Characteristics and variations of low-level jets in the contrasting warm season precipitation extremes of 2006 and 2007 over the Southern Great Plains
Characteristics and variations of low-level jets in the contrasting warm season precipitation extremes of 2006 and 2007 over the Southern Great Plains
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2006年和2007年南部大平原暖季极端降水对比中低空急流的特征和变化
DOI：
10.1007/s00704-018-2492-7
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发表时间：
2019
影响因子：
3.4
通讯作者：
Z. Pu
中科院分区：
文献类型：
--
作者：
Derek Hodges;Z. Pu
本研究调查的结构变化，在美国南部大平原（SGP）在温暖的季节（WS）和它们的关联与降水极端的低空急流（LLJs），与一个子集的强烈对比水文年（HY）的2006年（HY 06;干旱）和2007年（HY 07;洪水）。联合S.美国国家环境预测中心的北方美国区域再分析（NARR）和第四阶段降水数据产品。大尺度的天气格局之间的两个WS变化很大，百慕大高的位置，强度和方向的差异，东部和热低到西部。诊断的复合结构和LLJs的变化，其环境条件，和相关的降水。两个WS之间LLJ的强度、方向和尺寸存在显著差异。与LLJ相关的环境特征的特点是在垂直速度，温度，湿度和不稳定性的时间和分布的显着差异。这些差异的时间，分布和降水强度之间的两个WS的影响进行了讨论。这项研究的结果得出结论，LLJ可能不是驱动水文极端的主要因素，但它确实改变了极端。在WS 2007中，LLJ增强了水文循环，在更广泛的区域产生更多的降水。在WS 2006中，LLJ可能是进入该地区的干空气平流的来源。同时，低空急流也是辐合和上升运动的来源，导致其出口区域出现降水极大值。
This study investigates structural variations in the low-level jets (LLJs) over the Southern Great Plains (SGP) in the USA during the warm season (WS) and their association with precipitation extremes, with a subset of the strongly contrasting hydrologic years (HY) of 2006 (HY06; drought) and 2007 (HY07; flood). The U. S. National Centers for Environmental Prediction’s Northern American Regional Reanalysis (NARR) and stage IV precipitation data products are used. The large-scale synoptic pattern varied substantially between the two WSs, with differences in the position, strength, and orientation of the Bermuda high to the east and thermal low to the west. The composite structure and variations of LLJs, their environmental conditions, and associated precipitation are diagnosed. Significant differences were noted in the strength, orientation, and dimensions of the LLJs between the two WSs. Environmental features related to the LLJ are characterized by notable differences in timing and distribution of the vertical velocity, temperature, moisture, and instability. The implications of these differences for the timing, distribution, and intensity of precipitation between the two WSs are discussed. Results from this study conclude that the LLJ may not have been a major factor in driving the hydrologic extremes, but it did modify the extremes. In WS 2007, the LLJ enhanced the hydrologic cycle to produce more precipitation over a broader area. In WS 2006, the LLJ was likely a source of dry air advection into the region. Meanwhile, the LLJ was also a source of convergence and rising motion, which lead to a precipitation maximum in its exit region.
影响因子：
3.2
作者：
J. Marsham;S. Trier;T. Weckwerth;James W. Wilson
通讯作者：
J. Marsham;S. Trier;T. Weckwerth;James W. Wilson