阿留申低压与阿拉斯加湾上空温度的局地正反馈过程研究
投稿时间: 2017-11-17  最后修改时间: 2017-12-26  点此下载全文
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作者单位E-mail
平已川 国防科技大学气象海洋学院 pingyichuan1991@sina.com 
谭言科 国防科技大学气象海洋学院 polaristan@163.com 
李崇银 国防科技大学气象海洋学院  
中文摘要:利用欧洲中期天气预报中心(ECMWF)1900-2016年的再分析资料,研究了北太平洋冬季1000hPa等压面位势高度场和温度场定常波的特征,分析了阿拉斯加湾暖区温度变化的原因,探讨了阿留申低压及与其相伴的热力强迫中心之间的内在联系。结果表明,冬季1000hPa等压面位势高度准定常波表现为阿留申低压,温度准定常波表现为位于欧亚大陆的冷区和位于阿拉斯加湾的暖区,其中阿拉斯加湾暖区温度与阿留申低压强度存在更显著的相关关系,当阿拉斯加湾暖区温度偏高时,阿留申低压增强,位置偏东。这种良好的关系可由行星尺度的气压场和温度场之间的正反馈来解释。冬季近地面大气对北太平洋海盆尺度热力强迫的Rossby波响应形成了阿留申低压,其东侧的暖平流使准定常热源加强东移,大气Rossby波响应的结果导致阿留申低压也加强东移,反过来又使阿拉斯加湾暖平流增强,温度升高,由此形成了阿留申低压与阿拉斯加湾暖区温度的正反馈过程。
中文关键词:阿留申低压,阿拉斯加湾暖区温度,正反馈,Rossby波响应,温度平流
 
Local Positive Feedback between Aleutian Low and Temperature over Alaska Bay
Abstract:By using ECMWF reanalysis data from 1900 to 2016, the characteristics of the quasi-stationary wave of the geopotential height and temperature on 1000hPa over the Northern Pacific in winter, the reason that the temperature of Alaska Bay warm zone changes and the inherent connection between the Aleutian low and its concomitant thermal forcing center are deeply analyzed. The results show that the quasi-stationary wave of geopotential height appears as Aleutian low while temperature appears as cold area over Eurasia and warm zone over Alaska Bay. There is a more significant correlation between the temperature of Alaska Bay warm zone and the intensity of Aleutian low. The warmer of Alaska Bay warm zone, the stronger and the more eastward of Aleutian low. This good relationship can be explained by the positive feedback between pressure and temperature at planetary scale. The Aleutian low is the result of Rossby wave response at the near-surface atmosphere in winter to the North Pacific thermally forcing at basin scale, and its eastern warm advection makes the quasi-stationary heat source strengthen and eastward. In such a way the atmospheric Rossby wave response also causes the Aleutian low to reinforce and move eastward, and it in turn leads to the warm advection stronger and warmer over Alaska Bay. As a result, it is essentially a positive feedback between Aleutian Low and temperature over Alaska Bay.
keywords:Aleutian Low, Warm zone of Alaska bay, Positive feedback, Rossby wave response, Temperature advection
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