Turbulent UV Lidar BSE-5
- PDF / 1,723,414 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 109 Downloads / 180 Views
TICAL INSTRUMENTATION
Turbulent UV Lidar BSE-5 I. A. Razenkova, *, A. I. Nadeeva, N. G. Zaitseva, and E. V. Gordeeva a
V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk, 634055 Russia *e-mail: [email protected] Received January 17, 2020; revised January 17, 2020; accepted February 18, 2020
Abstract—An eye-safe turbulent UV (355 nm) lidar BSE-5 designed for the study of atmospheric turbulence is described. Lidar works on the basis of the backscatter enhancement effect, which occurs when a light wave propagates twice in a random medium. The design of the lidar is based on a transceiving afocal Mersen telescope, which supports thermomechanical stability during long-term operation of the device. To reduce the telescope size, the edges of the primary mirror have been cut off, because they are not used during the lidar operation. The lidar was tested at Tolmachevo airport, Novosibirsk. During the tests, the turbulence was continuously monitored over a runway and over the aircraft parking. The lidar confidently recorded a turbulent wake of any aircraft during takeoff and landing. The lifetime of a strong artificial turbulence over the airfield was found to be 2–3 min. Keywords: atmospheric turbulence, artificial turbulence, backscatter enhancement effect, lidar DOI: 10.1134/S1024856020040107
INTRODUCTION Turbulence is a characteristic property of an atmosphere under random changes in the air temperature and pressure and wind speed and direction. Turbulence is generated due to a number of factors and may exist at different distances from the ground; for an aircraft in flight, it is as natural as pitching for a ship at sea. Strong atmospheric turbulence can be dangerous during both takeoff and landing of aircraft and in flight at high altitudes. Therefore, the creation of new tools for turbulence control remains urgent. A specialized aerosol laser locator—a turbulent lidar—can be such a tool for remote monitoring of atmospheric turbulence [1–4]. The principle of the lidar operation is based on an increase in the average backscatter intensity–backscatter enhancement effect (BSE), which arises during double propagation of laser radiation in a random medium [5, 6]. The operation of the system is based on a relative change in the magnitudes of echoes inside a narrow laser beam and at some distance from it, under coincidence of apertures of the transmitter and receivers [3, 4]. An indispensable prerequisite for the device operation is the signal accumulation, i.e., temporal averaging of a signal over many sounding pulses. It is desirable that a modern laser system is eyesafe, compact, and reliable. These requirements are met by micropulse laser systems with low-energy (tens of μJ) sounding pulses at a pulse repetition rate of several kHz. The average output power of a small laser is several hundreds of mW. Such lasers are usually solid-
state with continuous diode pumping and air cooling and operate in the Q-switching mode. A turbulent BSE-5 lidar which operates at a wavelength of 35
Data Loading...
