High‐Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States
High‐Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States
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DOI：
10.1002/2017ef000642
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发表时间：
2017-12
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影响因子：
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通讯作者：
Zachary Zobel;Jiali Wang;D. Wuebbles;V. Kotamarthi
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文献类型：
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作者：
Zachary Zobel;Jiali Wang;D. Wuebbles;V. Kotamarthi
本研究的目的是利用具有不同边界条件的高空间分辨率动态降尺度模式模拟集合来检验21世纪美国大陆（CONUS）极端温度的预估。降尺度使用了空间分辨率为12公里的天气研究与预报模式，以及三个不同的耦合模式比对项目第5阶段全球气候模式的输出，这些模式提供了两种不同的未来温室气体（GHG）浓度轨迹下的边界条件。将两个年代际长度时间片（2045-2054和2085-2094）的结果与历史10年（1995-2004）进行了比较。分析了CONUS 7个气候凝聚区日最高/最低气温的概率密度函数。研究了不同边界条件和未来温室气体浓度对极端事件（如热浪和温度高于95°F的日子）的影响。结果表明：未来夏季极端暖温强度显著增加，冬季极端冷温频率显著减少；夏季日最高温度的分布经历了显著的暖侧偏移和变率的增加，而冬季日最低温度的分布则经历了不太显著的暖侧偏移和变率的减少。在“一切照旧”的情况下，预计大多数CONUS每年至少发生5 - 10次为期5天的热浪，到本世纪末，≥95华氏度的天数将增加1-2个月。
The aim of this study is to examine projections of extreme temperatures over the continental United States (CONUS) for the 21st century using an ensemble of high spatial resolution dynamically downscaled model simulations with different boundary conditions. The downscaling uses the Weather Research and Forecast model at a spatial resolution of 12 km along with outputs from three different Coupled Model Intercomparison Project Phase 5 global climate models that provide boundary conditions under two different future greenhouse gas (GHG) concentration trajectories. The results from two decadal‐length time slices (2045–2054 and 2085–2094) are compared with a historical decade (1995–2004). Probability density functions of daily maximum/minimum temperatures are analyzed over seven climatologically cohesive regions of the CONUS. The impacts of different boundary conditions as well as future GHG concentrations on extreme events such as heat waves and days with temperature higher than 95°F are also investigated. The results show that the intensity of extreme warm temperature in future summer is significantly increased, while the frequency of extreme cold temperature in future winter decreases. The distribution of summer daily maximum temperature experiences a significant warm‐side shift and increased variability, while the distribution of winter daily minimum temperature is projected to have a less significant warm‐side shift with decreased variability. Using “business‐as‐usual” scenario, 5‐day heat waves are projected to occur at least 5–10 times per year in most CONUS and ≥95°F days will increase by 1–2 months by the end of the century.