A temporal accessibility model for assessing the ability of search and rescue in Nansha Islands, South China Sea

Abstract

Time is an indispensable means in accessibility expression and also an important index of the search and rescue (SAR) ability to a country. In this paper, a method for forecasting the location and probability of patrol vessel which is responsible for SAR on the sea is presented; and a temporal accessibility model for assessing the SAR ability of countries around South China Sea in Nansha is structured. In this study, 19 islands and cays in Nansha Islands are selected as rescue targets; eight ports in four countries around South China Sea are selected as SAR bases; patrol vessels belong to coast guard or maritime agency of countries around South China Sea whose displacement is over 1000 tons are selected as principal searchers and rescuers. Based on the density of ships passing the area and the distance from ports of each homeland, the distributions of patrol vessel which belongs to four countries around South China Sea are obtained. The SAR time of China, Vietnam, Malaysia and Philippines in Nansha were calculated based on the proposed method. The results indicated that due to the number of big patrol vessels, China Coast Guard is able to get to Nansha in minimum time, only half an hour for SAR; Vietnam gets second, one and a half hours; Malaysia gets third, 4.6 h; Philippines costs almost 7 h at the bottom of the list, because of the distance and the number of vessels. Taking consideration of the scattered distribution of islands, rocky coral reefs, bad weather and complex marine conditions, it is a very difficult job for SAR vessels. So it is necessary to set up several sub centers and shelters on appropriate islands or atolls in Nansha. And more importantly, how to enhance connection and coordination among countries around South China Sea, build harmonious and smooth SAR mechanisms or channels for cooperation, and improve the ability for solving emergency accidents in Nansha and even the whole South China Sea.