中国地理科学(英文版) ›› 2007, Vol. 17 ›› Issue (4): 364-369.doi: 10.1007/s11769-007-0364-7

• 论文 • 上一篇    下一篇

A Method for Retrieving Water-leaving Radiance from Landsat TM Image in Taihu Lake, East China

WANG Deyu1, FENG Xuezhi1, MA Ronghua2, KANG Guoding3   

  1. 1. Department of Geographic and Information Science, Nanjing University, Nanjing 210093, China;
    2. Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China;
    3. Department of Demography and Economics, Nanjing College for Population Programme Management, Nanjing 210042, China
  • 收稿日期:2006-12-05 修回日期:2007-06-01 出版日期:2007-12-20 发布日期:2011-12-14
  • 通讯作者: WANG Deyu.E-mail:gisnju@126.com E-mail:gisnju@126.com
  • 基金资助:

    Under the auspices of National Natural Science Foundation of China (No.40671138)

A Method for Retrieving Water-leaving Radiance from Landsat TM Image in Taihu Lake, East China

WANG Deyu1, FENG Xuezhi1, MA Ronghua2, KANG Guoding3   

  1. 1. Department of Geographic and Information Science, Nanjing University, Nanjing 210093, China;
    2. Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China;
    3. Department of Demography and Economics, Nanjing College for Population Programme Management, Nanjing 210042, China
  • Received:2006-12-05 Revised:2007-06-01 Online:2007-12-20 Published:2011-12-14

摘要:

The visible and infrared bands of Landsat Thematic Mapper (TM) can be used for inland water studies. A method of retrieving water-leaving radiance from TM image over Taihu Lake in Jiangsu Province of China was investigated in this article. To estimate water-leaving radiance, atmospheric correction was performed in three visible bands of 485nm, 560nm and 660nm. Rayleigh scattering was computed precisely, and the aerosol contribution was estimated by adopting the clear-water-pixels approach. The clear waters were identified by using the Landsat TM middle-infrared band (2.1μm), and the water-leaving radiance of clear water pixels in the green band was estimated by using field data. Aerosol scattering at green band was derived for six points, and interpolated to match the TM image. Assuming the atmospheric correction coefficient was 1.0, the aerosol scattering image at blue and red bands were derived. Based on a simplified atmospheric radiation transfer model, the water-leaving radiance for three visible bands was retrieved. The water-leaving radiance was normalized to make it comparable with that estimated from other remotely sensed data acquired at different times, and under different atmospheric conditions. Additionally, remotely sensed reflectance of water was computed. To evaluate the atmospheric correction method presented in this article, the correlation was analyzed between the corrected remotely sensed data and the measured water parameters based on the retrieval model. The results show that the atmospheric correction method based on the image itself is more effective for the retrieval of water parameters from Landsat TM data than 6S (Second Simulation of the Satellite Signal in the Solar Spectrum) code based on standard atmospheric and aerosol models.

关键词: retrieval method, water-leaving radiance, Landsat TM image, Taihu Lake

Abstract:

The visible and infrared bands of Landsat Thematic Mapper (TM) can be used for inland water studies. A method of retrieving water-leaving radiance from TM image over Taihu Lake in Jiangsu Province of China was investigated in this article. To estimate water-leaving radiance, atmospheric correction was performed in three visible bands of 485nm, 560nm and 660nm. Rayleigh scattering was computed precisely, and the aerosol contribution was estimated by adopting the clear-water-pixels approach. The clear waters were identified by using the Landsat TM middle-infrared band (2.1μm), and the water-leaving radiance of clear water pixels in the green band was estimated by using field data. Aerosol scattering at green band was derived for six points, and interpolated to match the TM image. Assuming the atmospheric correction coefficient was 1.0, the aerosol scattering image at blue and red bands were derived. Based on a simplified atmospheric radiation transfer model, the water-leaving radiance for three visible bands was retrieved. The water-leaving radiance was normalized to make it comparable with that estimated from other remotely sensed data acquired at different times, and under different atmospheric conditions. Additionally, remotely sensed reflectance of water was computed. To evaluate the atmospheric correction method presented in this article, the correlation was analyzed between the corrected remotely sensed data and the measured water parameters based on the retrieval model. The results show that the atmospheric correction method based on the image itself is more effective for the retrieval of water parameters from Landsat TM data than 6S (Second Simulation of the Satellite Signal in the Solar Spectrum) code based on standard atmospheric and aerosol models.

Key words: retrieval method, water-leaving radiance, Landsat TM image, Taihu Lake