ASR - A Global Partner for the Sustainable Management of Coastal and Marine Resources

Quicksilver 2000 Tides

Location: Worldwide

Type of Project: Tide and sunrise/sunset prediction

Client: Quicksilver Inc., France

ASR Projects- Quicksilver 2000 Tides

Left: The quicksilver watch containing the data from this project. Right: An interface for the world tidal model.

Project Overview:

ASR Ltd was commissioned to predict the timing and heights of high and low tides along with and sunset/sunrise details for 2000 surf locations worldwide for use in a Quiksilver™ watch.

Project Outcomes:

World wide tidal prediction is a challenging task since tidal sea level oscillations follow a wide variety of patterns. On wide, open coastlines tidal oscillations can be easily predicted, however along more complex coastlines, such as those found around the British Isles, the sea level oscillates in a more complex way. In such areas, the times of high and low tides and the range of sea level variation can vary greatly over a small stretch of coastline – making accurate predictions difficult.

As such, tidal predictions for such a wide variety of locations required a multifaceted approach drawing on a range of tide models and incorporating analysis of actual tidal observations from gauge data. For surf-spots along open coastlines, the tidal prediction was mainly calculated using the world tide model developed by NASA and based on 13 years of satellite altimetry data. The model provided a model with ¼ degree output resolution based on 10 tidal constituents. In more complex areas, tidal analysis was performed on long term historic sea level observations from local gauges. Tidal constituents were extracted from the records and used to predict future tidal sea level variation. ASR’s in-house high resolution tidal model of New Zealand was also used for sites within New Zealand.

Sunset and sunrise timing was calculated using a solar tracking algorithm which determined the time at which the sun is seen on the horizon at spatially specific positions along the Earth geoid.

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