机载海洋激光荧光雷达测量海表层叶绿素浓度的实验和算法研究

发布时间：2020-07-31 13:18

【摘要】：Airborne ocean fluorescence lidar is an advanced technique in remote sensing scope. It has many advantages, such as its high efficiency, real time measuring and its measuring accuracy etc. With the improvement of the lidar technique and its increasingly broader applying prospect, in the year 2001, ORSI, OUC took on the item "Airborne ocean lidar oceanic environmental surveillance technique" , which belongs to National 863 Resource and Environment technique field. Since then, ORSI has been developing the Airborne ocean fluorescence lidar to measure the chlorophyll-a concentration in the sea surface. In November 2003, the Airborne ocean fluorescence lidar was installed on the China Marine Surveillance aeroplane B-3807, and its first aviation experiment was carried out successfully.The research contents of this dissertation are from the project. The primary work of this dissertation contains these parts as follows: The theory of measuring chlorophyll-a concentration in seawater surface layer is researched deeply and the radar equation is developed further. The first airborne ocean fluorescence lidar in China and its experiments in various sea areas are introduced. The experimental data are processed using the Raman Normalization Method to retrieve the chlorophyll-a concentration. The airborne ocean fluorescence lidar retrieval software is developed. Meanwhile, a new retrieval algorithm of the least squares simulation method for extracting signal peak values is proposed. The results are in agreement with the in situ sampling data in the same period in former years and the results using the least squares simulation method are much closer to those in-situ sampling data recently.The last part of this dissertation gives a brief summary of its work, and puts forward some advice towards the existing defects.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2004
【分类号】：P714
【图文】：

系统框图,系统框图

增加了一个准分子激光器和一个染料激光器，其中波长为3O8mn光器的激光用于泵浦染料激光器发出的波长为427mn的激光，427mn直接激发叶绿素分子的荧光，而波长为532mn的激光用作激发辅助色二是在AOL的荧光仪上安装了一只32通道的增益可调的高压光电倍增使用了微处理器进行实时光谱数据的监测。1985年后，AOL系统进行了一次大的改进。系统采用主被动同时测量一个照明校准球同时校准激光激发的荧光光谱和太阳光导致的海色背’71。1995年重新设计的AOL荧光传感器〔，8l‘9]，利用同一台Nd:YAG激光射波长为355nm和532mn的脉冲激光。它们激发的荧光通过同一望远栅和镜头组，在AOL光谱仪焦面上分别成像。系统由原来的两个激光的一个激光器，信噪比得到了很大的提高。这两束脉冲激光照射在海方，因而产生的荧光出现在接收器焦面和光谱仪焦面的不同位置，这同一个接收器和望远镜同时处理两个光谱。在1995年AOL的基础上，NAsA发展了第三代机载激光雷达AoL一3系3系统的传感器有测量太阳辐照度CDAS和海水辐亮度ADAS的被动传量海表温度的红外线辐射计。系统可以用来测量激光诱发的荧光，进出两种海水参数，一是，DCMO浮游植物藻胆红素(PEB)和藻红蛋白收系数。二是，海水的后向散射系数。

雷达系统,水深,海洋激光荧光雷达,飞行高度

“““‘一‘一).…’二”’陌陌卜‘~一一一(，)熟口Joc山oocoos价.J八.:工﨎图2一3雷达系统接收不同飞行高度下的荧光信号(左)和拉曼散射信号(右)图2一4雷达系统接收不同浓度的叶绿素的荧光信号(左)和接收不同水深的叶绿素的荧光信号(右)通常条件下，机载海洋激光荧光雷达在15m0~20m0的飞行高度进行实验，探测叶绿素剖面深度约为3m一6m。如果超过这个范围，由于系统的硬件设备和海水衰减等原因，接收的信号噪声过大，就难以准确的测量出叶绿素浓度的数值。实际所使用的机载海洋激光荧光雷达多是以脉冲激光器作为探测器，由于激光信号具有一定的脉冲宽度(纳秒级)，在二类海水中会对系统的探测深度产生影响。因为，脉冲激光从开始入射到海水中到完全进入海水的过程中，所诱发的叶绿素荧光的能量是不同的。所以

光谱图,黄色物质,浮游植物,光谱

和使用红外线辐射仪获取海表温度。量叶绿素浓度具有灵敏快速、经济方便等优点，但同原因是，测量中，容易把进入探测通道的海水中其荧光。在机载海洋激光荧光雷达测量海水的叶绿素荧质的荧光会在一些探测通道的波段范围内发生交叠，难，影响测量的精度，如海水中的可溶性有机物CDOicnissolvedorganieMatter)，因其通常呈黄色，质，是一类含有多种活性较高的化学功能团的无形大溶解的糖类和含氮有机物，此外还有脂类化合物和一蓝紫波段对光的吸收要比海水自身、海水中叶绿素、，所以，它是海洋中对该波段光吸收起主导作用的物受到紫外线照射时能够激发荧光，它具有较高的荧光物质浓度与其荧光强度遵循一定的规律，即随着海水对强度也呈线性增加。DCMO的最佳激发波长是330nm，550nm。因此，CDOM对荧光雷达测量叶绿素浓度带来的强吸收，二是受激产生的荧光对拉曼通道光信号荧光雷达OLS系统测量叶绿素浓度为例，他们采用的得的二类海水的光谱如下:

【引证文献】