Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesis
<p>Causal explanations for the 4.2 ka BP event are based on the amalgamation of seasonal and annual records of climate variability that was manifest across global regions dominated by different climatic regimes. However, instrumental and paleoclimate data indicate that se...
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| Series: | Climate of the Past |
| Online Access: | https://www.clim-past.net/15/781/2019/cp-15-781-2019.pdf |
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doaj-0b3d30a72cc54eef9755f0cefccb14952020-11-24T23:05:15ZengCopernicus PublicationsClimate of the Past1814-93241814-93322019-04-011578179310.5194/cp-15-781-2019Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesisA. Perşoiu0A. Perşoiu1M. Ionita2H. Weiss3Emil Racoviţă Institute of Speleology, Romanian Academy, Cluj Napoca, 400006, RomaniaStable Isotope Laboratory, Ştefan cel Mare University, Suceava, 720229, RomaniaAlfred Wegener Institute, Helmholtz Center for Polar and Marine Research, 27570 Bremerhaven, GermanySchool of Forestry and Environmental Studies, Yale University, New Haven, CT, USA<p>Causal explanations for the 4.2 ka BP event are based on the amalgamation of seasonal and annual records of climate variability that was manifest across global regions dominated by different climatic regimes. However, instrumental and paleoclimate data indicate that seasonal climate variability is not always sequential in some regions. The present study investigates the spatial manifestation of the 4.2 ka BP event during the boreal winter season in Eurasia, where climate variability is a function of the spatiotemporal dynamics of the westerly winds. We present a multi-proxy reconstruction of winter climate conditions in Europe, west Asia, and northern Africa between 4.3 and 3.8 ka. Our results show that, while winter temperatures were cold throughout the region, precipitation amounts had a heterogeneous distribution, with regionally significant low values in W Asia, SE Europe, and N Europe and local high values in the N Balkan Peninsula, the Carpathian Mountains, and E and NE Europe. Further, strong northerly winds were dominating in the Middle East and E and NE Europe. Analyzing the relationships between these climatic conditions, we hypothesize that in the extratropical Northern Hemisphere, the 4.2 ka BP event was caused by the strengthening and expansion of the Siberian High, which effectively blocked the moisture-carrying westerlies from reaching W Asia and enhanced outbreaks of cold and dry winds in that region. The behavior of the winter and summer monsoons suggests that when parts of Asia and Europe were experiencing winter droughts, SE Asia was experiencing similar summer droughts, resulting from failed and/or reduced monsoons. Thus, while in the extratropical regions of Eurasia the 4.2 ka BP event was a century-scale winter phenomenon, in the monsoon-dominated regions it may have been a feature of summer climate conditions.</p>https://www.clim-past.net/15/781/2019/cp-15-781-2019.pdf |
| collection |
DOAJ |
| language |
English |
| format |
Article |
| sources |
DOAJ |
| author |
A. Perşoiu A. Perşoiu M. Ionita H. Weiss |
| spellingShingle |
A. Perşoiu A. Perşoiu M. Ionita H. Weiss Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesis Climate of the Past |
| author_facet |
A. Perşoiu A. Perşoiu M. Ionita H. Weiss |
| author_sort |
A. Perşoiu |
| title |
Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesis |
| title_short |
Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesis |
| title_full |
Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesis |
| title_fullStr |
Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesis |
| title_full_unstemmed |
Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesis |
| title_sort |
atmospheric blocking induced by the strengthened siberian high led to drying in west asia during the 4.2 ka bp event – a hypothesis |
| publisher |
Copernicus Publications |
| series |
Climate of the Past |
| issn |
1814-9324 1814-9332 |
| publishDate |
2019-04-01 |
| description |
<p>Causal explanations for the 4.2 ka BP event are based on the
amalgamation of seasonal and annual records of climate variability that was
manifest across global regions dominated by different climatic regimes.
However, instrumental and paleoclimate data indicate that seasonal climate
variability is not always sequential in some regions. The present study
investigates the spatial manifestation of the 4.2 ka BP event during the boreal
winter season in Eurasia, where climate variability is a function of the
spatiotemporal dynamics of the westerly winds. We present a multi-proxy
reconstruction of winter climate conditions in Europe, west Asia, and
northern Africa between 4.3 and 3.8 ka. Our results show that, while winter
temperatures were cold throughout the region, precipitation amounts had a
heterogeneous distribution, with regionally significant low values in W Asia,
SE Europe, and N Europe and local high values in the N Balkan Peninsula, the
Carpathian Mountains, and E and NE Europe. Further, strong northerly winds
were dominating in the Middle East and E and NE Europe. Analyzing the
relationships between these climatic conditions, we hypothesize that in the
extratropical Northern Hemisphere, the 4.2 ka BP event was caused by the
strengthening and expansion of the Siberian High, which effectively blocked
the moisture-carrying westerlies from reaching W Asia and enhanced outbreaks
of cold and dry winds in that region. The behavior of the winter and summer
monsoons suggests that when parts of Asia and Europe were experiencing winter
droughts, SE Asia was experiencing similar summer droughts, resulting from
failed and/or reduced monsoons. Thus, while in the extratropical regions of
Eurasia the 4.2 ka BP event was a century-scale winter phenomenon, in the
monsoon-dominated regions it may have been a feature of summer climate
conditions.</p> |
| url |
https://www.clim-past.net/15/781/2019/cp-15-781-2019.pdf |
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