bluuebunny/crossref_metadata_2025 huggingface dataset:
Speleothems as archives for palaeofire proxies
Authors: Campbell Micheline , McDonough Liza , Treble Pauline , Baker Andy , Kosarac Nevena , Coleborn Katie , Wynn Peter , Schmitt Axel
Published: February 2023

Environmental proxy archives such as tree rings, sediment cores, and ice cores are commonly used to investigate past fire regimes. Speleothems, naturally forming cave decorations mainly comprising of stalagmites, stalactites, and flowstones, have been extensively used as palaeoenvironmental archives as their physical attributes and chemical composition change with changed environment. Research has shown that cave drip water chemistry responds to fire events, and more recently, that speleothems can record past fire events due to physical and chemical processes which alter speleothem composition. These processes include changes to water stores due to evaporation, fracturing of the host rock, changed soil hydrophobicity, production of highly soluble lime, changes in soil CO2 production, destruction of vegetation and deposition of ash above the cave. These changes can result in shifts in δ18O and δ13C, altered concentrations of vegetation, soil and bedrock-derived elements, and incorporation of soluble ash derived elements (including phosphorus, aluminium, copper, zinc, and lead) in speleothems (McDonough et al., 2022; Campbell et al., 2022).Changes in speleothem chemistry are typically determined using micro-analytical techniques (such as Synchrotron X-ray Fluorescence Microscopy and laser ablation inductively coupled plasma mass spectrometry) and isotope ratio mass spectrometry. These changes can be precisely and absolutely dated via uranium-series and carbon dating, and can often be resolved at high resolution via manual counting of seasonal fluctuations in organic matter and trace element concentration. This makes speleothems, particularly those grown in shallow caves in highly seasonal climates, ideal for identifying both short-lived events such as wildfires, and longer-term changes such as shifts in climate. This novel application of speleothems as archives for coupled climate and palaeofire proxies is still in its infancy but holds great potential.Here, we present a review of this new sub-discipline. We cover its origins in cave dripwater monitoring, discuss site and sample selection, and describe the current analytical and statistical approaches used to extract fire information from speleothems. Such records will enable land managers to develop improved methods for managing fire regimes.
McDonough, L.K., Treble, P.C., Baker, A., Borsato, A., Frisia, S., Nagra, G., Coleborn, K., Gagan, M.K., Zhao, J., Paterson, D., 2022. Past fires and post-fire impacts reconstructed from a southwest Australian stalagmite. Geochimica et Cosmochimica Acta. https://doi.org/10.1016/j.gca.2022.03.020
 

Campbell, M., McDonough, L., Treble, P., Baker, A., Kosarac, N., Coleborn, K., Wynn, P.M., Schmitt, A., 2022. Speleothems as Archives for Palaeofire Proxies [preprint], https://www.authorea.com/doi/full/10.1002/essoar.10511989.1

 
Long-term wave measurements and rogue wave events near Sakhalin Island
Authors: Didenkulova Ira , Kokorina Anna , Slunyaev Alexey , Zaytsev Andrey , Didenkulova Ekaterina , Moskvitin Aleksandr , Didenkulov Oleg , Pelinovsky Efim
Published: February 2023

Long-term measurements of bottom pressure variations obtained in four experimental campaigns near Sakhalin Island (Cape Svobodny) are analyzed. The statistical characteristics of 20-minute records of sea surface displacements reconstructed in the hydrostatic approximation, as well as individual wave parameters, such as wave height, period, and wave asymmetry, are studied. Records with similar meteorological conditions are sorted according to the significant wave height and the average wave period with the purpose to obtain statistically homogeneous data. The probability distributions of wave heights are constructed and compared with the Rayleigh and Glukhovsky distributions. A significant deviation from the theoretical curves in the range of anomalously high waves is demonstrated, which is associated with the records of intense wave groups in the winter season of 2014–2015.The research is supported by the Russian Science Foundation (Grant No. 22–17-00153).
Linking detrital zircon and supercontinent over the past 3 billion years
Authors: Jian Dongchuan , Williams Simon , Zhao Guochun , Yu Shan , Liu Bingxi
Published: February 2023

The assembly, tenure, and breakup of supercontinents is thought to have played a prominent role in Earth’s plate tectonic history and deeply influenced the paleogeography, crustal deformation, magmatic activity, climate, and biology. To date, at least three supercontinents that once existed on Earth are supported by most geologists. The evolution of Pangea is relatively well-understood, and only a small number of plates are controversial. By contrast, investigations of Rodinia and Nuna have led to many disagreements due to the limited, ambiguous evidence preserved from the Precambrian. Resolving these issues requires the integration of a wide variety of geological data within a quantitative reconstruction framework. In our previous work we linked the reconstruction of Pangea to an extensive global database of detrital zircon samples, demonstrating that samples with different zircon age spectra characteristics help to identify the tectonic setting in which they were deposited – and more broadly, form coherent patterns that delineate the periphery and core of Pangea.Here, we expand on our previous work to investigate the spatial and temporal characteristics of detrital samples deposited over the past 3 Ga. Although the number of available samples becomes more sparse back in time, the distribution patterns of the categorized samples in recent Rodinia reconstructions are nonetheless consistent with previous results for Pangea. General temporal trends reveal that, as supercontinents assemble, the proportion of samples characteristic of subduction tectonic settings increases while the proportion of samples from settings distal from subduction zones decreases, while the opposite trend defines periods of supercontinent dispersal. Together, these results show that quantitative reconstruction of global zircon databases holds important information related to past paleogeographic change.
Impact of structural heterogeneity on solute transport and mixing in unsaturated porous media: An experimental study
Authors: Borgman Oshri , Gomez Francesco , Le Borgne Tanguy , Méheust Yves
Published: February 2023

Solute transport in unsaturated porous media plays a crucial role in soil nutrient dynamics, pesticide leaching, and contaminant migration to aquifers through the vadose zone. Natural porous media are characterized by a strong structural heterogeneity, which impacts solute spreading and mixing and the resulting chemical reaction rates. In addition, incomplete pore-scale solute mixing requires high-resolution experimental measurements to understand the system’s mixing dynamics. Our goals are to 1) study the impact of structural heterogeneity on the spatial distribution of fluid phases and 2) establish how fluid phase arrangement impacts solute spreading and mixing during unsaturated flow. We use two-dimensional porous media consisting of circular posts in a Hele-Shaw-type flow cell. The positioning of the posts is random, but we control the medium’s heterogeneity by varying the disorder in the posts’ diameters and their spatial distribution’s correlation length; increasing this length introduces more structure in the porous medium.In our experiments, we first establish an unsaturated flow pattern with a connected liquid phase and then introduce a fluorescent solute pulse transported by the moving liquid phase. We track the solute concentration and gradients’ evolution by taking periodic images of the flow cell and analyzing the fluorescence intensity field. Our results suggest that, as previously shown, decreasing the saturation degree enhances and sustains mixing rates in a disordered porous media due to the emergence of several preferential flow pathways during unsaturated flow. Moreover, increasing the solid posts’ spatial correlation reduces the number of air clusters and their interface roughness, and increases their mean size. This leads to fewer preferential flow paths during unsaturated flow for the higher correlated, more structured, porous media, compared to the less structured ones. This reduction in preferential flow paths’ number suppresses mixing rate enhancement in the more structured porous media, compared with the less structured porous media, during unsaturated flow. Our experiments show the non-trivial effect of structural heterogeneity and saturation degree on solute mixing in porous media flows. The effects demonstrated by these results are likely to affect reactive solute transport processes such as dissolution and precipitation and adsorption-controlled solute migration.
Observation of intensification of western boundary current in summer of 202
Authors: Lee Seung-Woo , Noh Suyun , Pak Gyundo , Park Jae-Hyoung , Lee Su-Chan , Jeong Jin-Yong
Published: February 2023

Due to climate change, the occurrence of extreme events such as typhoons, marine heat waves, storminess, and cold waves is increasing in many regions, and these events could dramatically change with significant impacts on the marine environment (e.g., ocean circulation). The East Korea Warm Current (EKWC) has been recognized to flow along the western boundary current of the East Sea (Japan Sea). To examine the variations of EKWC, six bottom-mounted current profiler moorings were operated off the east coast of Korea (the Hupo Bank and Wangdolcho) since June 2021. The observed mean current speed and their principal axis were 0.40 m/s and 58o (counterclockwise from the east) implying northeastward EKWC over the region. In August 2021, an unprecedentedly strong surface current was observed with a maximum of 1.89 m/s and observed currents showed similar variability at mooring sites and several depths. This strong current lasted for about a month, and then rapidly disappeared within a few days. At that time, the geostrophic currents based on satellite-altimetry has a strong current pattern with the Inertial Boundary Current pattern, which is one of the EKWC patterns that flows strongly northward currents closer coast. In addition, the highest mean speed of the EKWC near the mooring sites from 1993 was found in August 2021. The high-speed period was similar to the period of the North Pacific marine heat waves that were already reported, and the low-speed period was related to typhoon passage. This study reported the results of observed EKWC for two years from 2021 and the unprecedentedly enhanced EKWC in August 2021. In particular, it can be a case in which the rapid changes of western boundary currents interact with extreme events such as marine heatwaves and typhoons.
Analysis of Surface Displacement Before and After the 2017 Pohang Earthquake using Sentinel-1 PSInSAR Technique
Authors: Jung Da-woon , Lee Hoonyol
Published: February 2023

The 5.4 Pohang earthquake occurred on November 15, 2017. It was the second-largest earthquake in South Korea since instrumental earthquake observations began. In this study, the PSInSAR method using Sentinel-1 satellite ascending and descending data were used to analyze the time-series surface displacement of the Pohang area before and after the earthquake. As a result, in the case of PSInSAR result using the descending pass data, surface uplift displacement up to 45 mm in the LOS direction was observed immediately after the earthquake near the epicenter. In addition, to identify the horizontal movement of the co-seismic uplift displacement, it was derived into the vertical component and horizontal component using the results of two different orbital data. And it shows the surface was spreading out into both sides, not just east or west. Besides, continuous subsidence with a velocity of up to 80 mm/year was found in a specific area of the footwall, which was continued before the earthquake. To identify the origin of the subsidence we compared it with the past optical images, and subsidence areas were consistent with the past river topography.
Benchmarking Study of EQTransformer Autopicker for Seismic Phase Identification in Northern Chile
Authors: Kasravi Javad , Folesky Jonas
Published: February 2023

One of the vital open questions in seismology is rapid, high quality phase identification and picking. Measurements of earthquake arrival time or phase picking are often done by expert judgment with many years of experience. Due to advances in technology and seismometer deployment, the amount of recorded data has increased dramatically in the previous decade, leading up to a point, where it has become almost impossible for humans to deal with this amount of data flow. Therefore, automatic picking algorithms are being used.  In recent years multiple machine learning algorithms have been introduced that bear the potential to combine both, high picking accuracy and the capability of processing large amounts of data. In this contribution, we demonstrate the performance of the EQTransformer autopicker, when applied to continuous seismic data from the Northern Chilean subduction zone. To test this deep neural network, we chose a random day and carefully hand picked the continuous data on 18 IPOC stations, selecting only combinations of picks which should lead to locatable events (e.g. with at least five picks). This results in the identification of  3040 P and 2310 S picks. We compare the results of two different training versions of EQTransformer with hand-picked data and with the IPOC seismicity catalog. As it turns out, the comparison is not straightforward, because the evaluation of the picks is highly complicated, given that the true number and type of phase arrivals is and remains unknown. However, the autopicker is able to detect most of the hand-picked phases and arrival times. It outperforms the IPOC catalog by a factor of about 10-15 and thusly it appears to be a valid alternative for advanced seismic catalog construction.
Precipitation Nowcasting Based on an Optimized Deep Learning Model Trained with Heterogeneous Weather Data
Authors: Chen Dian-You , Chang Chia-Tung , Chen Buo-Fu
Published: February 2023

    Due to the threat of extreme rainfall associated with mesoscale convective systems and summer afternoon thunderstorms, very short-term quantitative precipitation forecasting during 0−3 h is critical in Taiwan. In this study, deep learning models are developed for high-resolution quantitative precipitation nowcasting in Taiwan up to 3 h ahead. The baseline model based on the convolutional recurrent neural network is trained with a dataset containing radar reflectivity and rain rates at a granularity of 10 min. As previous works tend to produce overprediction in low-rainfall regions, the currently proposed model is improved and further driven by highly related heterogeneous weather data, including visible channel satellite observation, environmental winds, and environmental thermo-dynamical profiles. Note that an innovative “PONI module” is added to the deep learning model to integrate a variety of heterogeneous data with various spatial and temporal characteristics. Moreover, model performance is evaluated from statistical and spatial rescaling perspectives represented by R =  Ravg + R', where R denotes original rainfall, Ravg and R' are spatial moving averages and the values deviated from Ravg, respectively. Statistical verification shows that the Ravg of the new model outperforms the previous model, while the performance of R' is comparable. The new model integrated with heterogeneous data selected upon domain knowledge can restrain the nowcasts that overestimate in low-rainfall regions. Last but not least, quasi-operational verifications against other state-of-the-art techniques in Taiwan Central Weather Bureau are presented as follows: (1) the CSI of the first-hour prediction from the deep learning model is comparable with QPESUMS-QPF and better than RWRF and iTeen. (2) 3h ahead prediction CSI of RWRF and iTeen are inferior to the performance of deep learning model owing to their misprediction of rainfall regions. The deep learning model can accurately predict medium and extreme amounts of precipitation at a fraction of the computational cost.
Wildfire Effects on Air Quality: A Case Study of Wildfires in Korea in 2022
Authors: Chang Dong Yeong , Jeong Sujong
Published: February 2023

In March 2022, an unprecedented largest forest fire occurred in South Korea, burning 22,477 ha of forest for two weeks. In this study, we studied the causes of these fires based on an analysis of all meteorological data available over 100 years and also investigated their effects on air quality data obtained from ground-based observations (AirKorea and Asian Initiative for Clean Air Networks (AICAN)) and satellite data. Analysis results of meteorological data reveal changes in the climate regime from cold and wet winter conditions to hot and dry conditions. The temperature has been increased by 4 °C and precipitation has decreased by 17 mm over 100 years. The resistance level of forest fires is drastically reduced in the past few years and eventually lead to large-scale wildfires. These devastating wildfires emitted large amounts of ultrafine biomass-burning aerosols that were composed mainly of small particle sizes with diameters less than 1.0 mm. It elevated the air pollution level by more than 20 folds than usual condition. Carbon monoxide (CO) was also emitted from biomass burning that was detected as smoke paths (from 373 ppb to 1181 ppb) by the Tropospheric Monitoring Instrument (TROPOMI). This study highlights that climate change can make forests more vulnerable to fires and their effects on air quality could be more severe than expected.This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. RS-2022-00155875).
Characteristics of microseismicity in the Kiskatinaw area, northeastern British Columbia, Canada
Authors: Park Suhee , Heo Dabeen , Kang Tae-Seob , Rhie Junkee , Kim Seongryong , Dettmer Jan
Published: February 2023

Since the early 2000s, lots of induced earthquakes have occurred due to fluid-injection during the development of unconventional resources at the Kiskatinaw Seismic Monitoring and Mitigation Area (KSMMA) located in northeastern British Columbia, Canada. The spatial-temporal distribution of microearthquakes induced by fluid-injection are important to understand the characteristics of crack and movement of fluid. Also, to mitigate earthquake disasters, it is essential to continuously monitor microearthquakes in fluid-injection areas. We used the seismic data recorded at the EON-ROSE seismic network, which is a dense seismic network consisting of 16 broadband seismic stations, and GSC-BCOGC seismic network to analyze the characteristics of microseismicity of the KSMMA in 2020. We detected the seismic signal (P- and S-wave) using the automatic seismic phase detection method, which is based on the short-term-average to long-term-average ratio (STA/LTA) and kurtosis. And then, we associated the seismic phase arrival data to combine to earthquakes from the automatic seismic phase association method using the temporal distribution of the detected signals and the spatial distribution of the seismic stations used. The hypocenter parameters of associated earthquakes were determined with the HYPOINVERSE location algorithm and the existing 1-D velocity model of KSMMA. The epicenter distributions of the detected earthquakes are concentrated in the area known as active fluid-injection, and the focal depths are also distributed at about 2 km. We analyzed the seismicity by dividing it with three periods based on COVID-19 lockdown and confirmed the low-seismicity of the lockdown period, which is consistent with the result of the independent study performed at the region.
Normal fault network evolution in 3D numerical models
Authors: Brune Sascha , Wrona Thilo , Neuharth Derek , Glerum Anne , Naliboff John , Heckenbach Esther
Published: February 2023

Understanding how normal fault networks initiate and evolve is important for quantifying plate boundary deformation, assessing seismic hazard and finding natural resources. In recent years, 3D numerical models have been developed that can simulate the entire process of normal fault formation, from the start of rifting to the creation of new ocean floor. However, state-of-the-art methods treat faults as finite-width shear zones not as discrete entities, so additional work is needed to isolate individual faults and their characteristics in order to better understand fault system dynamics over geological scales.We present 3D numerical rift models of moderately oblique extension using the ASPECT software. These models reproduce the thermo-mechanical behavior of Earth's lithosphere and simulate fault system dynamics from inception to breakup accounting for visco-plastic rheology, strain softening and surface processes. We use a method that extracts surficial fault systems as 2D networks of nodes and edges to study the evolution of normal faulting. By applying data analysis techniques, we group nodes and edges into components that represent individual faults and track their geometry and movement over time.We find that the initial fault network forms through rapid fault growth and linkage, followed by competition between neighboring faults that leads to their coalescence into a stable network. At this point, modelled normal faults continue to accumulate displacement but do not grow any longer. As deformation localizes towards the center of the rift, the initial border faults shrink and disintegrate, being replaced by new faults in the center of the rift. During that transition, we document strain partitioning between predominantly dip-slip border faults and oblique-slip or strike-slip intra-basin faults. The longevity of faulting is thereby controlled by crustal rheology and surface process efficiency. Quantitative analysis of fault evolution allows us to deduce fault growth and linkage as well as fault tip retreat and disintegration in unprecedented detail.
Characterization of lake-catchments leveraging remote sensing data
Authors: Liu Junzhi
Published: February 2023

The management and conservation of lakes should be conducted in the context of catchments because lakes collect water and materials from their upstream catchments. Thus, the datasets of catchment-level characteristics are essential for limnology studies. Remote sensing is an important data source for the characterization of lake-catchments. Leveraging remote sensing data, we constructed the first dataset of lake-catchment characteristics for 1525 lakes with areas from 0.2 to 4503 km2 on the TP. Considering that large lakes block the transport of materials from upstream to downstream, lake catchments are delineated in two ways: the full catchment, which refers to the full upstream-contributing area of each lake, and the inter-lake catchments, which are obtained by excluding the contributing areas of upstream lakes larger than 0.2 km2 from the full catchment. There are six categories (i.e., lake body, topography, climate, land cover/use, soil and geology, and anthropogenic activity) and a total of 721 attributes in the dataset. Besides multi-year average attributes, the time series of 16 hydrological and meteorological variables are extracted, which can be used to drive or validate lumped hydrological models and machine learning models for hydrological simulation. The dataset contains fundamental information for analyzing the impact of catchment-level characteristics on lake properties, which on the one hand, can deepen our understanding of the drivers of lake environment change, and on the other hand can be used to predict the water and sediment properties in unsampled lakes based on limited samples. This provides exciting opportunities for lake studies in a spatially explicit context and promotes the development of landscape limnology on the TP. The details of this dataset can be found in our paper published in Earth Syst. Sci. Data (https://doi.org/10.5194/essd-14-3791-2022).
Determination of the frequency response of seismic and infrasonic IMS station sensors using a traceable on-site calibration approach
Authors: Schwardt Michaela , Pilger Christoph , Kristoffersen Samuel , Larsonnier Franck , Klaus Leonard , Bruns Thomas , Ceranna Lars
Published: February 2023

As part of the joint research project "Metrology for low-frequency sound and vibration - 19ENV03 Infra-AUV" laboratory calibration methods for seismometers and microbarometers in the low frequency range down to 0.01 Hz have been developed. These procedures provide the possibility of traceable on-site calibration during operation for field sensors of the Comprehensive Nuclear-Test-Ban Treaty Organization’s (CTBTO) International Monitoring System (IMS). The traceable calibration allows for accurate amplitude and phase information as well as for an assignment of uncertainties in amplitude and phase. Thereby, data quality and the identification of treaty-relevant events is improved. The on-site calibration procedure requires a reference sensor with a precise and traceable response function which is provided by the newly developed laboratory calibration methods, as well as the record of sufficient coherent excitation signals within the relevant frequency range. The reference sensors can be installed as transfer standards co-located to the operational IMS station sensors without disturbing their regular measurements for treaty validation purposes.At IMS stations PS19 and IS26 in Germany we performed on-site calibration tests with both seismometers and microbarometers calibrated in the laboratories at PTB and CEA, respectively, using signals from different natural and anthropogenic excitation sources. Following the approach of Gabrielson (2011) with modifications from Charbit et al. (2015) and Green et al. (2021), the gain ratio between the station sensor under test and the reference sensor is calculated. By multiplying the gain ratio with the precise frequency response of the reference, the frequency response function for both magnitude and phase of the station sensors including site-specific factors such as the wind noise reduction system or possible effects of pre-amplifiers and data loggers are determined.We present calibration results derived from the comparison of IMS station sensors with the laboratory-calibrated instruments along with the nominal responses. The results show agreement with deviations of less than 5% from the nominal response function for frequencies below 10 Hz for all components. The traceable determination of the response for the individual components in detail improves the sensor quality; subsequently waveform amplitudes can be estimated correctly.
Joint-Multifractal Analysis of High and Low Latitude Magnetospheric Dynamics.
Authors: Consolini Giuseppe
Published: February 2023

The dynamics of the Earth's magnetosphere are a tremendously complex system that exhibit nonlinear dynamics in response to variations in the solar wind and interplanetary magnetic field. It has been amply demonstrated in the past that scale-invariant processes define magnetospheric dynamics as measured by geomagnetic indices. Forced and/or Self Organized Criticality, a term coined by T.S. Chang in the 90s, describes the plasma dynamics in the magnetospheric tail region. The multifractal structure of the variations of geomagnetic indices is another distinctive feature of the Earth's magnetospheric response.  Here, we use the joint multifractal measures approach first proposed by Meneveau et al. (1990) and low and high latitude geomagnetic indices  (AE, AL, Sym-H, Asy-H ,etc) to examine the link between the intermittency degrees of high and low latitude dynamics. The findings are examined in regard to the coupling of storms and substorms. 
Crustal and Uppermost Mantle Structure beneath the Indian Ocean Geoid Low using Surface Wave Tomography
Authors: Sundaran Silpa , Rao Bommoju Padma , Maurya Satish
Published: February 2023

The Indian Ocean Geoid Low (IOGL) is a significant negative geoid anomaly (-106 m), located south of the Indian subcontinent. Several studies have been carried out to investigate the causes responsible for IOGL, results indicate that its origin could be low velocity/density anomalies in the depth range of mid-to-upper mantle and/or high velocity/density anomalies in the depth range of lower mantle. However, a concrete model to explain the origin of IOGL and especially the effect of the shallow structure on IOGL is still enigmatic. In the present study, we investigate the high-resolution 3D shear velocity structure beneath the Indian Ocean region down to a depth of 300 km using surface wave tomography. For this analysis, collated extensive data from more than 700 broadband seismological stations of various data centres (IRIS: Incorporated Research Institutions for Seismology, FDSN: International Federation of Digital Seismograph Networks, IN: Indian Stations) to obtain a good azimuthal and spatial coverage. This dataset has been pre-processed and utilized to measure the fundamental mode of Rayleigh wave group velocities sampling the IOGL region. Further, visually checked the quality of the dispersion curves and considered only good-quality ones, which resulted in ~19,300 good-quality dispersion curves in a frequency range of 10-120 s and then applied the regionalization to extract the geographical distribution of local group velocities in different periods. Later, inverted the regionalized dispersion data using the trans-dimensional inversion approach. Regionalized shear wave velocity maps are in good agreement with surface tectonics such as low-velocity anomalies along the large-scale ridges and previous tomography studies. The western Indian Ocean shows very fast velocity anomalies at short-period (~20 s) and low-velocity anomalies in long periods (>100 s) which could be attributed to the magmatic underplating originating from the various hotspots and the presence of channelled flows asthenosphere towards eastward to spreading ridges. Further, the results rules-out that the contribution of the lithosphere could be negligible in explaining the IOGL as there are no low-velocity anomalies beneath the IOGL region. In addition, the obtained high-resolution regional surface wave tomography from this study enables the research community to obtain/measure the precise IOGL anomaly and understand the detailed tectonics and crustal/lithospheric deformation beneath the study region.
Improved understanding of unstable finger formation in partially wettable soils
Authors: Brindt Naaran , Yan Jiuzhou , Min Xinying , Parlange Jean-Yves , Steenhuis Tammo
Published: February 2023

Understanding how water infiltrates soils is essential in groundwater recharge and surface runoff predictions and agrochemical contamination assessment. Infiltration fronts are often envisioned as flat, uniform wetting fronts in which water content and pressure decrease monotonically. However, water infiltration occurs as unstable gravity-driven flow in homogeneous coarse-textured or water-repellent soils as fingers, bypassing most of the soil. A characteristic of these fingers is that the advancing tips are near saturation, and the moisture content and pressure decrease behind the front. Despite many approaches to modeling this flow, the explanation for the increased pressure at the wetting front of these unstable flow fingers has remained elusive. We postulated a discontinuous matric potential at the wetting front resisting uniform water entry in the dry soil. Instead, water moves one pore at a time across the front, inducing high localized velocities that increase the static contact angle to a dynamic one, which the Hoffman-Jiang equation can describe. It causes the matric potential to increase at the front. These high velocities during pore invasion are akin to what is known as Haines jumps which require high-frequency sensors to detect.In this study, we aimed to prove the hypothesis experimentally and refine the theory using a high-speed camera and high-frequency pressure measurements of water infiltration into partially wettable sand. A 30X50X1.6 mm glass flowcell was packed with air-dry quartz sand. Water infiltration to the cell was 15 μl/min. Porewater pressure was recorded at 500 Hz through a needle tensiometer at the back of the flow cell wall. A high-resolution, high-speed camera recorded the pore invasion at 500 fps over an area of 32X32 mm surrounding the tensiometer. A second set of experiments was performed at even greater magnification, looking at a single pore (5X5 mm) where the wetting front’s contact angle could be measured visually during infiltration. The results showed that water advanced as a series of invasion events through one or two pores lasting a few milliseconds separated by longer periods where the front was static. The invasion pore flow velocities exceeded the saturated hydraulic conductivity by three orders of magnitude. In addition, the high magnification experiment found that the changes in the contact angle during pore invasion and the observed pore water velocities agreed with the Hofmann Jiang predictions. Our experimental results offer new insights into how water infiltrates the soil, as studies rarely measure infiltration with such small spatial and temporal scales.
Using stable isotopes and mean residence time to characterize the groundwater system in the Tatun Volcanic Group, Taiwan
Authors: Chen Yi-Ling , Kuo Ching-Huei
Published: February 2023

Stable isotopes, δ2H and δ18O, of precipitation and groundwater in two adjacent catchments, the north, and south, in the Tatun Volcanic Group, Taiwan were used to characterize the regional groundwater. The results show that the isotopic composition of precipitation exhibits seasonal variations, which suggests different sources of moisture generation for the rainfall in the study area. In general, the north catchment shows more enriched isotopic characteristics than that of the south one.  The seasonal variations of precipitation, with lighter in summer, arise from changes in isotopic water vapor composition associated with the seasonal activity of the Asian monsoon which was used in estimating the mean residence time (MRT) of groundwater in the region. The preliminary results show that the average MRT of the study area ranges from 180 to 500 days in the north catchment while it is 180 to 900 days in the south catchment.
Updated heliospheric modulation potential of cosmic rays and station-specific scaling factors for 1964-202
Authors: Väisänen Pauli , Usoskin Ilya , Kähkönen Riikka , Koldobskiy Sergey , Mursula Kalevi
Published: February 2023

Galactic cosmic rays (GCR) are energetic particles originating from galactic or extra-galactic sources. When they arrive inside our heliosphere, they are modulated by the magnetic irregularities in the solar wind flow from the Sun, deflecting and slowing down the GCR particles. The level of this modulation varies according to solar activity, especially the 11-year solar cycle. The heliospheric modulation potential, denoted by ϕ, describes the average energy loss of particle in MV and quantifies the level of modulation. It can be determined using ground-based neutron monitor (NM) measurements of GCRs by multiple stations. Here we use the most recent version of the NM yield function and a RMSE-minimization method to compute a new and more accurate version of the modulation potential ϕ and station-specific scaling factors κ, which can be used to scale the level of count rates to the theoretical NM count rate given by the model. The new version offers daily resolution of ϕ and can be conveniently updated with new measurements, stations, or updates to datasets whenever they might occur. The scaling factors and their variation can be used to scale the data for physical analyses or to identify outliers, errors or physical phenomena which do not match with the model.
Surface temperature of Mars: Exploring diurnal and seasonal variations with the Emirates Mars Mission
Authors: Atri Dimitra , Abdelmoneim Nour , Dhuri Dattaraj , Simoni Mathilde
Published: February 2023

The ~55 hour orbit of the Emirates Mars Mission (EMM) or the “Hope'" orbiter enables it to achieve a near-global coverage of the planet every 4 orbits, or ~9 sols. The Emirates Mars Infrared Spectrometer (EMIRS) instrument on board EMM is used to retrieve surface temperatures. We study the geographical and temporal variation of surface temperature on diurnal and seasonal timescales. We compare these measurements with NASA’s rover measurements —  from the Rover Environmental Monitoring Station (REMS) suite on board the Mars Science Laboratory (MSL) "Curiosity" rover, and the Mars Environmental Dynamics Analyzer (MEDA) suite on board the Mars 2020 "Perseverance” rover. We also compare these measurements with the Mars Climate Database (MCD), identify anomalies in surface temperature and discuss the role of thermal inertia. We discuss other implications of these findings leading to a better understanding of temperature variation on Mars and its impact on weather and climate.   
Transdisciplinary Research Framework on Climate Change Dynamic Decision-making.
Authors: Lin Meng-Hui , Tung Ching-Pin
Published: February 2023

Sustainability transition on climate change, energy systems, and low carbon society is a big issue in 21 century. However, it’s not a linear question in a specific single research community. This study aims to contribute a transdisciplinary research (TDR) framework to support climate change decision-making as wicked problems. To achieve the global goal of 2050 Net Zero, it needs a science-based scenario setting for both adaptation and mitigation while making decisions and climate risk assessment in business and governance. From knowledge to actions, academics and non-academics are encouraged to engage in climate actions at the same time. This study delivers a system-dynamic approach to integrate the environmental, social, and economical components from participants and stakeholders with different backgrounds in TDR to reduce climate risks including resilient adaptation for physical risk and low carbon transition for transition risk. The TDR framework on climate change dynamic decision-making would be demonstrated through a case of the Carbon Neutrality Project of National Taiwan University.
Past and future of the Arctic sea ice in HighResMIP
Authors: Selivanova Julia , Iovino Doroteaciro
Published: February 2023

Arctic sea-ice area and volume have dramatically decreased since the beginning of the satellite era. This alarming rate of ice decline raises a key scientific question: how soon will the Arctic meet the first “ice-free” summer? Coupled climate models are the primary tools to provide projections of future sea ice conditions. Increasing the horizontal resolution of general circulation models is a widely recognized way to improve the representation of the complex processes at high latitudes, and to obtain trustworthy predictions of ice variability. Here, we investigate the past and future changes of sea ice cover at hemispheric and regional scales using model outputs from the High Resolution Model Intercomparison Project (HighResMIP, Haarsma et al. 2016) of the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The main objective is to investigate the impact of ocean/atmosphere model resolution on the representation of Arctic sea ice area (SIA) and volume (SIV)  and their seasonal, interannual variability, and trends in the recent past. Model results over the period 1950–2014 are compared to a set of observational datasets. All models project substantial sea ice shrinking: from 1950 to 2050 the Arctic loses nearly 92% of SIV from 1950 to 2050. The individual models simulate the first summer ice-free Arctic as early as 2019 and as late as 2050. The ensemble mean of the three best performing models suggests the event to happen by 2044. Along with the overall reduction of sea ice cover, there are changes in the structure of sea ice cover: the marginal ice zone (MIZ) dominates the ice cover by the mid-XXI which implies the shift to a new sea ice regime closest to the Antarctic conditions. The MIZ-dominated Arctic might suggest to adapt and modify model physics parameterizations and sea ice rheology.Our analysis does not present a strong relationship between ocean/atmosphere spatial resolution and sea ice cover representation: the impact of horizontal resolution rather depends on the model used and the examined variables. However, the refinement of the ocean mesh has a more prominent effect compared to the atmospheric one, mainly due to a more realistic representation of the sea ice edges as a result of better simulated ocean currents and heat transports in the Northern Atlantic Ocean. 
Documenting the diversity of human responses to Quaternary environmental changes when the stratigraphic record is gone. The experience of the SPHeritage Project
Authors: Zerboni Andrea , Perego Alessandro , Ryan Deirdre , Starnini Elisabetta , Pappalardo Marta
Published: February 2023

Archaeological sequences and landscapes preserve evidence of the complex relationship between human communities and climatic/environmental changes occurred in the Quaternary. In this perspective, archaeological sediments and landscapes are proxy data for past ecosystems evolution, as much as for changes in land use, exploitation of natural resources, and human behavior. Most of the latter can be detected and explored with a geoarchaeological approach, using the tools and methods offered by Earth Sciences. For that reason, accurate sampling during the excavation of archaeological sites allows to increase the number and quality information useful to reconstruct the formation of an archaeological sequence, its preservation, and human activities. What can we do when archaeological excavations were carried out before the application of methods from the Earth Sciences? How can we gather information from residual strips or archaeological sediments? The SPHeritage Project (MUR grant: FIRS2019_00040, P.I.: M. Pappalardo) is coping with this challenging task reinvestigating the Balzi Rossi archaeological area (Western Liguria, Northern Italy). This area represents a key site for the reconstruction of how human populations have responded to Pleistocene environmental changes and sea-level variations since the Middle Pleistocene. Local anthropogenic cave sequences have been excavated since the half of the XIX century; unfortunately, the geological processes in charge of the formation of such deposits have been only occasionally considered. As most of the local archaeological sequences were removed, we are combining the analyses of the remnants of strips of anthropogenic sediments still preserved inside local rock shelters as much as sediment samples preserved in museums. Moreover, our geomorphological survey identified new sedimentary sequences preserving information on relative sea level changes, better constraining the time and steps of climate change, sea-level oscillations, and human settlements. Our results confirm that this approach is an effective tool to reconstruct the formative processes of anthropogenic sequences excavated in the past, thus expanding our possibility of understanding the climate-environment-human nexus.
Towards better identification of dominant controls in Earth system data
Authors: Reinecke Robert , Pianosi Francesca , Wagener Thorsten
Published: February 2023

We are in a state of simultaneous exuberance and starvation of Earth system data. Model ensembles of increasing complexity provide petabytes of output, while remote sensing products offer terabytes of new data every day. On the other hand, we lack data on processes that are more challenging to observe, like groundwater recharge, or have data heavily impacted by un-quantified anthropogenic change. These problems leave us with highly imbalanced datasets.Our ability to produce and collect mountains of data contrasts with our progress in improving scientific process understanding. How can we harness simulated and observed data alike to enhance our knowledge and test scientific hypotheses about process relationships given poorly known uncertainties? Our contribution discusses methods to approach this problem while being agnostic to the data source (model or observation). We introduce a new strategy that allows us to interrogate given datasets to identify correlational and possibly causal relationships between the variables included. We test the method on an ensemble of complex global hydrological models and observations to demonstrate its usefulness and limitations, i.e., from the ISIMIP experiments. We show that our approach can provide powerful insights into dominant process controls while scaling with large amounts of data.
Tropical Cyclone produced rainfall trends in Vietnam and their relationship with the North Pacific (NP) pattern during 1979 – 202
Authors: Thi Ngoc Huyen Ho , Yoon Jin-Ho
Published: February 2023

This study investigated long-term changes of tropical cyclones (TCs) activity and rainfall produced by TCs, hereafter TC-rainfall, over Vietnam in the period of 1979-2021. Furthermore, it is investigated how rainfall changes are influenced by the North Pacific (NP) pattern.First, it was found that TC activity has not changed significantly in its frequency, and its related rainfall including TC and tropical depression (TDs) produced rainfall, hereafter TCTD-rainfall over entire Vietnam. On the other hand, significant increasing trend of TC activity (XX per 10 year), TC-rainfall (65 mm per 10 year), TCTD-rainfall (75 mm per 10 year), and total rainfall (440 mm per 10 year) is found in North Vietnam in the period of 1979-2021. However, TC, TD activity, TC-rainfall and TCTD-rainfall did not show any significant trends in Central and South Vietnam. Second, decadal and inter-decadal variation of rainfall in North Vietnam are significantly correlated with the North Pacific (NP) pattern during autumn season (October-December). Negative (positive) phases of the NP is characterized by a low (high) sea level pressure (SLP) located over the northern North Pacific Ocean and anomalously warm (cold) sea surface temperature (SST) over central and eastern tropical Pacific, resulting in to less (more) TCs activity and rainfall events over the South China Sea and Vietnam. In summary, it is found that rainfall produced by TCTD exhibits significantly increasing trend in North Vietnam, as well as total rainfall and the NP pattern plays an active role in altering rainfall anomalies in North Vietnam in the decadal and inter-decadal timescales.