极地研究

极地研究 ›› 2010, Vol. 21 ›› Issue (2-English): 113-126.DOI: 10.3724/SP.J.1085.2010.00113

• 研究论文 •    下一篇

Calculation of photosynthetically available radiation using multispectral data in the Arctic

Zhao Jinping(赵进平)1* ,Wang Weibo(王维波)1 and Cooper Lee2
  

  1. 1 Ocean University of China, Qingdao 266100, China;
    2 Chesapeake Biological Laboratory, University of Maryland, Solomons, MD 20688, USA
  • 收稿日期:2010-07-30 修回日期:2010-10-11 出版日期:1960-06-30 发布日期:1960-06-30
  • 通讯作者: Zhao Jinping
  • 基金资助:

    北极环极流的研究

Calculation of photosynthetically available radiation using multispectral data in the Arctic

Zhao Jinping(赵进平)1* ,Wang Weibo(王维波)1 and Cooper Lee2
  

  1. 1 Ocean University of China, Qingdao 266100, China;
    2 Chesapeake Biological Laboratory, University of Maryland, Solomons, MD 20688, USA
  • Received:2010-07-30 Revised:2010-10-11 Online:1960-06-30 Published:1960-06-30
  • Contact: Zhao Jinping

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摘要：

Photosynthetically Available Radiation (PAR) is an important bio-optical parameter related to marine primary production. PAR is usually measured by a broadband sensor and can also be calculated by multispectral data. When the PAR is calculated by multispectral data in polar region, four factors are possible error sources. PAR could be overestimated as the wavelengths of multispectral instrument are usually chosen to evade main absorption zones of atmosphere. However, both PARs calculated by hyperspectral and multispectral data are consistent with the error less than 1%. By the fitting function proposed here, the PAR calculated by multispectral data could attain the same accuracy with that by hyperspectral data. To calculate the attenuation rate of the PAR needs PAR0, the PAR just under the surface. Here, an approach is proposed to calculate PAR0 by the best fit of the irradiance profile of 1-5 m with a content attenuation coefficient under surface. It is demonstrated by theory and observed data in different time at same location that the attenuation coefficient of PAR is independent of the intensity of radiation. But under sea ice, the attenuation coefficient of PAR is little bit different, as the spectrum of the light has been changed by selective absorption through the sea ice. Therefore, the difference of inclusions inside sea ice will result in different PAR, and impact the attenuation of PAR. By the results of this paper, PAR can be calculated reliably by multispectral data.

关键词: PAR, marine optice, field observation, multispectral, solar radiation

Abstract:

Photosynthetically Available Radiation (PAR) is an important bio-optical parameter related to marine primary production. PAR is usually measured by a broadband sensor and can also be calculated by multispectral data. When the PAR is calculated by multispectral data in polar region, four factors are possible error sources. PAR could be overestimated as the wavelengths of multispectral instrument are usually chosen to evade main absorption zones of atmosphere. However, both PARs calculated by hyperspectral and multispectral data are consistent with the error less than 1%. By the fitting function proposed here, the PAR calculated by multispectral data could attain the same accuracy with that by hyperspectral data. To calculate the attenuation rate of the PAR needs PAR0, the PAR just under the surface. Here, an approach is proposed to calculate PAR0 by the best fit of the irradiance profile of 1-5 m with a content attenuation coefficient under surface. It is demonstrated by theory and observed data in different time at same location that the attenuation coefficient of PAR is independent of the intensity of radiation. But under sea ice, the attenuation coefficient of PAR is little bit different, as the spectrum of the light has been changed by selective absorption through the sea ice. Therefore, the difference of inclusions inside sea ice will result in different PAR, and impact the attenuation of PAR. By the results of this paper, PAR can be calculated reliably by multispectral data.

Key words: PAR, marine optice, field observation, multispectral, solar radiation