Inversion And Application Of High-Precision Temperature And Humidity Profile Under Cloudy Conditions

The acquisition of cloud atmospheric temperature and humidity profile is of great significance for the analysis of climate change and weather modification.At present,microwave radiometer and Raman lidar are the commonly used ground-based instruments for continuous observation of atmospheric temperature and humidity.However,microwave radiometer in cloud sky has problems such as low inversion accuracy and insufficient resolution,and Raman lidar in cloud sky has limitations such as high signal attenuation and limited detection height.In order to make up for the limitations and deficiencies of the above observation methods and give play to the advantages of different instruments to obtain high-precision atmospheric temperature and humidity profiles under cloud conditions,this thesis studies the high-precision inversion and fusion algorithm of Raman lidar and microwave radiometer data:Combined first cloud base height and thickness of the cloud,and parameter optimization of the inversion precision of the microwave radiometer,on the basis of the microwave radiometer is studied by using the optimal estimation and Raman lidar fusion of temperature and humidity profile,improved the precision of inversion in the cloud area,and the high precision data applied in cloud precipitation in the assessment.In the aspect of microwave radiometer inversion,the inversion accuracy is improved by adding cloud base height and cloud thickness in the inversion process.The improvement of this method is most obvious for high cloud conditions.The square root error of temperature decreases from 2.53K to 0.96K,and the root error of water vapor mixing decreases from 1.55g/kg to 1.33g/kg.Under the condition of low cloud,the square mean root error of temperature decreases from 1.01K to 0.89K,and the mean root error of water vapor mixing decreases from 5.33g/kg to 2.44g/kg,which significantly improves the accuracy of water vapor mixing ratio.In order to further improve the accuracy of atmospheric temperature and humidity profiles,the atmospheric temperature and humidity profiles were retrieved by combining the optimal estimation method.Firstly,the data of Raman lidar and microwave radiometer in their high precision regions were stitched together,and the initial values were substituted into the optimal estimation method for inversion.After inversion,the accuracy of atmospheric temperature and humidity profile at the cloud has been greatly improved.The error of cloud base temperature decreases from 2.11K to 1.24K,and the error of water vapor mixing ratio decreases from 1.33g/kg to 0.23g/kg.The temperature error in the cloud decreases from 4.23K to 2.43K,and the vapor mixing ratio error decreases from 3.24 g/kg to 0.92g/kg.The temperature error of cloud top decreases from 2.12K to 2.33K,and the moisture mixing ratio error decreases from 0.36g/kg to 0.15.The atmospheric temperature and humidity at the cloud base height is an important part of calculating the cloud condensation cloud water rate.Based on the high-precision temperature and humidity profile data,combined with the data of other remote sensing equipment,the precipitation potential of precipitation cloud was calculated,and the precipitation potential and cloud parameters of different precipitation types were statistically analyzed combined with 41 precipitation events.The cloud bottom height is exponentially correlated with the probability distribution of condensation rate,and the lowest condensation rate is 0.25 mm/h when the cloud bottom height is 5 km.The average condensation of light rain is 44.8 mm,the average condensation of moderate rain is 42.2 mm,and the average condensation of heavy rain is 86.03 mm.The precipitation efficiency of light rain was 18.67%,that of medium rain was 56.29%,and that of heavy rain was 44.39%.The precipitation efficiency of moderate rain and heavy rain is not significantly different,but the amount of condensation is quite different.The total amount of precipitation is mainly affected by the total amount of condensation.If manual intervention can be carried out in the condensation stage of cloud water before precipitation,the purpose of increasing precipitation can be achieved by improving the condensation rate.