Chlorophyll fluorescence extraction from water-leaving radiance of algae-containing water through polarization
- 42 Downloads
When measuring reflectance spectra, it is very important to accurately extract chlorophyll fluorescence from elastic- scattering light in water-leaving radiance. The elastic scattering of light by water particles produces partially polarized light. In contrast, chlorophyll fluorescence in planktonic algae yields completely unpolarized light. These properties can be used to separate fluorescent signals from the water-leaving radiance and thus to determine chlorophyll concentration. The algal species Aureococcus anophagefferens was used to conduct a laboratory polarization experiment. For the tests, we used a field spectroradiometer and a polarizer; measurements were collected using two different observation modes. The chlorophyll fluorescence curve extracted through polarization shows an excellent match with the results obtained using the fluorospectro photometer for both measurement modes, suggesting that polarization-based chlorophyll fluorescence extraction may be feasible. The extracted fluorescence is more reliable at incident zenith angles ranging from 30° to 60°. For algae-containing water, the results improve with increasing chlorophyll concentration. This method could help improve chlorophyll concentration measurement and the remote-sensing detection of resulting harmful algae blooms.
Key wordschlorophyll fluorescence polarization technique water-leaving radiance extraction red shift
Unable to display preview. Download preview PDF.
This work was supported by the National Natural Science Foundation of China (Nos. 41406199, 41506197), the Program Foundation of Nanjing University of Information Science and Technology (No. KHYS1301), the Doctoral Scientific Research Foundation of Liaoning Province (No. 201501190), and the Fundamental Research Funds for the Central Universities (No. 3132015081).
- Ampe, E. M., Hestir, E. L., Bresciani, M., Salvadore, E., Brando, V. E., Dekker, A., Malthus, T. J., Jansen, M., Triest, L., and Batelaan, O., 2014. A wavelet approach for estimating chlorophyll-a from inland waters with reflectance spectroscopy. IEEE Geoscience and Remote Sensing Letters, 11 (1): 89–93.CrossRefGoogle Scholar
- Foster, R., Ibrahim, A., Gilerson, A., and Ahmed, S., 2015. Polarized above sea surface hyperspectral observations and their relationship with measured water properties. Hyperspectral Imaging and Sounding of the Environment, DOI: 10.1364/HISE.2015.HT3B.4.Google Scholar
- Gilerson, A., Ibrahim, A., Foster, R., and Ahmed, S., 2014. Retrieval of water optical properties using polarization of light: Case I and II waters. SPIE Remote Sensing International Society for Optics and Photonics, 9240 (46): 1235–42.Google Scholar
- Gilerson, A., Oo, M., Chowdhary, J., Gross, B. M., Moshary, F., and Ahmed, S. A., 2005. Polarization characteristics of water leaving radiance: Application to separation of fluorescence and scattering components in coastal waters. Proceedings of SPIE, 5885: 95–105.Google Scholar
- Gu, Y., Gilerson, A., Carrizo, C., and Ahmed, S., 2014. Polarization analysis of target imaging in an underwater environment. Proceedings of SPIE, 52 (7): 766–771.Google Scholar
- Ibrahim, A., 2015. Polarimetric light fields in the open ocean and coastal waters and retrieval of water parameters from polarimetric observations. PhD thesis. The City College of New York.Google Scholar
- Tang, J. W., Tian, G. L., Wang, X. Y., Wang, X. M., and Song, Q. J., 2004. The methods of water spectra measurement and analysis I: Above-water method. Journal of Remote Sensing, 8 (1): 37–44.Google Scholar
- Tyler, J. E., and Smith, R. C., 1970. Measurements of Spectral Irradiance under Water. Gordon and Breach Science Publishers, New York.Google Scholar
- Zhang, Y. L., Liu, M. L., Qin, B. Q., van der Woerd, H. J., Li, J. S., and Li, Y. L., 2009. Modeling remote-sensing reflectance and retrieving chlorophyll-a concentration in extremely turbid case-2 waters (Lake Taihu, China). IEEE Transactions on Geoscience and Remote Sensing, 47 (7): 1937–1948.CrossRefGoogle Scholar