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<p>Much effort has been dedicated to analyzing the relationship between extratropical cyclone (ETC) characteristics and common climate modes. However, uncertainties remain regarding the connection between the climate modes and inherently noisy ETC characteristics across interannual and decadal scales. Here, we perform correlative and composite analyses to reveal potential impacts of the Pacific-North American pattern (PNA), El Niño–Southern Oscillation (ENSO), Interdecadal Pacific Oscillation (IPO), North Atlantic Oscillation (NAO), and smoothed decadal NAO on six ETC characteristics derived using an impacts-based tracking algorithm. The correlations of the ETC characteristics with the PNA or ENSO and their composite ETC anomalies exhibit numerous similarities, particularly in the correlation patterns of ETC frequency, intensity, and area over the North Pacific and eastern North America. However, El Niño exhibits positive correlations with ETC frequencies over East Asia and negative correlations with ETC lifespans over the Rocky Mountains lee storm track, while these correlations are absent for PNA. Moreover, the 250&#xa0;hPa geopotential height composite anomalies over the Pacific exhibit a northwest to southeast tilt for ENSO but not for PNA. The IPO has a smaller impact on ETCs than the PNA and ENSO over much of the North Pacific storm track. Meanwhile, the previously established high-poleward-of-low pattern in ETC frequency appears in the NAO correlation and composite maps; whereas this pattern is relegated mainly to the North Atlantic and some of western Europe on the decadal scale, rather than including eastern North America on the interannual scale. Physically, a positive phase of the PNA, ENSO and IPO cause equatorward shifts in the subtropical North Pacific jet, altering the waveguide into North America via changes in baroclinic and barotropic energy conversion. Subtle differences in PNA- and ENSO-induced ridge-trough positioning and baroclinic and barotropic energy conversion lead to different ETC anomaly patterns over Canada and geopotential height patterns over the eastern Pacific, respectively. Meanwhile, the North Atlantic climate modes involve shifts in the North Atlantic jet stream and energy conversion, which are much weaker on decadal than interannual time scales.</p>

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Connections of cold-season northern hemisphere extratropical cyclone characteristics to common climate modes during 1950–2023

  • 期刊论文

  • 发表日期：

    2025年11月20日

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  • Matthew S. Lynne,
  • Aiguo Dai

摘要

Much effort has been dedicated to analyzing the relationship between extratropical cyclone (ETC) characteristics and common climate modes. However, uncertainties remain regarding the connection between the climate modes and inherently noisy ETC characteristics across interannual and decadal scales. Here, we perform correlative and composite analyses to reveal potential impacts of the Pacific-North American pattern (PNA), El Niño–Southern Oscillation (ENSO), Interdecadal Pacific Oscillation (IPO), North Atlantic Oscillation (NAO), and smoothed decadal NAO on six ETC characteristics derived using an impacts-based tracking algorithm. The correlations of the ETC characteristics with the PNA or ENSO and their composite ETC anomalies exhibit numerous similarities, particularly in the correlation patterns of ETC frequency, intensity, and area over the North Pacific and eastern North America. However, El Niño exhibits positive correlations with ETC frequencies over East Asia and negative correlations with ETC lifespans over the Rocky Mountains lee storm track, while these correlations are absent for PNA. Moreover, the 250 hPa geopotential height composite anomalies over the Pacific exhibit a northwest to southeast tilt for ENSO but not for PNA. The IPO has a smaller impact on ETCs than the PNA and ENSO over much of the North Pacific storm track. Meanwhile, the previously established high-poleward-of-low pattern in ETC frequency appears in the NAO correlation and composite maps; whereas this pattern is relegated mainly to the North Atlantic and some of western Europe on the decadal scale, rather than including eastern North America on the interannual scale. Physically, a positive phase of the PNA, ENSO and IPO cause equatorward shifts in the subtropical North Pacific jet, altering the waveguide into North America via changes in baroclinic and barotropic energy conversion. Subtle differences in PNA- and ENSO-induced ridge-trough positioning and baroclinic and barotropic energy conversion lead to different ETC anomaly patterns over Canada and geopotential height patterns over the eastern Pacific, respectively. Meanwhile, the North Atlantic climate modes involve shifts in the North Atlantic jet stream and energy conversion, which are much weaker on decadal than interannual time scales.