WIND PROFILE DATA: LIDAR - NOAA (FIFE)

The aim of this wind profile study was to derive wind profiles and momentum fluxes from the National Oceanic and Atmospheric Administration (NOAA)/Wave Propagation Laboratory (WPL) Doppler LIDAR, and compare LIDAR and airborne measurements of mean wind, turbulent structure, momentum flux, and heat flux. Another objective was to compare profiles of mean wind and temperature obtained from aircraft, balloon sondes, and wind LIDAR. These data were collected at one location near the center of the FIFE study area but in the northwest quadrant. Data were acquired for a two week period during June and July 1987. Pulsed Doppler LIDAR measures the radial (along-beam) velocity as a function of range using light-scattering particles in the air as tracers. When the LIDAR beam is directed straight upward and the backscattered return as a function of height is recorded, vertical aerosol profiles may be determined. Various pointing and scanning schemes permit measurement of a variety of mean and turbulent quantities based on assumptions about the flow. The remote-sensing character of LIDAR offers the ability to measure flow parameters simultaneously at all the heights in a profile. The winds were obtained with the VAD (Velocity Azimuth Display) technique. The LIDAR only operates above 500 m, therefore the wind profile begins above the ground surface. Data in the planetary boundary layer are usually continuous, but gaps appear occasionally in profiles extending to several kilometers. Profiles were unsmoothed, and the LIDAR's short pulse made adjacent data points almost independent.

本风廓线研究的目标是从美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）/波传播实验室（Wave Propagation Laboratory, WPL）的多普勒激光雷达（Doppler LIDAR）中反演获取风廓线与动量通量，并对比激光雷达与机载测量得到的平均风、湍流结构、动量通量及热通量。另一项研究目标是对比由航空器、气球探空仪和风廓线激光雷达获取的平均风与温度廓线。这些数据采集于FIFE研究区域中心附近的一处点位，但位于其西北象限。数据采集时段为1987年6月至7月，共计两周。脉冲多普勒激光雷达以空气中的光散射粒子作为示踪物，通过距离函数测量径向（沿波束）速度。当激光雷达波束垂直向上指向，并记录随高度变化的后向散射回波时，即可确定垂直气溶胶廓线。依托气流的相关假设，多种指向与扫描方案可实现各类平均量与湍流量的测量。激光雷达的遥感特性使其能够同时获取廓线内所有高度的流场参数。风速通过速度方位显示（Velocity Azimuth Display，VAD）技术获取。该激光雷达仅能在500米以上高度正常运行，因此风廓线起始于地表以上。行星边界层内的数据通常保持连续，但延伸至数公里的廓线偶尔会出现数据间隙。所有廓线均未经过平滑处理，且激光雷达的短脉冲特性使得相邻数据点几乎相互独立。