Supersymmetry in the Quark-Diquark and the Baryon-Meson Systems

A superalgebra extracted from the Jordan algebra of the 27 and 27 dim. representations of the group E6 is shown to be relevant to the description of the quark-antidiquark system. A bilocal baryon-meson field is constructed from two quark-antiquark fields. In the local approximation the hadron field is shown to exhibit supersymmetry which is then extended to hadronic mother trajectories and inclusion of multiquark states. Solving the spin-free Hamiltonian with light quark masses we develop a new kind of special function theory generalizing all existing mathematical theories of confluent hypergeometric type. The solution produces extra “hidden” quantum numbers relevant for description of supersymmetry and for generating new mass formulas

The importance of fronts for extreme precipitation

This is the final version. Available from AGU via the DOI in this recordExtratropical cyclones and their associated frontal systems are well known to be related to heavy precipitation events. Here an objective method is used to directly link extreme precipitation events with atmospheric fronts, identified using European Centre for Medium‐Range Weather Forecasts Interim Reanalysis data, to quantify the importance of fronts for precipitation extremes globally. In some parts of the major midlatitude storm track regions, over 90% of precipitation extremes are associated with fronts, with slightly more events associated with warm fronts than cold fronts. On average, 51% of global precipitation extremes are associated with fronts, with 75% in the midlatitudes and 31% in the tropics. A large proportion of extreme precipitation events occur in the presence of both a cyclone and a front, but remote fronts are responsible for many of the “front‐only” events. The fronts producing extreme precipitation events are found to have up to 35% stronger frontal gradients than other fronts, potentially providing some improved forecasting capabilities for extreme precipitation events.This study was supported by the Australian Research Council through the Linkage Project grant LP0883961, and the Discovery Project grant DP0877417

Climatology and dynamics of the link between dry intrusions and cold fronts during winter, Part II: Front-centred perspective

This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.The conceptual picture of an extratropical cyclone typically includes a cold front and a dry intrusion (DI) behind it. By objectively identifying fronts and DIs in ECMWF ERA-Interim data for 1979–2014, Part I quantified the climatological relationship between cold fronts and DIs. Driven by the finding that front intensity and frontal precipitation are enhanced in the presence of DIs, here we employ a front-centred perspective to focus on the dynamical and thermodynamical environment of cold fronts with and without DIs in the Northern Hemisphere winter. Distinguishing between trailing fronts (that connect to a parent cyclone) and isolated fronts, examples of DIs behind each type illustrate the baroclinic environment of the trailing front, and the lack of strong temperature gradients across the isolated front. Composite analyses of North Atlantic and North Pacific fronts outline the major differences in the presence of DIs, compared to similar fronts but without DIs in their vicinity. The magnitude and spatial structure of the modification by DIs depends on the front intensity. Yet, generally with DIs, trailing fronts occur with stronger SLP dipole, deeper upper-tropospheric trough, stronger 10-m wind gusts, enhanced ocean sensible and latent heat fluxes in the cyclone cold sector and heavier precipitation. Isolated weak fronts exhibit similar behaviour, with different spatial structure. This study highlights the central role of DIs for shaping the variability of fronts and their associated environment and impact.Australian Research Council DECR

Climatology and dynamics of the link between dry intrusions and cold fronts during winter. Part I: global climatology

This is the final version. Available on open access from Springer via the DOI in this recordData availability: ERA-Interim data are available online (http://apps.ecmwf.int/datasets/).Cold fronts are a primary feature of the day-to-day variability of weather in the midlatitudes, and feature in conceptual extratropical cyclone models alongside the dry intrusion airstream. Here the climatological frequency and spatial distribution of the co-occurrence of these two features are quantified, and the differences in cold front characteristics (intensity, size, and precipitation) when a dry intrusion is present or not are calculated. Fronts are objectively identified in the ECMWF ERA-Interim dataset for the winter seasons in each hemisphere and split into 3 sub-types: central fronts (within a cyclone area); trailing fronts (outwith the cyclone area but connected to a central front); and isolated fronts (not connected to a cyclone). These are then associated with dry intrusions identified using Lagrangian trajectory analysis. Trailing fronts are most likely to be associated with a DI in both hemispheres, and this occurs more frequently in the western parts of the major storm track regions. Isolated fronts are linked to DIs more frequently on the eastern ends of the storm tracks, and in the subtropics. All front types, when co-occurring with a DI, are stronger in terms of their temperature gradient, are much larger in area, and typically have higher average precipitation. Therefore, climatologically the link with DIs increases the impact of cold fronts. There are some differences in the statistics of the precipitation for trailing and isolated fronts that are further investigated in Part II of this study.Australian Research CouncilSwiss National Science FoundationBenoziyo Endowment Fund for the Advancement of Scienc

Axisymmetric plasma equilibrium in gravitational and magnetic fields

Plasma equilibria in gravitational and open-ended magnetic fields are considered for the case of topologically disconnected regions of the magnetic flux surfaces where plasma occupies just one of these regions. Special dependences of the plasma temperature and density on the magnetic flux are used which allow the solution of the Grad–Shafranov equation in a separable form permitting analytic treatment. It is found that plasma pressure tends to play the dominant role in the setting the shape of magnetic field equilibrium, while a strong gravitational force localizes the plasma density to a thin disc centered at the equatorial plane

Continental accretion and incremental deformation in the thermochronologic evolution of the Lesser Caucasus

Apatite fission-track analysis and thermochronologic statistical modeling of Precambrian\u2013Oligocene plutonic and metamorphic rocks from the Lesser Caucasus resolve two discrete cooling episodes. Cooling occurred during incremental crustal shortening due to obduction and continental accretion along the margins of the northern branch of the Neotethys. (1) The thermochronometric record of a Late Cretaceous (Turonian\u2013Maastrichtian) cooling/exhumation event, coeval to widespread ophiolite obduction, is still present only in a relatively small area of the upper plate of the Amasia-Sevan-Akera (ASA) suture zone, i.e. the suture marking the final closure of the northern Neotethys during the Paleogene. Such area has not been affected by significant later exhumation. (2) Rapid cooling/exhumation occurred in the Early-Middle Miocene in both the lower and upper plates of the ASA suture zone, obscuring previous thermochronologic signatures over most of the study area. Miocene contractional reactivation of the ASA suture zone occurred contemporaneously with the main phase of shortening and exhumation along the Bitlis suture zone marking the closure of the southern branch of the Neotethys and the ensuing Arabia-Eurasia collision. Miocene collisional stress from the Bitlis suture zone was transmitted northward across the Anatolian hinterland, which was left relatively undeformed, and focused along preexisting structural discontinuities such as the eastern Pontides and the ASA suture zone