Method to design a live coral cover sensitive index for multispectral satellite images

Abstract

Live coral cover (LCC) is regarded as the most efficient indicator of coral reef health. However, LCCs are usually sampled with standardized transect or photo quadrat techniques in field, which are incomplete and labour-intensive. To overcome such difficulties, we study a model to transfer the pixels of multispectral satellite images to quantitative LCCs. The idea is to extend band ratio-based (BR) indices to a novel index constructed using the ratio of different linear combinations (RDLC) of band reflectance and water depths. On the basis of field surveyed LCCs, an empirical process is further proposed to solve the unknown parameters of this RDLC. This approach provides new thinking for designing LCC-sensitive indices for given multispectral satellite images. The experimental results on Weizhou Island and Palmyra Atoll demonstrate that the method is effective and feasible, where the mean relative errors (MREs) are improved from 45 to 56% for BRs to 23-29% for RDLCs for Weizhou Island.

Analysis on the Live Coral Cover around Weizhou Island Using MODIS Data

“…Hence, this paper continues to use the Faviidae family to show the dominant family of corals around Weizhou Island). Weizhou Island was usually selected as the study area for our experiments on remote sensing of coral reefs, i.e., the bathymetry of the coral reefs [23] and the retrieval of LCCs [14,24]. Similarly, Weizhou Island was chosen as the study area for this study.…”

“…Similar to Liang et al [30], Wang and Li [17] also illustrated the LCCs around Weizhou Island in 2009. Besides, we have further observed the LCCs around Weizhou Island using the video line intercept transect technique [24,31]. Those LCC records were chosen as the study materials: 1) The LCCs surveyed by ourselves during 2015 and the LCC sequences of continuous multiyear provided by Chen et al [25] were selected in priority; 2) the LCCs provided by Huang et al [27], Liang et al [30], and Wang and Li [17], etc.…”