不同台风降水强度下风廓线雷达适用性研究

IMPACT OF TYPHOON PRECIPITATION INTENSITY ON THE APPLICABILITY OF WIND PROFILER RADAR

关键词:  风廓线雷达  激光测风雷达  探空  “利奇马”  降水

Key words:  wind profiler radar  Doppler wind lidar  radiosonde  Lekima  precipitation

摘要:

以2019年8月在浙江舟山对1909号超强台风“利奇马”的移动观测试验为基础，利用同一地点释放的9次GPS探空气球，对比了风廓线雷达和多普勒激光测风雷达与GPS探空的吻合程度，并利用车载雨滴谱仪对风廓线雷达在不同台风降水强度下的适用性进行了研究。结果表明，在100~300 m高度范围内激光测风雷达观测风速比风廓线雷达更准确。由水平风速对比结果可知，风廓线雷达在3~4 km高度范围内偏差最小(3.59 m/s)，相关性最高(0.86)，而在1 km高度下偏差最大(6.39 m/s)，相关性最低(0.54)；在中雨及大雨条件下适用性最差，最大风速偏差约为18 m/s。由水平风向对比结果可知，风廓线雷达与GPS探空总体上吻合较好，相关系数均大于0.85，均方根偏差均小于11 °。另外，降水强度对风廓线雷达的风向观测影响较小，风向偏差随降水强度的变化总体趋于平稳，基本分布在-20 °~20 °之间。

Abstract:

Based on the field experiment on Super Typhoon Lekima (2019), which was conducted in Zhoushan, Zhejiang Province in August 2019, the wind profiler radar (WPR) and doppler wind lidar (DWL) measurements are compared with those from nine balloon-borne GPS radiosondes launched at the same location. Besides, the impact of typhoon precipitation intensity recorded by the vehicle-mounted raindrop spectrometer on the applicability of WPR is investigated. The results show that the DWL data is more accurate than the WPR data within the height of 100~300 m. As indicated by the comparison of horizontal wind speed measured by the WPR and GPS radiosonde, the best agreement can be achieved at the height of 3~4 km with correlation coefficient of 0.86 and root mean square (RMS) of 3.59 m/s and the worst agreement appears when the height is lower than 1 km with correlation coefficient of 0.54 and RMS of 6.39 m/s. The WPR shows bad applicability in moderate and heavy rainfall with the maximum RMS of wind speed being up to approximately 18 m/s. The comparison of horizontal wind direction shows that the WPR and GPS radiosonde are generally in good agreement with correlation coefficient greater than 0.85 and RMS less than 11 °. The precipitation intensity has little influence on the WPR-measured wind direction, which tends to remain steady with the bias distributed between -20 ° and 20 °.