A novel quantitative analysis for diurnal dynamics of Ulva prolifera patch in the Yellow Sea from Geostationary Ocean Color Imager observation

Frontiers in Marine Science

Marine Science

Yu Fu¹  Xiaoyi Jiang¹  He Cui²  Feng Qiao³  Jianyu Chen⁴ 

[1]National Marine Data and Information Service, Ministry of Natural Resources, Tianjin, China

[2]Ocean College, Zhejiang University, Zhoushan, China

[3]State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China

[4]School of Oceanography, Shanghai Jiao Tong University, Shanghai, China

[5]State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China

[6]School of Oceanography, Shanghai Jiao Tong University, Shanghai, China

关键词: Ulva prolifera;    GOCI;    remote sensing detection;    NDVI;    DBSCAN clustering analysis;    diurnal variation;   

DOI  :  10.3389/fmars.2023.1177997

 received in 2023-03-02, accepted in 2023-07-11,  发布年份 2023

来源: Frontiers

【 摘 要 】

IntroductionIn the last decade, the outbreak of large-scale green tides caused by Ulva prolifera has continuously occurred in the Yellow Sea. Satellite remote sensing techniques have been widely used to monitor the distribution area and duration of green tides due to their advantages of their large-area synchronous observation. Ulva prolifera in the Yellow Sea is mainly distributed in bands or large patches during its flourishing stage. Previous studies have rarely reported the quantitative analysis of a single Ulva prolifera patch and its changes in the short term.MethodsConsidering the high temporal resolution of the Geostationary Ocean Color Imager (GOCI) sensor and the patchy distribution of Ulva prolifera floating on the sea surface, we developed a feasible method for monitoringUlva prolifera by performing clustering analysis with density-based spatial clustering of applications with noise (DBSCAN) to capture the diurnal variation characteristics of a single Ulva prolifera patch.ResultsThis new approach was used to extract informationfrom a single Ulva prolifera patch in the Yellow Sea in 2012 and 2017. The results showed that during the time of GOCI imaging, the tidal current was the main factor driving the drift of Ulva prolifera, and the drifting direction of Ulva prolifera was consistent with the direction of the local tidal current, with a coefficient of determination of 0.94.DiscussionBy changing the normalized difference vegetation index (NDVI) threshold, further more accurate atmospheric correction (AC) of GOCI data during the twilight periods was indirectly achieved. By comparing the areal change in the single patch before and after AC, we speculated that the daily change in signal intensity received by the GOCI sensor may be the main reason for the diurnal variation in the Ulva proliferacoverage area. The results showed the details of the diurnal variation in Ulvaprolifera patches in the dynamic marine environment, and the main reason that may cause this variation was speculated.

【 授权许可】

Unknown   
Copyright © 2023 Cui, Chen, Jiang, Fu and Qiao