Assessment of Better Prediction of Seasonal Rainfall by Climate Predictability Tool Using Global Sea Surface Temperature in Bangladesh
Md. Zakaria Hossain
Department of Mathematics, Bangladesh University, Dhaka 1207, Bangladesh.
Md. Abul Kalam Azad
Institute of Environmental Science, University of Rajshahi, Rajshahi 6205, Bangladesh.
Samarendra Karmakar
Bangladesh Centre for Advanced Studies (BCAS), Gulshan-1, Dhaka-1212, Bangladesh.
Md. Nazrul Islam Mondal *
Department of Population Science and Human Resource Development, University of Rajshahi, Rajshahi 6205, Bangladesh.
Mohan Das
Institute of Water and Flood Management (IWFM), Bangladesh University of Engineering and Technology (BUET), Dhaka-1000, Bangladesh.
Md. Mizanur Rahman
SAVE Earth Climate Services LTD, Dhaka, Bangladesh.
Md. Abdul Haque
Department of Applied Mathematics, University of Rajshahi, Rajshahi, Bangladesh.
*Author to whom correspondence should be addressed.
Abstract
This study was conducted to determine better prediction result of seasonal rainfall. To evaluate the better prediction of seasonal rainfall of rainy season (15 June-15 August) by Climate Predictability Tools (CPT) in the context of using sea surface temperature (SST) of starting month of rainy season compare to using SST of one month before the rainy season. The study was carried out at the South Asian Association for Regional Cooperation Meteorological Research Centre, Dhaka; Bangladesh between January and December, 2010. A correlation between rainfall at Rangpur, Dhaka, Barisal and Sylhet and global SST of different areas of the world was studied by using the both data of 1975- 2008 years with the help of the CPT to find more positive correlated SST with observed rainfall and use as predictor for giving the prediction of the year 2009. The statistical method applied using CPT which is canonical correlation analysis. Using SST of one month before rainy season as predictor, the positive deviation of predicted rainfall from observed rainfall was 1.34 mm/day at Sylhet and 0.9 mm/day at Dhaka. The negative deviation of mean rainfall was 1.16 mm/day at Rangpur and 1.10 mm/day at Barisal. Again, using of starting one month SST of rainy season as predictor, positive deviation of predicted rainfall from observed rainfall was 4.03 mm/day at Sylhet. The positive deviation of daily mean rainfall was found 6.58 mm/day at Dhaka and 6.23 mm/day over southern Bangladesh. The study reveals that SST of one month before rainy season was better predictor than SST of starting month of rainy season.
Keywords: Climate predictability tools, rainfall, prediction, season, sea surface temperature