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タイトル: The Relationship between Extreme Precipitation and Surface Air Temperature in Bangladesh
その他のタイトル: バングラデシュにおける極端降雨と地表面気温との関係
著者: Sarker, Ram Chandra
著者(別言語): サーカー, ラム チャンドラ
発行日: 2012年9月27日
抄録: First and foremost, Precipitation plays a crucial role in global hydrological cycle. Extreme precipitation has a huge influence on society. They are associated with flood disaster, erosion, water damage, and may have serious impacts on transport and safety. In fact, extreme hydro meteorological events'intensified by climate change due to nature and anthropogenic activity is a great concern for present society. According to IPCC (Intergovernmental Panel on Climate Change) 2007 report it is expected that the intensity of extreme precipitation will increase as the climate warms. The primary reason for this expectation is the fact that the maximum moisture content of the atmosphere increases with approximately 7% per degree temperature rise, which follows from the Clausius-Clapeyron relation. The increase in the atmospheric water holding capacity associated with a temperature increase considerably influences the changes in the extreme precipitation intensity under warmer climates. Besides, Bangladesh is very prone to flooding due to its location at the confluence of the Ganges, Brahmaputra and Meghna (GBM) rivers and because of the hydro-meteorological and topographical characteristics of the basins in which it is situated. 80 Percent of the annual rainfall occurs in the monsoon (June-September) across the river basins. It was observed that extreme flood events occurred due to excessive rainfall in the catchments. When WLs (Water Levels) in the three major rivers systems rises simultaneously and crosses the danger marks extreme flood situation usually occurs all over the country. This was observed during the three flood events occurred in 1987, 1988 and 1998. Water Levels crossing the danger marks start occurring from mid-July and continue till mid-September. Inundated area during 1987, 1988 and 1998 are 66%, 68% and 70% respectively. Duration of the extreme flood events usually extends from 15 days to 45 days, the longest one occurred during 1998. So, Extreme precipitation has its influence in flood disaster in Bangladesh. Hence study on extreme precipitation can result in better understanding of rainfall characteristics and contribution to society. This study aims exploring the characteristics of extreme precipitation due to surface air temperature change in Bangladesh using In-Situ data set. In-situ data set is obtained from Bangladesh Meteorological Department (BMD). Analysis for each seven division of Bangladesh has been accomplished separately. Afterward, analyses for each four season are performed here. In the next step, validation of historical extreme precipitation from GCM model MIROC simulation has been performed by comparing with observation. Model simulated data set is obtained from scenario of RCP8.5 of MIROC5. From the comparison of Temperature Distribution Curve between surface air temperature data set obtained from MIROC and In Situ, it is found that there is bias error in model MIROC simulated data set. Analysis is done considering bias error correction. Finally, model simulation is applied to analyze projection of future changes of extreme precipitation in the targeted region. Result shows that MIROC is a good simulation model as the analysis result of observation and MIROC present simulation has well agreement despite of some minor deviations. Also MIROC present simulation and future simulation has good agreement. So for future projection MIROC data set can be applied for the assessment of characteristics of extreme precipitation in tropical region like Bangladesh, though future climate is too much unpredictable. Yet, preliminary we can adopt MIROC as an assessment tool, indeed.
内容記述: 報告番号: ; 学位授与年月日: 2012-09-27 ; 学位の種別: 修士 ; 学位の種類: 修士(工学) ; 学位記番号: ; 研究科・専攻: 工学系研究科社会基盤学専攻
URI: http://hdl.handle.net/2261/52581
出現カテゴリ:025 修士論文
1130225 修士論文(社会基盤学専攻)

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