应用相干多普勒测风激光雷达对南极航程海域低空风场观测分析

      Observation and analysis of low-level wind fields over the sea areas of Antarctic voyage using coherent Doppler wind LiDAR

      • 摘要: 应用安装在“雪龙2”号破冰船上的我国自主研发的相干多普勒测风激光雷达(WindPrint S10000),本文首次获得了中国第40次南极考察航线上横跨北温带至南极圈范围、3000m高度以下的完整风场信息。雷达风数据分析结果表明:(1)采用船舶姿态补偿算法所得到的测风激光雷达数据能满足沿南极航程对低空风的观测需求,为随船飞行活动保障、洋流变化与低层风关系研究提供可靠的数据保障。(2)南北半球低层盛行风向比经典三圈环流形态更为复杂;相比于北半球,南半球的低空风多为纬向流动,并在高纬度地区表现更显著。(3)南半球高纬度西风带低空风速比北半球同纬度要大得多,急流带最大风速可达12级以上。西风带中锋面、低空急流等天气尺度系统活动比北半球更为活跃,导致低空水平和垂直风切变频繁且剧烈。(4)观测到极锋长期存在,其位置夏季南退、秋季北进,锋面附近有大范围低空急流及垂直上升气流区域。(5)南极圈内风速相对较平缓,盛行下沉气流,夏季仍有较多极锋活动。综上所述,在南半球航行或进行低空作业受到低空风的影响可能比北半球更为显著,测风激光雷达可提供稳定可靠的风场观测数据,为南极低空大气探测提供新的观测设备。

         

        Abstract: The coherent Doppler wind light detection and Ranging(LiDAR) developed by China was installed on the R/V Xuelong 2 and set sail in the 40 th Chinese National Antarctic Research Expedition. For the first time, the LiDAR obtained complete wind field data below 3000 meters on the route across the North Temperate Zone to the Antarctic Core Circle. The conclusions of the LiDAR data analysis are shown below.(1) The data calibrated by the attitude compensation algorithm met the requirements of low-level wind observation during the scientific expedition and provided reliable data support for ship-borne flight activities and research into the relationship between ocean current changes and low-level winds.(2) The prevailing low-level winds in the northern and southern hemispheres were more complex than the classic three-circle circulation pattern. Compared with that in the northern hemisphere, the low-level wind in the southern hemisphere was mostly zonal flow and was more significant at high latitudes.(3) The westerly wind speed at the mid and high latitudes of the southern hemisphere was much greater than that in the same latitudes of the northern hemisphere, and the maximum wind speed in the jet stream sometimes reached hurricane level. The activities of synoptic-scale systems such as front and low-level jets were more dynamic in the southern hemisphere than in the northern hemisphere, resulting in more frequent and severe low-level horizontal and vertical wind shears.(4) The polar front existed for a long time and was positioned southward in summer and northward in autumn. There was a large area of low-level jets and vertical ascent areas near the front.(5) The wind speed in the Antarctic Core Circle tended to be gentle with a prevailing sinking airflow. In summer, there were still more polar front activities. In summary, the impact of low-level winds on navigation or low-altitude operations may be more significant in the southern hemisphere than in the northern hemisphere.

         

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