Fluvial flood inundation and socio-economic impact model based on open data
Lukas Riedel, Thomas Röösli, Thomas Vogt, and David N. Bresch
Geosci. Model Dev., 17, 5291–5308, https://doi.org/10.5194/gmd-17-5291-2024, 2024
River floods are among the most devastating natural hazards. We propose a flood model with a statistical approach based on openly available data. The model is integrated in a framework for estimating impacts of physical hazards. Although the model only agrees moderately with satellite-detected flood extents, we show that it can be used for forecasting the magnitude of flood events in terms of socio-economic impacts and for comparing these with past events.
Abstract
The ionosphere shows regular changes such as daily, 27 days, seasonal, semi-annual, annual, and 11 years. These changes can be modeled and their effects largely determined. However, in addition to regular changes, irregular changes occur in the ionosphere due to space weather conditions, natural disasters, and human-induced irregularities. GNSS is one of the instruments along with many others that can give a piece of information on the ionospheric state. Various indices/parameters are used to determine the effect of space weather conditions. The well-known ones are solar activity indices, geomagnetic storm indices, magnetic field components, proton density, and proton flux parameters. It is important to take all of these indices into consideration when investigating the source of the anomaly. Considering only some of them may lead to incorrect inferences about the source of possible anomalies. To carry out comprehensive research in this field, it is necessary to analyze a very large data set. This indicates the requirement for an automatic system. With the Global and Regional Ionosphere Monitoring System (GRIMS) designed within the scope of this study, the ionosphere can be monitored globally and regionally. The GRIMS is online at https://www.online-grims.com/. By using Global ionospheric maps and GNSS receiver data, global, regional, and station-specific anomalies can be detected regularly through methods such as HDI (Highest Density Interval) and ARIMA (Autoregressive Integrated Moving Average). GRIMS gathers space weather-related parameters from ionospheric data centers to help users interpret the situation, and it allows users to download the results and request data for specific days. The details of the experimental results and output products of the system designed during the geomagnetic active days of March 17, 18, 2015 are given in this paper. Moreover, geomagnetic active days that occurred between 2000 and 2023 are given in the GRIMS.
Abstract
Global Navigation Satellite System fast precise positioning can be achieved with accurate ionospheric corrections computed from an adequate number of GNSS stations in a local region. In low-latitude regions, the presence of electron density gradients over short distances can lead to outliers in the map of ionospheric corrections and decrease its accuracy. In this study, we explored outlier detection in ionospheric correction mapping through statistical residuals during a four-month test in 2021. Our findings indicate that the residuals of the local ionospheric model conform to the Laplace distribution. To determine outliers, we use an empirical rule for the Laplace distribution, setting thresholds at μ ± 3b, μ ± 3.5b, and μ ± 5.8b for data retention rates of 95%, 97%, and 99.7%, respectively. Here, μ represents the location parameter, which corresponds to the median of data, and b is the scale parameter, calculated as the medium absolute deviation. We found that while removing outliers can improve model accuracy, it may result in unavailable prediction due to a lack of data in a spare network. For example, applying a μ ± 3.5b threshold for outlier removal led to approximately 2.5% of recording time having no ionospheric corrections map in low-latitude regions, however, the local model has the potential to improve its mean accuracy by up to 50% for both low and mid-latitudes. Therefore, choosing the appropriate percentile threshold depends on the network configuration and the desired accuracy. Removing erroneous satellite data to improve ionospheric accuracy brings positive impacts on precise positioning.
SummaryIn anticipation of a forthcoming scientific deep drilling initiative within the Western Alps near Balmuccia, Italy, a high-resolution seismic survey is performed at the proposed drill site. This site is situated within the Ivrea Verbano Zone (IVZ), characterized by lower-crustal materials and fragments of upper mantle rocks exposed adjacent to the Insubric Line. The 2-km-long seismic survey crosses an isolated km-scale outcrop of peridotite near the town of Balmuccia. Applying P-wave traveltime tomography, a substantial contrast in seismic velocities is identified, with velocities in the range of 1–8 km s−1. The peridotite displays velocities ranging from 6 to 8 km s−1. The higher velocities near 8 km s−1 are consistent with laboratory measurements on small-scale samples, while the low velocity areas within the peridotite body reflect the influence of fractures and faults. The mean velocity derived for the peridotite body is ca. 7 km s−1. The reflection seismic analysis reveals subvertical reflectors positioned at the peridotite boundaries mapped at the surface, converging at a depth of ca. 0.175 km b.s.l. which images a lens-like structure for the peridotite body. However, the area beneath the imaged lens and the deeper Ivrea Geophysical Body (IGB) suggested by earlier studies is not well imaged, which leaves room for other interpretations regarding the relationship of these two bodies. Prior geophysical investigations provide only approximate depth estimates for the top of the IGB, spanning between 1–3 km depth b.s.l. Although the reflection data does not exhibit a series of continuous reflectors beneath the peridotite, a prominent reflection at ca. 1.3 km depth may indicate the top of the IGB.
The Earthquake Early Warning System (EEWS) acts as a vital instrument for reducing seismic risks in regions with high seismic vulnerability. A rapid and accurate hypocenter estimation is pivotal for the EEWS, ...
An improved method for identifying sporadic E (Es) layer properties from radio occultation (RO) electron density profiles (EDPs) is presented. The data used are sourced from COSMIC-1 RO EDPs collected between ...
Publication date: Available online 1 July 2024
Source: Advances in Space Research
Author(s): B. Ramzan, S.N.A. Qazi, Irshad Salarzai, Muhammad Tahir, Arshad M. Mirza, A. Rasheed, M. Jamil
With a technique called seismic tomography, researchers use the shape of traveling seismic waves from nearby or distant earthquakes to create 3D images of inner Earth, allowing them to "see" hundreds of kilometers below the surface.
In the deepest parts of the ocean, below 4,000 meters, the combination of high pressure and low temperature creates conditions that dissolve calcium carbonate, the material marine animals use to make their shells.
An international team of geophysicists has found evidence that the Earth experienced plate tectonics earlier than previously thought. In their study, published in the Proceedings of the National Academy of Sciences, the group analyzed zircons from Jack Hills in Australia.
Isabel Hernando-Alonso, a researcher at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), is the lead author of a geochronological study published in the journal Quaternary Geochronology, in which the electron spin resonance and paleomagnetism methods were used to analyze the oldest sedimentary levels of the site known as Galería Complex in the Sierra de Atapuerca (Burgos), where the Covacha de los Zarpazos and Tres Simas Central caves lie.
As climate change advances, the vast bodies of ice on Antarctica and Greenland contribute significantly to sea level rise. To project their future effect on sea level rise, additional research is required to improve scientists' understanding of these masses of ice. Now, two groups of scientists are undertaking a joint effort to address what has long been a major obstacle to such research.
Development and Comparison of Empirical Models for All-sky Downward Longwave Radiation Estimation at the Ocean Surface Using Long-term Observations
Jianghai Peng, Bo Jiang, Hui Liang, Shaopeng Li, Jiakun Han, Thomas C. Ingalls, Jie Cheng, Yunjun Yao, Kun Jia, and Xiaotong Zhang
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-85,2024
Preprint under review for AMT (discussion: open, 0 comments)
Our study introduces a new model that improves predictions of heat interactions at the ocean's surface, using data from 65 buoys. This model, more accurate than previous ones, incorporates effects of cloud cover and atmospheric water, enhancing our understanding of the ocean’s role in climate regulation. This could significantly aid climate research and environmental monitoring.
Abstract
Determining the shear-velocity dependence of dry granular friction can provide insight into the controlling variables in a dry granular friction law. Some laboratories believe that the quality of this study is at the forefront of the discipline for the following reasons. Results suggest that granular friction is greatly affected by shear-velocity (v), but shear experiments over the large range of naturally occurring shear-velocities are lacking. Herein we examined the shear velocity dependence of dry friction for three granular materials, quartz sand, glass beads and fluorspar, across nine orders of magnitude of shear velocity (10−8–2 m/s). Within this range, granular friction exhibited four regimes, following a broad approximate “m” shape including two velocity-strengthening and two velocity-weakening regimes. We discuss the possible physical mechanisms of each regime. This shear velocity dependence appeared to be universal for all particle types, shapes, sizes, and for all normal stresses over the tested range. We also found that ultra-high frequency vibration as grain surfaces were scoured by micro-chips were formed by spalling at high shear velocities, creating ∼20 μm diameter impact pits on particle surfaces. This study provides laboratory laws of a friction-velocity (μ-v) model for granular materials.
As climate change advances, its impacts are not universally equal, with temperature rising differently by latitude and elevation. Climate heterogeneity is the study of this diversity in Earth's climate patterns, and the focus of recent research published in Geophysical Research Letters.
Aircraft engine dust ingestion at global airports
Claire L. Ryder, Clément Bézier, Helen F. Dacre, Rory Clarkson, Vassilis Amiridis, Eleni Marinou, Emmanouil Proestakis, Zak Kipling, Angela Benedetti, Mark Parrington, Samuel Rémy, and Mark Vaughan
Nat. Hazards Earth Syst. Sci., 24, 2263–2284, https://doi.org/10.5194/nhess-24-2263-2024, 2024
Desert dust poses a hazard to aircraft via degradation of engine components. This has financial implications for the aviation industry and results in increased fuel burn with climate impacts. Here we quantify dust ingestion by aircraft engines at airports worldwide. We find Dubai and Delhi in summer are among the dustiest airports, where substantial engine degradation would occur after 1000 flights. Dust ingestion can be reduced by changing take-off times and the altitude of holding patterns.
An improved dynamic bidirectional coupled hydrologic–hydrodynamic model for efficient flood inundation prediction
Yanxia Shen, Zhenduo Zhu, Qi Zhou, and Chunbo Jiang
Nat. Hazards Earth Syst. Sci., 24, 2315–2330, https://doi.org/10.5194/nhess-24-2315-2024, 2024
We present an improved Multigrid Dynamical Bidirectional Coupled hydrologic–hydrodynamic Model (IM-DBCM) with two major improvements: (1) automated non-uniform mesh generation based on the D-infinity algorithm was implemented to identify flood-prone areas where high-resolution inundation conditions are needed, and (2) ghost cells and bilinear interpolation were implemented to improve numerical accuracy in interpolating variables between the coarse and fine grids. The improved model was reliable.
Tsunami hazard assessment in the South China Sea based on geodetic locking of the Manila subduction zone
Guangsheng Zhao and Xiaojing Niu
Nat. Hazards Earth Syst. Sci., 24, 2303–2313, https://doi.org/10.5194/nhess-24-2303-2024, 2024
The purpose of this study is to estimate the spatial distribution of the tsunami hazard in the South China Sea from the Manila subduction zone. The plate motion data are used to invert the degree of locking on the fault plane. The degree of locking is used to estimate the maximum possible magnitude of earthquakes and describe the slip distribution. A spatial distribution map of the 1000-year return period tsunami wave height in the South China Sea was obtained by tsunami hazard assessment.
Modeling Seismic Hazard and Landslide Potentials in Northwestern Yunnan, China: Exploring Complex Fault Systems with multi-segment rupturing in a Block Rotational Tectonic Zone
Jia Cheng, Chong Xu, Xiwei Xu, Shimin Zhang, and Pengyu Zhu
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-96,2024
Preprint under review for NHESS (discussion: open, 3 comments)
The Northwestern Yunnan Region (NWYR), with a complex network of active faults, presents significant seismic hazards such as multi-segment ruptures and landslides. This article introduces a new seismic hazard model, which integrates fault slip parameters to assess the risks associated with multi-segment ruptures. The results reveal the intricate relationship between these ruptures and the regional small block rotation induced by regional low-crustal flow and gravitational collapse.
Abstract
The ground-based, high-frequency radars of the Super Dual Auroral Radar Network (SuperDARN) observe backscatter from ionospheric field-aligned plasma irregularities and features on the Earth's surface out to ranges of several thousand kilometers via over-the-horizon propagation of transmitted radio waves. Interferometric techniques can be applied to the received signals at the primary and secondary antenna arrays to measure the vertical angle of arrival, or elevation angle, for more accurate geolocation of SuperDARN observations. However, the calibration of SuperDARN interferometer measurements remains challenging for several reasons, including a 2π phase ambiguity when solving for the time delay correction factor needed to account for differences in the electrical path lengths between signals received at the two antenna arrays. We present a new technique using multi-frequency ionospheric and ground backscatter observations for the calibration of SuperDARN interferometer data, and demonstrate its application to both historical and recent data.
