Morphological Precision Assessment of Reconstructed Surface Models for a Coral Atoll Lagoon

Qi Wang,Yu Zhang,Fenzhen Su,Fei Cheng,Huiping Jiang

doi:10.3390/su10082749

Abstract

In addition to remote-sensing monitoring, reconstructing morphologic surface models through interpolation is an effective means to reflect the geomorphological evolution, especially for the lagoons of coral atolls, which are underwater. However, which interpolation method is optimal for lagoon geomorphological reconstruction and how to assess the morphological precision have been unclear. To address the aforementioned problems, this study proposed a morphological precision index system including the root mean square error (RMSE) of the elevation, the change rate of the local slope shape (CRLSS), and the change rate of the local slope aspect (CRLSA), and introduced the spatial appraisal and valuation approach of environment and ecosystems (SAVEE). In detail, ordinary kriging (OK), inverse distance weighting (IDW), radial basis function (RBF), and local polynomial interpolation (LPI) were used to reconstruct the lagoon surface models of a typical coral atoll in South China Sea and the morphological precision of them were assessed, respectively. The results are as follows: (i) OK, IDW, and RBF exhibit the best performance in terms of RMSE (0.3584 m), CRLSS (51.43%), and CRLSA (43.29%), respectively, while with insufficiently robust when considering all three aspects; (ii) IDW, LPI, and RBF are suitable for lagoon slopes, lagoon bottoms, and patch reefs, respectively; (iii) The geomorphic decomposition scale is an important factor that affects the precision of geomorphologic reconstructions; and, (iv) This system and evaluation approach can more comprehensively consider the differences in multiple precision indices.

Highlights

Coral reefs are some of the most productive and species-rich ecosystems on Earth
The main objectives of this study are as follows: (1) establish a morphological precision assessment approach for reconstructed geomorphological surfaces and (2) evaluate the performance of the morphological reconstruction methods to select the optimal methods for coral atoll lagoon geomorphology
Most GIS or data processing software integrates the above interpolation methods, which is convenient for us to study geomorphology

Summary

Introduction

Coral reefs are some of the most productive and species-rich ecosystems on Earth. Currently, 275 million people living near coral reefs, which provide fisheries, oil and gas resources, and shoreline protection for communities [1]. Many coral reefs have important strategic value, and their key locations play unique roles in the division of territorial waters and exclusive economic zones in oceans [4]. Coral reefs have suffered under the effects of human activities, including overfishing, destructive fishing, pollution, and habitat change due to coastal development, which have caused their degeneration [12,13,14]. The changes have affected the growth, transportation, degradation, and deposition of coral reefs, which have had important effects on their macro- and micro-morphological changes, causing the coral reefs to have highly dynamic geomorphology [15,16,17]. The geomorphic evolution study of coral reefs is significant for their exploitation, protection, and management

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Conclusion