Significant wave height prediction by using a spatial model Abdu ¨sselam Altunkaynak Hydraulics Division, Civil Engineering Faculty, Istanbul Technical University, Maslak 34469, Istanbul, Turkey Received 12 February 2004; accepted 25 October 2004 Available online 13 January 2005 Abstract Spatial assessment of variables in a considered region saves its significance for engineering applications. Branches in ocean engineering need the results of this assessment like radius of influence of stations that records the wave measurements and various meteorological variables values. Classical approaches like Kriging do not provide radius of influence for the concerned station. On the other hand, prediction of these measurements from other surrounding stations in the region is a basic requirement. In this paper, it is aimed to predict significant wave height records in a specific region by using trigonometric point cumulative semivariogram (TPCSV) concept. The main difference of this approach from the point cumulative semivariogram (PCSV) approach is the determination of influence radius. More accurate results can be obtained by TPCSV. The spatial correlation and weightings are also obtained through the TPCSV where the distance between two sites is known. The proposed method yields the least prediction error compared with other objective methodologies. The implementation of this methodology is presented for a set of offshore locations distributed along the west United States coastline. q 2004 Elsevier Ltd. All rights reserved. Keywords: Area of influence; Estimation; Interpolation; Objective analysis; Radius of influence; Semivariogram; Significant wave height 1. Introduction Spatial features of wave climatology have not been taken into consideration as frequent as temporal variations. O ¨ zger et al. (2004a,b) have discussed the temporal Ocean Engineering 32 (2005) 924–936 www.elsevier.com/locate/oceaneng 0029-8018/$ - see front matter q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.oceaneng.2004.10.012 E-mail address: altunkay@itu.edu.tr