scholarly journals Assessment of Better Prediction of Seasonal Rainfall by Climate Predictability Tool (CPT) using Global Sea Surface Temperature in Bangladesh

2019 ◽  
Author(s):  
Zakaria Hossain ◽  
Md. Abul Kalam Azad ◽  
Samarendra Karmakar ◽  
Md. Nazrul Islam Mondal ◽  
Mohan Kumar Das ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Rainy Season ◽  
Sea Surface ◽  
Seasonal Rainfall ◽  
Negative Deviation ◽  
Positive Deviation ◽  
Climate Predictability ◽  
The World ◽  
Global Sea Surface Temperature

The main objective of this study is to search better prediction result of rainy seasonal rainfall (15 June-15 August). A correlation between rainfall of Bengali rainy seasons at Rangpur, Dhaka, Barisal and Sylhet and global sea surface temperature (SST) of different areas of the world was studied by using the both data of 1975- 2008 years with the help of the Climate Predictability Tool (CPT) to find more positive correlated SST with observed rainfall and use as predictor for giving the prediction of the year 2009. 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 sea surface temperature (SST) of one month before rainy season was better predictor than SST of starting month of rainy season.

scholarly journals Assessment of Better Prediction of Seasonal Rainfall by Climate Predictability Tool Using Global Sea Surface Temperature in Bangladesh

2019 ◽  
pp. 1-13 ◽  
Author(s):  
Md. Zakaria Hossain ◽  
Md. Abul Kalam Azad ◽  
Samarendra Karmakar ◽  
Md. Nazrul Islam Mondal ◽  
Mohan Das ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
South Asian ◽  
Rainy Season ◽  
Regional Cooperation ◽  
Sea Surface ◽  
Seasonal Rainfall ◽  
Research Centre ◽  
Positive Deviation ◽  
Climate Predictability

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.

scholarly journals Wavelet Analysis of Seasonal Rainfall Variability of the Upper Blue Nile Basin, Its Teleconnection to Global Sea Surface Temperature, and Its Forecasting by an Artificial Neural Network

2014 ◽  
Vol 142 (5) ◽  
pp. 1771-1791 ◽  
Author(s):  
Mohamed Helmy Elsanabary ◽  
Thian Yew Gan
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
River Basin ◽  
Principal Component ◽  
Sea Surface ◽  
Seasonal Rainfall ◽  
Blue Nile ◽  
Artificial Neural ◽  
Mean Square Errors ◽  
Global Sea Surface Temperature

Abstract Rainfall is the primary driver of basin hydrologic processes. This article examines a recently developed rainfall predictive tool that combines wavelet principal component analysis (WPCA), an artificial neural networks-genetic algorithm (ANN-GA), and statistical disaggregation into an integrated framework useful for the management of water resources around the upper Blue Nile River basin (UBNB) in Ethiopia. From the correlation field between scale-average wavelet powers (SAWPs) of the February–May (FMAM) global sea surface temperature (SST) and the first wavelet principal component (WPC1) of June–September (JJAS) seasonal rainfall over the UBNB, sectors of the Indian, Atlantic, and Pacific Oceans where SSTs show a strong teleconnection with JJAS rainfall in the UBNB (r ≥ 0.4) were identified. An ANN-GA model was developed to forecast the UBNB seasonal rainfall using the selected SST sectors. Results show that ANN-GA forecasted seasonal rainfall amounts that agree well with the observed data for the UBNB [root-mean-square errors (RMSEs) between 0.72 and 0.82, correlation between 0.68 and 0.77, and Hanssen–Kuipers (HK) scores between 0.5 and 0.77], but the results in the foothills region of the Great Rift Valley (GRV) were poor, which is expected since the variability of WPC1 mainly comes from the highlands of Ethiopia. The Valencia and Schaake model was used to disaggregate the forecasted seasonal rainfall to weekly rainfall, which was found to reasonably capture the characteristics of the observed weekly rainfall over the UBNB. The ability to forecast the UBNB rainfall at a season-long lead time will be useful for an optimal allocation of water usage among various competing users in the river basin.

scholarly journals Tropical and Extratropical predictions of the summer and autumn Niño3.4 Index: a comparison

2016 ◽  
Vol 42 ◽  
pp. 73-81
Author(s):  
Miguel Tasambay-Salazar ◽  
María José OrtizBeviá ◽  
Antonio RuizdeElvira ◽  
Francisco José Alvarez-García
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Linear Models ◽  
Southern Oscillation ◽  
Heat Content ◽  
Sea Surface ◽  
South Pacific Convergence Zone ◽  
Lead Times ◽  
Convergence Zone ◽  
The World

Abstract. The El Niño-Southern Oscillation (ENSO) phenomenon is the main source of the predictability skill in many regions of the world for seasonal and interannual timescales. Longer lead predictability experiments of Niño3.4 Index using simple statistical linear models have shown an important skill loss at longer lead times when the targeted season is summer or autumn. We develop different versions of the model substituting some its variables with others that contain tropical or extratropical information, produce a number of hindcasts with these models using two different predictions schemes and cross validate them. We have identified different sets of tropical or extratropical predictors, which can provide useful values of potential skill. We try to find out the sources of the predictability by comparing the sea surface temperature (SST) and heat content (HC) anomalous fields produced by the successful predictors for the 1980–2012 period. We observe that where tropical predictors are used the prediction reproduces only the equatorial characteristics of the warming (cooling). However, where extratropical predictors are included, the predictions are able to simulate the absorbed warming in the South Pacific Convergence Zone (SPCZ).

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