Liu Hang, Chen Peng, Mao Zhihua, Pan Delu, He Yan
Opt Express. 2018 Oct 29;26(22):29134-29147. doi: 10.1364/OE.26.029134.
In recent years, airborne lidar has been used in a wide range of oceanic applications, including detection of bathymetry, bubbles, internal waves, and schools of fish. However, it has not yet been extensively applied in Chinese seas. For example, there have been no studies to detect subsurface plankton layers in the South China Sea (SCS) by airborne lidar. In this study, we investigated this technology's applicability for identifying subsurface plankton layers in Sanya Bay, SCS. Three airborne lidar flight experiments were carried out in March 2018 and in September 2017. Shipboard synchronous measurements were carried out in March 2018 to validate the lidar measurements. The method that is presented here can be used to detect a subsurface plankton layer, which is characterized by depth, thickness, and intensity. Compared with chlorophyll-a profile synchronously measured by shipborne fluorometer, there was a consistent relationship. The subsurface plankton layer depth error was less than 0.7 m. Next, the spatial distribution and seasonal variation of lidar measured subsurface plankton layers in Sanya Bay, SCS, was analyzed. The results showed that airborne lidar can potentially detect subsurface plankton layer within 50 meters deep in relatively clear water. This will enhance our understanding of biogeochemical processes in these optically complex aquatic systems.
近年来，机载激光雷达已被广泛应用于各种海洋学应用中，包括探测水深、气泡、内波和鱼群。然而，它尚未在中国海域得到广泛应用。例如，尚未有利用机载激光雷达探测南海（SCS）次表层浮游生物层的研究。在本研究中，我们调查了该技术在识别南海三亚湾次表层浮游生物层方面的适用性。2017年9月和2018年3月进行了三次机载激光雷达飞行实验。2018年3月进行了船载同步测量以验证激光雷达测量结果。本文提出的方法可用于检测以深度、厚度和强度为特征的次表层浮游生物层。与船载荧光计同步测量的叶绿素a剖面相比，存在一致的关系。次表层浮游生物层深度误差小于0.7米。接下来，分析了南海三亚湾激光雷达测量的次表层浮游生物层的空间分布和季节变化。结果表明，机载激光雷达能够在相对清澈的水中探测到深度达50米以内的次表层浮游生物层。这将增进我们对这些光学复杂的水生系统中生物地球化学过程的理解。
