6 research outputs found
Rainwater propagation through snowpack during rain-on-snow sprinkling experiments under different snow conditions
The mechanisms of rainwater propagation and runoff generation during
rain-on-snow (ROS) events are still insufficiently known. Understanding storage and transport of liquid water in natural snowpacks is crucial, especially for
forecasting of natural hazards such as floods and wet snow avalanches. In
this study, propagation of rainwater through snow was investigated by
sprinkling experiments with deuterium-enriched water and applying an
alternative hydrograph separation technique on samples collected from the
snowpack runoff. This allowed us to quantify the contribution of rainwater,
snowmelt and initial liquid water released from the snowpack. Four field
experiments were carried out during winter 2015 in the vicinity of Davos,
Switzerland. Blocks of natural snow were isolated from the surrounding
snowpack to inhibit lateral exchange of water and were exposed to artificial
rainfall using deuterium-enriched water. The experiments were composed of
four 30 min periods of sprinkling, separated by three 30 min breaks. The
snowpack runoff was continuously gauged and sampled periodically for the
deuterium signature. At the onset of each experiment antecedent liquid water
was first pushed out by the sprinkling water. Hydrographs showed four
pronounced peaks corresponding to the four sprinkling bursts. The
contribution of rainwater to snowpack runoff consistently increased over the
course of the experiment but never exceeded 86 %. An experiment conducted
on a non-ripe snowpack suggested the development of preferential flow paths
that allowed rainwater to efficiently propagate through the snowpack limiting
the time for mass exchange processes to take effect. In contrast,
experiments conducted on ripe isothermal snowpack showed a slower response
behaviour and resulted in a total runoff volume which consisted of less than
50 % of the rain input
Lindblad master equation approach to superconductivity in open quantum systems
We consider an open quantum Fermi-system which consists of a single
degenerate level with pairing interactions embedded into a superconducting
bath. The time evolution of the reduced density matrix for the system is given
by Linblad master equation, where the dissipators describe exchange of
Bogoliubov quasiparticles with the bath. We obtain fixed points of the time
evolution equation for the covariance matrix and study their stability by
analyzing full dynamics of the order parameter.Comment: 7 pages, 2 pdf figure