bluuebunny/crossref_metadata_2025 huggingface dataset:
Applying causal loop diagram to localize the Disaster Resilience Scorecard of UNDRR - a case study of Taipei City
Authors: Pan Tsung-Yi , Wang Jing-Ting , Cheng Cheng-Chi , Lai Jihn-Sung
Published: February 2023

In recent years, the impact of climate change and extreme weather has not only expanded the scale of disasters, but also increased the frequency of disasters. In order to reduce the impact of natural disasters on cities, Making Cities Resilient (MCR) 2030 promoted by the international community has become an important issue. This study uses the "Ten Essentials" Toolkit for Resistant City constructed by the UNDRR to evaluate the disaster prevention and resilience capabilities of cities. However, the key to quantifying urban resilience is to link the indicators of the Disaster Resilience Scorecard with the operations of local government departments to strengthen urban resilience. Taking Taipei City as an example, this study uses the causal loop diagram (CLD) method to explore the business relationship between "Ten Essentials" and various bureaus, and builds a localized disaster resistance scorecard through expert meetings. CLD provides a visual map of the links between resilience indicators and local government operations, providing a clear conceptual model of operating resilient systems.It can be seen from the analysis results that through the questionnaire survey, Taipei City's disaster prevention and resilience capabilities have achieved satisfied results in various Essentials. Among them, "Organizational Resilience", "Enhancing Organizational Resilience and Disaster Resilience", "Increasing Infrastructure Resilience", and "Ensuring Effective Disaster Response" performed best. At the same time, it is necessary to continue to strengthen the actuarial calculation of disaster risks, enhance financial resilience through catastrophe funds, and implement various measures such as community disaster prevention and business continuity plans, so as to continue to strengthen Taipei's urban resilience in the future.
Assessment the Influence of Social Capital on the Promotion of Resilient Community and preservation of Cultural Heritages in Taiwan
Authors: Ma Kuo-Chen , Chuang Mo-Hsiung
Published: February 2023

This study focus on different types of social capital in the field of cultural asset disaster prevention, and the structure of cooperation between different disaster prevention units. Due to the intensification of climate change, the scale and complexity of disasters had gradually increased. In 2019, the Notre Dame Cathedral in Paris caused the Zhurong incident due to a power line fire, which attracted attention from the world. Taiwan has also re-examined its current attitude, whether the asset disaster prevention policy is complete towards culture. This research take part in Danshui Old Street in New Taipei Vity and Guning Village in Kinmen City which are full of rich historical and cultural characteristics as the research scope. In the task of cultural asset disaster prevention, need the cooperation between various departments and fields to achieved the ultimate goal. This research is divided into three major research purposes to integrate the affect and harmonizations of different departments and fields of cultural assets disaster prevention. This study has conduct research through literature summarization, in-depth interviews and SWOT analysis by analyzing and comparing the interview results. It prove that linking social capital is positioned as a supporter, while bridging social capital is a link for cooperation and communication, the link that tie in bonding social capital is the first civil defense system for cultural assets disaster prevention. The structure of cultural assets disaster prevention cooperation and integration task can be summarize into three stages of disasters, which are integrated before, during and after disaster. Pre-disaster planning can be divided into three points: policy, resources and disaster prevention technology.  During disaster can be divide to monitoring system and disaster information platform. Post-disaster planning divided into three points: disaster loss statistics, disaster loss subsidies, and reconstruction and sustainable development. Based on the above structure, it can be used to examine whether there is any space to improve current disaster prevention policy, as to complete the coordination between cross-department disaster prevention in Taiwan. Therefore, this study two ways to suggest for tie-type social capital, cross-type social capital, and vertical-connection type social capital. First, implement cross-department cultural asset disaster prevention and rescue cooperation mechanism. Second, build a cross-departmental integration and cooperation communication platform, hoping to contribute the formulation of disaster prevention planning for cultural assets.
An Open-innovation and Open-development Framework for the Unified Forecast System Powered by the Earth Prediction Innovation Center
Authors: Huang Maoyi
Published: February 2023

The National Oceanic and Atmospheric Administration (NOAA) established the Earth Prediction Innovation Center (EPIC) to be the catalyst for community research and modeling focused on informing and accelerating advances in our nation’s operational NWP forecast modeling systems. The Unified Forecast System (UFS) is a community-based, coupled, comprehensive Earth modeling system. The UFS numerical applications span local to global domains and predictive time scales from sub-hourly analyses to seasonal predictions. It is designed to support the Weather Enterprise and to be the source system for NOAA‘s operational numerical weather prediction applications. EPIC applies an open-innovation and open-development framework that embraces open-source code repositories integrated with automated Continuous Integration/Continuous Deployment (CI/CD) pipelines on cloud and on-prem HPCs. EPIC also supports UFS public releases, tutorials and training opportunities (e.g., student workshops, hackathons, and codesprints), and advanced user support via a virtual community portal (epic.noaa.gov). This framework allows community developers to track the status of their contributions, and facilitate rapid incorporation of innovation by implementing consistent and transparent, standardized and community-driven validation and verification tests. In this presentation, I will demonstrate capabilities in the EPIC framework using the UFS Short-range Weather (SRW) Application as an example in the follow aspects:Public Releases of a Cloud-ready UFS SRW application with a scalable container following a modernize continuous release paradigm 
Test cases for challenging forecast environments released with datasets
Training and Tutorials for users and developers
Baseline for benchmarking in skill and computation on cloud HPCs , and
An Automated CI/CD pipeline to enable seamless transition to operations
Lightning activity in Mexico under climate change scenarios
Authors: Jaramillo Alejandro , Pérez Juárez Brian Gustavo , Dominguez Christian
Published: February 2023

Lightning has an important role in the Earth's energy balance, atmospheric chemistry, the initiation of natural forest fires, and a close relationship with the development of deep convection. On the other hand, lightning is also a significant meteorological hazard, particularly in Mexico, during the rainy season, causing deaths and disrupting socio-economic activities. According to the IPCC report, it is expected an increase in the frequency and severity of extreme events in North America due to climate change in the forthcoming decades. To understand the impacts of climate change on lightning in the Mexican territory, it is necessary to explore the future changes in the regional patterns of lightning activity in the region. We use different parameterizations of lightning activity over Mexico, using data from reanalysis and coupled models from CMIP6. We also evaluate the parameterization performance in representing the historical period against available lightning observations. Later, we obtain the projected changes at the end of the 21st Century in the selected CMIP models under the most extreme climate change scenario. At the end of this preliminary study, we provide insides into how climate change will impact extreme events and lightning activity over Mexico. 
The Biophysical Impacts of Idealized Afforestation on Surface Temperature in China: Local and Nonlocal Effects
Authors: Chen Chaorong , Ge Jun , Guo Weidong , Cao Yipeng , Liu Yu , Luo Xing , Yang Limei
Published: February 2023

Afforestation can impact surface temperature through local and nonlocal biophysical effects. However, the local and nonlocal effects of afforestation in China have rarely been explicitly investigated. In this study, we separate the local and nonlocal effects of idealized afforestation in China based on a checkerboard method and the regional Weather Research and Forecasting (WRF) Model. Two checkerboard pattern–like afforestation simulations (AFF1/4 and AFF3/4) with regularly spaced afforested and unaltered grid cells are performed; afforestation is implemented in one out of every four grid cells in AFF1/4 and in three out of every four grid cells in AFF3/4. The mechanisms for the local and nonlocal effects are examined through the decomposition of the surface energy balance. The results show that the local effects dominate surface temperature responses to afforestation in China, with a cooling effect of approximately −1.00°C for AFF1/4 and AFF3/4. In contrast, the nonlocal effects warm the land surface by 0.14°C for AFF1/4 and 0.41°C for AFF3/4. The local cooling effects mainly result from 1) enhanced sensible and latent heat fluxes and 2) decreases in downward shortwave radiation due to increased low cloud cover fractions. The nonlocal warming effects mainly result from atmospheric feedbacks, including 1) increases in downward shortwave radiation due to decreased low cloud cover fractions and 2) increases in downward longwave radiation due to increased middle and high cloud cover fractions. This study highlights that, despite the unexpected nonlocal warming effect, afforestation in China still has great potential in mitigating climate warming through biophysical processes.
Kinetic simulation of proton mirror instability
Authors: Chang Chun-Kai , Hau Lin-Ni
Published: February 2023

Mirror mode waves with anticorrelated density and magnetic field perturbations have been widely observed in the planetary magnetosheaths and solar wind. In this study we examine the time evolution of proton mirror instability based on the hybrid particle simulation with the focus being on the thermodynamics of mirror waves. A set of double-polytropic (DP) laws are adopted to infer the corresponding thermodynamic conditions characterized by the polytropic exponents, γ⊥and γ. It is shown that the γ⊥, values at the saturation stages are in the ranges of γ⊥ = 0.64±0.21 and γ = 1.07±0.12 which are consistent with the observations and linear kinetic theory (Hau et al. 2021). The saturated plasma β are well fitted by the modified DP MHD mirror condition of γβ = β⊥2/(2+γ⊥β⊥) with γ⊥ ≈ 0.8, γ ≈ 1.3 which may be used as a new mirror criterion for the mirror waves observed in the solar system.
Irrigation water quality management under the impact of climate change
Authors: Huang Ya-Zhen , Fan Chihhao
Published: February 2023

Agriculture is vital for human survival and irrigation water quality plays an important role in agricultural growing and harvest. Although Taiwan has abundant rainfall, the uneven distribution of rainfall in time and space makes the irrigation water management difficult. In the past two decades, climate change has led to frequent occurrence of extreme weather events and global disasters, and the increase in the frequency and intensity of extreme events enhances the potential disaster risk in Taiwan, impacting the water resource management severely. Meanwhile, industrial wastewater is a significant pollution source, and the surface water quality would be further deteriorated if the industrial wastewater was not treated properly before its release. In Taiwan, the needs of water resources for domestic and industrial uses have the higher allocation priority than that for agricultural use, considering the political concerns and economical contribution. Oftentimes, a supplementary water resource to meet irrigation need is required due to the scarce of available water resources. The situation may become even worse under the influence of climate change.Given the information above, this study explored the irrigation water quality variation under the influence of climate change on agricultural water resource management. The Taoyuan City (including Taoyuan irrigation Shimen irrigation areas) were selected as the study area. The potential impact of climate change on irrigation water quality, considering factors of pollution discharges and economic development, was assessed. Adaptive strategies including stabilizing irrigation water demand, strengthening irrigation water supply and building an agricultural technology auxiliary system were discussed. The result showed that the increasing frequency of heavy rainfall events in Bade, Xinwu, and Guanyin Districts. The surface pollutant would be washed out easily during heavy rainfall events, impacting neighboring water bodies. On the other hand, drought events appear in Daxi and Fuhsing Districts in extreme climate events. Therefore, a new strategy for sustainable water management is needed.
Observation space localizations for the maximum likelihood ensemble filter
Authors: Nakashita Saori , Enomoto Takeshi
Published: February 2023

The maximum likelihood ensemble filter (MLEF) can handle nonlinearity of observation operators more appropriately than conventional ensemble Kalman filters. Here we consider the observation space localization method for MLEF to enable application to large-scale problems in the atmosphere. Optimization of the cost function in MLEF, however, impedes local analysis, suitable for massive parallel computers, in the same manner as the local ensemble transform Kalman filter (LETKF). In this study two approaches to observation space localization for MLEF (LMLEF) are compared. The first method introduces local gradients to minimize the global cost function (Yokota et al. 2016). An alternative approach, proposed here, defines a local cost function for each grid assuming a constant ensemble weight in the local domain to enable embarrassingly parallel analysis. The two approaches are compared to LETKF in cycled data assimilation experiments using the Lorenz-96 and the SPEEDY models. LMLEFs are found to be more accurate and stable than LETKF when nonlinear observations are assimilated into each model. Our proposed method is comparable to Yokota's global optimization method when dense observations are assimilated into the Lorenz-96 model. This result is consistent with the fact that ensemble weights have high spatial correlations with those at neighboring grids. Although our method also yields similar analysis in the SPEEDY experiments with a more realistic observation network, Yokota’s global optimization method shows faster error convergence in the earlier cycles. The error convergence rate seems to be related to the difference between global and local optimization and the validity of the assumption of constant weights, which depends strongly on the observation density.
Positive and negative surface feedback and atmospheric control of land surface conditions on convective organization over the Tibetan Plateau
Authors: Yang Chenyi
Published: February 2023

The dependence of the feedback signal on atmospheric conditions is still poorly understood and may lead to an underestimation of feedback strength due to opposite responses of precipitation to soil moisture. Based on data from observation stations on the Tibetan Plateau and from satellites, this study evaluated the response of convective clouds to the change of evaporation fraction (EF) and analyzed how surface conditions affect the initiation and development of convection in different coupling regimes. After considering coupling regimes classified by the tropospheric state, the afternoon convective cloud showed a strong response to EF, which is negative feedback in the dry coupling regime and positive feedback in the wet coupling regime. Organized deep convection defined by both the cloud properties and the afternoon precipitation displayed this phenomenon. This shows that the lack of a strong response of convection to EF is due to the dependence of this response on the coupling regime, rather than on the method of defining convection. We also found that the difference in surface heat flux between the two regimes is more significant in the afternoon, while the difference of meteorological elements is most significant before noon. These results provide support for the use of ground-based meteorological data to determine coupling regimes. We also used a regression tree to decompose the effects of coupling regimes and EF into basic near-surface meteorological elements, the results of which provide support for some of our conclusions.
Stress change and fault interaction of adjacent dip-slip, creeping faults in Taiwan
Authors: Peng Wei , Chen Kate Huihsuan
Published: February 2023

Understanding the aseismic slip and its interplay with seismic slip is central to seismogenesis as it ultimately controls the space-time patterns of seismicity. The aseismic slip has mostly been documented on subduction zones, where the aseismic slip occurs close to the plate rate during the interseismic period and accelerates after/preceding a nearby mainshocks. In tectonically-active continental regions, the intensive efforts of mapping and characterizing aseismic slip have been made to strike-slip faults. Due to lack of recognized creep on dip-slip faults, the nature of fault creep and its role in large earthquake generation in dip-slip creeping fault remains unclear. Whether the spatial and temporal distribution of earthquakes?The two segmented, ~150-km-long, creeping fault systems in Taiwan are characterized by fast deep slip rate (4-5 cm/yr), large damaging earthquakes, repeating earthquakes, and swarm activities. They provide a rare opportunity for studying the nature of fault creep in the dip-slip faults. As a boundary between the Philippine Sea plate and the Eurasian plate, the Longitudinal Valley on the eastern Taiwan is composed of two parallel structures with opposite dipping direction: the east-dipping Longitudinal Valley fault (LVF) to the east and the west-dipping Central Range fault (CRF) to the west, with the surface separation of shorter than 10 km. Since 1990, thirteen M6 earthquakes have occurred along the two faults. To understand the characteristics and mechanisms of earthquake interaction between the two adjacent active faults, three major works are conducted: (1) Identifying earthquakes that are responsible for the LVF and CRF activities based on relocated seismicity (2) Identifying earthquake clusters using a statistics-based algorithm (3) Quantifying the interaction between seismicity on two separate faults using the spatiotemporal distribution of earthquake clusters (3) computing the static stress change to verify the stress triggering relationship between the two adjacent faults.Each of the two adjacent faults can be both divided into three segments. We found that only the southern segments exhibit strong interaction in earthquake clusters. On December 10, 2003, a M6.4 earthquake in the southern LVF likely triggered a M5.3 earthquake in southern CRF that occurred 8 days later, as promoted by 0.8 bar stress change. On April 1, 2006, a M6.2 earthquake in southern CRF on the other hand, is capable of triggering a M6.0 earthquake in the south segment of LVF two weeks later, imported by 0.6 bar stress change. Given that the southern segment of the LVF is characterized by the creep rate of 2-3 cm/yr on the surface and ~4 cm/yr at greater depth below 10 km, while the other segments reveal stronger fault coupling, we argue that the nature of fault creep may control the triggering potential in the adjacent fault. 
How flat subduction and the upper plate rheology control the deformation of the North China craton
Authors: Ballı Çetiner Açelya , Göğüş Oğuz , van Hunen Jeroen
Published: February 2023

The longevity of the cratonic lithosphere is controlled by its buoyancy, strength, and the viscosity contrast with that of the underlying sub-lithospheric mantle. A number of geodynamic models show that the style and characteristic of lithospheric removal/thinning mechanisms over cratons (i.e. whether delamination, drip, or hydration weakening) are accounted by their geological history and geodynamic evolution. For example, the question of which process(es) control lithospheric removal from beneath the Wyoming and North China cratons still enigmatic. To address this problem, we are using 2D numerical models to investigate how lithospheric mantle of the North China Block has been thinned in which geological, geophysical and petrological studies refers the areas as key example of cratonic destruction/removal that occurred (120-80 Ma). Considering the geological evolution of North China region, the main focus of the study is to investigate the effects of a set of parameters (e.g., viscosity, buoyancy and thickness) for the base of cratons which is likely weakened by fluids released from the subducting oceanic plate. Our preliminary results show that movement of the subducting plate is sensitive to the parameters affecting the stability of the lithosphere whereas overriding plate is mainly affected by viscosity. If the base of the cratonic lithospheric mantle is dense, thick and relatively less viscous, it forces oceanic slab to rollback, else the overlying plate slides through the base of the cratonic mantle. The model results with stagnated oceanic plate at the transition zone with low viscosity cratonic base is responsible for the deformation of the cratonic roots.
Large rockfall detection, location and characterization using broadband seismic records: A case study of Hongya rockfall
Authors: Li Wei , Wang Dongpo , Zhang Zhen
Published: February 2023

Large rockfalls often cause huge economic losses and casualties in densely populated mountain areas. Timely acquiring information on a large rockfall can help promptly assess the damage and residual risks and guide the emergency response. Recent works suggest that the seismic signals generated by large rockfalls can provide these key information, but most of them focused on exploring seismic signatures to understand rockfall dynamics, lacking a rapid disaster assessing scheme. Here, we establish a seismic signal-based assessment scheme and demonstrate its capability by taking a large event – the 5 April 2021 Hongya rockfall (Sichuan, China) – as a case study. This scheme consists of three components, which are rockfall identification, detection and location, and characterization. In the rockfall identification module, we show how a rockfall can be distinguished from an earthquake and a rockslide by analyzing its seismic signatures. In the detection and location module, we demonstrate how the kurtosis-based method can be used to rapidly detect the initiation of a rockfall and determine the seismic wave velocity accordingly, and how the arrival-time-based location method can be used to locate a rockfall event. In the rockfall characterization module, we show how rockfall volume can be estimated from the magnitude of radiated seismic energy and how to characterize the dynamic process of a rockfall by the signatures of seismogram, spectrum and recorded seismic energy. Our results show that the seismic signal-based scheme presented here is suitable to characterize large rockfalls and has certain potential for rapid and effective emergency management.
Metamorphic evolution of high-pressure garnet amphibolite from the Eastern Himalayan Syntaxis: Implications for the mechanism of crustal thickening and exhumation of southern Lhasa terrane during late Cretaceous
Authors: Zhang Yanling , Yin Changqing , Davis Donald Wayne , Li Shun , Qian Jiahui , Zhang Jian , Gao Peng , Wu Shangjing , Li Wangchao , Xia Yanfei
Published: February 2023

This study presents a comprehensive metamorphic study of geochronology, petrography, mineral chemical, and P-T path for late Cretaceous high-pressure garnet amphibolite from the southern Lhasa terrane of the Eastern Himalayan Syntaxis. Mineral textures and reaction relationships suggest that these rocks have experienced three metamorphic stages (M1-M3). The M1 stage is characterized by peak mineral assemblages of Grt + Hb + Ab + Ru + Ms + Qz, followed by the post peak (M2) assemblages of Grt + Hb + Pl + Ep + Bi + Ru + Qz in the matrix. Late retrograde stage (M3) is defined by Hb + Pl coronae surrounding garnet porphyroblasts, indicating a decompression process. These mineral compositions in combination with whole-rock phase equilibria modelling of high-pressure garnet amphibolite give P-T conditions of three metamorphic stages at 14-19 kbar/660-720 ℃ (M1), 8-10 kbar/650-660 ℃ (M2), and <7 kbar/<600 ℃ (M3), respectively. In summary, a P-T path involving a near-isothermal decompression process and late cooling accompanied by decompression has been reconstructed for high-pressure garnet amphibolite. Moreover, SIMS zircon U-Pb dating results show that metamorphic zircons yield a concordant age of ~90 Ma, suggesting a peak metamorphic age. The results indicate that the southern Lhasa terrane underwent a sequence of tectonometamorphic processes that were initiated by crustal thickening (M1) of up to 60 km at 90 Ma, followed by rapid exhumation along a subduction channel to the depth of 32-26 km (M1-M2) and later slow uplift (M2-M3).
Sulfate isotopes over termination II - Source decomposition and Southern Ocean productivity changes
Authors: Fischer Hubertus , Burke Andrea , Rae James , Wolff Eric , Pryer Helena , Doyle Emily , Severi Mirko , Markle Bradley , Hörhold Maria , Freitag Johannes , Erhardt Tobias
Published: February 2023

An important ingredient in the glacial reduction of atmospheric CO2 is the increase of marine biological productivity in the Southern Ocean region due to an alleviation of Fe limitation in glacial times. This is indeed documented in marine sediments north of the modern Antarctic Polar Front (APF). In contrast, productivity south of it appears to be reduced, however the marine information is incomplete due to the prevalence of winter and summer sea ice in major parts of this region during glacial times. The high-resolution Antarctic ice core sulfate aerosol record, which, among other sources, is influenced by the marine biogenic emission of dimethylsulfide, was so far unable to provide unambiguous estimates of such productivity changes. In particular, sulfate deposition fluxes in the EPICA Dome C ice core (EDC) showed no glacial/interglacial changes whatsoever, while the same data in the EPICA Dronning Maud Land core (EDML) suggested a slight increase in the glacial, despite the fact that these records should be dominated by biogenic sources south of the APF.
New high-precision stable sulfur isotope measurements on ice core sulfate over termination II on the EDML core together with high-resolution sulfate, sea-salt and mineral dust aerosol concentration records allow us for the first time to perform a quantitative decomposition of the sea salt, terrestrial, volcanic and biogenic sulfate contributions. This shows that despite a significant increase in terrestrial sulfate in the glacial, marine biogenic emissions are still by far the dominating source of sulfate during that time at least for the Atlantic sector of Antarctica but likely for the entire Antarctic plateau.
Using a simple atmospheric aerosol transport model to correct for the loss of sulfate aerosol en route by wet and dry deposition, we are able to reconstruct the atmospheric sulfate aerosol concentrations changes over the Atlantic sector of the Southern Ocean source region mainly south of the APF. This shows that despite lower sulfate ice concentrations at EDML during interglacials, atmospheric aerosol concentration at the ocean source south of the APF - hence marine biogenic sulfur emissions - were up to a factor of 2 higher during the last interglacial and the late termination II than during the penultimate glacial maximum.
A mechanism of ion exchange by interface-coupled dissolution-precipitation in the presence of an aqueous fluid
Authors: Putnis Christine V. , Putnis Andrew
Published: February 2023

The equilibration of minerals in the presence of an aqueous fluid phase, with which it is out of equilibrium, has been described in terms of a number of potential mechanisms, specifically mainly either by solid state exchange of elements within the solid phase and the aqueous solution, or by interface-coupled dissolution-precipitation where equilibration is approached by the incremental dissolution of the parent solid and the coupled precipitation of a new product solid (Ruiz-Agudo et al., 2014). The conditions determining the equilibration mechanism can be defined by the specific chemical potential differences at the mineral interface, the kinetics of potential reactions, the solubility of the solid phase in the specific fluid and physical properties such as the mineral: fluid ratio as well as the surface area: fluid ratio, temperature and pressure. We focus on the mechanism of ion exchange in a range of minerals and in most cases ion-exchange in the presence of an aqueous solution occurs by interface-coupled dissolution-precipitation (Putnis and Putnis, 2022).ReferencesPutnis C.V. and Putnis A. 2022. A mechanism of ion exchange by interface-coupled dissolution-precipitation in the presence of an aqueous fluid. J. Crystal Growth, 600, 126840Ruiz-Agudo E., Putnis C.V., Putnis A. 2014. Coupled dissolution and precipitation at mineral-fluid interfaces. Chemical Geology 383, 132-146.
.5 ka BP cold spell in the Nordic Seas: a potential trigger for a global cooling event?
Authors: Telesiński Maciej M. , Zajączkowski Marek
Published: February 2023

The present interglacial is a relatively warm and stable interval, especially compared to the preceding glacial period. However, several prominent cooling events have been identified within the Holocene epoch. Most of them occurred in its early or late part, while the middle Holocene was generally considered the warmest and most stable phase. Some of the cooling events (e.g., the well-known 8.2 ka BP event) have been proven to be of overregional importance. Here we focus on an event centred around 6.5 ka BP observed in marine records from the Norwegian Sea and the Fram Strait that has not been described previously. Planktic foraminiferal records from cores along the North Atlantic Drift reveal a subsurface water cooling that in the Fram Strait was more prominent than the well-known 8.2 ka BP event. The increase in the abundance of cold water foraminiferal species is preceded by a stepwise expansion of sea ice in the eastern Fram Strait and is accompanied by a decrease in the abundance of planktic foraminiferal species, an increase in shell fragmentation and IRD deposition. At the same time, alkenone-derived surface water temperatures in the north-eastern Norwegian Sea remain high, suggesting that the cooling was related to a drop in Atlantic Water advection rather than an external forcing. We discuss the possible causes of this event and its potential consequences, including the triggering of a global climatic deterioration that occurred shortly thereafter. Understanding the mechanisms behind such cold spells occurring within a generally warm interval is invaluable for future climate predictions. This study was supported by grant no. 2020/39/B/ST10/01698 funded by the National Science Centre, Poland.
Stress-strain relationships at elongated calderas in extensional settings: what analogue models say
Authors: Maestrelli Daniele , Facincani Pietro , Sani Federico , Bonini Marco , Montanari Domenico , Del Ventisette Chiara , Corti Giacomo
Published: February 2023

Collapsed calderas are circular to elongated large depressions originating from the subsidence induced by depletion and/or migration of magma from a shallow or deep reservoir during eruptions. Despite being distributed in all tectonic settings, they are particularly important in extensional settings where are often associated with rifting processes, e.g., the East African Rift System. Therefore, their structural architecture can be strongly perturbed by extensional faults associated with regional extension or related to earlier stages of caldera formation. Calderas often bear an elongated shape in plain view, and have been considered valuable proxies for the regional stress (e.g., Nakamura, 1977) and regional strain (e.g. Casey et al., 2006). Moreover, other authors have related the elongated calderas to the influence of preexisting structures reactivated during extension (Acocella et al., 2003). We therefore aim to investigate the mechanical interactions between collapsed calderas and regional extension leading to elongated edifices. Analogue models of caldera collapse were performed by placing a circular magma chamber (simulated with poly-glycerine) placed below a sand-mixture package. We induced the collapse by draining out the analogue magma from the base, reproducing the classical fault architecture observed at many collapsed calderas (i.e., early inner outward-dipping reverse faults and late outer inward-dipping normal fault). Once completed, the collapsed depression was stretched such that normal faulting produced caldera elongation and segmentation. Finally, we compared the elongation and the structural pattern deriving from the interacting caldera-related and rift-related structures with natural examples from the East African Rift System. Our results suggest that different interacting factors may contribute to the development of elongated calderas, thereby questioning whether elongated calderas can be considered as a fully reliable proxy for the regional strain.Acocella, V., Korme, T., Salvini, F., and Funiciello, R. (2003). Elliptic calderas in the Ethiopian Rift: control of pre-existing structures. J. Volcanol. Geotherm. Res., 119, 189–203.Casey, M., Ebinger, C., Keir, D., Gloaguen, R., and Mohamed, F. (2006). Strain accommodation in transitional rifts: extension by magma intrusion and faulting in Ethiopian rift magmatic segments. Geol. Soc. Lond. Spec. Publ., 259(1), 143–163.Nakamura, K., (1977). Volcanoes as possible indicators of tectonic stress orientation— principle and proposal. Journal of Volcanology and Geothermal Research 2, 1–
The hot and dry climate of the supercontinent Pangea
Authors: Hu Yongyun
Published: February 2023

The Pangea era was an exceptional phase in Earth’s history. It was characterized by its hothouse climate state and the latest supercontinent. And the supercontinent is South-North oriented, nearly extending from South Pole to North Pole. Geological evidence shows that the climate of the supercontinent Pangea was not only hot but also dry. In this talk, I will show simulation results that the dry climate condition of Pangea was largely due to the broad landmass and its South-North orientation. Such a particular continental configuration resulted in much weaker precipitation in the tropics and extratropics, not only over land but also over ocean, compared with other hot periods in the Phanerozoic. Associated mechanisms of the slower hydrological cycle of the supercontinent Pangea will also be discussed. 
Urbanization impacts on sequential flood-heatwave events in the Guangdong-Hong Kong-Macao Greater Bay Area , China
Authors: Liao Weilin , Zheng Kaican
Published: February 2023

Urbanization has been shown to significantly increase the frequency and intensity of extreme weather events, i.e., extreme precipitation events, and heatwave events. Actually, the occurrence of compound extreme events, such as sequential flood-heatwave (SFH) events, can lead to more severe impacts than singular extreme events. However, the impact of urbanization on these compound extreme events is not well understood. In this study, we examine urbanization effects on the growth of SFH events in the Guangdong-Hong Kong-Macao Greater Bay Area from 1961 to 2017. We classify stations into urban and rural types based on dynamic land use data and define SFH events using the criteria from previous studies. We find that the frequency of SFH events in urban stations increased from 0.218 events per year before the 1990s to 1.401 events per year after the 1990s, while the frequency of SFH events in rural stations increased from 0.250 events per year to 0.920 events per year. The urban impact of 0.131 events per decade also shows that urbanization can promote the occurrence of SFH events. Our analysis also indicates that urbanization promotes the growth of SFH events mainly by increasing the frequency of heatwave (HW) events. These findings highlight the need for further research on the effects of urbanization on compound extreme events and the development of effective management strategies to reduce their risks.
Abnormal local warming after reducing solar constant under special paleogeography configurations
Authors: Wei Mengyu , Yang Jun , Hu Yongyun , Li Xiang , Lan Jiawenjing , Guo Jiaqi , Hu Shineng
Published: February 2023

In the deep past the solar constant was lower than present. In this study, we employ the Community Earth System Model version 1.2.2 (CESM1.2.2) to examine the effect of reduced solar constant on the climate of the past 250 million years. Two groups of slice experiments (fixed pre-industrial solar constant versus decreased solar constant) with 26 different paleogeography configurations and with fixed CO2 concentration (2800 ppmv) were run. In all the experiments, the global-mean surface temperature decreases as reducing the solar constant, consistent with previous studies. However, there is significant local surface warming in the experiments of 70 Ma, 90 Ma, and 150 Ma. The warming has a magnitude of about 2 K and occurs in the sub-polar ocean region. At 70 Ma and 90 Ma, the dominant mechanism is atmospheric teleconnection between tropics and sub-polar regions. Cooling in the tropics induces abnormal atmospheric waves, and the waves propagate to the sub-polar region and subsequently change surface winds there. The abnormal winds cause an increased poleward ocean heat transport, warming the regional surface. The second mechanism is that the reducing solar constant shifts the westly jets equatorward and causes an eastern wind anomaly, which also explains the warming at 150 Ma. Moreover, positive thermohaline feedback related to enhanced surface evaporation enhances the thermohaline circulation and thereby acts to further warm the surface. The phase of the atmospheric waves and their propagation path strongly depend on the land-sea configurations, so the abnormal local warming occurs in special periods only.
Texture and trace element geochemistry of quartz in porphyry system: Perspective from the Gaogangshan Mo Deposit, NE China
Authors: Zhang Yongmei , Gu Xuexiang , Yao Shiyue , Zhao Wei
Published: February 2023

The Gaogangshan deposit in the northern Lesser Xing'an Range, NE China, consists of typical collision-type porphyry Mo mineralization related to Permo-Triassic granitic intrusions. Ore-forming process is recorded by multiple generations of quartz, including pre-ore stage quartz with unidirectional solidification texture (UST), early ore-stage quartz-molybdenite veins with K-feldspar alteration halos (Q1), late ore-stage quartz-sulfides veins with sericite alteration (Q2), and post-ore stage quartz veins (Q3) associated with calcite and fluorite. Cathodoluminescent textures, trace elements and fluid inclusions in quartz reveal physicochemical conditions, evolution of ore fluids and the Mo mineralization process. The UST quartz and Q1 veins are dominated by CL-bright homogenous and/or granular mosaic textures, containing more Ti concentrations (average = 35-42 ppm) than Q2 and Q3 veins. The molybdenite-bearing Q2 veins are dominated by CL-gray granular and zonal textures, displaying less CL intensity and lower Ti concentrations (average = 16 ppm) than early-stage quartz. The Q3 veins have the lowest CL-intensity and the lowest Ti concentrations (average = 2.5 ppm) among all quartz types. Three types of inclusions are identified in above quartz samples, including liquid-vapor aqueous inclusions, CO2-bearing liquid-vapor aqueous inclusions and halite-bearing multiphase aqueous inclusions. The ore-forming fluids in ore-stage Q1 and Q2 veins are dominated by large salinity variation (2.3-38.9 wt% NaCl equiv.), CO2-bearing (4.2-8.9 mol%) two-phase aqueous inclusions with vapor volumetric proportions of 30-65%. Intersections of fluid inclusion isochores with Ti-in-quartz isopleths yield quartz formation conditions of ~2.2 kbar at ~640°C for UST quartz, ~1.25 kbar at ~510°C for Q1, ~1.0 kbar at ~440°C for Q2, and ~0.37 kbar at ~220°C for Q3. The Gaogangshan porphyry Mo deposit formed at depths of 3.8 to 4.7 km. Fluid decompression and temperature decreasing resulted in molybdenite precipitation.
Fluid-mediated alteration of zircons to fergusonite-(Y) in A-type granites and pegmatite from the Jharsuguda district, India
Authors: panda Suratha , Roy Arkadeep , Pruseth Kamal
Published: February 2023

The A-type granites of Jharsuguda at the boundary between the Singhbhum Craton and Rengali Province have rare earth potential. Two populations of zircon are present. One of them represents the unaltered zircons of magmatic origin, as evidenced by the presence of oscillatory zoning and Th/U ratios > 0.7. The other population consists of the altered equivalents of these primary zircons. These zircons have Th/U ratios < 0.1, suggesting their metamorphic origin. Occasionally, single grains of zircon containing both altered and unaltered domains are also encountered. The unaltered zircons comprise a very small proportion. The altered zircons appear dark in CL images and are characterized by low EPMA totals with non-formulae elements like Al, P, Ca, Fe, Y, and REEs. Numerous mineral inclusions, including those of U- Th-bearing ones, are typical of these altered zircons. Xenotime inclusions are typical of altered zircons with xenotime overgrowths in the granites. Rare Nb-rich inclusions are also present in these altered zircons.   In both the granites and pegmatite, fluid-mediated alteration resulted in fergusonite-(Y) and other Nb-Ta-REE oxides in the cracks and fractures. Pseudomorphs of fergusonite-(Y), Nb-Ta-REE oxides, and allanite are also formed by replacing earlier zircon grains. The size of these fergusonite grains ranges from a few micrometers in granite to up to 500 micrometers in pegmatites. The LA-ICPMS U-Pb dating zircons yield a primary age of 2.95 Ga and metamorphism ages of 2.80 Ga and 2.45 Ga. Selected fergusonite-(Y) grains from the pegmatite suggest a 2.1 Ga U-Th-Pb EPMA age for these fergusonites. Rims of some zircon grains in both granites and pegmatite also yield an age of 2.1–2.2 Ga. The age data suggest that the Jharsuguda granites and pegmatite underwent at least three metamorphic/tectonothermal events, during the last of which fergusonites are formed by the remobilization of REEs and HFSEs, probably in the presence of complexing ligands like F– and PO4–, as confirmed by EPMA X-ray element maps of altered zircons.
New scheme for numerical computation of high degree Legendre polynomials
Authors: Panou Georgios , Koci Jason , Iossifidis Christos
Published: February 2023

Spherical harmonics are widely used to represent the gravitational field of the Earth and other celestial bodies. These harmonics include Legendre’s polynomials. However, the numerical computation of these polynomials is a difficult issue, especially to a high degree. In the literature, several algebraic or numerical methods have been proposed to compute Legendre polynomials with acceptable precision within reasonable time, avoiding instabilities due to underflow or overflow problems. These methods have their advantages and disadvantages. For example, cannot be used for parallel computations. In this contribution, we are developing a new scheme for the numerical computation of Legendre polynomials. The problem of underflow/overflow is managed by using trigonometric identities and a technique based on successive ratios. The performance of the proposed scheme is demonstrated by several numerical experiments. In addition, the results are compared with other methods in terms of stability, precision, and speed. Finally, we suggest means for the generalization of the proposed algorithm in the numerical computation of the related Legendre functions for high degrees and orders.
Using tunable diode laser (TDL) system in urban environments to measure anomalous CO2 concentrations: the case of Puerto Naos, La Palma, Canary Islands
Authors: Barrancos José , Padilla Germán D. , Melián Gladys V. , Rodríguez Fátima , Asensio-Ramos María , Padrón Eleazar , Hernández Pedro A. , Vilches Sarasate Jon , Pérez Nemesio M.
Published: February 2023

Carbon dioxide (CO2) is a colourless and odourless gas. It is non-flammable, chemically non-reactive and 1.5 times as heavy as air; therefore, may accumulate at low elevations. CO2 is a toxic gas at high concentration, as well as an asphyxiant gas (due to reduction in oxygen). Irritation of the eyes, nose and throat occurs only at high concentrations. Since the Tajogaite eruption ended on December 13, 2021, high concentrations of CO2 up to 20% (200.000 ppmv) have been observed inside of buildings of the neighborhoods of La Bombilla and Puerto Naos (La Palma, Canary Islands), which are located about 5 km distance from the Tajogaite eruption vent. Anomalous concentrations of CO2 are manily detected in the ground-floor and basement of the buildings in Puerto Naos, and the distribution of relatively high CO2 concentrations  is not homogeneous or uniform throughout the Puerto Naos area (Hernández P.A. et al, 2022).The purpose of this study was to use the Tunable Laser Diode (TDL) absorption spectroscopy method to monitor the indoor CO2 concentration of the ground-floor of one of the buildings of Puerto Naos. A CO2-TDL was installed on 9 January 2022 and continues measuring the CO2 concentration along an optical path of about 6 meters. During the period January-March 2022, daily averages of CO2 concentrations from fifteen-minute data ranged from 5000 to 25000 ppmv reaching values up to 40000 ppmv (4%). Over time, a clear decreasing trend of the indoor CO2 concentration has been observed at this observation site and the daily CO2 averages from fifteen-minute data during the last 3 months (October-December 2022) ranged from 1000 to 2500 ppmv. This clear decreasing trend over time has not been observed at other observation sites where the concentration of CO2 inside buildings is being monitored. This observation indicates the complexity of the problem and the need to install a dense network of sensors to monitor CO2 for civil protection purposes. Hernández, P. A., Padrón, E., Melián, G. V., Pérez, N. M., Padilla, G., Asensio-Ramos, M., Di Nardo, D., Barrancos, J., Pacheco, J. M., and Smit, M.: Gas hazard assessment at Puerto Naos and La Bombilla inhabited areas, Cumbre Vieja volcano, La Palma, Canary Islands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7705, https://doi.org/10.5194/egusphere-egu22-7705, 2022.