DETERMINATION OF MEAN SEA LEVEL FROM 1980 TO 2018 USING TIDAL OBSERVATION DATA, BONNY PRIMARY PORT, NIGERIA

Abstract

Mean Sea Level (MSL) is the average height of the sea for all stages of tide over 19 years; and it is obtained through tidal analysis. This research work aims at determination and assessment of the MSL for the Bonny port. Tidal data of 1980, 1994 and 2018 years of observation were employed using the Least Squares Adjustment method with MATLAB programming codes for data processing. The results of the monthly analysis were compared and subjected to statistical analysis (Mean, standard deviation, t-test and Analysis of variance (ANOVA). The difference between the computed 1980 yearly mean and that of 1994 is 3.0 mm; while that of 1994 and 2018 is 5.1 mm. The yearly variation for 1980 to 1994 is (3.0/14) mm  0.20 mm; and for 1994 to 2018 is (5.1/24) mm  0.21 mm. The variation for 1980 to 2018 is (0.20-0.21) mm. The results show gradual rise in MSL for the period of 1980 to 2018 as further explained by the month and the year variables. Therefore, it can be concluded that there is a gradual rise in sea level of about 0.01 mm for the period of study in Bonny which does not take into consideration the subsidence phenomenon. Although, the rate is low, however, the results suggest that the relative sea level could be much higher because there is a lot of fluid extraction.