Application of the Hydraulic Theory to Naturally Occurring Bora Flow

This paper deals with the application of Smith's (1985) internal hydraulic theory to some special cases of Adriatic bora during ALPEX SOP. ln particular, the case of 15 April 1982 is analysed for which the numerical simulation by Klemp and Durran (1987) is available. Their conclusion is that in this case neither inversion nor critical level are important for the bora occurrence, but the low-level wave breaking due to weak flow in the upstream region. While this conclusion seems reasonable, from the present analysis it is argued that these results are valid only for the characteristics of the local bora in Senj and not for the flow across the higher mountains along the northern Adriatic coast. This conclusion is based on a comparison with the results of the theory application to the stronger bora condition on the previous day and especially to the case of the strongest SOP bora on 6 March 1982 for which the hydraulic theory offered much better results.