Journal of Tropical Oceanography ›› 2021, Vol. 40 ›› Issue (1): 142-153.doi: 10.11978/2019110CSTR: 32234.14.2019110

• Marine Survey and Monitoring • Previous Articles    

Remote sensing retrieval of chlorophyll-a concentration in coastal aquaculture area of Zhelin Bay

PAN Cuihong1,2(), XIA Lihua1,3(), WU Zhifeng1,4, WANG Meng1, XIE Xuetong1, WANG Fang1   

  1. 1. School of Geography Science, Guangzhou University, Guangzhou 510006, China
    2. South China Institute of Environmental Science, MEE, Guangzhou 510006, China
    3. Guangdong Rural Water Environment Non-point Source Pollution Comprehensive Treatment Engineering Technology Research Center, Guangzhou 510006, China
    4. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511485, China
  • Received:2019-11-06 Revised:2020-03-24 Online:2021-01-10 Published:2020-04-09
  • Contact: XIA Lihua E-mail:853136314@qq.com;xialihua@gzhu.edu.cn
  • Supported by:
    Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0301);Guangdong Science and Technology Plan Project(2015A020216021);The National Natural Science Foundation of China(41876204)

Abstract:

Mariculture has become a major source of pollution in offshore waters. Chlorophyll-a, as a parameter of primary productivity, is an important indicator of water quality evaluation. We took Zhelin Bay of Guangdong Province as our study area. Using Sentinel-2 spectral image on September 4, 2018 and in-situ measured chlorophyll-a concentration, we constructed an estimation model of chlorophyll-a concentration to obtain the spatial distribution of chlorophyll-a concentration. In the chlorophyll-a concentration inversion model, we selected a linear regression model, a three-band model and the Normalized Difference Chlorophyll Index (NDCI) for comparative analysis. Through comparison and evaluation, a model with high inversion accuracy was used to estimate the chlorophyll-a concentration in multiple months of 2018 and analyze its distribution characteristics. The results showed that the inversion accuracy of the NDCI model was significantly higher than that of the other models. The decision coefficient R2 of the NDCI model was 0.8, the root mean square error (RMSE) was 9.7, and the mean absolute percentage error (MAPE) was 0.99. The time applicability of the NDCI model was tested by the measured data, which showed that the NDCI model could more accurately and effectively estimated the spatial distribution characteristics of chlorophyll-a concentration. The chlorophyll-a concentration showed a trend of decreasing from nearshore to the outside of the bay. The overall trend of chlorophyll-a concentration in the aquaculture area was as follows: pond breeding area > tidal flat breeding area > cage culture area > floating raft breeding area. Under the influence of water exchange, rainfall and culture activities, the concentration of chlorophyll-a in the culture area of the fish pond was the lowest in February when the fish was in the seedling stage, and its change trend was February < April < June < December. This study provides a valuable reference for environmental monitoring of marine aquaculture waters in Zhelin Bay.

Key words: marine aquaculture, chlorophyll-a concentration, back analysis, Sentinel-2, NDCI model

CLC Number: 

  • P714.11