Ground-based Spectral Measurements of Chlorophyll Fluorescence from Vegetation Canopies

[ABSTRACT]Detection of vegetation fluorescence is important for understanding physiology of vegetation leaves in relation to photosynthetic activities. We have developed a stand-off system that enables the observation of vegetation fluorescence under both laboratory and field conditions. The intrinsic difficulty in monitoring weak fluorescence signal is the separation between the fluorescence signal around 740 nm and the large reflection of vegetation leaves in the near infrared (NIR) spectral region. In the laboratory measurement, it has been proven that a LED-based light source coupled with cold- or hot- mirrors can provide illumination with only visible or NIR part of the spectrum. The “pure” visible illumination, which is mostly free from the NIR radiation, can lead to the observation of fluorescence signals without hindrance from large NIR reflection. The NIR illumination, on the other hand, enables the evaluation of pure reflectance in NIR free from the fluorescence contribution. The combination of such pieces of spectral information makes it possible to implement the detailed analysis of solar radiation induced fluorescence signals. For field applications, a stand-off measurement system based on an astronomical telescope has been developed to carry out the spectral measurement using a CCD spectrometer, together with the two-dimensional measurement of the fluorescence intensity distribution by means of a cooled CCD camera. A narrow-band optical filter centered at 760 nm, the wavelength of the oxygen A-band, is employed with the CCD camera to exploit the “solar blind” wavelength for the florescence measurement under daylight conditions. We describe the application of the system to a soya-bean field in Kyoto University.

https://opac.ll.chiba-u.jp/da/curator/107865/

https://opac.ll.chiba-u.jp/da/curator/107865/ceresIntlSympo-24-P404.pdf

Chiba University. Center for Environmental Remote Sensing

千葉大学環境リモートセンシング研究センター

会議発表用資料

Proceedings of the CEReS international symposium = CEReS国際シンポジウム資料集

24

404

407

2016-11-21

publisher

環境リモートセンシング研究センター「CEReSシンポジウム資料集」