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  • 1
    Publication Date: 2022-01-10
    Description: Southern New England exhibits diverse geologic features resulting from past tectonic events. These include Proterozoic and early Paleozoic Laurentian units in the west, several Gondwana-derived terranes that accreted during the Paleozoic in the east, and the Mesozoic Hartford Basin in the central part of the region. The Seismic Experiment for Imaging Structure beneath Connecticut (SEISConn) project involved the deployment of a dense array of 15 broadband seismometers across northern Connecticut to investigate the architecture of lithospheric structures beneath this region and interpret how they were created and modified by past tectonic events in the context of surface geology. We carried out P-to-S receiver function analysis on SEISConn data, including both single-station analysis and common conversion point (CCP) stacking. Our images show that the westernmost part of Connecticut has a much deeper Moho than central and eastern Connecticut. The lateral transition is a well-defined, ∼15 km step-like offset of the Moho over a ∼20 km horizontal distance. The Moho step appears near the surface boundary between the Laurentian margin and the Gondwana-derived Moretown terrane. Possible models for its formation include Ordovician underthrusting of Laurentia and/or modification by younger tectonic events. Other prominent features include a strong positive velocity gradient (PVG) beneath the Hartford basin corresponding to the bottom of the sedimentary units, several west-dipping PVGs in the crust and mantle lithosphere that may correspond to relict slabs or shear zones from past subduction episodes, and a negative velocity gradient (NVG) that may correspond to the base of the lithosphere.
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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  • 2
    Publication Date: 2022-08-05
    Description: Based on an improved model of the moon absorption of Jovian radiation belt particles, we investigate quantitatively and comprehensively the absorption probabilities and particle lifetimes due to encounters with four of the inner moons of Jupiter (Amalthea, Thebe, Io, and Europa) inside L 〈 10. Our results demonstrate that the resultant average lifetimes of energetic protons and electrons vary dramatically between ∼0.1 days and well above 1,000 days, showing a strong dependence on the particle equatorial pitch angle, kinetic energy and moon orbit. The average lifetimes of energetic protons and electrons against moon absorption are shortest for Io (i.e., ∼0.1–10 days) and longest for Thebe (i.e., up to thousands of days), with the lifetimes in between for Europa and Amalthea. Due to the diploe tilt angle absorption effect, the average lifetimes of energetic protons and electrons vary markedly below and above urn:x-wiley:21699097:media:jgre21827:jgre21827-math-0001 = 67°. Overall, the average electron lifetimes exhibit weak pitch angle dependence, but the average proton lifetimes are strongly dependent on equatorial pitch angle. The average lifetimes of energetic protons decrease monotonically and substantially with the kinetic energy, but the average lifetimes of energetic electrons are roughly constant at energies 〈∼10 MeV, increase substantially around the Kepler velocities of the moons (∼10–50 MeV), and decrease quickly at even higher energies. Compared with the averaged electron lifetimes, the average proton lifetimes are longer at energies below a few MeV and shorter at energies above tens of MeV.
    Type: info:eu-repo/semantics/article
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  • 3
    Publication Date: 2022-03-21
    Description: During the lithospheric buildup to an earthquake, complex physical changes occur within the earthquake hypocenter. Data pertaining to the changes in the ionosphere may be obtained by satellites, and the analysis of data anomalies can help identify earthquake precursors. In this paper, we present a deep-learning model, SeqNetQuake, that uses data from the first China Seismo-Electromagnetic Satellite (CSES) to identify ionospheric perturbations prior to earthquakes. SeqNetQuake achieves the best performance [F-measure (F1) = 0.6792 and Matthews correlation coefficient (MCC) = 0.427] when directly trained on the CSES dataset with a spatial window centered on the earthquake epicenter with the Dobrovolsky radius and an input sequence length of 20 consecutive observations during night time. We further explore a transferring learning approach, which initially trains the model with the larger Electro-Magnetic Emissions Transmitted from the Earthquake Regions (DEMETER) dataset, and then tunes the model with the CSES dataset. The transfer-learning performance is substantially higher than that of direct learning, yielding a 12% improvement in the F1 score and a 29% improvement in the MCC value. Moreover, we compare the proposed model SeqNetQuake with other five benchmarking classifiers on an independent test set, which shows that SeqNetQuake demonstrates a 64.2% improvement in MCC and approximately a 24.5% improvement in the F1 score over the second-best convolutional neural network model. SeqNetSquake achieves significant improvement in identifying pre-earthquake ionospheric perturbation and improves the performance of earthquake prediction using the CSES data.
    Description: Published
    Description: 779255
    Description: 7T. Variazioni delle caratteristiche crostali e "precursori"
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2022-10-26
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creaive Commons Attribution License. The definitive version was published in Eveleth, R., Glover, D. M., Long, M. C., Lima, I. D., Chase, A. P., & Doney, S. C. . Assessing the skill of a high-resolution marine biophysical model using geostatistical analysis of mesoscale ocean chlorophyll variability from field observations and remote sensing. Frontiers in Marine Science, 8, (2021): 612764, https://doi.org/10.3389/fmars.2021.612764.
    Description: High-resolution ocean biophysical models are now routinely being conducted at basin and global-scale, opening opportunities to deepen our understanding of the mechanistic coupling of physical and biological processes at the mesoscale. Prior to using these models to test scientific questions, we need to assess their skill. While progress has been made in validating the mean field, little work has been done to evaluate skill of the simulated mesoscale variability. Here we use geostatistical 2-D variograms to quantify the magnitude and spatial scale of chlorophyll a patchiness in a 1/10th-degree eddy-resolving coupled Community Earth System Model simulation. We compare results from satellite remote sensing and ship underway observations in the North Atlantic Ocean, where there is a large seasonal phytoplankton bloom. The coefficients of variation, i.e., the arithmetic standard deviation divided by the mean, from the two observational data sets are approximately invariant across a large range of mean chlorophyll a values from oligotrophic and winter to subpolar bloom conditions. This relationship between the chlorophyll a mesoscale variability and the mean field appears to reflect an emergent property of marine biophysics, and the high-resolution simulation does poorly in capturing this skill metric, with the model underestimating observed variability under low chlorophyll a conditions such as in the subtropics.
    Description: This work was supported in part by the National Aeronautics and Space Administration (NASA) as part of the North Atlantic Aerosol and Marine Ecosystems Study (NAAMES; NASA grant 80NSSC18K0018). The CESM project is supported by the National Science Foundation and the Office of Science (BER) of the United States Department of Energy. Computing resources were provided by the Climate Simulation Laboratory at NCAR’s Computational and Information Systems Laboratory (CISL), sponsored by the National Science Foundation and other agencies. This research was enabled by CISL compute and storage resources.
    Keywords: Geostatistical analysis ; North Atlantic Ocean ; Community Earth System Model ; Model validataion ; Chlorophyll
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 5
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    American Geophysical Union
    Publication Date: 2022-10-26
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Long, M. H. Aquatic biogeochemical eddy covariance fluxes in the presence of waves. Journal of Geophysical Research: Oceans, 126(2), (2021): e2020JC016637, https://doi.org/10.1029/2020JC016637.
    Description: The eddy covariance (EC) technique is a powerful tool for measuring atmospheric exchange rates that was recently adapted by biogeochemists to measure aquatic oxygen fluxes. A review of aquatic biogeochemical EC literature revealed that the majority of studies were conducted in shallow waters where waves were likely present, and that waves biased sensor and turbulence measurements. This review identified that larger measurement heights shifted turbulence to lower frequencies, producing a spectral gap between turbulence and wave frequencies. However, some studies sampled too close to the boundary to allow for a spectral turbulence‐wave gap, and a change in how EC measurements are conducted and analyzed is needed to remove wave‐bias. EC fluxes have only been derived from the time‐averaged product of vertical velocity and oxygen, often resulting in wave‐bias. Presented is a new analysis framework for removing wave‐bias by accumulation of cross‐power spectral densities below wave frequencies. This analysis framework also includes new measurement guidelines based on wave period, currents, and measurement heights. This framework is applied to sand, seagrass, and reef environments where traditional EC analysis resulted in wave‐bias of 7.0% ± 9.2% error in biogeochemical (oxygen and H+) fluxes, while more variable and higher error was evident in momentum fluxes (10.5% ± 21.0% error). It is anticipated that this framework will lead to significant changes in how EC measurements are conducted and evaluated, and help overcome the major limitations caused by wave‐sensitive and slow‐response sensors, potentially expanding new chemical tracer applications and more widespread use of the EC technique.
    Description: This work was supported by the Independent Research & Development Program at WHOI grant 25307and NSF OCE grants 1657727 and 1633951.
    Keywords: Coral reef ; Eddy covariance ; Sand ; Seagrass ; Waves
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 6
    Publication Date: 2022-11-10
    Description: We developed and validated a novel automated water incubator that measures in-situ rates of photosynthesis and respiration. This dataset includes raw data, Monte-Carlo simulation method, and processed results from field deployments in Summer, 2021. Deployment of the incubator was conducted near Ucantena Island, Massachusetts, USA. The dataset includes timeseries of automated incubation experiments, reporting dissolved oxygen concentration (DO), temperature, and photosynthetically active radiation (PAR). There are four deployments spanning from late august to early October, 2021. Each deployment lasted approximately 72 hours. Hourly DO fluxes from photosynthesis/respiration are calculated and reported for each deployment respectively. Data of derivative analysis are also included for various validation on the automated incubator and data analysis techniques.
    Description: National Science FoundationOTIC 1841092
    Keywords: Metabolic fluxes ; Dissolved oxygen ; Automated incubation ; Monte-Carlo simulation ; UV biofouling control
    Repository Name: Woods Hole Open Access Server
    Type: Dataset
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  • 7
    Publication Date: 2022-11-15
    Description: A study on the status and temporal changes in communities of coral reef fishes in Hon Cau Marine Protected Area was carried out at 12 reef sites in August 2020 in combination with the data from previous studies. A total of 351 species belonging to 128 genera and 45 families of coral reef fish were recorded. The average density in 2020 was 237.3 ± 82.8 individuals/100m2, mainly occupied with small-sized fishes (accounting for 86.8% of total density) and ornamental fish, with the dominant families of damselfishes, wrasses, and cardinalfishes, while the the large-sized fish accounts for a very low rate. Target fishes were found in very low density and dominated by herbivorous feeders (especially rabbitfishes). The area around Hon Cau Island have species diversity (accounting for 94.4% of total species recorded in 2020) and a density of reef fish compared to the Breda shoal and coastal areas. The analysis results show that there were three distinguished assemblages of reef fishes, in which the reef fish communities around Hon Cau Island are different from the shoal and coastal areas. After nearly ten years of establishing Hon Cau MPA, coral reef fish density is maintained relatively stable in the area around Hon Cau Island and significantly decreased in Breda shoal and the coastal areas. There is an increase in the density of herbivorous fishes, while the large-sized and inextricably linked to the coral reef (groupers, snappers, sweetlips, butterflyfishes) with very low or reduced densities over time.
    Description: Published
    Description: Refereed
    Keywords: Coral reef fish ; Marine protected area
    Repository Name: AquaDocs
    Type: Journal Contribution
    Format: 153-172
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  • 8
    Publication Date: 2022-11-16
    Description: Upwelling is an oceanographic phenomenon that involves the physical process and contributes to changes in chemistry, biology, and natural resources. So, systematically, it is the particular ecosystems of whole marine regions with the upwelling. The strong upwelling waters in South Central Regions of Vietnam have uncertain features of the East Vietnam Sea (Bien Dong) and special characteristics of a coastal upwelling area, recorded in international scientific papers in the twentieth century. Their first signals were discovered in the early 1930s through conceptual ideas. The upwelling phenomenon is officially confirmed by scientific results of marine investigations of the NAGA Expedition (1959–1961). The paper aims to review and discuss the physical from Vietnamese investigation and results since 1990s. The following factors are the most contributing to forming and developing the strong upwelling in Southern Central Waters: (1) Influence scale (Mezo- and micro-scale); (2) Forming causes and developing mechanism of upwelling phenomenon, such as monsoon, morphography, shoreline, and western boundary current system of the East Vietnam Sea; (3) Influence of the water-mass from Mekong River on the upwelling area; (4) Ecological environmental consequences; (5) Impacts of the atmospheric-oceanic interaction processes on the western EVS on upwelling. Additionally, the review has targeted findings of upwelling phenomenon mainly in Vietnamese waters based on remote sensing analysis and reanalysis data series to simulate their forming, mechanizing, fluctuating models and the impacts of upwelling in the EVS on resources and ecosystems. The coupled atmosphere-ocean models resulted the upwelling mechanisms and formation. The long-time series of upwelling phenomenon (Macroscale) were evaluated by remote sensing and reanalyzed data series. It is also providing the supplementing and detailing causes and mechanisms of upwelling formation; impacts and interactions of upwelling on marine physics and hydrodynamics (ocean vortexes, seawater temperature), biochemical (nutrients, plankton organisms), and resources (fish, seafood). Within the framework of strong upwelling waters in the Southern Central Regions (Vietnam), the review has not only mentioned partly clarified scientific results but also indicates the limitations and challenges which were faced and encountered in the forecasters of upwelling phenomena in the future.
    Description: Published
    Description: Refereed
    Keywords: Upwelling phenomenon ; Natural resources
    Repository Name: AquaDocs
    Type: Journal Contribution
    Format: 103-122
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  • 9
    Publication Date: 2022-07-14
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 10
    Publication Date: 2022-09-02
    Description: Risk management has reduced vulnerability to floods and droughts globally, yet their impacts are still increasing. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
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