Raindrop Size Distribution And Water Vapor Flux Retrieval Based On Wind Profile Radar Data

As a new type of meteorological remote sensing instrument, wind profile radar (WPR) could detect meteorological factors such as horizontal wind profiler, vertical flow and Cn2with high spatial and temporal resolution. Although the wind profile radar was designed primarily for the detection of atmospheric wind field, L/P band WPR for air probe at the same time, was sensitive to precipitation. Tow WPRs were used to retrieve the raindrop size distribution and Z-I relationship of six rainfall events at Nanjing and Dali. These events could be divided into three categories: stratiformis precipitation, convective precipitation and hybrid precipitation. WPR was also used to detected the vertical motion during rainfall event and to retrieve the near surface vertical water vapor flux.The return signals which detected by WPR included information about ambient atmosphere and precipitation particle. Raindrop size distribution and Z-I relationship could be retrieved by precipitation echo signal. The analysis shows that after the raindrop size distribution data was fitted in the form of Marshall-Palmer (M-P) exponential function, no (within7164m-3r·mm-1) increased with rainfall intensity and λ (within2-5.5mm-1) gets its minimum at the strongest rainrate for stratiformis precipitation. The raindrop size distribution spectral width, concentration parameter, rain rate, reflectivity factor and coefficient A of convective precipitation all gets its maximum. Classification of rainfall was good for Z-I relationships. Coefficient A and index b reduced one by one from convective precipitation to hybrid precipitation and finally to stratiformis precipitation. The Z-I relationships between Nanjing and Dali were geographical differences.Detection of atmospheric during rainfall found that a strong downdraft was appeared at high altitude before rainfall. Appearance of updraft during rainfall means precipitation getting weak or grind to a halt. Near surface vertical water vapor flux varies through the period of rainfall, but after rainfall, vapor transports upwardly.