Recent changes in the North Atlantic circulation simulated with eddy-permitting and eddy-resolving ocean models

Three eddy-permitting (1/4°) versions and one eddy-resolving (1/12°) version of the OCCAM ocean model are used to simulate the World Ocean circulation since 1985. The first eddy-permitting simulation has been used extensively in previous studies, and provides a point of reference. A second, improved, eddy-permitting simulation is forced in the same manner as the eddy-resolving simulation, with a dataset based on a blend of NCEP re-analysis and satellite data. The third eddy-permitting simulation is forced with a different dataset, based on the ERA-40 re-analysis data. Inter-comparison of these simulations in the North Atlantic clarifies the relative importance of resolution and choice of forcing dataset, for simulating the mean state and recent variability of the basin-scale circulation in that region. Differences between the first and second eddy-permitting simulations additionally reveal an erroneous influence of sea ice on surface salinity, dense water formation, and the meridional overturning circulation. Simulations are further evaluated in terms of long-term mean ocean heat transport at selected latitudes (for which hydrographic estimates are available) and sea surface temperature errors (relative to observations). By these criteria, closest agreement with observations is obtained for the eddy-resolving simulation. In this simulation, there is also a weak decadal variation in mid-latitudes, with heat transport strongest, by around 0.2 PW, in the mid-1990s. In two of the eddy-permitting simulations, by contrast, heat transport weakens through the study period, by up to 0.4 PW in mid-latitudes. The most notable changes of heat transport in all simulations are linked to a weakening of the subpolar gyre, rather than changes in the meridional overturning circulation. It is concluded that recent changes in the structure of mid-latitude heat transport in the North Atlantic are more accurately represented if eddies are explicitly resolved.     

Structure of pair winds from compact objects with application to emission from bare strange stars

We present the results of numerical simulations of stationary, spherically outflowing, e ^± pair winds, with total luminosities in the range 10³⁴–10⁴² ergs s^?1. In the concrete example described here, the wind injection source is a hot, bare, strange star, predicted to be a powerful source of e ^± pairs created by the Coulomb barrier at the quark surface. We find that photons dominate in the emerging emission, and the emerging photon spectrum is rather hard and differs substantially from the thermal spectrum expected from a neutron star with the same luminosity. This might help distinguish the putative bare strange stars from neutron stars.     

Large-scale Instability during Gravitational Collapse with Neutrino Transport and a Core-Collapse Supernova

Most of the energy released in the gravitational collapse of the cores of massive stars is carried away by neutrinos. Neutrinos play a pivotal role in explaining core-collape supernovae. Currently, mathematical models of the gravitational collapse are based on multi-dimensional gas dynamics and thermonuclear reactions, while neutrino transport is considered in a simplified way. Multidimensional gas dynamics is used with neutrino transport in the flux-limited diffusion approximation to study the role of multi-dimensional effects. The possibility of large-scale convection is discussed, which is interesting both for explaining SN II and for setting up observations to register possible high-energy (?10MeV) neutrinos from the supernova. A new multi-dimensional, multi-temperature gas dynamics method with neutrino transport is presented.     

Perrierite-(La), (La,Ce,Ca)4(Fe2+,Mn)(Ti,Fe3+,Al)4(Si2O7)2O8, a new mineral species from the Eifel volcanic district, Germany

Non-metamict perrierite-(La) discovered in the Dellen pumice quarry, near Mendig, in the Eifel volcanic district, Rheinland-Pfalz, Germany has been approved as a new mineral species (IMA no. 2010-089). The mineral was found in the late assemblage of sanidine, phlogopite, pyrophanite, zirconolite, members of the jacobsite-magnetite series, fluorcalciopyrochlore, and zircon. Perrierite-(La) occurs as isolated prismatic crystals up to 0.5 × 1 mm in size within cavities in sanidinite. The new mineral is black with brown streak; it is brittle, with the Mohs hardness of 6 and distinct cleavage parallel to (001). The calculated density is 4.791 g/cm³. The IR spectrum does not contain absorption bands that correspond to H₂O and OH groups. Perrierite-(La) is biaxial (-), α = 1.94(1), β = 2.020(15), γ = 2.040(15), 2V _meas = 50(10)°, 2V _calc = 51°. The chemical composition (electron microprobe, average of seven point analyses, the Fe²⁺/Fe³⁺ ratio determined from the X-ray structural data, wt %) is as follows: 3.26 CaO, 22.92 La₂O₃, 19.64 Ce₂O₃, 0.83 Pr₂O₂, 2.09 Nd₂O₃, 0.25 MgO, 2.25 MnO, 3.16 FeO, 5.28 Fe₂O₃, 2.59 Al₂O₃, 16.13 TiO₂, 0.75 Nb₂O₅, and 20.06 SiO₂, total is 99.21. The empirical formula is (La_1.70Ce_1.45Nd_0.15Pr_0.06Ca_0.70)_Σ4.06(Fe _0.53 ²⁺ Mn_0.38Mg_0.08)_Σ0.99(Ti_2.44Fe _0.80 ³⁺ Al_0.62Nb_0.07)_Σ3.93Si_4.04O₂₂. The simplified formula is (La,Ce,Ca)₄(Fe²⁺,Mn)(Ti,Fe³⁺,Al)₄(Si₂O₇)₂O₈. The crystal structure was determined by a single crystal. Perrierite-(La) is monoclinic, space group P2₁/a, and the unit-cell dimensions are as follows: a =13.668(1), b = 5.6601(6), c = 11.743(1) Å, β = 113.64(1)°; V = 832.2(2) ų, Z = 2. The strong reflections in the X-ray powder diffraction pattern are [d, Å (I, %) (hkl)]: 5.19 (40) (110), 3.53 (40) ( $\overline 3 $ 11), 2.96 (100) ( $\overline 3 $ 13, 311), 2.80 (50) (020), 2.14 (50) ( $\overline 4 $ 22, $\overline 3 $ 15, 313), 1.947 (50) (024, 223), 1.657 (40) ( $\overline 4 $ 07, $\overline 4 $ 33, 331). The holotype specimen of perrierite-(La) is deposited at the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, Russia, with the registration number 4059/1.     

The influence of atmospheric circulation on the dynamics of the intermediate water layer in the eastern part of the St. Anna Trough

This paper discusses the results of unique direct observations over the current velocities in the eastern part of the St. Anna deep-water trough, made in the period from August 2009 until September 2010, and analyzes the physical ways how the temporal variability of currents is formed. The stable northward barotropic transport with an average annual velocity of about 20 cm/s was discovered. It was found that changes in velocity with a characteristic timescale of several weeks occurred synchronously in the entire water column and were determined by the deformation of the sea level field due to long-period disturbances of the large-scale field of ground wind above the northern parts of Barents and Kara seas. For the winds of the southwest and west directions, the sea level??s gradient is formed across the St. Anna Trough and the northward meridional water transport is intensified owing to the geostrophic adjustment. These are verified by the results of numerical simulation.     

Osumilite-(Mg): Validation as a mineral species and new data

Osumilite-(Mg), the Mg-dominant analogue of osumilite, has been approved by the CNMNC IMA as a new mineral species. The holotype sample has been found at Bellerberg, Eifel volcanic area, Germany. Fluorophlogopite, sanidine, cordierite, mullite, sillimanite, topaz, pseudobrookite and hematite are associated minerals. Osumilite-(Mg) occurs as short prismatic or thick tabular hexagonal crystals reaching 0.5 × 1 mm in size in the cavities in basaltic volcanic glasses at their contact with thermally metamorphosed xenoliths of pelitic rocks. The mineral is brittle, with Mohs’ hardness 6.5. Cleavage was not observed. Color is blue to brown. D _meas = 2.59(1), D _calc = 2.595 g/cm³. No bands corresponding to H₂O and OH-groups are in the IR spectrum. Osumilite-(Mg) is uniaxial (+), ω = 1.539(2), ? = 1.547(2). The chemical composition (electron microprobe, average of 5 point analyses, wt %) is: 0.08 Na₂O, 3.41 K₂O, 0.04 CaO, 7.98 MgO, 0.28 MnO, 21.57 Al₂O₃, 3.59 Fe₂O₃, 62.33 SiO₂, total 99.28. The empirical formula is: (K_0.72Na_0.03Ca_0.01)(Mg_1.97Mn_0.04)[Al_4.21Fe _0.45 ³⁺ Si_10.32]O₃₀. The simplified formula is: KMg₂Al₃(Al₂Si₁₀)O₁₀. The crystal structure was refined on a single crystal, R = 0.0294. Osumilite-(Mg) is hexagonal, space group P6/mcc; a = 10.0959(1), c = 14.3282(2)Å, V = 1264.79(6) ų, Z = 2. The strongest reflections in the X-ray powder diffraction pattern [d, Å I %) (hkl)] are: 7.21 (37) (002), 5.064 (85) (110), 4.137 (45) (112), 3.736 (43) (202), 3.234 (100) (211), 2.932 (42) (114), 2.767 (51) (204). A type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 4174/1.     

Alumovesuvianite,Ca19Al(Al,Mg)12Si18O69(OH)9, a new vesuvianite-group member from the Jeffrey mine,asbestos, Estrie region,Québec,Canada

Mineralogy and Petrology - Alumovesuvianite (IMA 2016–014), ideally Ca19Al(Al,Mg)12Si18O69(OH)9, is a new vesuvianite-group member found in the rodingite zone at the contact of a gabbroid...     

Supernova Explosion Mechanism with the Neutrinos and the Collapse of the Rotation Core

Most of the energy released in the gravitational collapse of the cores of massive stars is carried away by neutrinos. Neutrinos play a pivotal role in explaining core-collapse supernovae. In this work the multidimensional gas dynamics is used with neutrino transport in the flux-limited diffusion approximation to study the role of multi-dimensional effects. The possibility of large-scale convection is discussed, which is interesting both for explaining SNII and for setting up observations to register possible high-energy (?10 MeV) neutrinos from the supernova. In compare with the previous work describing a new multidimensional gas dynamics method with neutrino transport we investigate the role of the rotation in the convection.