Modelling of Chlorophyll-a Concentration Patterns from Satellite Data Using Cubic Spline Function in Pattani Bay, Thailand

摘要

The modelling of chlorophyll-a concentration helps to restrict the harmful effects in marine species caused by increased nutrient loads. The derived satellite data are often used for the monitoring of marine ecology. The common usage of satellite data is monthly average data to avoid the problem of missing values. In order to reduce the effect of missing data, this study employed the cubic spline model by using a satellite data for investigating seasonal variations of chlorophyll-a mapped in an eight-day interval consisting of missing values in Pattani Bay, Thailand from the year 2003 to 2017. This study further used the spline-fitted data for creating the baseline model of chlorophyll-a in Pattani Bay, and for examining the difference between spline fitted and monthly average data. This study revealed that the cubic spline method was able to handle the missing values in satellite data to gain the smoothness in data. When both models were compared, the spline-fitted observation yielded a smoother curve pattern than the monthly average observation. The spline fitted model was also able to displaythe chlorophyll-a data at any particular day of the year. It was also shown that the chlorophyll-a concentration level in the coastal area of Pattani Bay was higher in the inshore pixels, especially in rainy season.