Diagnosing Non‐Gaussian Temperature Distribution Tails Using Back‐Trajectory Analysis
Diagnosing Non‐Gaussian Temperature Distribution Tails Using Back‐Trajectory Analysis
复制标题
使用后轨迹分析诊断非高斯温度分布尾部
DOI：
10.1029/2020jd033726
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
J. D. Neelin
中科院分区：
文献类型：
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作者：
A. Catalano;P. Loikith;J. D. Neelin
在整个地球仪上都存在表现出非高斯2米温度分布尾部的相干区域，这表明在未来变暖的情况下，极端温度的变化可能会以比关于平均值对称的基本分布更复杂的方式表现出来。为了进一步理解控制温度分布尾部形状的物理过程，这项工作利用了一个后向轨迹模型来诊断在显示非高斯尾部的选定外热带地区极端日平均温度发展的机制。虽然方向，距离和温度演变等特征在与极端温度日相关的反向轨迹中各不相同，但结果揭示了与大尺度环流中的首选模式相关的气团传播的主要途径。一个相对持久的天气系统会导致热平流，它与当地的地理特征相互作用，产生一个比高斯更短或更长的尾巴。与大气和海洋表面温度变率的经常性模式的显着关系进一步表明遥相关波模式和海洋温度对陆地上极端日温度发生的影响，尽管局部较小尺度的过程也很重要。在短尾位置传输极端温度的空气包通常起源于海洋环境，限制了温度极端的大小，而显示长冷尾的位置需要罕见的气象条件来传输来自极地源区的最冷空气，这些源区通常被地形或盛行风的下游部分阻挡。在所研究的地点，控制比高斯长的暖尾的过程更为微妙，而不是明显地由水平平流主导。研究结果为我们了解极端温度以及它们在区域尺度上未来可能如何变化提供了更多的见解。
Coherent regions exhibiting non‐Gaussian 2‐m temperature distribution tails are present across the globe, indicating changes in extreme temperatures under future warming may manifest in more complex ways than were the underlying distributions symmetric about the mean. To further the understanding of physical processes that govern temperature distribution tail shape, this work utilizes a back‐trajectory model to diagnose mechanisms for extreme daily mean temperature development at select extratropical locations exhibiting non‐Gaussian tails. Although characteristics such as direction, distance, and temperature evolution vary among back‐trajectories associated with extreme temperature days, results reveal principal pathways for air parcel propagation associated with preferred patterns in large‐scale circulation. A relatively persistent synoptic setup leads to thermal advection, which interacts with local geographic features to produce a shorter‐ or longer‐than‐Gaussian tail. Significant relationships with recurrent modes of atmospheric and sea surface temperature variability further suggest the influence of teleconnection wave patterns and ocean temperatures on extreme daily temperature occurrence over land, though local, smaller‐scale processes are also important. Air parcels transporting extreme temperatures at short‐tailed locations often originate in marine environments, constraining the magnitude of the temperature extreme, while locations exhibiting long cold tails require rare meteorological conditions to transport the coldest air from poleward source regions often partially blocked by topography or downstream of the prevailing wind. Processes governing longer‐than‐Gaussian warm tails at locations examined are more subtle and not as obviously dominated by horizontal advection. Results provide added insight into our understanding of temperature extremes and how they may change in the future at regional scales.