Usually,lidar detection systems are optimized for the measurement of the low intensity signal using the photon counting technique,but this approach results in the nonlinear signal response for the higher intensity sig...Usually,lidar detection systems are optimized for the measurement of the low intensity signal using the photon counting technique,but this approach results in the nonlinear signal response for the higher intensity signal.The problem is successfully solved by the combination of analog-to-digital (AD) and photoncounting (PC) detection.The optimized processing procedure of the signal combination of AD and PC is described,and the corrected result is analyzed and compared with the results by the dead-time correction method.In this way,the accuracy of wind and aerosol measurement in the nonlinear range is improved.In addition,the signal-to-noise ratios (SNRs) of the two detection methods of AD and PC are compared in the overall dynamic range of signal for the performance analysis.展开更多
本文利用常规观测资料、风廓线雷达资料,对2017年2月21日~2月22日沈阳地区出现的一次暴雪天气过程进行详细分析,结果表明:此次暴雪天气受高空槽和蒙古气旋共同影响,850 h Pa南北两支切变线同位相叠加,切变线南侧西南风急流为暴雪过程...本文利用常规观测资料、风廓线雷达资料,对2017年2月21日~2月22日沈阳地区出现的一次暴雪天气过程进行详细分析,结果表明:此次暴雪天气受高空槽和蒙古气旋共同影响,850 h Pa南北两支切变线同位相叠加,切变线南侧西南风急流为暴雪过程提供水汽条件。降雪前,以3500 m为冷暖平流边界,冷平流叠加在暖平流之上。高空大风速带和垂直风切变提前降雪10 h出现,并在降雪开始前2 h出现高空动量下传现象。降雪主要时段内,大气整层风向为西南风,大风速带扩展至近地面,中低空垂直风切变、垂直速度和大气折射率常数出现大值区。整层大气的垂直速度都为正时对应的降雪强度最大。降雪结束后,整层风向转为西北风。展开更多
基金This work is a part of the open project of the retrieval method of wind field from Doppler lidar which is financed bythe Key Laboratory of Ocean Remote Sensing, Ministry of Education of China. This work was supported by the National Natural Science Foundation of China under Grant Nos. 60578038 and 40427001.
文摘Usually,lidar detection systems are optimized for the measurement of the low intensity signal using the photon counting technique,but this approach results in the nonlinear signal response for the higher intensity signal.The problem is successfully solved by the combination of analog-to-digital (AD) and photoncounting (PC) detection.The optimized processing procedure of the signal combination of AD and PC is described,and the corrected result is analyzed and compared with the results by the dead-time correction method.In this way,the accuracy of wind and aerosol measurement in the nonlinear range is improved.In addition,the signal-to-noise ratios (SNRs) of the two detection methods of AD and PC are compared in the overall dynamic range of signal for the performance analysis.