-frequency climate variability.Low-frequency variability beyond multi-decadal timescales cannot be studied using only instrumental data due to data limitations and the confounding impact of anthropogenic forcing. Consequently, noisy and biased palaeoclimate proxy observations have to be utilised in order to investigate spatio-temporal patterns of climate change. Using a multi-archive and -proxy approach, we characterise the first-order spatial pattern of low-frequency climate variability of interglacial periods. By combining information on the spatio-temporal fingerprint derived from various archives and proxies with different characteristics, we aim to identify the common climate variability signal and assess the ability of climate models to explain the proxy-based spatial pattern of low-frequency variability.
Impact of rising temperature and drought on forest ecosystems across scales
Authors: Grossiord Charlotte
Published: March 2024

Recent decades have been characterized by increasing temperatures worldwide, resulting in an exponential climb in vapor pressure deficit (VPD) and soil droughts. Heat and VPD have been identified as increasingly important drivers of plant functioning in terrestrial biomes and are significant contributors to recent drought-induced tree mortality. Despite this, few studies have isolated the physiological response of plants to high VPD, heat, and soil drought, thus limiting our understanding and ability to predict future impacts on terrestrial ecosystems. I will present diverse experimental approaches to disentangle atmospheric and soil drivers of plan functions across scales in this presentation. I will further discuss recent findings suggesting that high temperature and VPD can lead to a cascade of impacts, including reduced photosynthesis, foliar overheating, and higher risks of hydraulic failure, independently of soil moisture changes. Moreover, I will highlight how species interactions can modulate the adverse impacts of soil and atmospheric droughts.
"Exploring pathways for the sustainable intensification of wheat production under current and future climate change scenarios in the Mediterranean region"
Authors: Tita Davide , Devkota Krishna , Mahdi Karrar , Devkota Mina
Published: March 2024

This scientific inquiry delves into the far-reaching implications of global warming and the continuous emission of anthropogenic greenhouse gases into the Earth's atmosphere. With a primary focus on the semi-arid regions of Morocco, the study broadens its perspective to conduct a comparative analysis of similar challenges faced by Spain, Egypt, Italy, Jordan, Turkey, and Iran. The paper aims to illuminate the intricate interplay between climate change and agriculture, underscoring the imperative for sustainable practices to alleviate the detrimental impacts on food security and economic stability. The methodology employed centers around the utilization of the DSSAT (Decision Support System for Agrotechnology Transfer) model, a reliable tool for simulating yield across different seasons. In this study, the performance of wheat varieties in the Mediterranean and MENA (Middle East and North Africa) regions was evaluated. Optimal yields were observed under treatments involving sprinkler or furrow irrigation and nitrogen application ranging from 60 to 120 kg/ha, resulting in an average yield trend of around 6 t/ha. The identified optimal seeding date was the 1st of November, with conservation or adaptation practices demonstrating superior outcomes. This finding was further validated by MIROC5 climate change projections, estimating yields of up to 6.4 t/ha in Spain and a slight increase in Morocco and one of the sites in Jordan, alas a reduction of 20% in Italy and up to 88% in Iran at the end of the century. The study's significance lies in its evaluation of nutrient and water trends in the MENA and Mediterranean regions, offering farmers and policymakers valuable insights to guide a sustainable transition, both economically and ecologically.
Remote mechanisms for shifting the tropical Pacific warming pattern
Authors: Kang Sarah M. , Watanabe Masahiro , Collins Matthew , Hwang Yen-Ting , McGregor Shayne , Stuecker Malte F.
Published: March 2024

Changes in the sea surface temperature (SST) pattern in the tropical Pacific modulate radiative feedbacks to greenhouse gas forcing, the pace of global warming, and regional climate impacts.  Therefore, elucidating the drivers of the pattern is critically important for reducing uncertainties in future projections.  However, the attribution of observed changes over recent decades, an enhancement of the zonal SST contrast coupled with a strengthening of the Walker circulation, has not been successful.  Here, we review existing mechanisms of the forced response, categorized as either an energy perspective that adopts global/hemispheric energy budget constraints or a dynamical perspective that examines the tropical atmosphere-ocean coupled processes. We then collectively discuss the relative contributions to the past and future SST pattern changes to propose a narrative that reconciles them. Despite uncertainties, the balance of evidence suggests that the mechanisms leading to strengthening the zonal SST contrast have been efficient in the past and those leading to a weakening were less efficient but will become dominant in a future climate. We particularly focus on the role of Southern Ocean SST changes in shifting the tropical Pacific warming pattern. Finally, we present opportunities to resolve the model-observation discrepancy regarding the recent trend.
African dust transport and deposition modelling verified through a successful citizen science campaign in Finland  
Authors: Meinander Outi , Kouznetsov Rostislav , Uppstu Andreas , Sofiev Mikhail , Kaakinen Anu , Salminen Johanna , Rontu Laura , Welti Andre , Francis Diana , A. Piedehierro Ana , Heikkilä Pasi , Heikkinen Enna , Laaksonen Ari
Published: March 2024

On 21–23 February 2021, dust from a sand and dust storm (SDS) in northern Africa was transported to Finland, north of 60°N. The episode was predicted 5 days in advance by the Finnish Meteorological Institute (FMI) global operational SILAM forecast (silam.fmi.fi), and its key features (e.g., spatial distribution of wet and dry deposition amounts and particle sizes) were confirmed and detailed by a retrospective analysis. SILAM is among the dust forecast models included in the Word Meteorological Organization Sand and Dust Storm Warning Advisory and Assessment System WMO SDS-WAS.  Dust deposition was observed on 23 February over a large area in the Southern and Central Finland from 60°N to >63.8°N. The ground was covered with snow making dust more easily detectable. The coloured snow caused people to contact FMI asking what is happening. FMI launched a citizen science campaign on Saharan dust with the help of social media, and people were asked to report their observations and to collect dust-containing snow and to extract the dust according to the guidelines. The campaign gained wide national interest in television, radio, newspapers and social media, and resulted in success in receiving citizen samples from 525 locations, with one to over ten samples in each. The amounts of deposition calculated from the citizen samples were found to be up to 1.1 g/m2 and such maximum amounts per unit area agree with the SILAM calculations. The SILAM model and particle magnetic properties confirmed that dust came from a wide Sahara and Sahel area, from 5000 km away. The median diameters of the dust particles were in the modes of 20 µm. The mineral composition was dominated by quartz, feldspars, and soft phyllosilicates such as micas and clay minerals.To extract dust from snow, Meinander et al. (2023) protocol recommends: 1. Collect snow samples within one week of the deposition event to minimize post-deposition changes. 2. Evaporate snow under 75oC to preserve the magnectic properties (particles should not be subjected to temperatures higher than 90oC). 3. Keep the remaining particles in the container in which the evaporation took place (e.g., a sheet of aluminium folio on a large oven tray and evaporating the snow in the oven) to best preserve all the particle sizes. Reference: Meinander, O., Kouznetsov, R., Uppstu, A. et al. African dust transport and deposition modelling verified through a citizen science campaign in Finland. Sci Rep 13, 21379 (2023). https://doi.org/10.1038/s41598-023-46321-7.   
E-MORB glasses reveal a metasomatized mantle source of nascent oceanic crust in the Guaymas Basin, Gulf of California
Authors: Xie Wei , Ge Zhen-Min , Huang Xiao-Long , Höfig Tobias W
Published: March 2024

The formation of nascent ocean basins represents the beginning of the periodic Wilson cycle, and the geochemical characteristics of nascent oceanic crust are crucial for understanding how an ocean initially opens. The Gulf of California, which hosts young (