Tide Prediction Calendars Save Lives


Development Objective 5 - Improve multi-sectoral responses to climate change and disasters

Many Pacific Island livelihoods rely on ocean and coastal activities that are affected by the highs and lows of daily tides. Fewer people realise, however, that accurate tide predictions are only available for a select few ports across the region.

When sufficient data is available, tide predictions can be calculated with precision many years in advance. This advance knowledge of the highest and lowest tides is saving lives in the Pacific.

According to Mr Reginald White, Director for the Marshall Islands Weather Office, “People are using Annual Tide Prediction Calendars to know when to cross between islands to avoid loss of lives and capsizing of boats.”

Although tide prediction calendars have been produced for many years through the Australian-funded Climate and Ocean Support Program in the Pacific (COSPPac), the design has been steadily improved in response to stakeholder consultation and requests since 2015. In addition to the tide predictions, now the full-colour calendars also include a local map, a table of highest and lowest predicted tides of the year, phases of the moon, indicators of highest and lowest tides of the month, and a fact sheet about tidal variability and extreme high tides (also known as King Tides in the region).

More than 1,800 Annual Tide Prediction Calendars were distributed for 19 Pacific locations in 2017.

The 2018 calendars will include an additional location (Vava’u, Tonga) as well as new factsheets about Traditional Ocean & Tidal Knowledge and Tide Datums for Coastal Development and Safety of Navigation. The predictions are calculated by the Australian Bureau of Meteorology’s Tidal Unit with information from the Pacific Sea Level Monitoring stations and a few additional tide gauges around the region.

National Meteorological Services act as distributors for the calendars in most countries, ensuring they are provided to key stakeholders who require tidal information. Users of the tide calendar range from local fishermen, tourism operators and community members, to Port Authorities, shipping companies, and other government agencies.

Through COSPPac, SPC organises national-level Ocean and Tides Workshops to provide National Meteorological Services and their stakeholders with introductory training on ocean science and information products. Training includes analysis of the local Tide Prediction Calendar and discussion of tidal phases, attributes, and local tidal knowledge. Discussions also encourage participants to indicate preferences for further information and one of the most frequently requested items is additional tide predictions for secondary ports and outer island locations.

We use the tide calendar to issue extreme high tide advice for Tonga. It is also being used by the Port Authority of Tonga to plan the arrival time of cruise ships to the Kingdom.’

-- Moleni Tu’uholoaki, Chief Quality Assurance Officer of Tonga Meteorological Service

Since SPC began producing and distributing the calendars in 2015, a number of lessons have come across strongly:

  • Benefits of in-country training and ocean stakeholder consultation to ensure information products are accessible and understood, but also to improve SPC understanding of local issues and requests;

  • Variety of uses and users of tide information, many of whom need precise heights;

  • Need for improved Ocean Literacy and understanding of tidal science in the region;

  • Potential for development of alternative, online products including a Pacific Tidal App;

  • Demand for tide prediction calendars for secondary ports and more outer islands.

Finally, the Pacific Regional Navigational Initiative (PRNI) has identified that COSPPac Tide Prediction Calendars are usually more accurate than the Admiralty Tide Tables- the official tables published for mariners around the globe. In coordination with Pacific national hydrographic focal points, SPC aims to have these tables officially recognised where relevant in 2018, to ensure countries and mariners are using the most accurate tide tables available.