The newtonian approach in the meteorological tide waves forecasting: preliminary observations in the East Ligurian harbours

Abstract

1. The phenomenon Abstract Sea level oscillations are the superposition of many contributions, the main ones being astronomic and meteorolog- ical low-frequency tides. In the Ligurian Sea meteo-tide components, being most ample than astronomic fluctuations, drive water exchange in harbours. The present note shows the first results on the port of Genoa concerning a coheren- cy study between atmospheric variation and corresponding sea level adjustment (meteorological tide). The Newton- ian forecasting method of meteorological tides is based on measurements of time elapsing between barometric sea level unbalance (∆g) and its meteorological tide compensation (inverse barometer component). Meteorological tide component is independent of the Earth-Moon-Sun gravitational relationships, and parameters related to the shifted water mass are too many to describe the phenomenon analytically (basin topography, barometric strength position and time, chemical water quality, off-shore sea circulation, etc.). Hence meteorological tide cannot be accurately foreseen by atmospheric pressure measurements only. A gravimeter can detect the geodetic imbalance starting time and a tide-gauge can detect the Newtonian compensation (tide wave) coming time. The difference between these two times is the meteorological tide delay. An opportune statistic of this delay provides an experimental law typical for each harbour to forecast the meteo-tide compensation wave delay. This paper describes the methodological proce- dure adopted and the first evidences of the phenomenon in Genoa harbour.