Comparative Analysis of Cloud Boundary Observed by Millimeter Wave Cloud Radar and Radiosonde

The observation data obtained by a Ka-band cloud radar and radiosondes during July to August 2013，in Inner Mongolia were used to detect the cloud boundary.The results show that the Cloud Base Height(CBH) determined by the cloud radar is about 300 m lower than that from the radiosonde，and the CBHs from two equipments are close in most cases；however，the heights of cloud top are largely different.The analysis of the case with larger CBH deviation indicates that the radar detection is more sensitive than the radiosonde because of the presence of an atmosphere "dry layer" under the cloud base；The main causes of the deviation are the horizontal drift of the radiosonde and the humidity sensor error that increases with increasing height.By calculating and comparing the variation rate of cloud reflectivity，a credibility criterion is given for cloud radar detection of the height of cloud base and cloud top.