Dependence Of Time Lag Research Articles

Effect of Snow Cover on Time Lag of Runoff from a Watershed

A large scale study on the dependence of time lag of runoff on snow depth and stratigraphy was carried out in a watershed. The time lag in peak runoff was found to be increased by 1.5 - 4 h per I m increment in snow depth. Although the data were widely scattered, it was found that the time lag series converged in a line every year and that discrete layers in the snow cover composed in a warm winter, accelerated meltwater flow.Subtracting the time of propagation through a snowcover from the total time lag, the effect of size of a watershed on a delay in runoff was rearranged, as follows: where Tf is the time lag in min after discharge from a snow cover, A the area of a watershed in km2, Re the effective snowmelt in mm/hr. The time lag Tf increases only by 1.5 times when an area of a watershed is increased by a factor of ten.

Excitation Process of the N2 IR (B3Πg-A3Σu+) Laser Transition

Excitation mechanism of the laser action on the first positive system (B3Πg-A3Σu+) of N2 molecule is studied with an emphasis on the time relationship between the ir and uv (C3Πu-B3Πg) laser pulses. Pressure dependence of time lag between the uv and ir pulses has been observed in the pressure range from 4 to 8 Torr using an axial-discharge tube. The observed time lag is well predicted by a model which involves direct electron-impact excitation, near-resonant collisional excitation transfer from the a1Πg state, and cascade excitation due to the uv laser action for the upper ir laser level. Relative importance of these excitation processes depends primarily on N2 pressure.