Ensemble Projection of the Sea Level Rise Impact on Storm Surge and Inundation in the Coastal Bangladesh
Ensemble Projection of the Sea Level Rise Impact on Storm Surge and Inundation in the Coastal Bangladesh
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DOI：
10.5194/nhess-2017-216
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发表时间：
2017-07
影响因子：
4.6
通讯作者：
Mansur Ali Jisan;S. Bao;L. Pietrafesa
中科院分区：
文献类型：
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作者：
Mansur Ali Jisan;S. Bao;L. Pietrafesa
采用水动力模型Delft3D研究了海平面上升对孟加拉国沿海地区风暴潮和洪水的影响。为了研究目前的淹没情况，我们使用了两个已知的热带气旋（TC）的路径：艾拉（2009年第一类）和锡德（2007年第五类）。用现有的观测结果验证了模型结果。未来的淹没情景是利用西德尔、艾拉和一系列历史上的西德拉路径的强度生成的，但考虑了单反的影响。由于SLR影响下风暴潮淹没的未来变化是一个概率事件，因此考虑了与TC路径、强度和登陆时间相关的不确定性，计算了未来淹没面积的可能变化范围。模式输出表明，如果在21世纪中期的气候情景中出现0.26米的SLR，则TC Sidr的淹没面积（计算为1860 km2）将比目前情景高31%。与此类似，在21世纪末的气候情景中发现了增加的趋势。研究发现，当单反为0.54米时，淹没面积将比现在增加53%。随着淹没面积的增加，考察了单反对未来风暴潮水位变化的影响。如果海平面在21世纪中期上升0.26米，则Barisal站TC Sidr的风暴潮水位将显著增加21%。与此相似，在21世纪末的气候情景中，该地区风暴潮水位增加了37%，SLR为0.54米。基于未来TC事件不确定性的综合预估也表明，对于SLR变化0.54米，淹没面积将在3500-3750 km2之间，而对于目前的SLR模拟，淹没面积在1000-1250 km2之间。这些结果表明，即使未来的TCs保持与目前相同的强度，预计的SLR变化将在浪涌高度和淹没面积方面产生更严重的威胁。
The hydrodynamic model Delft3D is used to study the impact of Sea Level Rise (SLR) on storm surge and inundation in the coastal region of Bangladesh. To study the present day inundation scenario, track of two known tropical cyclones (TC) were used: Aila (Category 1; 2009) and Sidr (Category 5; 2007). Model results were validated with the available observations. Future inundation scenarios were generated by using the strength of TC Sidr, TC Aila and an ensemble of historical TC tracks but incorporating the effect of SLR. Since future change in storm surge inundation under SLR impact is a probabilistic incident, that’s why a probable range of future change in inundated area was calculated by taking in to consideration the uncertainties associated with TC tracks, intensities and landfall timing. The model outputs showed that, the inundated area for TC Sidr, which was calculated as 1860 km 2 , would become 31 % higher than the present day scenario if a SLR of 0.26 meter occurs during the mid-21 st century climate scenario. Similar to that, an increasing trend was found for the end of the 21 st century climate scenario. It was found that with a SLR of 0.54 meter, the inundated area would become 53 % higher than the present day case. Along with the inundation area, the impact of SLR was examined for the changes in future storm surge level. A significant increase of 21 % was found in storm surge level for the case of TC Sidr in Barisal station if a Sea Level Rise of 0.26 meter occurs at the middle of the 21st century. Similar to that, an increase of 37 % was found in storm surge level with a SLR of 0.54 meter in this location for the end of the 21 st century climate scenario. Ensemble projections based on uncertainties of future TC events also showed that, for a change of 0.54 meters in SLR, the inundated area would range between 3500–3750 km 2 whereas for present day SLR simulations it was found within the range of 1000–1250 km 2 . These results revealed that even if the future TCs remain at the same strength as at present, the projected changes in SLR will generate more severe threats in terms of surge height and extent of inundated area.