Met Office Hadley Centre, FitzRoy Road, Exeter, Devon, UK.
Environ Sci Process Impacts. 2015 Jun;17(6):1047-56. doi: 10.1039/c4em00650j. Epub 2015 Apr 21.
South Asia is a region of complex atmospheric dynamics and therefore changes resulting from increasing greenhouse gas concentrations, combined with existing vulnerability to extreme weather events such as flooding, could put the region at particular risk from climate change. However, current climate projections for the region show a range of uncertainty, particularly in terms of changes in the variability and extremes of precipitation. Focusing on Bangladesh and the region encompassing parts of the Ganges, Brahmaputra and Meghna river basins, we aim to explore and quantify climate model uncertainty in climate change projections for the 21(st) century. We use results from a 17-member perturbed physics ensemble of projections from a global climate model which have been used to drive a higher resolution (25 km) regional climate model over the south Asia region from 1971 to 2099. The range of temperature and precipitation responses across the ensemble are assessed including representation of the annual cycle, trends, and changes in precipitation extremes. The 17 ensemble members consistently simulate increasing annual mean temperatures by 2100 compared with present day, ranging between 2.6 °C and 4.8 °C. Additionally, all ensemble members indicate increasing annual precipitation by 2100 of between around 8% and 28%, though with interdecadal variability which results in one ensemble member showing a slight decrease in precipitation in the mid-century period. The frequency of light precipitation events is projected to decrease in the future, but with an increase in the frequency of heavy events. Three members of the climate model ensemble, representing a range of projected climate outcomes, have been selected for use in further impacts modelling for the region.
南亚地区的大气动力学十分复杂，因此，在温室气体浓度不断增加的情况下，该地区发生的变化，再加上其已经容易受到洪水等极端天气事件的影响，可能会使该地区面临特别大的气候变化风险。然而，该地区目前的气候预测显示出了一系列的不确定性，特别是在降水的可变性和极值变化方面。我们专注于孟加拉国以及恒河、雅鲁藏布江和梅格纳河流域部分地区，旨在探索和量化气候变化预测中对 21 世纪气候变化的气候模型不确定性。我们使用了来自一个全球气候模型的 17 个成员的物理扰动集合的预测结果，这些结果被用来驱动一个更高分辨率（25 公里）的区域气候模型，该模型覆盖了南亚地区，从 1971 年到 2099 年。对整个集合的温度和降水响应范围进行了评估，包括对年循环、趋势和降水极值变化的表示。17 个集合成员一致地模拟了到 2100 年，与当前相比，年平均气温上升 2.6-4.8°C。此外，所有集合成员都表明，到 2100 年，年降水量将增加 8%-28%，尽管存在跨十年的可变性，导致一个集合成员在中期显示出降水量略有减少。未来，轻量级降水事件的频率预计将减少，但重量级事件的频率将增加。从集合中选择了三个气候模型成员，代表一系列预测的气候结果，用于该地区的进一步影响建模。
