VSE knjižnice (vzajemna bibliografsko-kataložna baza podatkov COBIB.SI)
  • Laser system for atmospheric monitoring
    Filipčič, Andrej ; Zavrtanik, Marko ; Arčon, Iztok
    In recent years laser based spectroscopic techniques have shown to be very useful tool for atmospheric monitoring. They exploit different kinds of direct or indirect scattering of laser light by ... atmospheric constituents. In this paper we present a simple single ended laser system (LIDAR) which can be used to the measure the absorption of UV or visible light in the troposphere and detect the presence of aerosols in the radius of about 10 km. The system consists of a Q-switched Nd:Yag laser with a frequency tripler and a telescope. The laser provides 5 ns pulses at 355 nm in the third harmonic. The energy per pulse is 8mJ at repetition rate of 15 Hz. The main part of the telescope is a parabolic mirror with the diameter of 0.8 m and a focal distance of 0.4 m. A photomultiplier tube (PMT) is used as a detector. It is mounted in the mirror focus and protected by a broad band UV filter (300 - 400 nm) to reduce the background light. The signal from the PMT is recorded as a function of time by a digital oscilloscope to provide a range-resolved measure of atmospheric scattering. System collects the data in a single shot mode. Light pulses of a known energy are fired into the night sky at a known direction. The collection of the signal from the scattered light is triggered by a laser pulse. Backscattering properties of the atmosphere at a given height determine the pulse height at a certain time delay. The latter equals to the time needed by the light to travel from the source to the portion of atmosphere in question and back. The recorded signals are analyzed later on to provide information on the atmospheric condition on a extended scale in space and time by the means of backscattering length (1/[beta]) and extinction length (1/[alpha]) determination.
    Vir: Book of abstracts (Str. 56)
    Vrsta gradiva - prispevek na konferenci
    Leto - 1999
    Jezik - angleški
    COBISS.SI-ID - 57851

Vnos na polico