Subseasonal Great Plains Rainfall via Remote Extratropical Teleconnections: Regional Application of Theory‐Guided Causal Networks
Subseasonal Great Plains Rainfall via Remote Extratropical Teleconnections: Regional Application of Theory‐Guided Causal Networks
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DOI：
10.1029/2022jd037795
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发表时间：
2023-02
期刊：
影响因子：
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通讯作者：
K. Malloy;B. Kirtman
中科院分区：
文献类型：
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作者：
K. Malloy;B. Kirtman
美国夏季降雨长期预测能力较低。季风变化，特别是西北太平洋季风（WNPM）和/或东亚季风（EAM）地区，可以通过强迫Rossby波响应影响美国大平原水文气候变化。在这里，我们探讨了亚季节季风变化作为大平原降雨的可预测性的来源。北方夏季季节内振荡（BSISO）与大平原对流和大平原低空急流（LLJ）异常以及跨太平洋波列有关。使用因果效应网络，我们发现BSISO相关的位势高度异常和大平原降雨异常之间的时间约为2周;因此，BSISO对流可能是大平原对流异常亚季节预测的有价值的预测机会。更具体地说，因果联系模式/地图显示，高于正常的每周EAM降雨量，而不是WNPM降雨量或东亚地区的一般位势高度活动，与大平原LLJ加强和大平原对流活跃在接下来的一周有因果关系。
Long‐range U.S. summer rainfall prediction skill is low. Monsoon variability, especially over the West North Pacific Monsoon (WNPM) and/or East Asian Monsoon (EAM) region, can influence U.S. Great Plains hydroclimate variability via a forced Rossby wave response. Here, we explored subseasonal monsoon variability as a source of predictability for Great Plains rainfall. The boreal summer intraseasonal oscillation (BSISO) is related to Great Plains convection and Great Plains low‐level jet (LLJ) anomalies as well as a cross‐Pacific wave train. Using a causal effect network, we found that the time between BSISO‐related geopotential height anomalies and Great Plains rainfall anomalies is about 2 weeks; therefore, BSISO convection may be a valuable forecast of opportunity for subseasonal prediction of Great Plains convection anomalies. More specifically, causal link patterns/maps revealed that the above‐normal weekly EAM rainfall, rather than WNPM rainfall or general geopotential height activity over the East Asia, was causally linked to Great Plains LLJ strengthening and active Great Plains convection the following week.