A quantitative approach to monitoring new sand cay migration in Nansha Islands
-
摘要: 由珊瑚礁碎屑和生物碎屑组成的沙洲是南沙群岛的一类常见的岛礁。虽然这类沙洲在海洋战略和海洋经济中扮演着重要的角色,但是我们仍然对其知之甚少,尤其是对于一些新生沙洲更是连基本资料都十分匮乏。本研究中我们利用一系列QuickBird和WorldView-2数据,在2006年7月至2013年8月期间对南薰礁上一处新生沙洲进行了连续卫星遥感监测。根据这些资料我们对沙洲移动距离和海风观测资料进行了回归分析以确定沙洲的变迁模式。沙洲移动距离是通过NDWI提取沙得到的,海风数据则是从NOAA网站下载并整理而来。基于线性回归结果,我们得出以下结论:该沙洲的移动与东风、西风和北风明显相关,其中东风是沙洲移动的主要影响因素,其影响能力几乎是西风和北风的两倍。而南风由于被沙洲南部的人工建筑阻挡,对该沙洲的移动几乎没有影响。Abstract: Sand cay is a special kind of islet formed by coral detritus and bioclast, which is common in Nansha Islands of China. Some sand cays play an important role in ocean strategy and economy, but surprisingly we know little about them, especially those recently formed sand cays. In this research, we monitor migration of a new sand cay in Nanxun Jiao (Gaven Reef) using a series of QuickBird and WorldView -2 satellite images between June 2006 and August 2013. We conduct a regression between migration distance and wind observational data to examine the migration patterns of the new sand cay. The migration distance is calculated based on the sand cay locations extracted based on Normalized Difference Water Index (NDWI). The wind observational data downloaded from NOAA are reformed into four wind direction vectors. Based on the results of regression, we concluded that the migration of the new sand cay on Nanxun Jiao was significantly associated with the east, west and north wind. East wind was the main influence factor of the migration; its impact strength was almost twice as the west and north wind. The south wind has little effect on the migration of the sand cay, which is partly blocked by the artificial structure in the south.
-
Key words:
- Nansha Islands /
- new sand cay /
- migration pattern /
- remote sensing /
- high resolution /
- linear regression
-
Cordner L G. 1994. The spratly islands dispute and the law of the sea. Ocean Development and International Law, 25(1):61-74 Digital Globe. 2013. Standard Imagery Data Sheet. https://www.digit-alglobe.com/sites/default/files/StandardImagery_DS_10-14_forWeb.pdf[2013-5-31/2015-1-15] Encyclop.dia Britannica Inc. 2015. Encyclop.dia Britannica Online. http://www.britannica.com/EBchecked/topic/100777/cay[2015-1-26] Gong Jianming, Zhu Guoqiang, Yang Juan, et al. 2014. A Study on the object-oriented model for geomorphic unit extraction of coral reefs in the South China Sea. Journal of Geo-Information Sci-ence (in Chinese), 16(6):997-1004 LeDrew E F, Holden H, Wulder M A, et al. 2004. A spatial statistical operator applied to multidate satellite imagery for identifica-tion of coral reef stress. Remote Sensing of Environment, 91(3-4):271-279 Li Shu, Yu Kefu, Chen Tianran, et al. 2011. Assessment of coral bleaching using symbiotic zooxanthellae density and satellite remote sensing data in the Nansha Islands, South China Sea. Chinese Science Bulletin, 56(10):1031-1037 Liu Nanwei. 1995. The nomenclature of the South China Sea Islands in ancient China. Chinese Geographical Science, 5(1):30-38 Liu Baoyin, Wang Yanfeng, Gao Junguo, et al. 1999. The remote sens-ing composite information entropy and types of Nansha coral reef atolls. Acta Oceanologica Sinica, 18(3):389-400 Liu Baoyin, Wang Yanfeng, Hao Qingxiang. 1996. The research on the remote sensing's information tree model of the Nansha coral is-lets and reef's spatial structure. Acta Oceanologica Sinica, 15(3):331-344 McFeeters S K. 1996. The use of the Normalized Difference Water In-dex (NDWI) in the delineation of open water features. Interna-tional Journal of Remote Sensing, 17(7):1425-1432 Shi Wei, Su Fenzhen, Zhou Chenghu, et al. 2014. Research on access-ibility model of Nansha Islands and surrounding seaports. Acta Geographica Sinica (in Chinese), 69(10):1510-1520 The Navigation Guarantee Department of the Chinese Navy Head quarters (NGD). 2006. China Sailing Directions. A103 South China Sea (in Chinese). Tianjin:China Navigation Press, 184-186 Wolf A F. 2012. Using worldview-2 Vis-NIR multispectral imagery to support land mapping and feature extraction using normalized difference index ratios. Baltimore, Maryland:SPIE Defense, Se-curity, and Sensing Xu Hanqiu. 2006. Modification of normalised difference water index (NDWI) to enhance open water features in remotely sensed im-agery. International Journal of Remote Sensing, 27(14):3025-3033 Xu Jingping, Zhao Dongzhi. 2014. Review of coral reef ecosystem re-mote sensing. Acta Ecologica Sinica, 34(1):19-25 Yamamoto L, Esteban M. 2014. Atoll Island States and International Law:Climate Change Displacement and Sovereignty. Berlin:Springer-Verlag, 35-36 Yamano H, Tamura M. 2004. Detection limits of coral reef bleaching by satellite remote sensing:Simulation and data analysis. Re-mote Sensing of Environment, 90(1):86-103 Zou Yarong, Liang Chao, Zhu Haitian. 2012. Research about monitor-ing the development status of coral reefs based on QuickBird Data. Haiyang Xuebao (in Chinese), 34(2):57-62
点击查看大图
计量
- 文章访问数: 1319
- HTML全文浏览量: 87
- PDF下载量: 1274
- 被引次数: 0