Journal articles: 'Basin impact ejecta model'

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Ji, Jinzhu, James W. Head, and Jianzhong Liu. "Pre-Orientale Southwest Peak-Ring Basin: Gravity Structure, Geologic Characteristics, and Influence on Orientale Basin Ring Formation and Ejecta Emplacement." Remote Sensing 13, no. 13 (July 5, 2021): 2635. http://dx.doi.org/10.3390/rs13132635.

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The Orientale impact basin is the youngest and most well-preserved of the lunar multi-ring basins. The generally well-preserved ring structures and basin facies are distinctly anomalous in the southwestern quadrant; the outer Cordillera ring extends significantly outward, the Outer and Inner Rook mountain rings are more poorly developed and show anomalous characteristics, and the Montes Rook Formation varies widely from its characteristics elsewhere in the basin interior. Based on the gravity, image, and topography data, we confirmed that the southwest region of the Orientale basin represents the location of a pre-existing ~320 km rim–crest diameter peak–ring basin centered at 108.8°W, 28.4°S, and characterized by an ~170 km peak–ring diameter. We model the structure and morphology of this large pre-Orientale peak–ring basin (about one-third the diameter of Orientale) and show that its presence and negative relief had a distinctive influence on the development of the basin rings (disrupting the otherwise generally circular continuity and causing radial excursions in their locations) and the emplacement of ejecta (causing filling of the low region represented by the peak–ring basin, creating anomalous surface textures, and resulting in late stage ejecta movement in response to the pre-existing peak–ring basin topography. The location and preservation of the peak–ring basin Bouguer anomaly strongly suggest that the rim crest of the Orientale basin excavation cavity lies at or within the Outer Rook Mountain ring.

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Lin, Honglei, Zhiping He, Wei Yang, Yangting Lin, Rui Xu, Chi Zhang, Meng-Hua Zhu, et al. "Olivine-norite rock detected by the lunar rover Yutu-2 likely crystallized from the SPA-impact melt pool." National Science Review 7, no. 5 (November 14, 2019): 913–20. http://dx.doi.org/10.1093/nsr/nwz183.

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Abstract Chang’E-4 landed in the South Pole-Aitken (SPA) basin, providing a unique chance to probe the composition of the lunar interior. Its landing site is located on ejecta strips in Von Kármán crater that possibly originate from the neighboring Finsen crater. A surface rock and the lunar regolith at 10 sites along the rover Yutu-2 track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission operations. In situ spectra of the regolith have peak band positions at 1 and 2 μm, similar to the spectral data of Finsen ejecta from the Moon Mineralogy Mapper, which confirms that the regolith's composition of the landing area is mostly similar to that of Finsen ejecta. The rock spectrum shows similar band peak positions, but stronger absorptions, suggesting relatively fresh exposure. The rock may consist of 38.1 ± 5.4% low-Ca pyroxene, 13.9 ± 5.1% olivine and 48.0 ± 3.1% plagioclase, referred to as olivine-norite. The plagioclase-abundant and olivine-poor modal composition of the rock is inconsistent with the origin of the mantle, but representative of the lunar lower crust. Alternatively, the rock crystallized from the impact-derived melt pool formed by the SPA-impact event via mixing the lunar crust and mantle materials. This scenario is consistent with fast-cooling thermal conditions of a shallow melt pool, indicated by the fine to medium-sized texture (<3 mm) of the rock and the SPA-impact melting model [Icarus 2012; 220: 730–43].

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Gorter, J. D. "THE PETROLEUM POTENTIAL OF AUSTRALIAN PHANEROZOIC IMPACT STRUCTURES." APPEA Journal 38, no. 1 (1998): 159. http://dx.doi.org/10.1071/aj97009.

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This paper examines proven, probable, possible and speculative impact structures in Australian Phanerozoic strata and their petroleum potential. There are two classes of crater: simple and complex. The former usually assumes a bowl shaped depression with a raised and overturned rim with a diameter rarely more than three kilometres, with complex structures generally occurring above diameters of two kilometres in sedimentary rocks and four kilometres in crystalline rocks. Complex craters are characterised by a central uplifted area and a classic 'sombrero' structure and can be very large and have diameters of over 800 km. Criteria for the identification of terrestrial impact structures include: (a) circular plan; (b) faulted rim structure; (c) flat floor with central uplift (may not always be present) or interior ring(s); (d) negative gravity anomaly; (e) magnetic low with subdued magnetic relief; (f) brecciated crater fill; (g) low seismic velocities in the crater fill; (h) shock metamorphism (coesite, multiple sets of planar shock lamellae in quartz grains, shatter cones); (i) meteoric material; (j) presence of melt rock; (k) distal ejecta; and occurrence of an annular trough between the central uplift and the outer faulted rim.Proven impact features, like Gosses Bluff and Mt Toondina, are well exposed, contain indisputable evidence of shock metamorphism, and have had extensive geophysical surveys conducted over them: these structures provide models to interpret completely buried structures. Subsurface impact structures have been detected in areas where there has been intensive seismic surveying in the search for hydrocarbons. The Tookoonooka, Talundilly and Mulkarra structures all occur in the Cooper-Eromanga Basin, an area of high intensity exploration. The best known wholly subsurface impact feature is the 66 km diameter Tookoonooka Structure in southwestern Queensland, which exhibits several of the accepted criteria for an impact origin, including shock metamorphism, and is classified as a probable complex type impact structure. The Talundilly Structure, a possible impact feature, lies 300 km to the northeast of the Tookoonooka Structure and is of the same general age. The two structures could reflect the impact of fragments of the same bolide. The Yallallie Structure lies in a moderately explored hydrocarbon province in the central Perth Basin. It has a classic 'sombrero' shape in section view with a central uplift and evidence of shock metamorphism. Yallallie is a probable complex impact structure. The Mulkarra Structure, located in northeastern South Australia, has been classified as a simple type of impact crater lacking a central uplift, but recent geophysical work indicates a probable complex impact origin. Other possible and speculative impact related features described here owe their recognition to good quality seismic surveying.'there are yet some geologists who, adhering to Lyellian dogma, devoutly refuse to accept that large objects fall out of the sky.' (Shoemaker, 1997).

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Zhu, Meng‐Hua, Kai Wünnemann, and Natalia Artemieva. "Effects of Moon's Thermal State on the Impact Basin Ejecta Distribution." Geophysical Research Letters 44, no. 22 (November 27, 2017): 11,292–11,300. http://dx.doi.org/10.1002/2017gl075405.

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Buchner, Elmar, and Martin Schmieder. "The Steinheim Basin impact crater (SW-Germany) – Where are the ejecta?" Icarus 250 (April 2015): 529–43. http://dx.doi.org/10.1016/j.icarus.2014.12.026.

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Wada, K., K. Ishibashi, H. Kimura, M. Arakawa, H. Sawada, K. Ogawa, K. Shirai, et al. "Size of particles ejected from an artificial impact crater on asteroid 162173 Ryugu." Astronomy & Astrophysics 647 (March 2021): A43. http://dx.doi.org/10.1051/0004-6361/202039777.

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A projectile accelerated by the Hayabusa2 Small Carry-on Impactor successfully produced an artificial impact crater with a final apparent diameter of 14.5 ± 0.8 m on the surface of the near-Earth asteroid 162173 Ryugu on April 5, 2019. At the time of cratering, Deployable Camera 3 took clear time-lapse images of the ejecta curtain, an assemblage of ejected particles forming a curtain-like structure emerging from the crater. Focusing on the optical depth of the ejecta curtain and comparing it with a theoretical model, we infer the size of the ejecta particles. As a result, the typical size of the ejecta particles is estimated to be several centimeters to decimeters, although it slightly depends on the assumed size distribution. Since the ejecta particles are expected to come from a depth down to ~1 m, our result suggests that the subsurface layer of Ryugu is composed of relatively small particles compared to the uppermost layer on which we observe many meter-sized boulders. Our result also suggests a deficit of particles of less than ~1 mm in the subsurface layer. These findings will play a key role in revealing the formation and surface evolution process of Ryugu and other small Solar System bodies.

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Yue, Zongyu, Meiping Yang, Mengna Jia, Gregory Michael, Kaichang Di, Sheng Gou, and Jianzhong Liu. "Refined model age for Orientale Basin derived from zonal crater dating of its ejecta." Icarus 346 (August 2020): 113804. http://dx.doi.org/10.1016/j.icarus.2020.113804.

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Premovic, Pavle, Nikola Nikolic, Mirjana Pavlovic, and Katja Panov. "Geochemistry of the cretaceous-tertiary transition boundary at Blake Nose (N. W. Atlantic): Cosmogenic Ni." Journal of the Serbian Chemical Society 69, no. 3 (2004): 205–23. http://dx.doi.org/10.2298/jsc0403205p.

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The Cretaceous-Tertiary (KT) boundary transition at the Blake Nose Plateau recovered by ODP Leg 171B (site 1049, hole A, core 17X, section 2) contains an ejecta bed (thickness ca. 17 cm) marking a late Cretaceous asteroid impact. The nature and geochemical composition of this bed imply that it originated mainly from the target rocks of the Chicxulub impact site (Yucatan Peninsula, Mexico), the site of the presumed asteroid impact. The ejecta bed of hole 1049A contains relatively high concentrations of Ni (up to 165 ppm) within the carbonate fraction. It is reasoned that this enhancement represents a sudden and rapid air fall of high cosmogenic Ni into he Blake Nose Basin. The source of the metal was the Chicxulub impacting (carbonaceous) chondrite. It is suggested that many calcareous planktons in the KT ocean surface water of the Blake Nose Plateau were probably vulnerable to the high influx of superacid rainfall and associated toxic metals (e.g. Ni) created by the impact.

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Dessart, L., D. J. Hillier, and K. D. Wilk. "Impact of clumping on core-collapse supernova radiation." Astronomy & Astrophysics 619 (October 30, 2018): A30. http://dx.doi.org/10.1051/0004-6361/201833278.

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There is both observational and theoretical evidence that the ejecta of core-collapse supernovae (SNe) are structured. Rather than being smooth and homogeneous, the material is made of over-dense and under-dense regions of distinct composition. Here, we have explored the effect of clumping on the SN radiation during the photospheric phase using 1D non-local thermodynamic equilibrium radiative transfer and an ejecta model arising from a blue-supergiant explosion (yielding a Type II-peculiar SN). Neglecting chemical segregation, we adopted a velocity-dependent volume-filling factor approach that assumes that the clumps are small but does not change the column density along any sightline. We find that clumping boosts the recombination rate in the photospheric layers, leading to a faster recession of the photosphere, an increase in bolometric luminosity, and a reddening of the SN colors through enhanced blanketing. The SN bolometric light curve peaks earlier and transitions faster to the nebular phase. On the rise to maximum, the strongest luminosity contrast between our clumped and smooth models is obtained at the epoch when the photosphere has receded to ejecta layers where the clumping factor is only 0.5 – this clumping factor may be larger in nature. Clumping is seen to have a similar influence in a Type II-Plateau SN model. As we neglected both porosity and chemical segregation, our models underestimate the true impact of clumping. These results warrant further study of the influence of clumping on the observables of other SN types during the photospheric phase.

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Nozaki, Kenta, Masahiro Nishida, Koichi Hayashi, and Sunao Hasegawa. "Ejecta Size Distribution Resulting from Hypervelocity Impacts between Aluminum Alloys." Applied Mechanics and Materials 566 (June 2014): 338–43. http://dx.doi.org/10.4028/www.scientific.net/amm.566.338.

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We investigated the effects of impact velocity on ejecta size when aluminum alloy 2017-T4 spheres with a diameter of 3.2 mm impacted aluminum alloy 6061-T6 targets with a thickness of 30 mm at velocities of 2 to 7 km/s. We used a two-stage light-gas gun at the Institute of Space and Astronautical Science (ISAS)/Japan Aerospace Exploration Agency (JAXA). To examine the scattering angles of the ejecta, the following was placed 50 mm in front of the target: a witness plate (150 mm × 150 mm, 2 mm in thickness) made of copper with a hole of 30 mm. The ejection behaviors of fragments were observed using a high-speed video camera. The size distributions of the ejecta were examined in detail. The cumulative number of ejecta was proportional to the square of the impact velocity; in other words, to the impact energy of the projectiles. An experimental formula was created by curve fitting of the cumulative number distribution of the projected areas to a bilinear exponential distribution model when the aluminum alloy spheres struck the aluminum alloy targets.

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Wallace, M. W., V. A. Gostin, and R. R. Keays. "Geological Note: Discovery of the acraman impact ejecta blanket in the officer basin and its stratigraphic significance." Australian Journal of Earth Sciences 36, no. 4 (December 1989): 585–87. http://dx.doi.org/10.1080/08120098908729511.

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Zain, P. S., R. P. Di Sisto, and G. C. de Elía. "Impacts on Ceres and Vesta: Source regions, cratering, and fragmentation." Astronomy & Astrophysics 652 (August 2021): A122. http://dx.doi.org/10.1051/0004-6361/202039373.

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Context. Ceres and Vesta are the largest members of the main belt (MB). They were visited by the NASA Dawn spacecraft between 2011 and 2018, which provided a great sample of detailed observations of the surface of both bodies. Aims. We perform a study on the impacts on Ceres and Vesta. We aim to determine the size-frequency distribution (SFD) of impactors and to identify and quantify the contribution of each source region, as well as the craters produced and fragments ejected in these impact events. Methods. We used a multipart collisional evolution model of the MB called ACDC (Asteroid Collisions and Dynamic Computation) that simulates the collisional evolution of the MB, which is split into six regions (namely Inner, Middle, Pristine, Outer, Cybele, and High-Inclination belts), according to the positions of the major resonances present there (ν6, 3:1J, 5:2J, 7:3J, and 2:1J). Furthermore, it includes the Yarkovsky effect as a dynamical remotion mechanism. We applied ACDC to Ceres and Vesta by keeping a record of all the bodies larger than 100 m that hit them during 4 Gyr. We performed 1600 simulations and, for our analysis, selected the runs that provide the best fits with the SFD of the six regions of the MB and also those that are able to form the Rheasilva and Veneneia, the two large basins on Vesta. Results. The six regions of the MB provide, to a greater or lesser extent, impactors on Ceres and Vesta. The Outer belt is the main source of impactors smaller than 10 km on Ceres, providing more than half of the impacts, while the Middle belt is the secondary source. On Vesta, the relative impactor contribution of the Inner, Middle, and Outer belts is almost even. We are able to reproduce the craters larger than 100 km in Vesta and identify two large depressions identified in Ceres as impact craters: one called Vendimia Planitia of ~900 km and a second one of ~570 km. As an outcome of these impacts, Ceres and Vesta eject fragments into the MB. We obtain fragmentation rates of tens of fragments larger than 1 m per year for both bodies, to tens of fragments larger than 100 m per million years for Vesta and a factor of ~4 greater for Ceres. We find that hundreds of bodies larger than 10 km should have been ejected from Ceres and Vesta during their history.

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Inceli, Ozge. "The Perceptions of English Teachers to the SIOP® Model and Its Impact on Limited English Proficiency." Journal of Ethnic and Cultural Studies 2, no. 1 (July 6, 2015): 15. http://dx.doi.org/10.29333/ejecs/13.

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Limited English proficiency is the difficulty in comprehension and production in English. In this study, the efficiency of the Sheltered Instruction Observation Protocol (SIOP) Model was examined to indicate the components that are lesson preparation, building background, comprehensible input, strategies, interaction, practice and application, lesson delivery, review and assessment. The basic purpose of the research was to investigate how teachers improve the student’s language performance for limited English proficiency through using the SIOP® Model. In this paper, a qualitative research approach and semi-structured interview were used to discover the teacher’s perceptions about the SIOP® Model, and the research is to find out the problems in limited English proficiency. 10 participants (3 males and 7 females) aged from 26 to 34 (M = 30.9). The results indicate that the factors of SIOP® model can guide limited English proficient students and suggest some useful strategies for language teachers to handle the students’ difficulties in language comprehension.

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Li, L., Z. Yue, C. Zhang, and D. Li. "REMOTE SENSING OBSERVATIONS AND NUMERICAL SIMULATION FOR MARTIAN LAYERED EJECTA CRATERS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3 (April 30, 2018): 865–70. http://dx.doi.org/10.5194/isprs-archives-xlii-3-865-2018.

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To understand past Martian climates, it is important to know the distribution and nature of water ice on Mars. Impact craters are widely used ubiquitous indicators for the presence of subsurface water or ice on Mars. Remote sensing observations and numerical simulation are powerful tools for investigating morphological and topographic features on planetary surfaces, and we can use the morphology of layered ejecta craters and hydrocode modeling to constrain possible layering and impact environments. The approach of this work consists of three stages：Firstly, the morphological characteristics of the Martian layered ejecta craters are performed based on Martian images and DEM data. Secondly, numerical modeling layered ejecta are performed through the hydrocode iSALE (impact-SALE). We present hydrocode modeling of impacts onto targets with a single icy layer within an otherwise uniform basalt crust to quantify the effects of subsurface H2O on observable layered ejecta morphologies. The model setup is based on a layered target made up of a regolithic layer (described by the basalt ANEOS), on top an ice layer (described by ANEOS equation of H2O ice), in turn on top of an underlying basaltic crust. The bolide is a 0.8&thinsp;km diameter basaltic asteroid hitting the Martian surface vertically at a velocity of 12.8&thinsp;km/s. Finally, the numerical results are compared with the MOLA DEM profile in order to analyze the formation mechanism of Martian layered ejecta craters. Our simulations suggest that the presence of an icy layer significantly modifies the cratering mechanics, and many of the unusual features of SLE craters may be explained by the presence of icy layers. Impact cratering on icy satellites is significantly affected by the presence of subsurface H2O.

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Hassler, Scott W., Bruce M. Simonson, Dawn Y. Sumner, and Louis Bodin. "Paraburdoo spherule layer (Hamersley Basin, Western Australia): Distal ejecta from a fourth large impact near the Archean-Proterozoic boundary." Geology 39, no. 4 (April 2011): 307–10. http://dx.doi.org/10.1130/g31526.1.

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Kyte, Frank T., and Jennifer A. Bostwick. "Magnesioferrite spinel in Cretaceous/Tertiary boundary sediments of the Pacific basin: Remnants of hot, early ejecta from the Chicxulub impact?" Earth and Planetary Science Letters 132, no. 1-4 (May 1995): 113–27. http://dx.doi.org/10.1016/0012-821x(95)00051-d.

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Bulla, M. "possis: predicting spectra, light curves, and polarization for multidimensional models of supernovae and kilonovae." Monthly Notices of the Royal Astronomical Society 489, no. 4 (September 7, 2019): 5037–45. http://dx.doi.org/10.1093/mnras/stz2495.

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ABSTRACT We present possis, a time-dependent three-dimensional Monte Carlo code for modelling radiation transport in supernovae and kilonovae. The code incorporates wavelength- and time-dependent opacities, and predicts viewing-angle dependent spectra, light curves, and polarization for both idealized and hydrodynamical explosion models. We apply the code to a kilonova model with two distinct ejecta components, one including lanthanide elements with relatively high opacities and the other devoid of lanthanides and characterized by lower opacities. We find that a model with total ejecta mass $M_\mathrm{ej}=0.04\, \mathrm{M}_\odot$ and half-opening angle of the lanthanide-rich component Φ = 30° provides a good match to GW 170817/AT 2017gfo for orientations near the polar axis (i.e. for a system viewed close to face-on). We then show how crucial is the use of self-consistent multidimensional models in place of combining one-dimensional models to infer important parameters, such as the ejecta masses. We finally explore the impact of Mej and Φ on the synthetic observables and highlight how the relatively fast computation times of possis make it well-suited to perform parameter-space studies and extract key properties of supernovae and kilonovae. Spectra calculated with possis in this and future studies will be made publicly available.

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SCHULTE, PETER, JAN SMIT, ALEXANDER DEUTSCH, TOBIAS SALGE, ANDREA FRIESE, and KILIAN BEICHEL. "Tsunami backwash deposits with Chicxulub impact ejecta and dinosaur remains from the Cretaceous-Palaeogene boundary in the La Popa Basin, Mexico." Sedimentology 59, no. 3 (August 8, 2011): 737–65. http://dx.doi.org/10.1111/j.1365-3091.2011.01274.x.

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Premovic, Pavle, Milena Krsmanovic, Bratislav Todorovic, Mirjana Pavlovic, Nikola Nikolic, and Dragan Djordjevic. "Geochemistry of the cretaceous-tertiary boundary (Fish Clay) at Stevns Klint (Denmark): Ir, Ni and Zn in kerogen." Journal of the Serbian Chemical Society 71, no. 7 (2006): 793–806. http://dx.doi.org/10.2298/jsc0607793p.

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Geochemical analyses of trace metals (Ir, Ni and Zn) in the kerogen of the black marl of the Cretaceous-Tertiary boundary succession (Fish Clay) at Stevns Klint (H?jerup Church) were undertaken. The data for this kerogen were in accordance with a previous hypothesis that this (insoluble) geoorganic polymer was derived from humic substances (mainly humic acids) of a nearshore soil. Substantial proportions of Ir, Ni and Zn within the kerogen structure were probably contained in these substances arriving at the sedimentary site. It is proposed that these humics were probably transported by acid surface waters (induced by the KT asteroid impact) into the shallow marine basin of Stevns Klint. It is also suggested that local leaching/weathering of the asteroidal impact fallout on the land near these waters played an important role in providing Ir, Ni and Zn for these substances. Apparently, Ir, Ni and Zn of the kerogen were created by the chondritic component of the impact ejecta fallout.

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Mercer, Cameron M., Kelsey E. Young, John R. Weirich, Kip V. Hodges, Bradley L. Jolliff, Jo-Anne Wartho, and Matthijs C. van Soest. "Refining lunar impact chronology through high spatial resolution 40Ar/39Ar dating of impact melts." Science Advances 1, no. 1 (February 2015): e1400050. http://dx.doi.org/10.1126/sciadv.1400050.

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Quantitative constraints on the ages of melt-forming impact events on the Moon are based primarily on isotope geochronology of returned samples. However, interpreting the results of such studies can often be difficult because the provenance region of any sample returned from the lunar surface may have experienced multiple impact events over the course of billions of years of bombardment. We illustrate this problem with new laser microprobe 40Ar/39Ar data for two Apollo 17 impact melt breccias. Whereas one sample yields a straightforward result, indicating a single melt-forming event at ca. 3.83 Ga, data from the other sample document multiple impact melt–forming events between ca. 3.81 Ga and at least as young as ca. 3.27 Ga. Notably, published zircon U/Pb data indicate the existence of even older melt products in the same sample. The revelation of multiple impact events through 40Ar/39Ar geochronology is likely not to have been possible using standard incremental heating methods alone, demonstrating the complementarity of the laser microprobe technique. Evidence for 3.83 Ga to 3.81 Ga melt components in these samples reinforces emerging interpretations that Apollo 17 impact breccia samples include a significant component of ejecta from the Imbrium basin impact. Collectively, our results underscore the need to quantitatively resolve the ages of different melt generations from multiple samples to improve our current understanding of the lunar impact record, and to establish the absolute ages of important impact structures encountered during future exploration missions in the inner Solar System.

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Mayer, Hans C., and Rouslan Krechetnikov. "Flat plate impact on water." Journal of Fluid Mechanics 850 (July 12, 2018): 1066–116. http://dx.doi.org/10.1017/jfm.2018.461.

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While the classical problem of a flat plate impact on a water surface at zero dead-rise angle has been studied for a long time both theoretically and experimentally, it still presents a number of challenges and unsolved questions. Hitherto, the details of the flow field – especially at early times and close to the plate edge, where the classical inviscid theory predicts a singularity in the velocity field and thus in the free surface deflection, so-called ejecta – have not been studied experimentally, which led to mutually contradicting suppositions in the literature. On one hand, it motivated Yakimov’s self-similar scaling near the plate edge. On the other hand, a removal of the singularity was previously suggested with the help of the Kutta–Joukowsky condition at the plate edge, i.e. enforcing the free surface to depart tangentially to the plate. In the present experimental study we were able to overcome challenges with optical access and investigate, for moderate Reynolds ($0.5<Re<25\,000$) and Weber ($1<We<800$) numbers, both the flow fields and the free surface dynamics at the early stage of the water impact, when the penetration depth is small compared to the plate size, thus allowing us to compare to the classical water impact theory valid in the short time limit. This, in particular, enabled us to uncover the effects of viscosity and surface tension on the velocity field and ejecta evolution usually neglected in theoretical studies. While we were able to confirm the far-field inviscid and the near-edge Stokes theoretical scalings of the free surface profiles, Yakimov’s scaling of the velocity field proved to be inapplicable and the Kutta–Joukowsky condition not satisfied universally in the studied range of Reynolds and Weber numbers. Since the local near-edge phenomena cannot be considered independently of the complete water impact event, the experiments were also set up to study the entirety of the water impact phenomena under realistic conditions – presence of air phase and finite depth of penetration. This allowed us to obtain insights also into other key aspects of the water impact phenomena such as air entrapment and pocketing at the later stage when the impactor bottoms out. In our experiments the volume of trapped air proved not to decrease necessarily with the impact speed, an effect that has not been reported before. The observed fast initial retraction of the trapped air film along the plate bottom turned out to be a consequence of a negative pressure impulse generated upon the abrupt deceleration of the plate. This abrupt deceleration is also the cause of the subsequent air pocketing. Quantitative measurements are complemented with basic scaling models explaining the nature of both retraction of the trapped air and air pocket formation.

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Ricardo, Nomensen, Hendra Amijaya, and Salahuddin Husein. "Basin Evolution Palispatic Model of Bonaparte Basin, Australia Northwest Shelf." Journal of Applied Geology 2, no. 2 (October 23, 2018): 83. http://dx.doi.org/10.22146/jag.39988.

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This research area is located on the Australian NW Shelf close to the westernedge of the Sahul Platform. This research is aimed to generate the palispatic basin model of Bonaparte Basin, Australian Northwest Shelf. It is to predict the impact of Neogene collision on the petroleum system distribution on Australian Northwest Shelf. The main data used in this research are seismic data using qualitative method analysis. The well data is used to well-seismic tied. After data acquisition, the seismic data are interpreted based on the horizon and structure interpretation. These interpretation are to reconstruct the basin evolution thorough geologic time. According to data analysis, the basin evolution palispatic model are divided into Paleo-proterozoic, Paleozoic, Triassic, Early Jurassic, Middle Jurassic, Late Jurassic, Early Cretaceous, Late Cretaceous, Early Eocene, Late Miocene and Recent condition. Regional tectonically there are at least three important events in NW Shelf: Middle Triassic-Jurassic NNE–SSW extension phase, Late Jurassic NE–SW extension phase and the Neogen collision phase; the Neogen collision effects on Northwest Shelf Australia. These three events contributed in forming and disturbing the Paleozoic and Mesozoic petroleum system in Bonaparte basin especially.

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Figueira, Joana, Jordi José, Enrique García-Berro, Simon W. Campbell, Domingo García-Senz, and Shazrene Mohamed. "Three-dimensional simulations of the interaction between the nova ejecta, accretion disk, and companion star." Astronomy & Astrophysics 613 (May 2018): A8. http://dx.doi.org/10.1051/0004-6361/201731545.

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Context. Classical novae are thermonuclear explosions hosted by accreting white dwarfs in stellar binary systems. Material piles up on top of the white dwarf star under mildly degenerate conditions, driving a thermonuclear runaway. The energy released by the suite of nuclear processes operating at the envelope, mostly proton-capture reactions and β+-decays, heats the material up to peak temperatures ranging from 100 to 400 MK. In these events, about 10−3–10−7 M⊙, enriched in CNO and, sometimes, other intermediate-mass elements (e.g., Ne, Na, Mg, and Al) are ejected into the interstellar medium. Aims. To date, most of the efforts undertaken in the modeling of classical nova outbursts have focused on the early stages of the explosion and ejection, ignoring the interaction of the ejecta, first with the accretion disk orbiting the white dwarf and ultimately with the secondary star. Methods. A suite of 3D, smoothed-particle hydrodynamics (SPH) simulations of the interaction between the nova ejecta, accretion disk, and stellar companion were performed to fill this gap; these simulations were aimed at testing the influence of the model parameters—that is, the mass and velocity of the ejecta, mass and the geometry of the accretion disk—on the dynamical and chemical properties of the system. Results. We discuss the conditions that lead to the disruption of the accretion disk and to mass loss from the binary system. In addition, we discuss the likelihood of chemical contamination of the stellar secondary induced by the impact with the nova ejecta and its potential effect on the next nova cycle.

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Desai, D., B. D. Metzger, and F. Foucart. "Imprints of r-process heating on fall-back accretion: distinguishing black hole–neutron star from double neutron star mergers." Monthly Notices of the Royal Astronomical Society 485, no. 3 (March 14, 2019): 4404–12. http://dx.doi.org/10.1093/mnras/stz644.

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ABSTRACT Mergers of compact binaries containing two neutron stars (NS–NS), or a neutron star and a stellar mass black hole (NS–BH), are likely progenitors of short-duration gamma-ray bursts (SGRBs). A fraction ${\gtrsim } 20{{\ \rm per\ cent}}$ of SGRBs is followed by temporally extended (≳minute-long), variable X-ray emission, attributed to ongoing activity of the central engine. One source of late-time engine activity is fall-back accretion of bound tidal ejecta; however, observed extended emission light curves do not track the naively anticipated, uninterrupted t−5/3 power-law decay, instead showing a lull or gap in emission typically lasting tens of seconds after the burst. Here, we re-examine the impact of heating due to rapid neutron capture (r-process) nucleosynthesis on the rate of the fall-back accretion, using ejecta properties extracted from numerical relativity simulations of NS–BH mergers. Heating by the r-process has its greatest impact on marginally bound matter, hence its relevance to late-time fall-back. Depending on the electron fraction of the ejecta and the mass of the remnant black hole, r-process heating can imprint a range of fall-back behaviour, ranging from temporal gaps of up to tens of seconds to complete late-time cut-off in the accretion rate. This behaviour is robust to realistic variations in the nuclear heating experienced by different parts of the ejecta. Central black holes with masses ${\lesssim } 3\, \mathrm{M}_{\odot }$ typically experience absolute cut-offs in the fall-back rate, while more massive ${\gtrsim } 6\!-\!8\, \mathrm{M}_{\odot }$ black holes instead show temporal gaps. We thus propose that SGRBs showing extended X-ray emission arise from NS–BH, rather than NS–NS, mergers. Our model implies an NS–BH merger detection rate by LIGO that, in steady state, is comparable to or greater than that of NS–NS mergers.

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Hernandez Pardo, Orlando. "Vichada meteorite impact effects from simulation of regional environmental consequences of a meteoroid impact on Earth." Earth Sciences Research Journal 22, no. 1 (January 1, 2018): 7–12. http://dx.doi.org/10.15446/esrj.v22n1.65459.

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This study estimates the regional environmental consequences of the impactor extraterrestrial body that could produce the probable Vichada impact crater structure on the Vichada Plain, in Colombia, South America. This paper details the parameter assumptions upon which the estimation is made. It describes an approach to quantifying the principal impact processes that could have affected the landscape in the vicinity of the probable Vichada impact event in the past. The key parameters are impactor diameter, impactor density, impact velocity before atmospheric entry, impact angle, and the distance from the impact at which the environmental effects are to be calculated, and the target type of sedimentary rock or crystalline rock. These parameters were chosen with support from The Vichada Structure dimensions obtained from remote sensing data interpretation, regional geologic mapping and interpreted satellite data and ground-based gravity and magnetic anomalies. The calculations are based on compiled novel algorithms for estimating the thermal radiation emitted by the impact-generated vapor plume or fireball, and the intensity of seismic shaking. Model validation is performed by obtaining the approximates various dimensions of the Vichada impact crater and ejecta deposit, as well as estimating the severity of the air blasting both crater-forming and air burst impacts. We illustrate the utility of the calculations by examining the predicted environmental consequences in seven localities of the Colombian territory, through hypothetical impact scenarios occurring in Cumaribo and Puerto Carreño (Vichada), Puerto Inirida (Guainía), Puerto Gaitán and Villavicencio (Meta), Mitú (Vaupes) and Bogotá, D.C. It is concluded that the most wide-reaching environmental consequence is seismic shaking. Both ejecta deposit thickness and air-blast pressure decay much more rapidly with distance than with seismic ground motion. Close to the impact site, the most devastating effect is from thermal radiation; however, the curvature of the Earth implies that distant localities are shielded from direct thermal radiation because the fireball is below the horizon. These results would guide further detailed fieldwork hunting for direct impact crater evidence and interpret high-resolution geophysical studies and borehole that could be carried out in the probable Vichada impact crater area shortly.

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Heinzel, J., M. W. Coughlin, T. Dietrich, M. Bulla, S. Antier, N. Christensen, D. A. Coulter, R. J. Foley, L. Issa, and N. Khetan. "Comparing inclination-dependent analyses of kilonova transients." Monthly Notices of the Royal Astronomical Society 502, no. 2 (January 28, 2021): 3057–65. http://dx.doi.org/10.1093/mnras/stab221.

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ABSTRACT The detection of the optical transient AT2017gfo proved that binary neutron star mergers are progenitors of kilonovae (KNe). Using a combination of numerical-relativity and radiative-transfer simulations, the community has developed sophisticated models for these transients for a wide portion of the expected parameter space. Using these simulations and surrogate models made from them, it has been possible to perform Bayesian inference of the observed signals to infer properties of the ejected matter. It has been pointed out that combining inclination constraints derived from the KN with gravitational-wave measurements increases the accuracy with which binary parameters can be estimated, in particular breaking the distance-inclination degeneracy from gravitational wave inference. To avoid bias from the unknown ejecta geometry, constraints on the inclination angle for AT2017gfo should be insensitive to the employed models. In this work, we compare different assumptions about the ejecta and radiative reprocesses used by the community and we investigate their impact on the parameter inference. While most inferred parameters agree, we find disagreement between posteriors for the inclination angle for different geometries that have been used in the current literature. According to our study, the inclusion of reprocessing of the photons between different ejecta types improves the modeling fits to AT2017gfo and, in some cases, affects the inferred constraints. Our study motivates the inclusion of large ∼ 1-mag uncertainties in the KN models employed for Bayesian analysis to capture yet unknown systematics, especially when inferring inclination angles, although smaller uncertainties seem appropriate to capture model systematics for other intrinsic parameters. We can use this method to impose soft constraints on the ejecta geometry of the KN AT2017gfo.

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Thuillet, Florian, Patrick Michel, Shogo Tachibana, Ronald-L. Ballouz, and Stephen R. Schwartz. "Numerical modelling of medium-speed impacts on a granular surface in a low-gravity environment application to Hayabusa2 sampling mechanism." Monthly Notices of the Royal Astronomical Society 491, no. 1 (October 24, 2019): 153–77. http://dx.doi.org/10.1093/mnras/stz3010.

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ABSTRACT Even if craters are very common on Solar System body surfaces, crater formation in granular media such as the ones covering most of visited asteroids still needs to be better understood, above all in low-gravity environments. JAXA’s sample return mission Hayabusa2, currently visiting asteroid (162173) Ryugu, is a perfect opportunity for studying medium-speed impacts into granular matter, since its sampling mechanism partly consists of a 300 m s−1 impact. In this paper, we look at medium-speed impacts, from 50 to 300 m s−1, into a granular material bed, to better understand crater formation and ejecta characteristics. We then consider the sampler horn of Hayabusa2 sampling mechanism and monitor the distribution of particles inside the horn. We find that the cratering process is much longer under low gravity, and that the crater formation mechanism does not seem to depend on the impact speed, in the considered range. The Z-model seems to rightly represent our velocity field for a steady excavation state. From the impact, less than $10{{\ \rm per\ cent}}$ is transmitted into the target, and grains are ejected mostly with angles between 48° and 54°. Concerning the sampling mechanism, we find that for most of the simulations, the science goal of 100 mg is fulfilled, and that a second impact increases the number of ejecta but not necessarily the number of collected particles.

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Joy, K. H., J. F. Snape, A. A. Nemchin, R. Tartèse, D. M. Martin, M. J. Whitehouse, V. Vishnyakov, J. F. Pernet-Fisher, and D. A. Kring. "Timing of geological events in the lunar highlands recorded in shocked zircon-bearing clasts from Apollo 16." Royal Society Open Science 7, no. 6 (June 2020): 200236. http://dx.doi.org/10.1098/rsos.200236.

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Apollo 16 soil-like regolith breccia 65745,7 contains two zircon-bearing clasts. One of these clasts is a thermally annealed silica-rich rock, which mineralogically has affinities with the High Alkali Suite (Clast 1), and yields zircon dates ranging from 4.08 to 3.38 Ga. The other clast is a KREEP-rich impact melt breccia (Clast 2) and yields zircon dates ranging from 3.97 to 3.91 Ga. The crystalline cores of both grains, which yield dates of ca 3.9 Ga, have undergone shock pressure modification at less than 20 GPa. We interpret that the U-Pb chronometer in these zircon grains has been partially reset by the Imbrium basin-forming event when the clasts were incorporated into the Cayley Plains ejecta blanket deposit. The zircon grains in Clast 1 have been partially decomposed, resulting in a breakdown polymineralic texture, with elevated U, Pb and Th abundances compared with those in the crystalline zircon. These decomposed areas exhibit younger dates around 3.4 Ga, suggesting a secondary high-pressure, high-temperature event, probably caused by an impact in the local Apollo 16 highlands area.

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Pan, Li, Xudong Chen, Lu Zhao, and Anran Xiao. "Does Information Asymmetry Impact Sub-Regions’ Cooperation of Regional Water Resource Allocation?" International Journal of Environmental Research and Public Health 16, no. 21 (November 5, 2019): 4292. http://dx.doi.org/10.3390/ijerph16214292.

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Water resources allocation is an urgent problem for basin authorities. In order to obtain greater economic benefits from limited water supplies, sub-regions must cooperate with each other. To study the influence of cooperation among sub-regions and the symmetry of cooperation information on the interests of the basin authority and each sub-region, this study proposes a regional water allocation model in three different situations: (1) non-cooperation; (2) cooperation and information symmetry; (3) cooperation and information asymmetry. The proposed model clearly reflects the Stackelberg game relationship between the basin authority and sub-regions. Finally, the model is applied to the Qujiang River Basin in China, and the decisions of the basin authority and sub-regional managers of the Qujiang River Basin under three different situations are discussed. The results show that regional cooperation benefits both the cooperative regions and the social welfare value of the entire river basin, when compared with non-cooperation.

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Dessart, Luc, and D. John Hillier. "Radiative-transfer modeling of nebular-phase type II supernovae." Astronomy & Astrophysics 642 (October 2020): A33. http://dx.doi.org/10.1051/0004-6361/202038148.

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Nebular phase spectra of core-collapse supernovae (SNe) provide critical and unique information on the progenitor massive star and its explosion. We present a set of one-dimensional steady-state non-local thermodynamic equilibrium radiative transfer calculations of type II SNe at 300 d after explosion. Guided by the results obtained from a large set of stellar evolution simulations, we craft ejecta models for type II SNe from the explosion of a 12, 15, 20, and 25 M⊙ star. The ejecta density structure and kinetic energy, the 56Ni mass, and the level of chemical mixing are parametrized. Our model spectra are sensitive to the adopted line Doppler width, a phenomenon we associate with the overlap of Fe II and O I lines with Ly α and Ly β. Our spectra show a strong sensitivity to 56Ni mixing since it determines where decay power is absorbed. Even at 300 d after explosion, the H-rich layers reprocess the radiation from the inner metal rich layers. In a given progenitor model, variations in 56Ni mass and distribution impact the ejecta ionization, which can modulate the strength of all lines. Such ionization shifts can quench Ca II line emission. In our set of models, the [O I] λλ 6300, 6364 doublet strength is the most robust signature of progenitor mass. However, we emphasize that convective shell merging in the progenitor massive star interior can pollute the O-rich shell with Ca, which would weaken the O I doublet flux in the resulting nebular SN II spectrum. This process may occur in nature, with a greater occurrence in higher mass progenitors, and this may explain in part the preponderance of progenitor masses below 17 M⊙ that are inferred from nebular spectra.

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Young, James A., and William S. Longland. "Impact of Alien Plants on Grant Basin Rangelands." Weed Technology 10, no. 2 (June 1996): 384–91. http://dx.doi.org/10.1017/s0890037x00040136.

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Our purpose is to discuss the impact of alien plants on rangeland ecosystems of the Great Basin in terms of their effects on biological functions. The sagebrush/bunchgrass ranges of western North America are used as a model ecosystem for the impact of alien plants. Alien weed species have been introduced in successive waves, with the success of each new introduction dependent on how well adapted to the environment and how competitive the new weed is with those previously introduced. Annual species have been successful across extensive areas of Great Basin rangelands. Biennial and short- and long-lived perennial introductions have been restricted to much more specific habitats. Alien plants impact rangelands through stand renewal and successional processes. Alien weeds can cause such processes to be accelerated and/or truncated depending on the species and range site.

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Guo, ShengLian, Jing Guo, Jun Zhang, and Hua Chen. "VIC distributed hydrological model to predict climate change impact in the Hanjiang basin." Science in China Series E: Technological Sciences 52, no. 11 (November 2009): 3234–39. http://dx.doi.org/10.1007/s11431-009-0355-2.

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Kuo, Chun-Chao, Thian Yew Gan, and Jingwen Wang. "Climate change impact to Mackenzie river Basin projected by a regional climate model." Climate Dynamics 54, no. 7-8 (March 11, 2020): 3561–81. http://dx.doi.org/10.1007/s00382-020-05177-7.

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Crawford, David A. "Models of fragment penetration and fireball evolution." International Astronomical Union Colloquium 156 (May 1996): 133–56. http://dx.doi.org/10.1017/s0252921100115490.

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A new analytical model that is calibrated against numerical simulations performed with the CTH shock physics code provides a useful description of the entry of Periodic Comet Shoemaker-Levy 9 into the Jovian atmosphere. Mass loss due to radiative heating of fragments larger than 100 m in diameter is insignificant because of energy conservation during the ablative process. Nevertheless, radiative ablation is a major contributor to atmospheric energy deposition at high altitude and plays an important role in early-time fireball evolution. The analytical model provides the initial conditions from which fireball and plume evolution can be calculated using CTH. The results from these simulations suggest that if the tops of the plumes originated from a specific level of the Jovian atmosphere then maximum plume heights are independent of fragment size provided the fragments penetrated at least 30 km below this level. If the tops of the plumes originated from the visible cloud tops, then fragment masses greater than 4 x 1012 g, corresponding to 200 m diameter fully dense water ice, are required to explain the observations. If the plumes originated from the NH4SH layer then masses greater than 3 x 1013 g (400 m water ice) are required. The lateral extent and mass of the observable plume are functions of fragment size and contribute to the lateral extent and albedo of the debris patterns after re-impact with the atmosphere. The apparent gap between the central disturbance of the impact site and the inner front of the crescent-shaped ejecta may reflect the fragment's depth of penetration below the source layer of the visible ejecta.

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Glikson, Andrew, and Charlotte Allen. "Iridium anomalies and fractionated siderophile element patterns in impact ejecta, Brockman Iron Formation, Hamersley Basin, Western Australia: evidence for a major asteroid impact in simatic crustal regions of the early Proterozoic earth." Earth and Planetary Science Letters 220, no. 3-4 (April 2004): 247–64. http://dx.doi.org/10.1016/s0012-821x(04)00062-7.

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Xue, Feng, Peng Shi, Simin Qu, Jianjin Wang, and Yanming Zhou. "Evaluating the impact of spatial variability of precipitation on streamflow simulation using a SWAT model." Water Policy 21, no. 1 (December 12, 2018): 178–96. http://dx.doi.org/10.2166/wp.2018.118.

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Abstract The spatial variability of precipitation is often considered to be a major source of uncertainty for hydrological models. The widely used Soil and Water Assessment Tool (SWAT) is insufficient to calculate a sub-basin's mean areal precipitation (MAP) since it only uses data from the rainfall station nearest to the centroid of each sub-basin. Therefore, Inverse Distance Weighting (IDW), Thiessen Polygons (TP) and Ordinary Kriging (OK) were applied as alternative interpolation methods in this study to calculate sub-basin MAP. The MAP results from the four methods used for the Xixian Basin were quite different in terms of amount and spatial distribution. The SWAT model performance was then assessed at monthly and daily timescales, based on Nash–Sutcliffe efficiency (NSE), the Coefficient of Determination (R2) as well as Percentage Bias (PBIAS) at the basin outlet. The results under different network densities and spatial distributions of gauge stations indicated that the modified MAP models did not have an advantage over the default Nearest Neighbour (NN) method in simulating monthly streamflow. However, the modified areal precipitation obtained through IDW and TP showed relatively high accuracy in simulating daily flows as the applied rainfall stations changed. The difference in terms of estimated rainfall and streamflow in this study confirmed that evaluation of interpolation methods is necessary before building a SWAT model.

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Gao, Yuqin, Yu Yuan, Huaizhi Wang, Zhenxing Zhang, and Liu Ye. "Analysis of impacts of polders on flood processes in Qinhuai River Basin, China, using the HEC-RAS model." Water Supply 18, no. 5 (January 10, 2018): 1852–60. http://dx.doi.org/10.2166/ws.2018.008.

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Abstract Flood control with polders is prevalent in East China. Their impact on flood processes is critically important for flood control, but has not been well documented. The Qinhuai River Basin was selected as the study area. A Hydrologic Engineering Center – River Analysis System (HEC-RAS) hydraulic model was developed to simulate and predict storm flood processes and the associated impact of polders. The study shows that the HEC-RAS model is capable of simulating the impact of polders on flood processes in the Qinhuai River Basin. The polders increased the water level outside of the polders. The polders in upstream watersheds have a greater impact on the water level than polders close to basin outlets when individually distributed. The maximum water level at Dongshan section shows an increasing trend for different sized flood with the increasing number of polders in the basin, and a linear increasing trend associated with urbanization. The smaller the flood scale is, the greater the maximum water level changes.

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Yu, Yang, Patrick Michel, Stephen R. Schwartz, Shantanu P. Naidu, and Lance A. M. Benner. "Ejecta cloud from the AIDA space project kinetic impact on the secondary of a binary asteroid: I. mechanical environment and dynamical model." Icarus 282 (January 2017): 313–25. http://dx.doi.org/10.1016/j.icarus.2016.09.008.

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Walker, James D., Sidney Chocron, and Donald J. Grosch. "Size scaling of hypervelocity-impact ejecta mass and momentum enhancement: Experiments and a nonlocal-shear-band-motivated strain-rate-dependent failure model." International Journal of Impact Engineering 135 (January 2020): 103388. http://dx.doi.org/10.1016/j.ijimpeng.2019.103388.

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Lyra, Barbara Ucelis, and Daniel Rigo. "Deforestation impact on discharge regime in the Doce River Basin." Ambiente e Agua - An Interdisciplinary Journal of Applied Science 14, no. 4 (June 26, 2019): 1. http://dx.doi.org/10.4136/ambi-agua.2370.

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The construction of scenarios using hydrological models can evaluate the hydrological response in watersheds, due to changes in the soil use. In this context, this study analyzed the consequences of deforestation in the hydrological behavior of the Doce River Basin, which has a drainage area of approximately 86.715 km². The basin presents problems regarding water availability, floods, indiscriminate deforestation and inadequate soil management. The Model of Large Basins (MGB-IPH) was selected, using daily data from 1990 to 2014, 11 fluviometric, 81 rainfall and 12 meteorological stations, numerical model of the land, soil maps, and use and land cover. Hydrological modeling was performed in the following steps: calibration of parameters (1990 and 2005), validation (2006 to 2014) and simulation of deforestation scenarios (2000 to 2014). It was observed that the replacement of forests by pasture caused reductions in the average annual flows, indicating a decrease in average flows in deforestation scenarios. As for the behavior of floods, deforestation caused them to increase, while the annual minimum flows reduced with deforestation. The results demonstrate the worsening that the simulated scenarios can cause in the problems already found in the basin, such as floods and water shortages, to supply the uses for which the basin is intended.

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Carnahan, Evan, Jason M. Amundson, and Eran Hood. "Impact of glacier loss and vegetation succession on annual basin runoff." Hydrology and Earth System Sciences 23, no. 3 (March 21, 2019): 1667–81. http://dx.doi.org/10.5194/hess-23-1667-2019.

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Abstract. We use a simplified glacier-landscape model to investigate the degree to which basin topography, climate regime, and vegetation succession impact centennial variations in basin runoff during glacier retreat. In all simulations, annual basin runoff initially increases as water is released from glacier storage but ultimately decreases to below preretreat levels due to increases in evapotranspiration and decreases in orographic precipitation. We characterize the long-term (> 200 years) annual basin runoff curves with four metrics: the magnitude and timing of peak basin runoff, the time to preretreat basin runoff, and the magnitude of end basin runoff. We find that basin slope and climate regime have strong impacts on the magnitude and timing of peak basin runoff. Shallow sloping basins exhibit a later and larger peak basin runoff than steep basins and, similarly, continental glaciers produce later and larger peak basin runoff compared to maritime glaciers. Vegetation succession following glacier loss has little impact on the peak basin runoff but becomes increasingly important as time progresses, with more rapid and extensive vegetation leading to shorter times to preretreat basin runoff and lower levels of end basin runoff. We suggest that differences in the magnitude and timing of peak basin runoff in our simulations can largely be attributed to glacier dynamics: glaciers with long response times (i.e., those that respond slowly to climate change) are pushed farther out of equilibrium for a given climate forcing and produce larger variations in basin runoff than glaciers with short response times. Overall, our results demonstrate that glacier dynamics and vegetation succession should receive roughly equal attention when assessing the impacts of glacier mass loss on water resources.

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Hogg, Charlie A. R., Stuart B. Dalziel, Herbert E. Huppert, and Jörg Imberger. "Inclined gravity currents filling basins: the impact of peeling detrainment on transport and vertical structure." Journal of Fluid Mechanics 820 (May 5, 2017): 400–423. http://dx.doi.org/10.1017/jfm.2017.196.

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Transport of dense fluid by an inclined gravity current can control the vertical density structure of the receiving basin in many natural and industrial settings. A case familiar to many is a lake fed by river water that is dense relative to the lake water. In laboratory experiments, we pulsed dye into the basin inflow to visualise the transport pathway of the inflow fluid through the basin. We also measured the evolving density profile as the basin filled. The experiments confirmed previous observations that when the turbulent gravity current travelled through ambient fluid of uniform density, only entrainment into the dense current occurred. When the gravity current travelled through the stratified part of the ambient fluid, however, the outer layers of the gravity current outflowed from the current by a peeling detrainment mechanism and moved directly into the ambient fluid over a large range of depths. The prevailing model of a filling box flow assumes that a persistently entraining gravity current entrains fluid from the basin as the current descends to the deepest point in the basin. This model, however, is inconsistent with the transport pathway observed in visualisations and poorly matches the stratifications measured in basin experiments. The main contribution of the present work is to extend the prevailing filling box model by incorporating the observed peeling detrainment. The analytical expressions given by the peeling detrainment model match the experimental observations of the density profiles more closely than the persistently entraining model. Incorporating peeling detrainment into multiprocess models of geophysical systems, such as lakes, will lead to models that better describe inflow behaviour.

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Shi, Yu Zhi, Hai Jiao Liu, Ming Yuan Fan, and Ji Wen Huang. "Quantifying Impact of Climate Change on Watershed Hydrologic Cycle Based on Multi-GCM Model." Advanced Materials Research 726-731 (August 2013): 3451–56. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.3451.

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Single climate model has much uncertainty on quantifying climate change, this paper proposes a new method, reliability ensemble averaging based on Bayesian weighted average (REA-BMA) to calculate the comprehensive climate change and then combines large-scale distributed watershed hydrologic cycling model SWAT to quantifying the effect of future climate change on basin water resources. The data sets from 1961 to 2040 of GCM models (HadCM3, CGCM3, BCCR, CSIRO) and three emission scenarios (A2, A1B and B2) are taking for uncertainty analysis and Huntai River basin in China is selected as study case. The results show that the proposed method could efficiently quantify the affect of climate change on watershed hydrologic cycle.

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Bui, Quy Ngoc, Nga Thi Le, Quan Anh Duong, and Anh Mai Thi Tran. "Asessment of flood risk on human in downstream of Vu Gia - Thu Bon river basin by combining GIS and hydraulic model." Journal of Mining and Earth Sciences 61, no. 4 (August 31, 2020): 46–56. http://dx.doi.org/10.46326/jmes.2020.61(4).05.

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Flooding is a natural disaster that occurs in most parts of Vietnam, causing a lot of damage to people, assets and influence on socio-economic activities. This article analyzes the impact of floods on population in the Vu Gia – Thu basin. In this study, the authors used the result of the hydrolic modeling, the simulated floods in conjunction with the use of GIS software (ArcGIS) to analyze the impact on the population of downstream the Vu Gia – Thu Bon river basin. From there, the study indicated the impact and influence of floods caused on flooded areas in the river basin. The ArcGIS software is used to prepare data, integrate and analyze the spatial data that is included with the attribute information. This study show that GIS provides more accurate solutions for flood impact assessment and this assessment method can be applied to any river basin.

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Malamakal, Tom, L. W. Antony Chen, Xiaoliang Wang, Mark C. Green, Steven Gronstal, Judith C. Chow, and John G. Watson. "Prescribed burn smoke impact in the Lake Tahoe Basin: model simulation and field verification." International Journal of Environment and Pollution 52, no. 3/4 (2013): 225. http://dx.doi.org/10.1504/ijep.2013.058457.

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Meng-Hua, Zhu, Liu Liang-Gang, and Xu Ao-Ao. "An Impact Model of the Imbrium Basin for Distribution of Thorium on Lunar Surface." Chinese Physics Letters 25, no. 12 (December 2008): 4490–92. http://dx.doi.org/10.1088/0256-307x/25/12/086.

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Joseph, John F., Hatim O. Sharif, Jeffrey G. Arnold, and David D. Bosch. "The Impact of Asynchronicity on Event-Flow Estimation in Basin-Scale Hydrologic Model Calibration1." JAWRA Journal of the American Water Resources Association 49, no. 2 (December 10, 2012): 300–318. http://dx.doi.org/10.1111/jawr.12011.

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Yates, David N. "WatBal: An Integrated Water Balance Model for Climate Impact Assessment of River Basin Runoff." International Journal of Water Resources Development 12, no. 2 (June 1996): 121–40. http://dx.doi.org/10.1080/07900629650041902.

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Zahabiyoun, B., M. R. Goodarzi, A. R. Massah Bavani, and H. M. Azamathulla. "Assessment of Climate Change Impact on the Gharesou River Basin Using SWAT Hydrological Model." CLEAN - Soil, Air, Water 41, no. 6 (February 6, 2013): 601–9. http://dx.doi.org/10.1002/clen.201100652.

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Ogbu, Kingsley Nnaemeka, Emeka L. Ndulue, Isiguzo Edwin Ahaneku, and Ikenna Joseph Ubah. "Evaluation of the Impact of Climate Change on Streamflow Using SWAT Model." ASM Science Journal 13 (June 24, 2020): 1–8. http://dx.doi.org/10.32802/asmscj.2020.494.

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The Soil and Water Assessment Tool (SWAT) model was applied in this study to simulate stream-flow in the Oyun River Basin. The model was calibrated and validated using monthly stream-flow data for the basin. Model performance was satisfactory for calibration and validation with a coefficient of determination (R2) of 0.69 and 0.88, respectively. Climate change impact on Oyun River was assessed by driving the SWAT model with climate parameters obtained from two global climate models (HadGEM2-ES and BCC-CCSM1-1M) based on RCP 2.6 for 2050 – 2059 and 2080 – 2089 periods. With respect to a baseline period of 2000 – 2009, HadGEM2-ES predicted a 4.62% decrease in total stream-flow while the BCC-CSM1-1M predicted stream-flow increase by 6.18% for the 2050 – 2059 period. However, both HadGEM2-ES and BCC-CCSM1-1M predicted stream-flow to increase by 18.92% and 11.25% respectively for the 2080 period. The HadGEM2-ES model showed consistency in relating future rainfall predictions with future discharge trends for the periods under study. Model results show the need for adaptive measures to mitigate climate change impacts on the water resource system.

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Journal articles on the topic 'Basin impact ejecta model'

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