Study on mechanism of formation and variability of the Arctic Oscillation

北极涛动形成及变化机制研究

基本信息

批准号：
11640421
负责人：
YAMAZAKI Koji
金额：
$ 1.98万
依托单位：
HOKKAIDO UNVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640421/
关键词：
Arctic Oscillation North Atlantic Oscillation wave-mean flow interaction Troposphere-Stratosphere interaction Sea ice on Sea of Okhotsk 極夜ジェット振動天候レジームプラネタリー波

项目摘要

The Arctic Oscillation the most dominant variation mode of the wintertime sea-level pressure in the Northern extratropics and it is the seesaw variation between the midlatitudes and the Arctic region. It has an equivalent barotropic structure and it has a signal up to the lower stratosphere. This mode resembles the North Atlantic Oscillation, but it is more annular and global. It was named as the Arctic Oscillation by Thompson and Wallace(1998).A perpetual February simulation by an AGCM clearly showed the Arctic Oscillation is not a forced mode but an internal mode of the atmosphere. The composite analysis of the simulation results showed the dominance of the Arctic Oscillation is caused by the wave-mean flow interaction. Mostly planetary-scale wave contributes to the transition to positive and negative phases of the Arctic Oscillation and the synoptic-scale wave also contributes to the transition.The perpetual February experiment also shows that the wintertime Arctic Oscillation is related to the polar night jet oscillation in the stratosphere. When the polar night jet is stronger than normal, the Arctic Oscillation in the troposphere tends to shift to posituve phase.In reality after the stratospheric sudden warming, which corresponds to weak polar night jet and negative phase of the stratospheric Arctic Oscillation, the tropospheric Arctic Oscillation tends to have a negative phase, which bring severe cold weather in midlatitudes.In interannaul and intraseasonal time scales, the Arctic Oscillation has a good correlation with the winter climate over Eurasia, northern Japan and Sea of Okhotsk. Analyzing the sea ice extent over Sea of Okhotsk, it is found that the sea ice extent has a good correlation with the Arctic Oscillation(also with the North Atlantic Oscillation).

北极涛动是北温带冬季海平面气压最主要的变化模式，是中纬度地区与北极地区之间的拉锯式变化。它具有等效的正压结构，并且信号可达平流层下部。这种模式类似于北大西洋涛动，但它更具环形性和全球性。汤普森和华莱士将其命名为北极涛动（1998）。AGCM 的永久二月模拟清楚地表明北极涛动不是强迫模式，而是大气的内部模式。模拟结果的综合分析表明，北极涛动的主导地位是由波浪与平均流的相互作用引起的。大多数行星尺度波有助于北极涛动向正相位和负相位的转变，天气尺度波也有助于这种转变。永久二月实验还表明，冬季北极涛动与极地夜间急流振荡有关。平流层。当极夜急流比正常强时，对流层北极涛动往往会转向正位相。现实中，平流层突然变暖后，对应极夜急流较弱，平流层北极涛动负位相，北极涛动往往有负相位，这会给中纬度地区带来严寒天气。在年际和季节内时间尺度上，北极涛动与冬季有很好的相关性欧亚大陆、日本北部和鄂霍次克海的气候。对鄂霍次克海海冰范围的分析发现，海冰范围与北极涛动（也与北大西洋涛动）有很好的相关性。