bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat flow and thermal regime in the Guaymas Basin, Gulf of California: Estimates of conductive and advective heat transport
Authors: Neumann Florian , Negrete-Aranda Raquel , Harris Robert N. , Contreras Juan , Galerne Christophe , Peña-Salinas Manet S. , Spelz-Madero Ronald , Lizarralde Daniel , Teske Andreas , Hoefig Tobias ,   Expedition 385 Scientists
Published: March 2022

Heat flow is estimated at eight sites drilled during Integrated Ocean Drilling Program (IODP) Expedition 385 in the sedimented Guaymas Basin, Gulf of California. One of the expedition objects was designed to understand the thermal regime of the basin and to better understand heat transfer mechanisms from sill intrusions into organic-rich sediment. Sedimentation corrections are significant and increase basin values of heat flow values on average by 12% and range from 119 to 221 mW/m2 in the basin. Thermal analysis suggests that heat flow in the basin is distributed equally between conductive and advective heat transfer for plate ages older than 0.2 Ma. At Ringvent, Site U1547 a young sill intrusion is related to locally elevated heat flow displaying values between 257 and 1000 mW/m2. Thermal analysis of the five holes drilled at Site U1547 suggests that the sill structure hosts an active hydrothermal system. Our study suggests that rapidly cooling intrusion led to discharge velocities between 15 – 40 mm/yr and possibly recharge of the system may occur through normal faults. To be consistent with the heat output, we estimate the sill intrusion thickness to be ~240 m. The highly three-dimensional nature of the sill intrusion at Site U1547 and the question of its thickness add considerable complications which are currently investigated in complementary studies.
Testing spatial aftershock forecasts accounting for large secondary events during on going earthquake sequences: A case study of the 2017-2019 Kermanshah sequence
Authors: Maleki Asayesh Behnam , Zafarani Hamid , Hainzl Sebastian , Sharma Shubham
Published: March 2022

Large earthquakes are always followed by aftershocks sequence that last for months to years. Sometimes, these aftershocks are as destructive as the mainshocks. Hence, accurate and immediate prediction of aftershocks’ spatial and temporal distribution is of great importance for planning search and rescue activities. Despite large uncertainties associated with the calculation of Coulomb failure stress changes (ΔCFS), it is the most commonly used method for predicting spatial distributions of aftershocks. Recent studies showed that classical Coulomb failure stress maps are outperformed by alternative scalar stress quantities, as well as a distance-slip probabilistic model (R) and deep neural networks (DNN). However, these test results were based on the receiver operating characteristic (ROC) metric, which is not well suited for imbalanced data sets such as aftershock distributions. Furthermore, the previous analyses also ignored the potential impact of large secondary earthquakes.

In order to examine the effects of large events in spatial forecasting of aftershocks during a sequence, we use the 2017-2019 seismic sequence in western Iran. This sequence started by Azgeleh M7.3 mainshock (12 November 2017) and followed by Tazehabad M5.9 (August 2018) and Sarpol-e Zahab M6.3 (November 2018) events. Furthermore, 15 aftershocks with magnitude > 5.0 and more than 8000 aftershocks with magnitude > 1 were recorded by Iranian seismological center (IRSC) during this sequence (12.11.2017-04.07.2019). For this complex sequence, we applied the classical Coulomb failure stress, alternative stress scalars, and R forecast models and used the more appropriate MCC-F1 metric to test the prediction accuracy. We observe that the receiver independent stress scalars (maximum shear and von-Mises stress) perform better than the classical CFS values relying on the specification of receiver mechanisms (ΔCFS resolved on master fault, optimally oriented planes, and variable mechanism). However, detailed analysis based on the MCC-F1 metric revealed that the performance depends on the grid size, magnitude cutoff, and test period. Increasing the magnitude cutoff and decreasing the grid size and test period reduces the performance of all methods. Finally, we found that the performance of all methods except ΔCFS resolved on master fault and optimally oriented planes improve when the source information of large aftershocks is additionally considered, with stress-based models outperforming the R model. Our results highlight the importance of accounting for secondary stress changes in improving earthquake forecasts.
Predictable Patterns of Wintertime Surface Air Temperature in Northern Hemisphere and Their Predictability Sources in the SEAS5
Authors: Fan Hongdou , Wang Lin , Zhang Yang , Tang Youmin , Duan Wansuo , Wang Lei
Published: March 2022

Slow-varying atmospheric boundaries are the main sources of seasonal climate predictions, and their footprints on climate variables may be captured as predictable patterns. Based on 36-yr hindcasts from the fifth-generation seasonal forecast system of the European Centre for Medium-Range Weather Forecasts (SEAS5), the most predictable patterns of the wintertime 2-m air temperature (T2m) in the extratropical Northern Hemisphere are extracted via the maximum signal-to-noise (MSN) empirical orthogonal function (EOF) analysis, and their associated predictability sources are identified. The main findings of this study are as following:

The MSN EOF1 captures the warming trend that amplifies over the Arctic but misses the associated warm Arctic–cold continent pattern. The MSN EOF2 delineates a wavelike T2m pattern over the Pacific–North America region, which is rooted in the tropical forcing of the eastern Pacific-type El Niño–Southern Oscillation (ENSO). The MSN EOF3 shows a wavelike T2m pattern over the Pacific–North America region, which has an approximately 90° phase difference from that associated with MSN EOF2, and a loading center over midlatitude Eurasia. Its sources of predictability include the central Pacific-type ENSO and Eurasian snow cover. The MSN EOF4 reflects T2m variability surrounding the Tibetan Plateau, which is plausibly linked to the remote forcing of the Arctic sea ice.

The information on the leading predictable patterns and their sources of predictability is further used to develop a calibration scheme to improve the prediction skill of T2m. The calibrated prediction skill in terms of the anomaly correlation coefficient improves significantly over midlatitude Eurasia in a leave-one-out cross-validation, implying a possible way to improve the wintertime T2m prediction in the SEAS5.
The Mid-Pleistocene Transition: A delayed response to an increasing positive feedback?
Authors: Omta Anne Willem , Shackleton John , Follows Mick , Thomas Peter
Published: March 2022

Glacial-interglacial cycles constitute large natural variations in Earth's climate. The Mid-Pleistocene Transition (MPT) marks a shift of the dominant periodicity of these climate cycles from ~40 to ~100 kyr. Ramping with frequency locking is a promising mechanism to explain the MPT, combining an increase in the internal period with lockings to an external forcing. We identify the strength of positive feedbacks as a key parameter to induce increases in the internal period and allow ramping with frequency locking. Using the calcifier-alkalinity model, we simulate changes in periodicity similar to the Mid-Pleistocene Transition through this mechanism. However, the periodicity shift occurs up to 10 Million years after the change in the feedback strength. This result puts into question the assumption that the cause for the MPT must have operated around the same time as the observed periodicity shift.
Interactions between land cover change and temperature-humidity variability on a global scale
Authors: Hemshorn de Sánchez Anna Luisa , Stevens Bjorn , D’Odorico Paolo , Shokri Nima
Published: March 2022

The change of land cover affects regional and global climate through the surface energy budget and the water cycle, which determine the interactions between the terrestrial biosphere and the atmosphere. Land cover change not only affects the climate but is also influenced by it. The projected climate change and the occurrence of extreme climate events will profoundly affect the land cover, crop production, as well as water and food security. Yet, the complex interactions between land cover changes and climate variability are not fully understood. Previous studies have shown that land cover change influences the mean and extreme values of climate variables such as temperature. However, most research focused on specific types of land cover change such as deforestation or urbanisation and looked at only one climate variable (e.g., temperature). A comprehensive multivariate analysis relating multiple land cover changes and climate variables at the global scale is still missing. Here, we take an observation-based approach that analyses the complex interactions between different types of land cover change and the joint effect of temperature and humidity variability at the global scale. We analyse almost three decades of remotely sensed land cover and climate data to investigate the complex coupling between the patterns of different types of land cover change and the variability of temperature and relative humidity across the globe. Our analysis identifies hotspots of change on a global scale and correlations which will help to devise necessary action plans for sustainable land management and climate change mitigation measures crucial to the achievement of the United Nations Sustainable Development Goals.
 
Authors: Goosse Hugues , Dalaiden Quentin , Lyu Zhiqiang
Published: March 2022

The agreement between simulated and reconstructed multidecadal to centennial climate variability has improved over the past decades. However, significant disagreements still exist, especially at regional scale. In the Southern Ocean, both reconstructions and climate models display large variability at those timescales but models fail in reproducing some key elements such as the centennial variability in the strength of the westerly winds inferred from various types of proxy data. Data assimilation combines in an optimal way information from proxy data and climate models. It can help in identifying the cause of such model-data mismatch by improving the reconstructions as well as by testing the compatibility of those reconstructions with model physics or between different types of proxy data. Two examples will be discussed here. The first one focuses on the shift in the westerly winds between the 14th and 16th century, showing that it is clear in reconstructions based on classical statistical methods and on data assimilation but it is not simulated in models without data assimilation. In the second example, we will discuss the deep ocean convection and open ocean formation in the Southern Ocean that induce large multi-decadal to centennial variability in some global models while it is totally absent in many others. We will check how data assimilation can be used to test the validity of the simulations and to determine which model behavior is the most realistic. 
Multiple-sound-source-excitation quartz-enhanced photoacoustic spectroscopy based on a single-line spot pattern multi-pass cell
Authors: Cui Ruyue , Wu Hongpeng , Tittel Frank K. , Dong Lei , Chen Weidong
Published: March 2022

Laser-based spectroscopic methods, such as tunable diode laser absorption spectroscopy (TDLAS) [1] and quartz-enhanced photoacoustic spectroscopy (QEPAS) [2], have been developed for trace gas detection, leading to the advent of reliable and robust gas sensors. Among them, QEPAS is an attractive approach characterized by high cost-effectiveness, high sensitivity and small footprint, due to the use of a high Q-factor, low-cost quartz tuning fork (QTF) [3] as acoustic detector [4]. In the traditional single-pass QEPAS, modulated laser beam is focused at the QTF gap and only one acoustic source is generated between the QTF prongs. In the present work, multiple sound-source excitation has been applied to quartz-enhanced photoacoustic spectroscopy (MSSE-QEPAS) by using a single-line spot pattern multi-pass cell (MPC) [5]. The single-line spot pattern MPC is designed to make laser beam passing through the QTF 60 times to produce 60 acoustic sources between the QTF prongs. A signal gain factor of ~ 20 was realized in the MSSE-QEPAS approach with respect to the traditional single-pass QEPAS. A theoretical mode based on convolution method is proposed to modeling the MSSE-QEPAS approach. Highly sensitive QEPAS sensors based on MSSE-QEPAS described in this paper represents high opportunities for applications in atmospheric monitoring, industry process control and medical diagnostics.

 

Acknowledgments : The project is sponsored by National Key R&D Program of China (2019YFE0118200), National Natural Science Foundation of China (NSFC) (62075119, 61805132), Sanjin Scholar (2017QNSJXZ-04) and Shanxi “1331KSC”. Frank K. Tittel acknowledges support by the Robert Welch Foundation (Grant #C0586).

 

References

[1] R. Cui, L. Dong, H. Wu, W. Ma, L. Xiao, S. Jia, W. Chen, and F. K. Tittel, Anal. Chem. 92 (2020) 13034-1304.

[2] H. Wu, L. Dong, H. Zheng, Y. Yu, W. Ma, L. Zhang, W. Yin, L. Xiao, S. Jia, F. K. Tittel, Nat. Commun. 8 (2017) 15331.

[3] T. Wei, A. Zifarelli, S. Dello Russo, H. Wu, G. Menduni, P. Patimisco, A. Sampaolo, V. Spagnolo, L. Dong, Appl. Phys. Rev. 8 (2021) 041409.

[4] P. Patimisco, A. Sampaolo, L. Dong, F. K. Tittel, V. Spagnolo, Appl. Phys. Rev. 5 (2018) 011106.

[5] R. Cui, H. Wu, L. Dong, W. Chen, F. K. Tittel, Appl. Phys. Lett. 118 (2021) 161101.
Infrasound Detection and Location of Sources in and around the Korean Peninsula
Authors: Park Junghyun , Arrowsmith Stephen , Che Il-Young , Hayward Chris , Stump Brian
Published: March 2022

Infrasound event catalogs that span long durations are useful in identifying repeating sources from a common location, which can provide ground truth for studying the time varying nature of the atmosphere as well as quantifying event characteristics. We focus on producing a regional infrasound bulletin for the Korean peninsula region for 1999 to 2021. We use data from six South Korean infrasound arrays that are cooperatively operated by SMU and KIGAM. The detection procedure uses an adaptive F-detector (Arrowsmith et al., 2008) that inputs arrival time and backazimuth into the Bayesian Infrasonic Source Location (Modrak et al., 2010) procedure. The bulletin consists of 16,417 events over 22 years with repeated events from many locations and with source types that include shallow-depth earthquakes, limestone mines and quarries. We show that the majority of these events occur during working hours and days, suggesting a human cause. Installations of additional infrasound arrays in South Korea and the IMS infrasound arrays in Russia and Japan increase the number of infrasound events while improving location accuracy. Events that have associated signals at a large number of arrays are reviewed and evaluated to assess their quality. Infrasound amplitudes from the events are normalized for propagation effects to estimate source size. Ray tracing using the G2S atmospheric model generally correctly predicts the arrivals when strong stratospheric winds exist. Local weather data which captures small-scale variations in the wind velocity can, in some cases, explain observations that are not predicted by the G2S model.
Connecting actions to ecological and human health endpoints - evaluating the benefits of wastewater and stormwater projects
Authors: Clark Timothy , Greyell Carly , Kates Norah , Lanksbury Jennifer , Nidzgorski Daniel
Published: March 2022

Local wastewater and stormwater utilities invest millions to billions of dollars collected from ratepayers to meet regulatory requirements, protect human life and infrastructure, and protect water quality. In their project prioritization and planning efforts, utilities consider many factors, including the benefit to environmental outcomes. Utilities often compare the environmental benefits of potential projects by only evaluating changes in pollutant loads rather than looking at whether those projects will accomplish better environmental outcomes for people and wildlife. Many utilities lack a framework for considering these ultimate outcomes. In an effort for better-informed decision-making in King County, WA, we developed a framework (the Water Quality Benefits Evaluation toolkit) that connects actions to environmental outcomes.

The toolkit is an adaptable framework containing a watershed pollutant loading model, a pollutant-reduction and cost optimization model, and causal models representing systems surrounding specified environmental outcomes. We developed causal models for six endpoints: toxics in edible fish, fecal contamination at shellfish beds, fecal contamination at swimming beaches, algal toxins at swimming beaches, natural-origin Chinook salmon population health, and Southern Resident Killer Whale population health. The causal models include Bayesian networks, narrative conceptual models, and fish bioaccumulation models. The holistic evaluation of environmental outcomes provides better information to decision-makers to consider alongside other factors such as costs to ratepayers and reversing environmental inequities.

This presentation focuses on the development of the causal models and how they can be applied to support King County’s utility planning decisions. The presentation will also provide insight on how the framework can be employed for additional environmental endpoints and may be adapted to include other types of endpoints, such as equity and community health.
High and flat spectral responsivity of quartz tuning fork used as infrared photodetector in tunable diode laser spectroscopy
Authors: Wei Tingting , Zifarelli Andrea , Dello Russo Stefano , Wu Hongpeng , Menduni Giansergio , Patimisco Pietro , Sampaolo Angelo , Vincenzo Vincenzo , Dong Lei , Chen Weidong
Published: March 2022

In the past decade, the rapid development of infrared laser technology has led to an increasing demand for photodetectors with high sensitivity and a wide operative spectral range suitable for spectroscopic applications [1-2]. In this work, we report on the performance of a custom quartz tuning fork (QTF), having a fundamental resonance frequency of 9.78 kHz and quality factor of 11500 at atmospheric pressure, which was used as a sensitive and broadband infrared photodetector for laser absorption spectroscopy [3]. Fourier infrared spectrometer was used to characterize the infrared absorption capacity of quartz material at the wavelength of 1-20 μm. Wide spectral response capability of the used QTF detector was investigated based on tunable diode absorption spectroscopy using lasers operating at five different wavelengths (1.6-10.35 μm). A spectrally flat responsivity of ~2.2 kV/W was demonstrated, corresponding to a noise-equivalent power of 1.5 nW/Hz1/2, without employing any thermoelectrical cooling systems. In order to compensate for the drift of inherent characteristics (resonance frequency and quality factors) of the QTF detector, a heterodyne detection scheme was implemented to retrieve the resonance properties of the QTF detector together with the gas concentration in a single, fast measurement [4]. Experimental details including theoretical simulation and application demonstration will be discussed and presented.

Acknowledgments

The authors acknowledge financial support from National Key R&D Program of China (No. 2019YFE0118200), THORLABS GmbH, within PolySense, a joint-research laboratory, and the National Natural Science Foundation of China (Nos. 62075119 and 61805132).

References

[1] L. Dong, F. K. Tittel, C. Li, N. P. Sanchez, H. Wu, C. Zheng, Y. Yu, A. Sampaolo, and R. J. Griffin, Opt. Express 24 (2016) A528-A535.

[2] S. Dello Russo, A. Zifarelli, P. Patimisco, A. Sampaolo, T. Wei, H. Wu, L. Dong, and V. Spagnolo, Opt. Express 28 (2020) 19074-19084.

[3] T. Wei, A. Zifarelli, S. Dello Russo, H. Wu, G. Menduni, P. Patimisco, A. Sampaolo, V. Spagnolo, L. Dong, Appl. Phys. Rev. 8 (2021) 041409.

[4] H. Wu, L. Dong, H. Zheng, Y. Yu, W. Ma, L. Zhang, W. Yin, L. Xiao, S. Jia, and F. K. Tittel, Nat. Commun. 8 (2017) 15331.
An experimental study of melt migration in crystal-rich mushes
Authors: Ryan Amy , Hansen Lars , Zimmerman Mark , Pistone Mattia
Published: March 2022

Increasingly, volcanologists model mature volcanic systems as being fed by stratified magma reservoirs, that is, small lenses of eruptible magma suspended within a larger volume of non-eruptible, crystal-rich mush. Erupted lavas record geochemical evidence for long-term deep storage of distinct magma bodies followed by their ascent and coalescence shortly before eruption. Conditions and flow mechanisms that allow deep-seated magmas to rise quickly in reservoirs despite the high viscosity and low permeability of crystal-rich mushes are a subject of debate. We present results of melt migration experiments conducted in a triaxial, gas-medium apparatus. We prepared multiple crystal-rich mushes by hot pressing crushed borosilicate glass mixed with different amounts of subrounded quartz sand (44-106 μm diameter). Prepared mushes have crystal fractions from 0.59 to 0.83. A single disk of mush is stacked on a disk of soda lime glass, representing the intruding crystal-free magma, then heated to 900°C (above the glass transitions) and pressurized to 100-300 MPa. The bottom and circumference of the mush experience the confining pressure, but the top is at room pressure, resulting in a pore pressure gradient (~33-100 MPa/mm) that could drive the underlying melt into the mush. After several hours samples are cooled, decompressed, cut and imaged to determine the distribution of the soda lime glass that migrated in to the mush while at the experimental conditions. High crystal fraction samples (>0.80; Hi X) have glass filling intergranular space. In low crystal fraction samples (<0.70; Lo X), glass forms finger-like intrusions in the mush, indicating melt migration displaced crystals in the mush. Samples with intermediate crystal fractions (Int X) have both morphologies. Mush crystal fraction significantly influences the amount of melt migration, quantified as the measured area fractions of soda lime glass in mush normalized to the available intergranular space (1 - crystal fraction). Glass fills ~10%, ~60% and ~30% of the intergranular space for Lo X, Int X and Hi X samples, respectively. Glass area fraction is not correlated with the imposed pressure gradient, indicating melt migration is moderated by viscosity contrasts between the melt and mush (melt to mush viscosity ratio: 10-1.7 to 10-8.6). The observed increase in the amount of melt migration with decreasing crystal fraction is coincident with the onset of mush deformation. Applied to natural systems, these results suggest small changes in mush crystal fraction significantly influence the amount of melt migration that occurs and that melt migration in magma reservoirs peaks near the transition from deformable mush to partially-molten rock (i.e., at the rheologically critical melt fraction).
Parameterized Lifetime of Energetic Electrons due to Interactions with Chorus Waves
Authors: Wang Dedong , Shprits Yuri , Haas Bernhard
Published: March 2022

Chorus waves can cause the loss of energetic electrons in the Earth's radiation belts and ring current via pitch-angle diffusion. To quantify the effect of chorus waves on energetic electrons, we calculated the bounce-averaged quasi-linear diffusion coefficients. In this study, using these diffusion coefficients, we parameterize the lifetime of the electrons with an energy range from 1 keV to 2 MeV. In each magnetic local time (MLT), we calculate the lifetime for each energy and L-shell using two different methods. By applying polynomial fits, we parameterize the electron lifetime as a function of L-shell and electron kinetic energy (Ek) in each MLT and geomagnetic activity (Kp). The parameterized electron lifetimes show a strong functional dependence on L-shell and electron energy. During storm time, the lifetimes for higher energy (> 100 keV) electrons range from hours to days in the heart of the radiation belts. In contrast, the lifetimes for electrons with lower energy (< 100 keV) range from minutes to hours. This parameterization of electron lifetime is convenient for inclusion in simulations in the inner magnetosphere. 
Landslide hazard monitoring by combining geophysical and remote sensing data.
Authors: Fiolleau Sylvain , Falco Nicola , Dafflon Baptiste , Uhlemann Sebastian
Published: March 2022

Landslides are a major natural hazard, threatening communities and infrastructure worldwide. The mitigation of these hazards relies on the understanding of their causes and triggering processes, directly depending on soil properties, land use, and their variations over time. Firstly, we propose a new approach combining geophysical and remote sensing data into hydro-geomechanical modeling to provide a robust estimate of the probability of failure of slopes endangering surrounding structures, with a focus on an urban area. We performed a sensitivity analysis of the main parameters of the hydro-geomechanical model, which highlighted strong sensitivity to variations in soil thickness and cohesion. Based on those results, we use seismic noise measurements to assess soil thickness around our study site and remote sensing data to assess the vegetation cover, which impacts the cohesion. Our results highlight that relatively thick soil layers (above 2 m) have up to 4 times higher probability of failure. The presence of tall vegetation has a significant effect on soil cohesion, especially when the soil layer is relatively thin. The addition of vegetation cover showed a drastic reduction in the probability of failure when the soil thickness is less than 5 m. Secondly, we used those results to locate an area highly prone to sliding and endangering a bridge. We monitored this area using passive seismic and low-cost tiltmeter landslide mechanisms to better define the precursors of landslide activation. The combination of the two monitoring methods provided an accurate description of a small reactivation that occurred during a heavy rainfall event after a 7-month drought. Seismic monitoring provided a means of tracking changes in soil properties and the tiltmeter provided accurate displacement rates. Eventually, these developments will enable us to provide an accurate hazard assessment and landslide early warning.
Performance of the multiscale alignment ensemble filter in reducing vortex position errors
Authors: Ying Yue , Anderson Jeffrey , Bertino Laurent
Published: March 2022

Position errors in coherent features have been a challenging problem for data assimilation (DA) due to their high nonlinearity. To effectively reduce position errors, a multiscale alignment (MSA) method was introduced to compute ensemble Kalman filter (EnKF) updates on a sequence of model states at low to high resolutions (large to small scales). Large-scale state has less nonlinearity due to position errors, therefore linear EnKF updates are optimal. The large-scale analysis increments are then utilized to compute the displacement vectors that warp the model grid, reduce position errors and precondition the state at smaller scales before the EnKF update is computed again. This study further tests the performance of the MSA method in an idealized vortex model. The asymptotic behavior is documented for a multiscale solution as number of scales (Ns) increases. We show that the optimal Ns depends on the degree of nonlinearity caused by the position errors. When feature-based observations (such as the vortex position) are used, the MSA performs well with Ns  3 no matter how large the position errors are. A challenging scenario is identified for the MSA method, when the large-scale background flow is incoherent with the small-scale vortex position error (deviation from coherence assumption). In cycling DA experiments, the MSA performs better than the traditional EnKF at equal cost (using decreased ensemble size for MSA to compensate for its increased cost when Ns >1), showing good scalability for real application and potential for improving prediction skill in many multiscale Earth systems.
Bacterial motility dynamics in open and confined porous media
Authors: Perez Lazaro J. , Plymale Andrew , Parashar Rishi
Published: March 2022

Diverse processes such as bioremediation, biofertilization, and microbial drug delivery rely on bacterial migration in porous media. However, how pore-scale confinement alters bacterial motility is unknown due to the inherent physical heterogeneities on porous media. As a result, models of migration are limited and often employ ad hoc assumptions.

We aim to determine the impact of pore confinement in the spreading dynamics of two populations of motile metal-reducing bacteria by directly visualizing individual Acidovorax and Pelosinus in an unconfined liquid medium and a microfluidic chip containing arrays of pillars placed at regular intervals. We observe that the length of runs of the two species differs between the unconfined and confined medium. Results show that bacteria in the confined medium display systematic shorter jumps due to grain obstacles when compared to the open porous medium. Close inspection of the trajectories reveals that cells are intermittently and transiently trapped, producing superdiffusive motion at early and subdiffusion behavior at late times as they navigate through the confined pore spaces. While in the open medium, we observe a linearly increasing variance with respect to time for Acidovorax, and for Pelosinus the variance increases at a much faster rate showing superdiffusive behavior at early times. At late times, the rate of growth in spreading increases for Acidovorax while it reduces for Pelosinus. We finally discuss that the paradigm of run-and-tumble motility is dramatically altered in confined porous medium, which can have strong implications for large-scale transport.
Identification of extreme sea-level events in climate model data for the Swedish West Coast (Kattegatt)
Authors: Karami Mehdi Pasha , Schenk Frederik , Kruschke Tim , Drews Martin , Nilsson Erik , Rutgersson Anna
Published: March 2022

Coastal flooding due to extreme sea level events have hazardous socio-economic impact on coastal communities, and water, energy and transport infrastructures. Predicting changes in frequency and magnitude of occurrence of such extreme events on timescales ranging from the next season to the coming decade(s) is of high importance for timely preparation and decision-making. This requires having climate information at time scales beyond the weekly weather forecasts at long range as well as century-long timescales. Such data, however, are normally provided on the global scale, and thus have a relatively coarse resolution compared to the local events such as extreme sea-level. Here, a new empirical event-identification method is developed to detect extreme sea-level events for the western Swedish coast (Kattegatt) using data from global climate models and reanalysis. It, therefore, serves as an add-on to climate model forecast/projection data. The event-identification method considers both dynamical and statistical relations between high sea-level events and multivariate atmospheric variables by using peak-over-threshold wind speeds in combination with a catalogue of surge-relevant sea-level-pressure and wind-field patterns at both local as well as large scales. The identification performs well when tested for ERA5 data and captures significant number of observed high sea-level events in the Swedish West Coast. Using our method, we investigate the changes in the frequency of occurrence and magnitude of extreme events in the coming decade and until the end of the century. For this purpose, we use data from EC-Earth model experiments from the Decadal Climate Prediction Project (DCPP) and the SMHI Large Ensemble (LENS) for future climate scenarios (1970-2100; 50 members). Our new approach is also used to explore compound events when extreme sea-level and heavy precipitation occurring together under current and climate change conditions.
Development of a method to analyze the error factor of GNSS-A system using SGO-A data
Authors: Yokota Yusuke , Ishikawa Tadashi , Watanabe Shun-ichi , Nakamura Yuto
Published: March 2022

The GNSS-A seafloor geodetic observation array (SGO-A) has been operated in about 20 years by the Japan Coast Guard [Ishikawa et al., 2020]. It has become possible to measure interplate coupling condition and shallow slow slip events along the Nankai Trough in recent years [Yokota et al., 2016; Yokota and Ishikawa, 2020], and it has become possible to interpret the time change of postseismic deformation following the 2011 Tohoku-oki earthquake [Watanabe et al., 2021]. For understanding the detail physical process of the plate boundary (e.g., SSE), it is necessary to understand the accuracy of the GNSS-A system and study the quantification and attenuation of the error source.

SGO-A data is very useful for this purpose. This dataset is located in the SGO-A site, and basic analysis software GARPOS is also open to the public [Watanabe et al., 2020]. The format is also defined, and a lot of information necessary for error analysis is published.

For example, using the estimation result of SGO-A data by GARPOS, the relationship between the vertical movement and the sound speed structure’s disturbance can be investigated from the residual of the vertical movement and the estimated sound speed structure. In addition, the existence of unexpected errors and their effects can be considered by examining the correlation with the position of the seafloor station.

It is also possible to understand the disturbance in the ocean from the estimated disturbance of the sound speed structure. Recently, the theoretical background for this estimation has been organized and made easier to handle. Considering this result and the comparison of the ocean fields that are likely to occur in reality, it was also found that the observation accuracy is expected to be improved depending on the observation points. In this presentation, we introduce the interpretation method of GNSS-A data that is being developed in recent years.

 

SGO-A data: https://www1.kaiho.mlit.go.jp/KOHO/chikaku/kaitei/sgs/datalist_e.html

GARPOS: https://doi.org/10.5281/zenodo.4522027
LitMod3D_4inv: Multi-observable and multi-scale geophysical inversions for the physical state of the Earth.
Authors: Fomin Ilya , Afonso Juan , Manassero Constanza
Published: March 2022

Characterising the physical state of the Earth's interior with high resolution requires the joint inversion of complementary geophysical datasets. LitMod3D_4inv is a method/software that allows regional and continental scale joint inversions within a probabilistic framework for the 3D thermochemical structure of the lithosphere and upper mantle. The software can simultaneously invert gravity anomalies, geoid height, gravity gradients, Love and Rayleigh surface-wave dispersion curves, receiver functions, body-wave travel times, surface heat flow, absolute elevation and magnetotelluric data, or any combination of them. The result is a collection of Earth models (a probabilistic distribution) with exceptional explicative power and robust estimates for uncertainties.

We use equations of state and Gibbs free energy minimisation routines to produce self-consistent sets of the seismic velocities, densities, and other properties from the actual parameters (unknowns) of the inversion – mantle chemical compositions, thermal profiles, and properties of the crustal layers (thickness, reference densities, Vp/Vs). The code relies on highly-optimised solvers for gravity, seismic, and magnetotelluric forward problems and multi-level hybrid parallel architecture to make use of multiple interacting markov chains. The modular structure of the code allows for extending the set of solvers to include new observables or to implement new Markov chain Monte Carlo algorithms.

In this presentation we will discuss recent developments in the LitMod3D_4inv suite and illustrate their performance with real examples in eastern Canada, in southern and central Africa, and north eastern Australia.
Excess ice loads prior to the Last Glacial Maximum in the Indian Ocean sector of East Antarctica derived from sea-level observations and GIA modeling
Authors: Ishiwa Takeshige , Okuno Jun'ichi , Suganuma Yusuke
Published: March 2022

Further understanding of Antarctic Ice Sheet responses to global climate changes requires an accurate and continuous reconstruction of the AIS changes. However, the erosive nature of ice-sheet expansion and sea-level drop and the difficulty of accessing much of Antarctica make it difficult to obtain field-based evidence of ice-sheet and sea-level changes before the Last Glacial Maximum. Limited sedimentary records from the Indian Ocean sector of East Antarctica demonstrate that the sea level of Marine Isotope Stage 3 was close to the present level despite the global sea-level drop lower than −40 m. Although previous GIA-derived sea levels hardly explain these sea-level observations, we demonstrate glacial isostatic adjustment modeling with refined Antarctic Ice Sheet loading histories. Our experiments reveal that the Indian Ocean sector of the Antarctic Ice Sheet would have been required to experience excess ice loads before the Last Glacial Maximum in order to explain the observed sea-level highstands during Marine Isotope Stage 3. We also conduct a sensitivity test of the small Northern American Ice Sheet during Marine Isotope Stage 3, suggesting that this small ice sheet is not enough to achieve sea-level highstands during Marine Isotope Stage 3 in the Indian Ocean sector of East Antarctica. As such, we suggest that the Indian Ocean sector of the East Antarctic Ice Sheet reached its maximum thickness before the global Last Glacial Maximum.

 

Reference

Ishiwa, T., Okuno, J., and Suganuma, Y., 2021. Excess ice loads in the Indian Ocean sector of East Antarctica during the last glacial period. Geology, 49, 1182–1186. https://doi.org/10.1130/g48830.1
Vulnerability and Resilience of Urban Traffic to Precipitation in China
Authors: Zhang Min , Liu Yufu , Xiao Yixiong , Sun Wenqi , Zhang Chen , Wang Yong , Bai Yuqi
Published: March 2022

    The concept of Healthy Cities, introduced by the World Health Organization, demonstrates the value of health for the whole urban system. As one of the most important components of urban systems, transportation plays an important role in Healthy Cities. Many transportation evaluation systems focus on factors such as road networks, parking spaces, transportation speed, accessibility, convenience, and commuting time, while the vulnerability and resilience of urban transportation are rarely evaluated. This study presents the preliminary progress in the evaluation of traffic vulnerability and resilience during precipitation events in 39 Chinese cities. Traffic congestion index data, derived from the Baidu Map Smart Transportation Platform, and rainfall data, derived from NASA’s global precipitation measurement, are utilized. Traffic vulnerability index, traffic resilience index, and the corresponding quantitative methods are proposed, and the analysis results are presented. This study is of value in improving the understanding of urban traffic vulnerability and resilience, and in enabling the quantitative evaluation of them in urban health assessment and the Healthy Cities program.
The role of transient eddies and diabatic heating in the maintenance of heat waves: a nonlinear quasi-stationary wave perspective
Authors: Franzke Christian , Ma Qiyun
Published: March 2022

Heat waves result from large-scale stationary waves and have major impacts on the economy and mortality. However, the dynamical processes leading to and maintaining heat waves are still not well understood. Here we use a nonlinear stationary wave model (NSWM) to examine the role played by anomalous stationary waves and how they are forced during heat waves. We will discuss heat waves in Europe and Asia. We show that the NSWM can successfully reproduce the main features of the observed anomalous stationary waves in the upper troposphere. Our results indicate that the dynamics of heat waves are nonlinear, and transient momentum fluxes are the primary drivers of the observed anomalous stationary waves. We will also discuss the role of anomalous SSTs in influencing heat waves.
Effects of regional and local stresses on fault slip tendency in the southern Taranaki Basin, New Zealand
Authors: Massiot Cecile , Seebeck Hannu , Nicol Andrew , McNamara David D. , Lawrence Mark J.F. , Griffin Angela G. , Thrasher Glenn P. , Viskovic G. Paul D.
Published: March 2022

Determining the potential for faults to slip is widely employed for evaluating fault slip potential and associated earthquake hazards, and characterising reservoir properties. Here we use borehole and 3D seismic reflection data to estimate stress orientations and magnitudes, fault geometries and slip tendency in the southern Taranaki Basin, New Zealand. We highlight uncertainties in maximum horizontal stress (SHmax) magnitude calculations from borehole breakout width and rock strength. As in other settings, breakout width is uncertain on resistivity images because one of the breakout edges often lies in-between the resistivity imager pads, so only a subset of borehole breakouts can be used with confidence. The main uncertainty on SHmax magnitude is the rock strength at the borehole depth at which breakouts form. Given the rarity of basin-specific rock mechanical data, we rely on equations used to convert downhole acoustic compressional wave slowness into rock strength defined in sandstone and mudstones. However, lithologies in the southern Taranaki Basin are commonly muddy sandstones and sandy mudstone that can be interlayered. In addition, we show an example where breakouts are confined to moderately cemented carbonate units without change in acoustic compressional wave slowness. Using a range of rock strength equations based on sandstones and mudstones provides a possible SHmax magnitude range. With only one focal mechanism available in the study area, constraints on SHmax magnitudes from borehole data remain valuable and inform on stresses in the shallow crust.

Although the southern Taranaki basin is undergoing active deformation at plate tectonic scales, the stress magnitudes appear insufficiently high to reactivate the faults assuming a classic coefficient of friction. SHmax azimuths and SHmax:Sv magnitude ratios vary locally between boreholes and with depth. A borehole that intersects an inactive seismic-scale fault and borehole-scale faults over a 150-m interval shows SHmax to rotate by up to 30° proximal to the faults, which are favourably orientated for slip in both strike-slip and normal regimes. The small borehole-scale faults may, however, be active within the inactive seismic scale fault's damage zone. We highlight changes of slip tendency along faults resulting from local variations in the stress field and non-planar fault geometries that could not be resolved using only seismic reflection data and regional stress tensor.
How to develop site-specific urban pluvial flooding mitigation strategies? A new approach to investigating the spatial heterogeneous driving forces of urban pluvial flooding
Authors: Zhang Qifei , Wu Zhieng , Guo Guanhua , Tarolli Paolo
Published: March 2022

With the acceleration of urbanization, urban pluvial flooding seriously threatens urban sustainable development and human life. It is widely accepted that various landscape elements contribute to the magnitude of urban pluvial flooding. Considerable efforts investigated the universal mechanism of urban pluvial flooding by regarding the whole study area as spatial homogeneous while ignoring its local specific mechanism. The spatially heterogeneous effects of landscape elements on urban pluvial flooding remain poorly understood. Additionally, it is still unclear how the interactive effects of landscape elements affect urban pluvial flooding. In most practical situations, urban pluvial flooding is affected by multiple factors, rather than by a single factor alone. These shortcomings make it impossible to formulate urban pluvial flooding mitigation measures based on the relative contribution of various landscape elements on urban pluvial flooding. To shed some light on this topic, an innovative method that integrated the all subsect regression model, cubist regression tree, and geographical detector model is presented to spatially explicit the heterogeneous forces driving urban pluvial flooding variation and identify the pluvial flooding dominant driving forces with different local conditions. By comparing with two other commonly used regression methods (global regression model, spatial lag model), the proposed method can fully quantify this spatial non-stationarity mechanism and spatially explicit the local driving forces. Urban pluvial flooding dominant driving factors and their contribution vary with the local site conditions. Even for the same dominant factor, its contribution to pluvial flooding varies considerably in different watersheds. Based on this, local authorities can develop site-specific urban pluvial flooding mitigation strategies according to the dominant factors in different areas. The results of this study extend our scientific understanding of the site-specific mechanism of urban pluvial flooding, providing useful information for formulating more targeted and effective urban pluvial flooding mitigation strategies with different local conditions, rather than a “one-size-fits-all” policy.
Potential Flood-Prone Areas in the Municipality of Saint Bernard, Southern Leyte, Philippines: Risk Evaluation and Flood Susceptibility Mapping using GIS-based Analytical Hierarchy Process (AHP)
Authors: Bendijo John Reige , Morales Maria Divina
Published: March 2022

Floods are processes that significantly affect populations, the environment, economy and infrastructure. The Municipality of Saint Bernard, a rural, data-scarce locality, is one of the areas in the Philippines frequently affected by flooding. Risk Evaluation and Flood Susceptibility Mapping are critical components of flood prevention and mitigation techniques because they identify the most susceptible locations based on physiographic attributes that influence flooding propensity. The first objective of this study is to generate a flood susceptibility map for the identification of barangays or zones susceptible to flood in the Municipality of Saint Bernard based on the eight (8) physiographic maps, namely: (i) Fluvial Geomorphology, (ii) Slope, (iii) Elevation, (iv) Lithology, (v) Land cover, (vi) Topographic Wetness Index (TWI), (vii) Drainage density, and (viii) Distance from the Rivers and Streams. AHP serves to determine the weights of the aforementioned factors. The distance to rivers and streams is ranked as the essential factor for finding areas susceptible to flooding, with the highest weighted rate of 20.10%. The authors utilized a quantitative approach to validate the generated flood susceptibility map by correlating with the historical flood datasets. The quantitative validation showed an excellent agreement between the susceptibility zones and historical flood events, of which 74.6% were coincident with high or very high susceptibility levels, thus confirming the effectiveness of AHP. The second objective of this study is to evaluate the relative percentage risk of flooding in every barangays or zones and the generation of risk exposure maps, which is essential to visualize each barangays' or zones' builtups, roads, and the population at risk.