...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Climate dynamics >Bjerknes' hypothesis on the coldness during AD 1790-1820 revisited
【24h】

Bjerknes' hypothesis on the coldness during AD 1790-1820 revisited

机译：Bjerknes关于公元1790-1820年寒冷的假设被重新审视

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The aim of this paper is to re-examine and quantify a hypothesis first put forward by J. Bjerknes concerning the anomalous coldness during the AD 1790-1820 period in western Europe. Central to Bjerknes' hypothesis is an anomalous interaction between ocean and atmosphere studied here using an ocean-atmosphere coupled climate model of intermediate complexity. A reconstruction of the sea-level pressure pattern over the North Atlantic sector averaged over the period 1790-1820 is assimilated in this model, using a recently developed technique which has not been applied to paleoclimatic modelling before. This technique ensures that averaged over the simulation the reconstructed pattern is retrieved whilst leaving atmospheric and climatic variability to develop freely. In accordance with Bjerknes' hypothesis, the model results show anomalous southward advection of polar waters into the northeastern North Atlantic in the winter season, lowering the sea-surface temperatures (SSTs) there with 0.3-1.0 degrees C. This SST anomaly is persistent into the summer season. A decrease in western European winter surface air temperatures is found which can be related almost completely to advection of cold polar air. The decrease in summer surface air temperatures is related to a combination of low SSTs and anomalous atmospheric circulation. The modelled winter and summer temperatures in Europe compare favourably with reconstructed temperatures. Enhanced baroclinicity at the Atlantic seaboard and over Baffin Island is observed along with more variability in the position of the North Atlantic storm tracks. The zone of peak winter storm frequency is drawn to the European mid-latitudes.
机译：本文的目的是重新审查和量化J. Bjerknes最初提出的关于西欧1790-1820年期间的异常寒冷的假设。 Bjerknes假说的核心是，本文使用中等复杂性的海洋-大气耦合气候模型研究了海洋与大气之间的异常相互作用。使用最近开发的技术（该方法以前未应用于古气候模拟），该模型吸收了1790-1820年期间平均的北大西洋海平面气压模式的重建。这项技术可确保在模拟过程中取平均值，而在保持大气和气候变化自由发展的同时，可以检索重建的模式。根据Bjerknes的假设，模型结果显示，冬季冬季，极地水向南平流异常进入北大西洋东北部，使那里的海表温度（SST）降低了0.3-1.0摄氏度。这种SST异常持续存在夏季。发现西欧冬季地表气温下降，这几乎完全与极地冷空气的平流有关。夏季地面气温的下降与海表温度低和大气环流异常有关。欧洲模拟的冬季和夏季温度与重建后的温度相比具有优势。观察到大西洋沿岸和巴芬岛上空的斜压增强，并且北大西洋风暴路径的位置变化更大。冬季风暴高峰频率区域被吸引到欧洲中纬度地区。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号