21 research outputs found
Energy- and flux-budget turbulence closure model for stably stratified flows. Part II: the role of internal gravity waves
We advance our prior energy- and flux-budget turbulence closure model
(Zilitinkevich et al., 2007, 2008) for the stably stratified atmospheric flows
and extend it accounting for additional vertical flux of momentum and
additional productions of turbulent kinetic energy, turbulent potential energy
(TPE) and turbulent flux of potential temperature due to large-scale internal
gravity waves (IGW). Main effects of IGW are following: the maximal value of
the flux Richardson number (universal constant 0.2-0.25 in the no-IGW regime)
becomes strongly variable. In the vertically homogeneous stratification, it
increases with increasing wave energy and can even exceed 1. In the
heterogeneous stratification, when IGW propagate towards stronger
stratification, the maximal flux Richardson number decreases with increasing
wave energy, reaches zero and then becomes negative. In other words, the
vertical flux of potential temperature becomes counter-gradient. IGW also
reduce anisotropy of turbulence and increase the share of TPE in the turbulent
total energy. Depending on the direction (downward or upward), IGW either
strengthen or weaken the total vertical flux of momentum. Predictions from the
proposed model are consistent with available data from atmospheric and
laboratory experiments, direct numerical simulations and large-eddy
simulations.Comment: 37 pages, 5 figures, revised versio
Observational and Numerical Simulation Study of a Sequence of Eight Atmospheric Density Currents in Northern Spain
Ultrathin high band gap solar cells with improved efficiencies from the world’s oldest photovoltaic material
A fatal case of cytomegalovirus ventriculoencephalitis in a mycosis fungoides patient who received multiple umbilical cord blood cell transplantations
Glucocorticoid Stress Responses of Reintroduced Tigers in Relation to Anthropogenic Disturbance in Sariska Tiger Reserve in India
<div><p>Tiger (<i>Panthera tigris</i>), an endangered species, is under severe threat from poaching, habitat loss, prey depletion and habitat disturbance. Such factors have been reported causing local extermination of tiger populations including in one of the most important reserves in India, namely Sariska Tiger Reserve (STR) in northwestern India. Consequently, tigers were reintroduced in STR between 2008 and 2010, but inadequate breeding success was observed over the years, thus invoking an investigation to ascertain physiological correlates. In the present study, we report glucocorticoid stress responses of the reintroduced tigers in relation to anthropogenic disturbance in the STR from 2011 to 2013. We found anthropogenic disturbance such as encounter rates of livestock and humans, distance to roads and efforts to kill domestic livestock associated with an elevation in fecal glucocorticoid metabolite (fGCM) concentrations in the monitored tigers. In this regard, female tigers seem more sensitive to such disturbance than males. It was possible to discern that tiger’s fGCM levels were significantly positively related to the time spent in disturbed areas. Resulting management recommendations include relocation of villages from core areas and restriction of all anthropogenic activities in the entire STR.</p></div