测绘学报(英文版) ›› 2021, Vol. 4 ›› Issue (1): 17-23.doi: 10.11947/j.JGGS.2021.0102

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  • 收稿日期:2020-10-10 接受日期:2020-12-25 出版日期:2021-03-20 发布日期:2021-04-06

On Radar Signatures of Upwelling

Werner ALPERS1(),Kan ZENG2   

  1. 1. Institute of Oceanography, University of Hamburg, Hamburg 20146, Germany
    2. Ocean Remote Sensing Institute, Ocean University of China, Qingdao 266003, China
  • Received:2020-10-10 Accepted:2020-12-25 Online:2021-03-20 Published:2021-04-06
  • About author:Werner ALPERS (1936-), male, professor, majors in remote sensing of the ocean. E-mail: werner.alpers@uni-hamburg.de
  • Supported by:
    Fundation of Ocean University of China(201965003)

Abstract:

In studies of upwelling, usually data from infrared and optical sensors is used which provides information on the sea surface temperature (SST) and the chlorophyll-a (Chl-a) concentration. In this paper, we show that also synthetic aperture radars (SAR) images can give valuable contribution to such studies. Upwelling regions become detectable by SAR because they are associated with a reduction of the radar backscatter due to ① the change of the stability of the air-sea interface or/and ② the presence of biogenic slicks. Furthermore, the boundary of upwelling regions consists of a line of increased radar backscatter due to the presence of convergent surface flow.

Key words: upwelling, synthetic aperture radar, cyclonic eddies, Agulhas Return Current, biogenic surface films, chlorophyll concentration, air-sea interface, sea surface temperature