The Tidal Predictions for African Sea Level Network.
The Intergovernmental Oceanographic Commission (IOC) of UNESCO, through the Ocean Data and Information Network for Africa (ODINAFRICA) initiated a programme to analyse data from sea level stations installed along the African coast and prepare tidal predictions for the stations. These stations are part of the Global Sea Level Observing System (GLOSS) program launched by UNESCO/IOC in 1985 to address the growing concern about changes in the mean sea level. The objective of GLOSS was to provide high quality standardized data from which valuable sea level products can be produced for international oceanographic programmes, regional research programmes as well as for practical application on a national and regional level. In this project, National Experts from Kenya, Mauritius, Mozambique, Seychelles and Tanzania were identified to prepare National Reports on Tidal Analysis and Prediction for their respective countries, and in particular: Collect and analyze sea level data from selected tide gauge stations in the WIO region and prepare tidal predictions for those stations for the period 1 January 2008 – 31 December 2009,
- Compare predictions and actual observations for the period January - June 2008 and submit graphs of the tidal residuals for this period.
- Avail the tidal predictions in an appropriate format on the ODINAFRICA and WIOMSA websites
- Prepare comprehensive national reports which should include: (a) the listing of high and low waters (height against local time and GMT) as well as hourly heights for January 2008 – December 2009, (b) graphs of the tidal variations, as well as tidal residuals for the period for the period January – June 2008.
- Preparation of a comprehensive report on the status of tide gauges in the region and available data.
- Prepare an inventory of scientific and technical capacity available for installation, levelling and maintenance of gauges, as well as analysis and interpretation of sea level data
- Provide an insight on the status of sea level monitoring and related activities in some selected locations in the WIO region.
The project kicked-off with a workshop for the experts, hosted by the Kenya Marine and Fisheries Research Institute in Mombasa from 1-5 April 2008 to harmonise the methods to be applied in the analysis of available sea level data and identification of suitable software to be used for tide predictions. The experts also drafted the guidelines to be used in preparing the national reports.Three software packages were agreed on:
- SLPR2 by University of Hawaii Sea Level Centre (UHSLC)
- TASK-2000 by Permanent Service for Mean Sea Level (PSMSL)
- T_TIDE by University of British Columbia
The national and regional reports prepared by the experts are provided here.This programme will be extended to cover the analysis of other oceanographic parameters.