A Regional-Scale Evaluation of Changes in Environmental Stability for Summertime Afternoon Precipitation under Global Warming from Super-High-Resolution GCM Simulations: A Study for the Case in the Kanto Plain
A Regional-Scale Evaluation of Changes in Environmental Stability for Summertime Afternoon Precipitation under Global Warming from Super-High-Resolution GCM Simulations: A Study for the Case in the Kanto Plain
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DOI：
10.2151/jmsj.2012-a10
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发表时间：
2012-02
影响因子：
3.1
通讯作者：
T. Takemi;Syohei Nomura;Y. Oku;H. Ishikawa
中科院分区：
文献类型：
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作者：
T. Takemi;Syohei Nomura;Y. Oku;H. Ishikawa
了解和预报无明显天气尺度影响的快速发展的积雨云造成的夏季午后降水，对预防和减轻其诱发的灾害具有重要意义。这种降水事件的未来变化最近引起了科学和社会的兴趣。本文利用20 km网格超高分辨率大气环流模式（GCM）模拟结果，采用政府间气候变化专门委员会（IPCC）A1B排放情景，研究了全球变暖背景下夏季午后降水的环境稳定性。选择关东平原作为分析区域。在用观测和网格化的中尺度分析验证了GCM当前气候输出的有用性后，我们通过统计分析研究了下午降水环境稳定性的未来变化。在未来的气候中，对流层低层的温度直减率减小，而整个对流层深层的水汽混合比增加。温度和湿度廓线的变化导致可降水量和对流有效位能的增加。这些预计的变化将在今后一个时期得到加强。此外，对各模拟气候期内天气扰动条件下无雨日与有雨日稳定性参数差异的统计分析表明，区分无雨日与有雨日的稳定性参数的代表性在当前与未来气候中基本不变。这一结果表明，在全球变暖的影响下，在天气学未扰动的环境中，有利于午后降水的环境特征不会改变。
Understanding and forecasting of summertime afternoon precipitation due to rapidly developing cumulonimbus clouds without any significant synoptic-scale influences are important to prevent and mitigate the induced disasters. Future changes in the behavior of such precipitation events have recently gained scientific and societal interests. This study investigates the environmental stability for afternoon precipitation that develops under synoptically undisturbed conditions in summer by using the outputs of 20-km-mesh, super-high-resolution atmospheric general circulation model (GCM) simulations for a present, a near-future, and a future climate under global warming with the Intergovernmental Panel on Climate Change A1B emission scenario. The Kanto Plain was chosen as the analysis area. After verifying the usefulness of the GCM present-climate outputs with observations and gridded mesoscale analyses, we examine the future changes in the environmental stability for the afternoon precipitation by conducting statistical analyses. In the future climates, temperature lapse rate decreased in the lower troposphere, while water vapor mixing ratio increased throughout the deep troposphere. The changes in the temperature and moisture profiles resulted in the increase in both precipitable water vapor and convective available potential energy. These projected changes will be enhanced with the future period. Furthermore, the statistical analyses for the di¤erences of the stability parameters between no-rain and rain days under the synoptically undisturbed condition in each simulated climate period indicated that the representations of the stability parameters that distinguish no-rain and rain events are basically unchanged between the present and the future climates. This result suggests that the environmental characteristics favorable for afternoon precipitation in the synoptically undisturbed environments will not change under global warming.