This paper presents an inter-comparison of rainfall parameters (median volume diameter and rain rate) using C-band polarimetric radar, a 2D-video disdrometer and a 400 MHz profiler for the Baiu front event of 8-9 June 2005 in Okinawa, Japan. These instruments are part of the Okinawa Sub-Tropical Environment Remote Sensing Center, operated by the National Institute of Information and Communications Technology (NICT). The 2D-video disdrometer is used to derive the mean axis ratio of raindrops versus drop diameter, as well as the drop size distribution for the Baiu event. The data are then used to simulate various relations between polarimetric scattering parameters such as: specific attenuation ðA h Þ, and specific differential attenuation ðA dp Þ, versus specific differential phase ðK dp Þ which are required to correct the measured reflectivity at horizontal polarization ðZ h Þ, and the differential reflectivity ðZ dr Þ for rain attenuation. The 2D-video disdrometer data are also used to arrive at retrieval formulas for median volume diameter ðD o Þ from radar Z dr , and rain rate from radar K dp .The These inter-comparisons demonstrate the accuracy of C-band polarimetric radar to retrieve important rainfall parameters, as well as the accurate correction for rain attenuation using differential propagation phase.
A coherent 2-mm differential absorption and wind lidar (Co2DiaWiL) has been built with a high-power Q-switched Tm,Hm:YLF laser to measure CO 2 concentration and radial wind speed. The performance of the Co2DiaWiL is described and analyzed, with a view to demonstrating system capabilities for remote measurements of wind velocities in the atmospheric boundary layer and free troposphere. Bias in the velocity measurements was estimated at 20.0069 m s 21 using measurements from a stationary hard target. The Co2DiaWiL achieved a velocity precision of 0.12 m s 21 , derived from the magnitude of random error in radial wind velocity measurements. These measurements were made for ranges out to 20-25 km by using a horizontally fixed beam mode for average times of 1 min. Quantitative intercomparisons of 1-min averages between the Co2DiaWiL and a sonic anemometer revealed a correlation coefficient of 0.99. This study demonstrated measurements of horizontal wind profiles, by making radial wind velocity measurements with the Co2DiaWiL using conical scanning. Profile differences at higher levels could be attributed to probable large horizontal separations of the radiosondes and the low signal-to-noise ratio of the Co2DiaWiL. A pseudo-dual-Doppler technique was developed to retrieve horizontal wind components with a single-Doppler lidar and a steering mirror. Intercomparisons of the 1-min-averaged u and y components from the pseudodual-Doppler lidar measurements with those from the sonic anemometer revealed correlation coefficients of 0.84 and 0.83, respectively.
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