Simulation Calculation And Research Of Radiative Transmission In Cirrus Atmosphere

The increase of carbon dioxide concentration in the atmosphere affects the global climate change.The influence of cirrus coverage and physical and optical properties on the balance of atmospheric radiation balance in cirrus clouds draws attention.This paper focuses on the inversion of carbon dioxide in cirrus clouds atmospheric conditions.Firstly,the SCIATRAN atmospheric radiative transmission mode was used to simulate the radiative transmission in the 1.6-micron short-wave infrared band of the TANSO_FTS of the GOSAT satellite.The 1320 sets of clear-sky atmospheric radiation spectrum data and 7920 sets of cirrus clouds atmospheric radiation spectrum data were obtained.Sensitivity tests showed that:?1?The simulated radiation spectrum of the bidirectional reflectance type prosail_Erectophile when considering the linear function and mode of the GOSAT satellite is closest to the actual product.?2?As the surface albedo increases,the radiation value also increases;The radiation value decreases as the solar zenith angle increases;The spectrum of radiation gradually decreases as the cirrus optical thickness increases.Then,the PCA principal component analysis method was used to reduce the dimension,noise and decorrelation of the radiation spectrum data,and the BP neural network algorithm was used to invert the radiation spectrum data of the clear air atmosphere and the cirrus cloud atmosphere into three cases:?1?Neural network training is conducted in using radiation simulation data under clear air atmosphere to form a clear sky inversion mode to obtain carbon dioxide inversion results under clear air conditions.?2?Simulated radiation data under cirrus conditions is inverted in the clear sky mode to obtain inversion results.?3?Neural network training is performed using data under cirrus cloud conditions to form an inversion mode under cirrus cloud atmospheric conditions,and a comparison of the inversion results of the cirrus optical thickness addition or not is made.Through comparison of inversion experiments,the inversion mode under clear air conditions is not suitable for CO₂ inversion with cirrus clouds.The consideration of cirrus optical thickness will improve the accuracy of CO₂inversion and make the mean square error less than 0.0546ppm.