French Frigate Research Articles

Development of the Virtual Reality Application: “The Ships of Navarino”

Virtual reality and 3D modeling techniques are increasingly popular modes of representation for historical artifacts and cultural heritage, as they allow for a more immersive experience. This article describes the process that was adopted for the development of a virtual reality application for four ships involved in the historic battle of Navarino. The specific naval battle was the culmination of military operations during the Greek Revolution in 1827, in which the allied British, Russian, and French fleet defeated Turkish-Egyptian forces. Representative 3D models of four significant warships that participated in the battle of Navarino were created: the British “Asia”, the French frigate “Armide”, the Russian “Azov”, and the Ottoman “Kuh-I-Revan”. These historic ships were digitally designed according to historical drawings and a VR battle environment was developed, which visitors can experience. In addition, the 3D models were generated by a 3D printer and painted according to the digitized ship-models. The development was conducted within the realm of the NAVS Project. The VR application, “The Ships of Navarino”, as well as the 3D-printed models were presented as part of a physical exhibition hosted in the Eugenides Foundation in Athens, Greece.

Inferences and Observations of Turbulent Dissipation and Mixing in the Upper Ocean at the Hawaiian Ridge

Abstract The Hawaiian Ridge is one of the most energetic generators of internal tides in the pelagic ocean. The density and current structure of the upper ocean at the Hawaiian Ridge were observed using SeaSoar and Doppler sonar during a survey extending from Oahu to Brooks Banks and up to 200 km from the ridge peak. Survey observations are used to quantify spatial changes in internal-wave-induced turbulent dissipation and mixing. The turbulent dissipation rate of kinetic energy ɛ and diapycnal eddy diffusivity Kρ are inferred from an established parameterization using internal wave shear as input. At the Kauai Channel (KC) and French Frigate Shoals/Brooks Banks sites, ɛ and Kρ decay away from the ridge with maxima exceeding minima by 5 times. At both sites, average Kρ is everywhere greater than the canonical open-ocean value of 10−5 m2 s−1. Along the ridge, ɛ and Kρ vary by up to 100 times and are largest at sites of largest numerical model internal tide energy density. In the eastern KC, Kρ > 10−3 m2 s−1 is typical in a patch more than 200 m thick located above the path of an M2 internal tide ray. An upper limit on the dissipation rate from M2 internal tides to turbulence within 50 km of the Hawaiian Ridge is roughly estimated to be in the range of 4–9 GW. At KC, the depth-integrated internal wave energy density and dissipation rate are positively correlated. Potential density inversions occur near the main ridge axis at significant topographic features. Average Kρ is larger inside inversions.

2000-2002 Rapid Ecological Assessment of Corals (Anthozoa) on Shallow Reefs of the Northwestern Hawaiian Islands. Part 1: Species and Distribution

Rapid Ecological Assessment (REA) surveys at 465 sites on 11 reefs in the Northwestern Hawaiian Islands (NWHI) inventoried coral species, their relative abundances, and their distributions during 2000-2002. Surveys (462) around the 10 islands were in depths of a 20 m, and three surveys on the submerged Raita Bank were in depths of 30Ð35 m. Data from 401 REA sites met criteria for quantitative analysis. Results include 11 first records for stony coral species in the Hawaiian Archipelago and 29 range extensions to the NWHI. Several species may be new to science. There are now 57 stony coral species known in the shallow subtropical waters of the NWHI, similar to the 59 shallow and deep-water species known in the better-studied and more tropical main Hawaiian Islands. Coral endemism is high in the NWHI: 17 endemic species (30%) account for 37-53% of the abundance of stony corals on each reef of the NWHI. Three genera (Montipora, Porites, Pocillopora) contain 15 of the 17 endemic species and most of the endemic abundance. Seven Acropora species are now known from the central NWHI despite their near absence from the main Hawaiian Islands. Coral abundance and diversity are highest at the large, open atolls of the central NWHI (French Frigate, Maro, Lisianski) and decline gradually through the remaining atolls to the northwest (Pearl and Hermes, Midway, and Kure). Stony corals are also less abundant and less diverse off the exposed basalt islands to the southeast (Nihoa, Necker, La Perouse, Gardner), where soft corals (Sinularia, Palythoa) are more abundant. Exposure to severe wave action appears to limit coral development off these small islands and surrounding deep platforms. Temperature extremes and natural accumulation of lagoon sediments may contribute to decline of coral species and abundance at the northwestern end of the chain.