天空光遮蔽法在高叶绿素水体中的阴影问题研究  

Study on the Shading Issue of SBA in High-chlorophyll Waters

作　　者：陈旭磊[1,2] 林供[1,3] 石良海 单宇杰 商少凌[1,3] 

机构地区：[1]厦门大学水声通信与海洋信息技术教育部重点实验室 [2]厦门大学环境与生态学院 [3]厦门大学海洋与地球学院,福建厦门361102

出　　处：《厦门大学学报（自然科学版）》2016年第2期203-209,共7页Journal of Xiamen University：Natural Science

基　　金：国家科技支撑计划项目(2013BAB04B00)

摘　　要：天空光遮蔽法（SBA）是一种直接测量离水辐亮度的方法.该方法通过浮体结构实现,其关键是用于屏蔽天空光的元件——遮光锥.目前浮体结构及遮光锥在高叶绿素水体中产生的阴影效应尚不清楚.本研究依前人经验建立了SBA测量系统,评估浮体结构对SBA的影响发现：在晴天,辐亮度光谱仪观测方位角处于0°-90°以及270°-360°时,浮体结构带来的影响可以忽略;在阴天,浮体结构对各观测方位角的离水辐亮度测量值均有显著影响,即现有的浮子系统SBA可能并不适用于阴天条件.而关于遮光锥阴影问题的探讨发现,在高叶绿素水体中（叶绿素质量浓度〉50mg/m^3）,若将遮光锥阴影半径由原设计的4.5cm减至2.2cm,Gordon自阴影校正模型的临界太阳天顶角可由37°降至12°.Skylight-blocked approach（SBA）,developed in 2013,was an innovative method to directly measure water-leaving radiance based on the floating structure,and its key part was the skylight-blocking cone.The shading effect caused by the floating structure and cone,however,is not known yet.In this study,SBA system was established according to the previous study,and the influence on measurement by the floating structure of the SBA instrument was evaluated.It was found that the influence was negligible when the observation azimuth angle of the upwelling radiance radiometer was 0°to 90°and 270°to 360°in sunny days;while the influence was significant at all observation azimuth angles in overcast days,so the floating SBA may not be applicable in such weather conditions.The self-shading of cone would make the critical minimum zenith angle of the self-shading correction model decrease from37°to 12°,when the radius of shading zone decreased from 4.5cm to 2.2cm in high-chlorophyll waters（ρ（Chl）50mg/m3）.

关 键 词：天空光遮蔽法(SBA) 浮体结构 自阴影 遮光锥 

分 类 号：P76[天文地球—海洋科学]