bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of extreme heat days and nights on urban heat environment: a perspective of local climate zones
Authors: Wang Bin , Gao Meiling , Li Zhenhong
Published: March 2024

Increasing human activities and urbanization have posed huge challenges to the urban climate, such as the urban heat island effect, which makes air temperature in urban areas higher than that in suburban areas. Meanwhile, the urban heat island intensity (UHII) suffers impacts from the exacerbation of observed extreme heat events, but how extreme heat events affect UHII in different subdivided urban spaces remains unclear. In this paper, we attempt to address the impact of extreme heat days and nights on urban heat environment from the perspective of local climate zones (LCZs). Firstly, we propose a framework for LCZ classification for higher precision LCZ mapping over the Guanzhong Plain urban agglomeration in China. Secondly, to select extreme heat days and nights based on six extreme temperature indices (TXx, TNx, TX90p, TN90p, SU25 and TR20), the daily maximum, minimum and average seamless 1-km air temperatures are estimated using the random forest method for the period from 2000 to 2020. Finally, combining the LCZ map and gridded temperature product, we analyze variance in air temperature and UHII among different LCZs at daytime and nighttime, as well as the influence of extreme heat conditions on air temperature and UHII in different LCZs.Our results indicate that the air temperature difference within LCZs is greater under extreme heat conditions compared against that under non-extreme conditions. Meanwhile, extreme heat conditions aggravate the urban heat risks at daytime, which is manifested in the following two aspects: (1) the temperature difference within LCZs on extreme heat days is greater than that on extreme heat nights; and (2) UHII at nighttime is stronger than that at daytime in most LCZs under non-extreme conditions, but under extreme heat conditions, it is the opposite. In addition, although the rank of UHII in different LCZs varies due to differences in time and definition of extreme heat days and nights, LCZ 6a (agricultural greenhouse) stands out for suffering the highest UHII under all conditions (different extreme temperature indices, on days and nights), to which particular attention should be paid. Our results could be contributed to conducting mitigation measures of urban heat risks and providing more explicit guidance to policymakers and urban planners.
Australia’s drift as a pacemaker for the seasonal variability of warm pool precipitation
Authors: Yin Zihan , Nie Ji
Published: March 2024

Tropical precipitation is profoundly influenced by continental evolution across geological time scales. However, the effects of Australia’s drift on warm pool precipitation remains poorly understood. Using a fully coupled climate model with realistic geography, our results reveal a significant amplification of the seasonal migrations of warm pool precipitation in longitude and latitude due to the equatorward drift of Australia. Notably, the observed feature aligns with paleoclimate simulations over the past 40 million years, highlighting the dominant role of Australia’s drift in comparison to the other continental drifts. This study provides insight into how Australia’s drift has shaped the characteristics of warm pool precipitation over the geological timescales.
Analysis of seismic characteristics for permafrost according to porosity ratio using 3D printing technology
Authors: Kim Daechul , Shin Sungryul , Chung Wookeen
Published: March 2024

Permafrost means soil that remains below 0 ℃ for at least two continuous years. Due to climate change, permafrost is thawing, releasing greenhouse gases(Schuur et al., 2015; Colett et al., 1988). Greenhouse gas emissions from permafrost could accelerate climate change. Therefore, it is necessary to detect and predict changes by estimating the distribution and thickness of permafrost. One of the methods to detect permafrost and detect changes is seismic exploration. Permafrost has various geological characteristics depending on the region, and the porosity of permafrost affects the acoustic wave characteristics(Brothers et al., 2016). Therefore, in order to detect permafrost and detect changes in seismic exploration data, a study is needed to analyze seismic characteristics according to the porosity of permafrost.In order to create a model according to the porosity of the permafrost and analyze the characteristics of seismic, the porosity was controlled using 3D printing technology and seismic data was acquired through an seismic physical modeling. In this study, an FDM(fused deposition modeling) 3D printer was used to control the porosity of permafrost. Since the porosity of permafrost is about 20-50 % depending on the region, the pore size was set to 3, 4, and 5 mm to create a model similar to the porosity of permafrost. Permafrost was simulated by saturating and freezing water in the pores of the porosity model according to porosity.A seismic physical modeling was performed to acquire seismic data in permafrost according to porosity. The seismic physical modeling is an experiment that reduces field exploration to a laboratory scale and has excellent field reproducibility. A 1 MHz transducer was used as the source and receiver, and signals were generated using a pulser/receiver. Signals were received and stored using a digital oscilloscope. In order to analyze the characteristics of permafrost according to porosity, the velocity and maximum amplitude were analyzed in the time domain from the acquired seismic data. In addition, the maximum frequency and magnitude according to the porosity of the permafrost were analyzed in the frequency domain.In this study, 3D printing technology was used to control the porosity of permafrost. Additionally, seismic characteristics were analyzed according to the porosity of the permafrost using a seismic physical modeling. The results of this study are expected to be used as basic data to understand the characteristics of permafrost according to its porosity and to detect and detect changes in permafrost. AcknowledgementThis research was supported by Korea Institute of Marine Science & Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries, Korea (RS-2023-00259633).
'DiTing' and 'DiTingtools':a large multi-label dataset and algorithm set for intelligent seismic data processing established based on the China Seismological Network
Authors: Zhao Ming , Xiao Zhuowei , Zhang Bei , Zhang Bo , Chen Shi
Published: March 2024

As the amount of seismic data increasing drastically worldwide, there are ever-growing needs for high-performance automatic seismic data processing  methods and high-quality, standardized professional datasets. To address this issue, we recently updated the 'DiTing' dataset, one of the world's largest seismological AI datasets with ~2.7 million traces and corresponding labels,  with 1,089,920 three-component waveforms from 264,298 natural earthquakes in mainland China and adjacent areas, and 958,076 Pg, 780603 Sg, 152752 Pn, 25956 Sn earthquake phase arrival tags, in addition to 249,477 Pg, 41610 Pn first motion polarity tags from 2020 to 2023. We also collected 15375 non-natural earthquake waveforms in mainland China from 2009 to 2023 and a manually labeled noise dataset containing various typical noise signals from the China Seismological Network. With the support of the 'DiTing' dataset, we developed and trained several deep learning models referred as 'DiTingTools' for automatic seismic data processing. In the continuous waveform detection and evaluation of more than 1,000 stations over a year across China, 'DiTingTools' has achieved an average recall rate of 80% for event detection, mean square error ±0.2s for P phase picking, and ±0.4s for S, the average identification accuracy rate of Pg first motion polarity reached 86.7% (U) and 87.9% (D), and 75.1% (U) and 73.1% (D) for Pn first motion polarity, the average magnitude prediction error of a single station is mainly concentrated at ±0.5. The remarkable generalization capabilities of 'DiTingTools' were demonstrated through its application on the China Seismic Network. Specifically, 'DiTingPicker', a model within 'DiTingTools' designed for earthquake detection and phase picking, was employed to analyze the M 6.8  earthquake that struck Luding County, Sichuan Province, in 2022. This tool was instrumental in automatically processing data to examine the main shock and intricate fault structures of the aftershocks. The effectiveness of 'DiTingTools' in earthquake prevention and disaster reduction was further validated through these practical applications.
Development of a comprehensive and ultrasensitive isotope calibration method for soil amino acid profiles using Orbitrap mass spectrometry
Authors: Li Tao , Li Yuhua , Tian Ye , Salas Erika , Liu Xiaofei , Wanek Wolfgang
Published: March 2024

Bound amino acids constitute a significant portion of soil organic nitrogen, which represents an essential source of nitrogen for plant and microbial nutrition. The analysis of the content and isotope enrichment of bound amino acids still represents a significant challenge due to the degradation of certain amino acids following the conventional acid hydrolysis method, due to the low isotope enrichment levels reached under near-native soil conditions and due to the lack of isotopically labelled standards for some key amino acids. In this study, we used both a 13C-labeled and unlabeled 16 algal amino acid mixture to establish standard calibration curves for various amino acids, using the 6-Aminoquinolyl-N-hydroxysccinimidyl carbamate (AQC) derivatization method and the ultra-high-performance liquid chromatography with high-resolution Orbitrap mass spectrometry (UPLC-Orbitrap MS) platform. Molecular ions of AQC-derivatives for all amino acids were identified at the expected m/z values of the respective isotopologues, and the isotope calibration curves exhibited excellent linearity for those amino acids where we had isotope standards at hand (polynomial R2 > 0.9896). However, the polynomial fitting terms differed between single amino acids. Subsequently, we developed equations to relate the calibrated regression terms to physicochemical properties of the respective amino acids. First, we conducted a linear regression using the Orbitrap-derived 13C atom % of unlabeled standards against the carbon atom number of the specific amino acid-AQC derivative molecules, demonstrating great linearity (R2 = 0.9728). This linear regression curve allowed us to predict the natural 13C abundance of amino acids unavailable as isotopically labelled standards (e.g. hydroxyproline, meso-diaminopimelic acid). Consequently, based on further regressions, we could ultimately develop isotope calibration curves for those amino acids unavailable as 13C labelled standards based on the integrated isotope calibration functions. This general predictive model can be applied to comprehensively and highly sensitively (13C enrichment ~0.01 at %) quantify isotope enrichments of the whole soil amino acids profile, providing valuable insights for a better understanding of the overall fate of different amino acids in soils.
Geochemical effects of hydrothermal alteration in the Neotethyan oceanic lithosphere: inferences from the serpentinized mantle rocks of the Spongtang ophiolite, Ladakh, NW Himalaya
Authors: Nayak Bikash Ranjan , Ovung Thungyani N
Published: March 2024

The Spongtang Ophiolite positioned along the Indus Suture Zone (ISZ) in Ladakh, NW Himalaya, stands as a key geological site for unraveling the origin and tectonic evolution of serpentinized ultramafic rocks. The petrographic study of highly serpentinized ultramafic rocks is characterized by presence of relict olivines and orthopyroxenes exhibiting porphyroclastic texture. Orthopyroxene grains exhibit bastite texture pseudomorphing the primary relict grains and are altered along their rims to form lizardite. Olivine grains have been mostly altered to lizardite having mesh and hourglass texture and show characteristic peaks at 230 cm-1, 383 cm-1 and 692 cm-1 under Raman spectroscopy. Chrysotiles are observed to have fibrous vein cross-cutting relict orthopyroxene and olivine grains and show peaks at around 135 cm-1, 232 cm-1, 385 cm-1 and 694 cm-1. Antigorites show interlocking to interpenetrating planar texture peaking at 229 cm-1, 377 cm-1 and 687 cm-1. All these major phases are associated with minor brucite, indicating initial stage of serpentinization, and showing characteristic peak at 276 cm-1 and 442 cm-1, 721 cm-1 and 1086 cm-1. Magnetites are formed as alteration products along the rims of chromites and within the serpentine veins indicating mature stage of serpentinization. Lizardite and chrysotile commonly occur during sea floor serpentinization at temperature condition ranging between 50-400˚C. Antigorite mostly occurs in a subduction setting and formed at temperature between 300-600˚C. Mineral chemistry data of serpentines exhibit wide variation in MgO (8.66 wt. % to 27.20 wt. %) and FeO (4.10 wt. % to 12.26 wt. %). However, SiO2 (43 wt. % to 40.82 wt. %) and Al2O3 (0.16 wt. % to 1.07 wt. %) content in serpentines varies within a small range indicating that Si and Al are relatively immobile compared to Mg and Fe during serpentinization. The crosscutting brucite veins have high MgO and FeO composition of 50.53 wt. % and 16.56 wt. % respectively. Mg# of serpentines vary between 0.80 to 0.85, which is much lower than olivines (Mg# = 0.91-0.92) and pyroxenes (Mg# = 0.91-0.97) indicates that magnesium loss has been taken place during serpentinization from the primary minerals. High CaO (22.84 wt. % to 24.73 wt. %) content in diopside grains than the surrounding serpentine grains (0.19 wt. % to 0.55 wt. %) implies that Ca has been removed from the serpentines during serpentinization. The base metal sulfide (BMS) mineral assemblages in serpentinized Spongtang ultramafics are dominated by presence of pyrrhotite, pentlandite, awaruite, magnetite and a few Cu-Fe-Ni alloys. Pyrrhotite, pentlandite and awaruite occur together in serpentine mesh centers and indicate presence of reducing condition at low water-rock ratio during their mineralization. Magnetites formed within serpentinized veins suggest a high water-rock condition leading to a more oxidizing environment.
Insights to anomalous positive carbonyl sulfide fluxes in a boreal forest by using eddy covariance flux measurements.
Authors: Thomas Abin , Laasonen Asta , Kohonen Kukka-Maaria , Vesala Timo , Aslan Toprak , Kolari Pasi , Maseyk Kadmiel , Dewar Roderick , Mammarella Ivan
Published: March 2024

Vegetation is the major sink of carbonyl sulfide (COS), and for this reason, COS is a valuable proxy for assessing gross primary productivity (GPP). In this study, a comprehensive analysis of three years (2020-2022) of eddy-covariance measurements over a boreal forest in Hyytiälä (Finland) has unravelled intriguing patterns in COS fluxes in response to environmental conditions. The measurements were done following a partial harvest of the forest stand, where 40% of the basal area was removed from the footprint area. An anticipated reduction in uptake was observed in the summer of both 2020 and 2022. However, during the summer of 2021, anomalous positive COS fluxes (emission of COS) were consistently observed. The primary mechanism responsible for the removal of COS in leaves is hydrolysis, facilitated by the enzyme carbonic anhydrase (CA), leading to the production of hydrogen sulfide (H2S) and carbon dioxide (CO2). In the case of the Hyytiälä forest, CA-driven hydrolysis of the canopy acted as the dominant sink for COS. A detailed examination of environmental conditions prevailing during this period revealed a confluence of factors contributing to the unusual COS fluxes. Elevated temperatures, higher vapour pressure deficit, and decreased soil water content during the 2021 summer were identified as potential reasons for the anomalous COS flux responses. These conditions could collectively exert a suppressing effect on both stomatal and non-stomatal uptake of COS by the vegetation and soil. The empirical soil model used in the study also points towards increased abiotic production of COS from the soil due to increased soil temperature. However, the environmental conditions alone cannot explain the positive emissions during the daytime. Examining night-time fluxes shows that the canopy still uptakes COS even at a reduced rate. The analyses point towards the photodegradation production of COS from litter from the forest floor, which is overlooked in the empirical soil models and canopy uptake models. The thinning of the forest stand has led to a more open subcanopy, allowing increased sunlight penetration to the forest floor. The pine needles and residuals from the thinning are speculated to be the source of the photodegradation production of COS. Understanding the possible sources of these anomalous COS fluxes is crucial for refining our interpretation of COS as a proxy for GPP and, consequently, enhancing our ability to model and predict ecosystem productivity in a changing climate. In summary, the discovery of anomalous positive COS fluxes in the Hyytiälä boreal forest during the summer of 2021 represents a unique and significant observation, prompting further research into the complex interplay of environmental variables influencing COS fluxes within the boreal forest ecosystem.
Post-glacial paleoenvironmental changes of sedimentary processes recorded in the contourite drifts of Hupo Basin in the eastern margin of Korean Peninsula, East Sea
Authors: Kim Hyesung , Bahk Jangjun , Jang Junho , Kim Soojin , Sim Gyutae , Jeong Jiwon , Lee Kyung-Eun
Published: March 2024

The Hupo Basin is a slope-perched half-graben bounded on the east by the Hupo Bank in the eastern margin of Korean Peninsula. In the western slope of the Hupo Bank, moats, formed by bottom current activity, occur along the base of slope at water depths ranging from 208 to 238 m. Associated drift deposits with the moats which fills the Hupo Basin, thin out as they extend from the moat toward the coast. This study aims to understand post-glacial changes of sedimentary processes in the Hupo Basin, influenced both by transgression and variations in the along-slope bottom current activity based on the sedimentary characteristics of three piston cores acquired along an east-west transect from the drift deposit. The core sediments consist of bioturbated mud, bioturbated sandy mud, or muddy sand, which show abrupt upward fining trends after the Last glacial Maximum to about 8 ka, indicating progressively deepening offshore environments during the post-glacial sea-level rise. The overall mean grain sizes of the core sediments exhibit a fining trend towards the Hupo Bank decreasing from 51 μm at the shallowest (161 m) western-most site (P02), to 7 μm at the deepest (182 m) eastern-most site (P01), while the sedimentation rates since ca. 8 ka drastically increase towards the Hupo Bank, ranging from 38 to 104 cm/kyr. Moreover, the mean grain size of the P01 site slightly coarsens since ca. 2.3 ka, exhibiting significant cyclic fluctuations with ca. 100 – 200 yr periods and around 4 μm amplitude.The spatial temporal variations of grain sizes and sedimentation rates demonstrate how the sedimentary characteristics of shallow water contourites, such as the moat-drift system in the Hupo Basin, can be influenced by an interplay between variations in offshore-directed hydrodynamic conditions and associated along-slope bottom current activity due to sea-level changes. The sedimentary records of the contourite drifts of the Hupo Basin indicate initiation of vigorous bottom current activity in the western slope of the Hupo Bank by the East Korean Warm Current, a branch of Tsushima Warm Current flowing northward along the eastern margin of the Korean Peninsula since ca. 8 ka, with increased variability since ca. 2.3 ka.
LETKF-based Ocean Research Analysis (LORA): A new ensemble ocean analysis dataset
Authors: Ohishi Shun , Miyoshi Takemasa , Kachi Misako
Published: March 2024

Various ocean analysis products have been produced and used for geoscience research. In the Pacific region, there are four high-resolution regional analysis datasets [JCOPE2M (Miyazawa et al. 2017) and FRA-ROMS II (Kuroda et al. 2017) with 3D-VAR; NPR-4DVAR (Hirose et al. 2019) with 4D-VAR; and DREAMS with a Kalman filter (Hirose et al. 2013)], but there are no EnKF-based analysis datasets to the best of the authors’ knowledge.Recently geostationary satellites such as Himawari-8 and -9 have been providing sea surface temperatures (SSTs) at high spatiotemporal resolution. To use these data effectively, we have developed an eddy-permitting EnKF-based ocean data assimilation system at horizontal resolution of 0.25° with a short assimilation interval of 1 day and demonstrated that the combination of three schemes [incremental analysis update (IAU; Bloom et al. 1996), relaxation-to-prior perturbation (RTPP; Zhang et al. 2004), and adaptive observation error inflation (AOEI; Minamide and Zhang 2017)] significantly improved dynamical balance and analysis accuracy (Ohishi et al. 2022a, b). With the recent enhancement of computational resources, we have developed higher-resolution eddy-resolving ocean data assimilation systems at horizontal resolution of 0.1° and produced ensemble analysis products for the western North Pacific (WNP) and Maritime Continent (MC) regions called the LETKF-based Ocean Research Analysis (LORA)-WNP and -MC, respectively (Ohishi et al. 2023). The validation results show that the LORA has sufficient accuracy for geoscience research and various applications such as fisheries and marine transport. Since March 2023, the LORA-WNP and -MC have been released at JAXA-RIKEN Ocean Analysis website (https://www.eorc.jaxa.jp/ptree/LORA/index.html).
The variability determining the initial conditions for ensemble spread in the ZEC (CESM2) scenario
Authors: Seung-Hwon Hyun , Soon-Il An
Published: March 2024

In this study, we analyze the results of a multiple ensemble experiment using a single model (CESM2) for the Zero Emission Commitment (ZEC) scenario, where atmospheric CO2 emissions are initially increased as in a warming scenario and then reduced to zero. We found a significant increase in the ensemble spread of global temperature during the Zero Emission period following the warming phase. Ensembles which initially have the relatively higher salinity in the North Atlantic during the early Zero Emission period show the higher North Atlantic temperatures and salinity, along with less Arctic sea ice distribution, in later (ZEC) periods. Conversely, ensembles with initially lower salinity displayed opposite characteristics. We propose that the initial conditions of the Zero Emission period are associated to long-period internal variability that occurred during the previous period of positive CO2 emission fluxes (the warming period). The increase in ensemble spread in the Northern Atlantic is due to the the Atlantic Meridional Overturning Circulation (AMOC) salinity feedback becoming elongated due to strong ocean stratification. This suggests a prolonged period for this feedback mechanism, associated with the internal variability in AMOC.
Toward developing a streamlined workflow for methane emission monitoring, reporting, and verification in the oil and gas industry
Authors: Gao Mozhou , Liang Steve
Published: March 2024

Establishing a streamlined workflow within the Monitoring, Measuring, Reporting, and Verifying (MMRV) framework is crucial for effective methane emission management and accurate methane emission reconciliation in the oil and gas (O&G) industry. Despite existing MMRV standards such as the Oil & Gas Methane Partnership 2.0 (OGMP 2.0), Veritas 2.0, and MIQ providing valuable guidance, the O&G industry still faces obstacles in compliance with these standards. These obstacles include (1) The Bottom-Up (BU) inventory, constructed with generic activity and emission factors, underestimates emissions and poses gaps in closing uncertainties during the reconciliation process, (2) The decision to deploy one or multiple methane sensing technologies, relying on emission profiles derived from limited sample measurements, can not accurately represent all emissions due to their inherent limitations and the stochasticity and intermittency of emissions, (3) No standard has been employed to assimilate observations from sensing technologies with varying measurement scales and data from operational events, and (4) Addressing various uncertainties, including those arising from direct measurements, atmospheric inversion modeling, and population inference from sample emission events, proves challenging in the final stages of the reconciliation process.In this study, we present a streamlined MMRV-focused workflow integrating established and novel methodologies for reconciling emissions. The workflow consists of five key steps: Firstly, using the Oil and Gas Production Greenhouse Gas Emissions Estimator (OPGEE) to construct more accurate BU inventories and emission profiles for each type of equipment; secondly, determining the technology deployment plan and work practice based on constructed emission profiles using the Leak Detection and Repair Simulator (LDAR-Sim); thirdly, assimilating real measurements from deployed technologies through an ISO/OGC standard-based integrated sensor web architecture; fourthly, leveraging assimilated measurements and operational data to resolve emission events and reconcile the emissions; and finally estimating uncertainties from emission quantifications, inaccuracies in establishing emission event duration, and missed emission events. We demonstrate this workflow using data from the upstream O&G sites provided by an anonymous company. At the end of the demonstration we reconcile and report emissions by following the OGMP 2.0 guidelines. 
Estimation of Aircraft Icing Intensity Using Z-LWC Relationship from Radar and Aircraft Data
Authors: Ye Bo-Young , Kim Yura
Published: March 2024

Aircraft icing, a hazardous phenomenon involving the accumulation of ice or supercooled water droplets on an aircraft’s wings and airframe in freezing temperatures when an airplane flies through clouds, poses substantial risks to aviation safety. From a meteorological perspective, aircraft icing is determined by the air temperature, and the number and size of water droplets. In particular high values with water contents are a crucial factor correlating with increased icing intensity. Since weather radar can detect ice and water droplets larger than 2 mm in diameter within precipitable clouds, we have developed two radar-based aircraft icing products (icing potential areas and icing intensity) to facilitate safe aviation services in real-time. In this study, the estimation algorithm of aircraft icing intensity using Z-LWC relationship was presented. We utilized data from a ground-based S-band radar mosaic, an icing detector, and a cloud droplet probe installed on the aircraft (KMA/NIMS atmospheric research aircraft; NARA) for 13 cases of icing. Within the icing areas determined by the icing detector, 3-dimensional gridded reflectivity (Z) and liquid water content (LWC) were matched based on time and location. A Z-LWC relationship was then derived using the paired dataset sorted by size. We calculated LWC from Z using this relationship and categorized icing intensity into Trace, Light, Moderate, Heavy, and Severe, according to FAA criteria (FAA 2001). The estimation of icing intensity was solely focused within the identified icing potential areas (Kim et al. 2023). The algorithm was validated using a “Light” intensity icing case from aircraft report (AIREP), showing good performance, but further verification is needed. ACKNOWLEDGEMENTSThis research was supported by “Development of integrated radar analysis and customized radar technology (KMA2021-03021)” of “Development of integrated application technology for Korea weather radar” project funded by the Weather Radar Center, Korea Meteorological Administration.This work was funded by the Korea Meteorological Administration Research and Development Program "Developing Application Technology using Atmospheric Research Aircraft" under Grants (KMA2018-00222).
Temperature Profiles due to Groundwater Flow in a Subsurface Porous Medium with a Heat Convective Boundary
Authors: Chang Chia-Hao , Wang Bo-Tsen , Tsai Jui-Pin
Published: March 2024

The temperature in subsurface porous media (i.e., subsurface temperature) has been popularly treated as a natural tracer of groundwater flow. Several previous studies usually neglected the thermal boundary effects to build simple geothermal models for simulating the subsurface temperature. Although a few studies considered the thermal boundary effects, their models considered the thermal boundaries under either specific-temperature or specific-heat-flux conditions. However, these models are expectedly inapplicable to the cases of subsurface porous media with convective thermal boundary conditions. This study hence proposes a heat-transport model for describing the subsurface temperature induced by a heat convective boundary. The model is composed of a heat conduction-advection equation subject to a convective boundary condition at the bottom of a porous medium. The study results show how the convective boundary effects influence he subsurface temperature and indicate the effects are dominated by some parameters, including the medium thicknesses, medium thermal conductivity, heat transport coefficient, and groundwater flux.
Deformation of carbonated serpentinite controlled by Al- and Si-partitioning in phyllosilicates: a record of deep episodic tremor and slip?
Authors: Okazaki Keishi , Papeschi Samuele , Kawaguchi Kenta , Hirose Takehiro
Published: March 2024

Fluids are generally thought to assume a key role in controlling fast and slow earthquakes, not only because they lower the effective stress, but also because they act as catalysers of mineral reactions, moving chemicals in the rock mass. Serpentinites are particularly prone to carbonation reactions, which cause bulk-rock and volume change. The feedback between CO2 ingress in serpentinites, H2O-release, and tectonic appears to be able to sustain cycles of fluid pressure build-up and stress release that may be compatible with slow slip and tremor. However, the carbonation of pure serpentine (Mg3Si2O5(OH)4) should run to completion over geologic time scales, bearing the question if carbonation can sustain slow earthquakes in the long term at the subduction interface. On the other hand, the presence of Al, which does not enter the structure of talc, should slow down carbonation reactions and the products of serpentinite carbonation, allowing the process to be sustainable over long time scales.We, therefore, investigated natural samples of sheared carbonated serpentinite from a fossil shear zone in the Sanbagawa metamorphic belt exhumed from ~ 35–45 km and ~ 450–550 °C, corresponding to the present-day conditions of the source region of deep episodic tremor and slow slip in the nearby Nankai Trough. The shear zone preserves ‘intact’ antigorite-serpentinite, talc- and chlorite-bearing serpentinite breccia, and complex brittle/ductile shear zone consisting of quartz-bearing carbonate-chlorite-talc schists, talc - carbonate veins, and talc-rich mylonitic shear zones. We document that the presence of Al in antigorite and spinel causes the formation of abundant chlorite which inhibits carbonation reaction. We show that the formation of talc- and carbonate-rich domains is primarily related to the formation of veins crosscutting the carbonated rock fabric. Hence, the formation of talc mylonites is primarily associated with parts of the rock that became Si-rich, whereas Al-rich domains deform primarily by fracturing and veining. Finally, the presence of fractured sulphides in the rock documents multiple cycles of fracturing, sulphide precipitation, and healing, compatible with successive embrittlement, stress release, fluid infiltration, and fluid pressure drop events.We suggest that the presence of Al in the protolith serpentinitic material, which is common for ultramafic rocks, (1) slowed-down carbonation reactions, (2) prevented the rapid formation of talc-rich domains, and (3) kept the fabric heterogeneous and the rheology mixed, overall preventing the formation of weak domains that should have localized aseismic creep and possibly hosting episodic tremor and slow slip.
Urban heat trends across global cities
Authors: Naserikia Marzie , Hart Melissa , Nazarian Negin , Sismanidis Panagiotis , Kittner Jonas , Bechtel Benjamin
Published: March 2024

Urban heat is characterised by elevated temperatures in cities, resulting not only from global climate change but also from urban development and human activities. Previous research on urban heat has predominantly relied on satellite-derived land surface temperature (LST) data to investigate the changes in near-surface thermal environments. However, the applicability of LST for examining the temporal variation of air temperature is still not well understood. Using crowdsourced air temperature observations and satellite imagery, we explore the temporal variation of air temperature and its relationship with LST in more than 50 populated cities worldwide. Results show that city-average air temperature values are highly correlated with LST. However, the intensity of this correlation differs by season, day/night cycle, and is further influenced by background climate. Using satellite LST data, we expanded our analysis to include over 1500 urban areas and evaluated temperature changes in the past two decades. We observed a general trend of increasing temperatures in cities globally, although the rates of warming vary. The highest rate of temperature change was found in cold climate cities, with a more rapid increase during winter days. These cities are predominantly located in Eastern Europe, extending into parts of Western Asia. These findings provide new insights into the application of satellite-based LST for predicting future air temperature changes and identifying areas most vulnerable to urban overheating.
Investigating evapotranspiration calculations within conceptual hydrological models: an intercomparison among models. 
Authors: Burns Gabrielle , Fowler Keirnan , Stephens Clare , Peel Murray
Published: March 2024

Hydrological models, ranging from conceptual frameworks to complex physical representations, play a pivotal role in diverse applications including climate change projections and characterising floods and droughts. One crucial aspect of these models is the incorporation of vegetation dynamics, often achieved through links to evapotranspiration and interception. Our study will delve into the critical role of evapotranspiration in the terrestrial water cycle, and how this intricate relationship is simplified across various hydrological models.Despite the versatility of hydrological models, a common limitation is the static representation of vegetation over time. This limitation becomes particularly significant under climate change, where the consequences of altered vegetation behaviour might not be accurately reflected in the model results. Our research will address this gap by exploring numerous evapotranspiration equations utilised by conceptual rainfall-runoff models, by employing a novel rainfall-runoff model comparison toolbox (MARRMoT), and integrating flux tower measurements into the calibration processes.By examining how different evapotranspiration equations are utilised across the models and integrating flux tower measurements into the hydrological modelling processes, we seek to improve the models' adaptability to changing environmental conditions. We will do this by interchanging the numerous evapotranspiration equations, whilst keeping all other aspects of the hydrological model constant to explore potential benefits and differences among methods. Further, we will include in-situ measurements by calibrating the model outputted actual-evapotranspiration to flux tower evapotranspiration data, as well as the traditionally calibrated streamflow data.This research contributes to advancing the accuracy of hydrological predictions and improving the reliability of models in forecasting catchment responses to future climatic shifts.
Aerosol perturbation in the UTLS region over the Tibetan Plateau
Authors: Li Dan , Bian Jianchun , Bai Zhixuan
Published: March 2024

The Asian tropopause aerosol layer (ATAL) was thicker than other regions at the same latitude due to the strong confinement effect of the Asian summer monsoon anticyclone. The size distribution of the particles remains unknown and requires further investigation. Aerosol profiles were measured by balloon-borne sensors (Cobald, POPS) launched from Lhasa (29.66 °N, 91.14 °E), Golmud (36.48 °N, 94.93 °E), and Kunming (25.01 °N, 102.65 °E) China, from 2019 to 2022 over the Tibetan Plateau at the part of the SWOP (Sounding Water vapor, Ozone, and Particle) campaign. The measurements combined with backward trajectories show that the volcano Raikoke (48°N, 153°E) in June 2019 and the dust storm in March 2021 over the Taklamakan desert have significantly impacted on the aerosol layer in the upper troposphere and lower stratosphere (UTLS). The backscatter ratio at wavelength 455 nm of the volcanic plume and dust storm was higher than the ATAL. The particle number density in the volcanic plume is 30 cm-3, higher than the ATAL and dust storm (10 cm-3) in the lower stratosphere, with particle diameters centered around 0.42-3.4 μm. In contrast, the dust storm has a high density of up to 100 cm-3 in the upper troposphere with particle diameters less than 0.42 μm.
Distal records of Katla’s explosive past: Ocean-rafted pumice found in archaeological contexts and raised shorelines in Norway
Authors: Zernack Anke , Jørgensen Erlend Kirkeng , Newton Anthony , Romundset Anders
Published: March 2024

Ocean-rafted pumice is found on modern and paleo-beaches from the North Atlantic to the South Pacific. Correlation of ocean-rafting events to their volcanic source can help date sedimentary records and landforms, while geochemical fingerprinting of artefacts made from ocean-rafted pumice provides age constraints for pumice-bearing archaeological sites. These pumices also record large explosive eruptions that might not be preserved near the volcano due to extensive erosion or a submarine volcanic source and as such can be used for petrological and geochemical investigations.This study explores links between spatiotemporal patterns of Holocene pumice deposition along the Norwegian coastline and prehistoric human use of this versatile resource. We first focused on a suite of pumice pieces from archaeological contexts of variable isostatic uplift in Northern Norway with most showing evidence of use as abrasive tools. These samples were geochemically correlated to individual Holocene eruptions or groups of tephras (SILK) from the Katla Volcanic System in Iceland. Our age data revealed that the estimated eruption dates typically predate the contexts by several hundred and up to 2-3,000 years, probably reflecting abundance and availability of certain pumice types at the time.To investigate how distal resource availability is influenced by geological processes like eruption frequency, ocean-currents, and deposition/preservation we conducted field surveys of two coastal stretches with different climates, geomorphic settings and uplift histories. On Varanger Peninsula in Northern Norway strong Holocene uplift rates and sea-level changes have built a unique record of raised shorelines that provide windows into fossil beach ridges up to the marine limit, covered in little vegetation. We found that pumice was abundant on specific paleo-shorelines and in defined geomorphic settings but absent from older beach ridges. Most samples correlated with the
GCM selection for dynamical downscaling of extreme rainfall changes over Belgium
Authors: Van Schaeybroeck Bert , Vandelanotte Kobe , Ghilain Nicolas , Van de Vyver Hans , Serras Fien , Van Lipzig Nicole , Termonia Piet
Published: March 2024

Regional climate models (RCMs) may provide detailed climate information that is required by local stakeholders. Additionally, RCMs have shown added value in their representation of extremes such as extreme rainfall, with respect to Global Climate Models (GCMs). However, RCM simulations are computationally very expensive and depend strongly on the forcing GCM. Therefore, it is essential to carefully select the GCM. Previous coordinated ensemble simulations from EURO-CORDEX forced by GCMs from CMIP5 did not include a coordinated GCM selection. Recent efforts using CMIP6, on the other hand, do provide a framework for GCM selection (Sobolowski et al., 2023) based on different criteria for Europe. These criteria include model performance, availability and reliability of the climate-change signal. In Belgium, the CORDEX.be II project aims to provide regional climate-change information for climate services in support of climate adaptation and mitigation.  This information will be extracted using three regional climate models: ALARO-SURFEX, COSMO-TERRA-URB and MAR at convection-permitting resolutions (Termonia, et al., 2018). We present the overall setup of the CORDEX.be II methodology and the GCM selection. Thereby, the selection criterion of covering the entire range of climate-change signals, as used within the EURO-CORDEX effort, is replaced with the criterion to obtain the strongest changes in climate extremes possible, in line with the demand from the main stakeholders. More specifically, based on the EURO-CORDEX downscaling results forced by CMIP5, we outline a methodology for GCM selection to obtain the highest likelihood of strong changes in rainfall extremes. We explore the dependence of this likelihood with respect to different model predictors, RCM and GCM model groups and regions over Europe. We then apply this methodology on the CMIP6 ensemble over Belgium to obtain a list of selected runs for dynamic downscaling.Termonia, et al. (2018). The CORDEX. be initiative as a foundation for climate services in Belgium. Climate Services, 11, 49-61.Sobolowski et al. (2023) 10.5281/zenodo.7673399.
Synergies of Land Use Land Cover and Climate Change on Water Balance Components in SSP–RCP Scenarios over Munneru basin, India
Authors: Kotapati Narayanaswamy Loukika , Keesara Venkata Reddy , Buri Eswar Sai
Published: March 2024

The growing human population accelerates alterations in land use and land cover (LULC) over time, putting tremendous strain on natural resources. Rapid land use transformations, encompassing urbanization, intensive agriculture, and changes in natural landscapes, have a profound impact on water cycle. This necessitates the development and implementation of sustainable land management strategies to mitigate adverse effects on water resources. Anticipating future land use and cover (LU&LC) dynamics in the Munneru river basin is pivotal for modelling of hydrological processes. This study delves into the combined impact of Land Use and Land Cover Scenarios (LU&LC) which is based on Shared Socioeconomic Pathway (SSP2-45, SSP3-75 and SSP5-85) and climate change within the context of representative concentration pathway (RCP 4.5 & RCP 8.5) scenarios on water resources for Munneru river basin, India. Landsat data was employed for preparing LU&LC maps from the Google Earth Engine (GEE) using the random forest (RF) method for the period 2005-2020 with the accuracy of 91% and kappa coefficient of 0.89. The future scenarios of LU&LC’s were projected by integrating Global Change Assessment Model (GCAM) data and DynaCLUE model for 2030, 2050 and 2080. DynaCLUE model uses driving factors, Binary Logistic Regression analysis for past LU&LC maps for projecting future LU&LC maps. The SWAT model is calibrated and validated for the period 1983–2017 in SWAT-CUP using the SUFI2 algorithm for 2015 LU&LC map. The future projected LU&LC maps based on SSP’s are incorporated in SWAT model for future periods under both RCP 4.5 & 8.5 scenarios. The average monthly streamflow’s are simulated for the baseline period (1983–2005) and for three future periods, namely the near future (2021–2039), mid future (2040–2069) and far future (2070–2099) under both LU&LC and climate change scenarios. Results indicate that there is increase in surface runoff and water yield and decrease in evapotranspiration, groundwater and total aquifer for three SSP scenarios under both RCP’s. Assessing the impact on water balance components, provides the necessity for adaptive strategies in the face of shifting climate and land use dynamics.
 pH variations during the last and current interglacial stages at the western Iberian margin
Authors: Mega Aline , Calvo Eva , D. Pena Leopoldo , Salgueiro Emília , Rebotim Andreia , Voelker Antje , Cruz Joana , Abrantes Fátima
Published: March 2024

The intricate interplay among atmospheric CO2 concentrations, surface ocean pH dynamics, and their profound impact on marine ecosystems is of paramount importance in the context of contemporary climate change. Pre-industrial atmospheric CO2 concentrations oscillated in phase with glacial-interglacial cycles, showcasing low levels during glacial periods and elevated concentrations during interglacial periods. Nevertheless, this natural variability has been significantly disrupted due to the surge in anthropogenic CO2 emissions over recent decades. According to the Intergovernmental Panel on Climate Change, if global atmospheric CO2 concentrations persist in rising at the current rate, it is anticipated that the average ocean pH will decrease by 0.3 pH units in surface waters by the conclusion of this century. This scenario could exacerbate the impacts already observed in marine calcifying organisms, including in marine calcifying organisms such as planktonic foraminifera, affecting their diversity, abundance, and calcification. The main objective of this study is to understand the surface ocean pH evolution in a seasonal upwelling region, during two distinct interglacial periods in Earth's history: the Marine Isotopic Stage 5e (MIS 5e), the last interglacial without anthropogenic influence; and the Holocene, the present interglacial but subjected to anthropogenic influence. In upwelling regions, the upwelling of aged and CO2-rich subsurface waters together with high rates of primary production and respiration, is expected to regionally amplify ocean acidification. This study concentrates on the reconstruction of surface ocean pH using boron isotopes in a surface planktonic foraminifera species, Globogerinoides bulloides. This species is typically found in upwelling regions and was preserved in the marine sediment corer MD03-2699 (39°02.20′N, 10°39.63′W). Our preliminary findings indicate a pH difference between MIS 5e and the Holocene, with lower pH values during the Holocene.  It is argued that during the Holocene, a potential increase in wind intensity may have triggered a strong and persistent upwelling increasing productivity and respiration, consequently leading to lower pH. Additionally, the increase of atmospheric CO2, reconstructed from Antarctic ice cores during this period could also contribute to the ocean pH reduction. These variations in upwelling and/or atmospheric CO2 could be a pivotal factor influencing the observed pH differences, contributing to our comprehension of natural pH variations on the western Iberian margin through advanced pH reconstruction techniques and other multi-proxy environmental data integration for both periods in the region.