Cloud particle detecting system and method based on polarization detection

Abstract

The invention discloses a cloud particle detecting system and method based on polarization detection. The system comprises a laser transmitting optical unit for generating polarized light, a forward scattering detecting unit and a backward scattering detecting unit, wherein the laser transmitting optical unit generates the polarized light by using a laser diode, a polaroid and a half wave plate; the forward scattering detecting unit is used for judging whether particles are recorded and sizes of cloud particles are obtained; and the depolarization ratio of the scattered light is obtained through the backward scattering detecting unit to determine a phase state of the particles. According to the method, information such as the size and the phase state of the particles is determined by the forward scattering detecting unit and the backward scattering detecting unit jointly, particle size spectrum distribution of cloud droplets and ice crystals is obtained, and then, solid water content and liquid water content in cloud are obtained.

Description

technical field [0001] The invention relates to a cloud particle detection system and method based on polarization detection, in particular to a cloud particle detection system and method based on continuous light semiconductor lasers, scattering multi-angle reception, and polarization detection, and belongs to the technical field of cloud particle detection. Background technique [0002] The size spectrum information of small ice crystals in clouds plays an important role in the scientific research of cloud radiology and cloud physics. The Fifth Assessment Report of the IPCC pointed out that there are still great uncertainties in the role of clouds in radiative forcing and climate change, and an important source of uncertainty is caused by cold cloud radiation. The radiation characteristics of cold clouds depend not only on the ice water content, but also on its shape and scale spectrum distribution information. In order to deeply understand its radiation transfer character...

AI Technical Summary

Problems solved by technology

Cotton reported in 2010 that the second-generation ice crystal detector SID-2 uses a custom-made phase function detector (32 detectors) distributed in concentric circles, and the sensitivity of the detector has also been greatly improved, but when the cloud particle concentration exceeds 20 piece / cm 3 When , SID-2 cannot distinguish individual particles

The third-generation SID-3 uses a high-resolution camera to perform two-dimensional imaging of fringes to obtain high angular resolution. However, due to the slow processing speed of the camera, when the concentration of ice crystal particles is large, particle degeneracy occurs. The actual measurement The number of particles is smaller than the actual particle book

The scattering ratio measurement method is limited by the oscillation of the Mie scattering phase function, and the imaging technology, due to the response of the imaging detector, will produce degeneracy when there are many ice crystal particles, and the detection of small ice crystals based on polarization detection is rarely studied.

Therefore, the detection of small ice crystals (less than 50 μm) in ice clouds or mixed-phase clouds is still an unsolved problem

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