Formation of Libyan Desert Glass: Numerical simulations of melting of silica due to radiation from near‐surface airbursts

2020 ◽  
Vol 55 (4) ◽  
pp. 895-910
Author(s):  
Vladimir Svetsov ◽  
Valery Shuvalov ◽  
Igor Kosarev
Keyword(s):  
Numerical Simulations ◽  
Near Surface ◽  
Libyan Desert ◽  
Libyan Desert Glass

A handaxe of Libyan Desert glass

Antiquity ◽  
1982 ◽  
Vol 56 (217) ◽  
pp. 88-92 ◽  
Author(s):  
Derek A. Roe ◽  
John W. Olsen ◽  
James R. Underwood ◽  
Robert F. Giegengack
Keyword(s):  
Distribution Area ◽  
Southern Boundary ◽  
Extensive Field ◽  
Libyan Desert ◽  
Libyan Desert Glass

The handaxe of Libyan Desert glass (PL. XIIIb & FIG. I) was found on 23 June 1979, in the Sand Sea of S.W. Egypt, at latitude 25°o8' N, longitude 25° 35·5' E, near the southern boundary of the known distribution area of the glass. Lying just north of the Gilf Kebir, this part of the Sand Sea is characterized by an extensive field of linear dunes, trending almost exactly N-S, which are up to Ioom high, tens of km long, and separated by interdune corridors or ‘streets’ 2–5 km wide.

scholarly journals Investigation of inclusions trapped inside Libyan desert glass by Raman microscopy

2010 ◽  
Vol 397 (7) ◽  
pp. 2659-2665 ◽  
Author(s):  
Marcel Swaenen ◽  
Elżbieta Anna Stefaniak ◽  
Ray Frost ◽  
Anna Worobiec ◽  
René Van Grieken
Keyword(s):  
Raman Microscopy ◽  
Libyan Desert ◽  
Libyan Desert Glass

A New Time-dependent Theory of Tropical Cyclone Intensification

2021 ◽  
Author(s):  
Yuqing Wang ◽  
Yuanlong Li ◽  
Jing Xu
Keyword(s):  
Boundary Layer ◽  
Tropical Cyclone ◽  
Numerical Simulations ◽  
Strong Dependence ◽  
Surface Wind ◽  
Time Dependent ◽  
Quasi Equilibrium ◽  
Free Atmosphere ◽  
Near Surface ◽  
Tangential Wind

AbstractIn this study, the boundary-layer tangential wind budget equation following the radius of maximum wind, together with an assumed thermodynamical quasi-equilibrium boundary layer is used to derive a new equation for tropical cyclone (TC) intensification rate (IR). A TC is assumed to be axisymmetric in thermal wind balance with eyewall convection becoming in moist slantwise neutrality in the free atmosphere above the boundary layer as the storm intensifies as found recently based on idealized numerical simulations. An ad-hoc parameter is introduced to measure the degree of congruence of the absolute angular momentum and the entropy surfaces. The new IR equation is evaluated using results from idealized ensemble full-physics axisymmetric numerical simulations. Results show that the new IR equation can reproduce the time evolution of the simulated TC intensity. The new IR equation indicates a strong dependence of IR on both TC intensity and the corresponding maximum potential intensity (MPI). A new finding is the dependence of TC IR on the square of the MPI in terms of the near-surface wind speed for any given relative intensity. Results from some numerical integrations of the new IR equation also suggest the finite-amplitude nature of TC genesis. In addition, the new IR theory is also supported by some preliminary results based on best-track TC data over the North Atlantic and eastern and western North Pacific. Compared with the available time-dependent theories of TC intensification, the new IR equation can provide a realistic intensity-dependent IR during weak intensity stage as in observations.

Libyan desert glass, cut

2009 ◽  
pp. 524-524
Keyword(s):  
Libyan Desert ◽  
Libyan Desert Glass

scholarly journals The Role of Horizontal Divergence in Submesoscale Frontogenesis

2019 ◽  
Vol 49 (6) ◽  
pp. 1593-1618 ◽  
Author(s):  
Roy Barkan ◽  
M. Jeroen Molemaker ◽  
Kaushik Srinivasan ◽  
James C. McWilliams ◽  
Eric A. D’Asaro
Keyword(s):  
Numerical Simulations ◽  
Analytical Solutions ◽  
Field Measurements ◽  
Careful Analysis ◽  
Rossby Number ◽  
Asymptotic Model ◽  
Near Surface ◽  
Boundary Layer Turbulence ◽  
Oceanic Surface ◽  
Gradient Fields

AbstractOceanic surface submesoscale currents are characterized by anisotropic fronts and filaments with widths from 100 m to a few kilometers; an O(1) Rossby number; and large magnitudes of lateral buoyancy and velocity gradients, cyclonic vorticity, and convergence. We derive an asymptotic model of submeoscale frontogenesis—the rate of sharpening of submesoscale gradients—and show that in contrast with “classical” deformation frontogenesis, the near-surface convergent motions, which are associated with the ageostrophic secondary circulation, determine the gradient sharpening rates. Analytical solutions for the inviscid Lagrangian evolution of the gradient fields in the proposed asymptotic regime are provided, and emphasize the importance of ageostrophic motions in governing frontal evolution. These analytical solutions are further used to derive a scaling relation for the vertical buoyancy fluxes that accompany the gradient sharpening process. Realistic numerical simulations and drifter observations in the northern Gulf of Mexico during winter confirm the applicability of the asymptotic model to strong frontogenesis. Careful analysis of the numerical simulations and field measurements demonstrates that a subtle balance between boundary layer turbulence, pressure, and Coriolis effects (e.g., turbulent thermal wind; Gula et al. 2014) leads to the generation of the surface convergent motions that drive frontogenesis in this region. Because the asymptotic model makes no assumptions about the physical mechanisms that initiate the convergent frontogenetic motions, it is generic for submesoscale frontogenesis of O(1) Rossby number flows.

Neutron and photon activation analyses in geochemical characterization of Libyan Desert Glass

2016 ◽  
Vol 311 (2) ◽  
pp. 1465-1471 ◽  
Author(s):  
Jiří Mizera ◽  
Zdeněk Řanda ◽  
Ivana Krausová
Keyword(s):  
Photon Activation ◽  
Geochemical Characterization ◽  
Libyan Desert ◽  
Libyan Desert Glass

Cooling and crystallization rates of libyan desert glass

1985 ◽  
Vol 71 (1-3) ◽  
pp. 387-395 ◽  
Author(s):  
W.R. Seebaugh ◽  
D.L. Kinser ◽  
R. Hoff ◽  
R.A. Weeks
Keyword(s):  
Libyan Desert ◽  
Libyan Desert Glass

scholarly journals Fluvial Transport Model from Spatial Distribution Analysis of Libyan Desert Glass Mass on the Great Sand Sea (Southwest Egypt): Clues to Primary Glass Distribution

Geosciences ◽  
2015 ◽  
Vol 5 (2) ◽  
pp. 95-116 ◽  
Author(s):  
Nancy Jimenez-Martinez ◽  
Marius Ramirez ◽  
Raquel Diaz-Hernandez ◽  
Gustavo Rodriguez-Gomez
Keyword(s):  
Spatial Distribution ◽  
Transport Model ◽  
Glass Mass ◽  
Distribution Analysis ◽  
Fluvial Transport ◽  
Libyan Desert ◽  
Libyan Desert Glass

scholarly journals Evidence for shock metamorphism in sandstones from the Libyan Desert Glass strewn field

2001 ◽  
Vol 36 (9) ◽  
pp. 1277-1282 ◽  
Author(s):  
Barbara KLEINMANN ◽  
Peter HORN ◽  
Falko LANGENHORST
Keyword(s):  
Shock Metamorphism ◽  
Libyan Desert ◽  
Libyan Desert Glass
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