Estimation of missing daily temperature and rainfall for longer durations at Hatiya and Sandwip islands in the Bay of Bengal

Abstract

This study has estimated the missing values of minimum temperature, maximum temperature and rainfall records of longer lengths, respectively, from 1994 to 1996 in Hatiya and 2000–2003 in Sandwip islands of the Bay of Bengal with harmonic regression analysis to realize the past climate. The work has provided past climate of records, which have justified with the mean absolute error, root mean squared error and skill score respectively 1.50, 2.00 and 0.84 for minimum temperature, 1.66, 2.10 and 0.48 for maximum temperature, and 8.60, 14.69 and –0.43 for rainfall for the stations with known records. The mean of the two estimations varies respectively for temperature and rainfall from –0.69 to 0.64°C and –0.36 to 4.79 mm, where one estimation is done with the proposed harmonic analysis and another estimation has been done with inverse-distance-weighting technique for the stations with missing records. The study is advantageous because it uses data from its own station on the island rather than data from neighbouring stations on the continent. It has avoided the probability of mixing up the continental climate with the climate of the island and vice versa. Hence, the estimations provided are spatially unbiased and meaningful past climate.