基于偏振技术的藻类水体散射光中叶绿素荧光分离方法研究

浮游藻类细胞内的叶绿素分子吸收光能后，会以释放能量的形式发射叶绿素荧光。水中颗粒物的弹性散射光是部分偏振光，而叶绿素荧光则是非偏振光，因此利用这一特性可以从总散射光谱中分离出荧光，从而达到反演叶绿素浓度的目的。但对于近岸等复杂水体，该方法能否适用并不清楚，基于此，实验通过测量分别分析了不同无机颗粒物浓度和叶绿素浓度对偏振分离方法的影响。结果表明，对含不同浓度无机颗粒物的藻类水体，分离出的荧光峰会随浓度增加有降低趋势，但是当颗粒物浓度达到300 mg·L-1时，反演结果仍然可靠。对含不同浓度叶绿素的藻类水体，叶绿素浓度越高，偏振方法分离荧光的效果越好，对低浓度正常水体，仍能识别。实验证明了利用偏振方法分离叶绿素荧光对复杂水体仍然有效，对进一步遥感探测近岸水体的叶绿素浓度具有重要意义。

Separation of Chlorophyll Fluorescence from Scattering Light of Algal Water Based on the Polarization Technique

Once chlorophyll molecules within the planktonic algae cells absorb light energy,they will release energy in the form of chloro phyll fluorescence emission.The elastic scattering light of particles in water is partially polarized,while chlorophyll fluorescence is unpolarized,so we can use the properties to separate the fluorescence signal from total scattering sp ectra for further retrieval the concentration of chlorophyll.But for coastal wa ters,the approach feasibility is still unclear.Based on this,we conducted the experiment in laboratory to analyze the influence of different concentrations o f inorganic particles (IOP) and chlorophyll on the fluorescence extraction using polarization discrimination technique.The results indicate that,for algae wat er with different concentrations of IOP,the fluorescence peak will decrease whi le the concentration increase,but the retrieval result is still reliable when t he concentration up to 300 mg·L-1.For algae water with different concent rations of chlorophyll,the concentration of chlorophyll more higher,the effici ency of extracted fluorescence using polarization method is better,for common w ater,this approach can still work.The study proves that the polarization metho d is also applicable for complex water;it is of great importance for further de tecting the concentration of chlorophyll in coastal waters using remote sensing.