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<p>The interannual variations of persistent extreme cold events (ECE) in northeastern China (NEC) and associated tropical and high-latitude forcings were investigated through both observational analyses and idealized numerical model experiments. The yearly accumulated ECE number exhibits a marked interannual fluctuation at a dominant period of 2–3 years. During the more frequent ECE winters, the NEC is controlled by a local cyclonic anomaly. This cyclonic anomaly is a part of a quasi-barotropic Rossby wave train with an alternated cyclone-anticyclone-cyclone pattern across the Eurasian Continent. Accompanied with this Rossby wave train are positive sea surface temperature (SST) anomalies in the Barents Sea (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="382_2025_7749_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="55" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:{\text{S}\text{S}\text{T}}_{\text{B}\text{A}\text{S}}^{{\prime\:}}\)</EquationSource> </InlineEquation>) and enhanced precipitation over the Maritime Continent (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="382_2025_7749_Article_IEq2.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="55" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:{\text{P}\text{R}\text{E}}_{\text{M}\text{C}}^{{\prime\:}}\)</EquationSource> </InlineEquation>). The possible roles of the two forcing factors in triggering the Rossby wave train were further demonstrated through idealized general circulation model experiments. The results show that <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="382_2025_7749_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="55" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:{\text{S}\text{S}\text{T}}_{\text{B}\text{A}\text{S}}^{{\prime\:}}\)</EquationSource> </InlineEquation> stimulates a southeastward Rossby wave activity flux through induced local positive geopotential height anomalies, whereas <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="382_2025_7749_Article_IEq2.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="55" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:{\text{P}\text{R}\text{E}}_{\text{M}\text{C}}^{{\prime\:}}\)</EquationSource> </InlineEquation> tends to force a northeastward wave activity flux with anticyclonic anomalies in southern China and cyclonic anomalies over the northeastern Asia. The numerical experiments indicate that the effect of <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="382_2025_7749_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="55" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:{\text{S}\text{S}\text{T}}_{\text{B}\text{A}\text{S}}^{{\prime\:}}\)</EquationSource> </InlineEquation> is about 20–30% stronger than that of <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="382_2025_7749_Article_IEq2.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="55" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:{\text{P}\text{R}\text{E}}_{\text{M}\text{C}}^{{\prime\:}}\)</EquationSource> </InlineEquation>.</p>

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Interannual variations of persistent extreme cold events in northeastern China

  • 期刊论文

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  • 发表日期：

    2025年6月18日

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  • Ming Yang,
  • Tim Li,
  • Qingjiu Gao

摘要

The interannual variations of persistent extreme cold events (ECE) in northeastern China (NEC) and associated tropical and high-latitude forcings were investigated through both observational analyses and idealized numerical model experiments. The yearly accumulated ECE number exhibits a marked interannual fluctuation at a dominant period of 2–3 years. During the more frequent ECE winters, the NEC is controlled by a local cyclonic anomaly. This cyclonic anomaly is a part of a quasi-barotropic Rossby wave train with an alternated cyclone-anticyclone-cyclone pattern across the Eurasian Continent. Accompanied with this Rossby wave train are positive sea surface temperature (SST) anomalies in the Barents Sea ( \(\:{\text{S}\text{S}\text{T}}_{\text{B}\text{A}\text{S}}^{{\prime\:}}\) ) and enhanced precipitation over the Maritime Continent ( \(\:{\text{P}\text{R}\text{E}}_{\text{M}\text{C}}^{{\prime\:}}\) ). The possible roles of the two forcing factors in triggering the Rossby wave train were further demonstrated through idealized general circulation model experiments. The results show that \(\:{\text{S}\text{S}\text{T}}_{\text{B}\text{A}\text{S}}^{{\prime\:}}\) stimulates a southeastward Rossby wave activity flux through induced local positive geopotential height anomalies, whereas \(\:{\text{P}\text{R}\text{E}}_{\text{M}\text{C}}^{{\prime\:}}\) tends to force a northeastward wave activity flux with anticyclonic anomalies in southern China and cyclonic anomalies over the northeastern Asia. The numerical experiments indicate that the effect of \(\:{\text{S}\text{S}\text{T}}_{\text{B}\text{A}\text{S}}^{{\prime\:}}\) is about 20–30% stronger than that of \(\:{\text{P}\text{R}\text{E}}_{\text{M}\text{C}}^{{\prime\:}}\) .