Research On The Method Of Judging Aircraft Icing Based On The Retrieval Of Cloud Microphysical Parameters

Aircraft icing has an important impact on flight safety,and the study of cloud microphysical parameters is of great significance to the judgment of aircraft icing.In this paper,we use the related principle of the fact that the reflection function of clouds at a non-absorbing band in the visible wavelength region is primarily a function of the cloud optical thickness,whereas the reflection function at a water(or ice)absorbing band in the near infrared is primarily a function of cloud particle.The satellite's visible light channel(0.55~0.90?m)and mid-infrared channel(IR4:3.5~4.0?m)data were combined with the SBDART radiation transmission mode to perform a two-channel inversion test on cloud optical thickness and cloud effective radius.Based on the inversion results,the cloud liquid water path is calculated,and combined with the aircraft ice accretion judgment algorithm to judge and verify the aircraft ice accretion.This paper introduces the basic principle of the inversion calculation of cloud microphysical parameters.According to the calculation formula of aircraft icing probability and the division standard of aircraft icing intensity,the judgment algorithms of aircraft icing probability and aircraft icing intensity are designed respectively.The effects of two channel reflection function on cloud optical thickness,cloud effective radius,scattering geometry angle,surface reflectivity,surface temperature,cloud bottom height and atmosphere are studied.The results show that the sensitivity of the two channels to scattering geometry angle,surface reflectivity and other parameters is less than that to cloud optical thickness and cloud effective particle radius.The visible channel data can be used to invert cloud optical thickness,and the infrared channel data can be used to invert cloud effective particle radius.In this paper,the cloud microphysical parameters of the area recorded in the aircraft icing report are inversed by using the inversion method,and the MODIS cloud product data at the same time are selected for comparative analysis with the inversion results.The research results show that the cloud optical thickness and cloud effective radius inversed by FY-2F satellite data and the cloud optical thickness distribution and cloud effective radiusdistribution in MODIS cloud product data are basically the same,but there are differences in the specific values.The cloud optical thickness retrieved is slightly smaller than that in MODIS cloud product data,while the cloud effective radius retrieved is larger than that in MODIS cloud product data,and the cloud liquid water path calculated according to the inversion results is smaller than that in MODIS cloud product data.According to the inversion results,the aircraft icing probability and intensity of the corresponding area in the icing report are calculated by combining the aircraft icing probability and the aircraft icing intensity algorithm.The test results show that the aircraft icing probability of the corresponding area in the icing report calculated by the inversion results is about 80%,and the icing intensity level of the area is heavy icing,which is basically the same as that recorded in the aircraft icing report.Finally,the reliability of the inversion of cloud microphysical parameters and the judgment of aircraft icing is verified.