Wind Characteristics and the Associated Risk of Erosion in Seribu Islands Patch Reef Complexes, Java Sea, Indonesia

摘要

This paper explores design event and entrainment of cay beach sands due to wave shear stresses from winds. Univariate frequency analysis is used to predict recurrence intervals of extreme winds from 30-year (1984-2013) global assimilated data set. Two primary clusters of wind directions representing East and West monsoons are examined. This identifies the equivalence of characteristics of regime among the two clusters. Taking into account the threshold of bottom shear stress of cay beach sands, conceptual relationship between height of wind-generated waves (forecasted from predefined fetch length and wind speed) and erosion of cay beach sand is prescribed. The results indicate that East monsoon is the predominant occurrence of wind and facilitates persistent north-westward shift of cay beach sands, while West monsoon provides extreme events in shorter time span. It is suspiciously thought that due to these, net north-westward drift of sand is indicated. These imply that many of cays in the domain being investigated is at risk of erosion due to unequal balance forcing of winds.