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利用1979-2015年美国环境预报中心和美国大气研究中心发布的再分析资料和由日本海洋科学技术中心提供的El Ni?o/La Ni?a Modoki距平指数(EMI)资料,对比研究了近36 a冬季两类El Ni?o-南方涛动(ENSO)事件对欧亚关键区阻塞高压(阻高)的影响及其环流成因.结果表明,当发生El Ni?o(EN)事件时,欧亚3个关键区瞬时阻塞都有不同程度的减小,尤其是乌拉尔山地区瞬时阻塞减少32%,阻塞事件的平均持续天数降低了14.7%;La Ni?a(LN)事件导致乌拉尔山地区瞬时阻塞偏多53%,阻塞事件的平均持续天数增多27.9%,但导致了鄂霍次克海地区阻塞事件的平均持续天数减少24%;新型海温异常模态ENSO Modoki对于欧亚阻高的影响与传统的ENSO事件不同.发生EN Modoki时,与正常年份相比,欧亚3个关键区瞬时阻塞都有不同程度的增加,其中鄂霍次克海地区的瞬时阻塞偏多最多,达到55%,阻塞事件的平均持续天数增多18.2%;发生LN Modoki事件时,乌拉尔山地区瞬时阻塞偏多15%,阻塞事件平均持续天数偏多25%,但鄂霍次克海地区瞬时阻塞偏少29%,阻塞事件的平均持续天数偏少10.6%,两类ENSO事件对于贝加尔湖地区的阻高影响均较小.两类ENSO事件对阻高影响不同的直接原因是其对大气环流影响的不同.从500 hPa位势高度场及风场的配置可见,当发生EN事件时,乌拉尔山及鄂霍次克海地区风场有气旋性环流异常,配合位势高度场负异常,导致阻高偏少;发生LN事件时,乌拉尔山及贝加尔湖西部偏北的地区有大范围反气旋性环流异常,500 hPa位势高度偏强,阻高偏多;而在EN Modoki事件发生时,欧亚3个关键区的500 hPa位势高度均有不同程度的正异常,有利于3个地区阻高的偏多;在LN Modoki事件下,乌拉尔山及贝加尔湖北侧地区位势高度偏高,有利于这两个地区阻高的偏多,而不利于鄂霍次克海地区阻高的生成.
Based on the reanalysis data released by the US Environmental Foreclosure Center and the American Center for Atmospheric Research from 1979 to 2015 and the El Niño / La Niña Modoki Anomaly Index (EMI) data provided by the Japan Marine Science and Technology Center, 36 a The effects of two types of El Niño-Southern Oscillation (ENSO) event on the blocking high pressure in Europe and Asia during the winter and the genesis of the circulation The results show that when the El Niño event occurs, The instantaneous occlusions in the three key areas of Eurasia decreased to some extent. Especially, the instantaneous occlusion in the Ural Mountains decreased by 32% and the average duration of occlusion events decreased by 14.7%. La Niña (LN) event caused the Ural Mountains While the average duration of occlusion events increased by 27.9%, while the mean duration of occlusion events in the Sea of Okhotsk decreased by 24%. The effects and traditions of the new SST anomaly modeled on ENSO Modoki Of the ENSO events were different.When EN Modoki occurred, compared with the normal years, the instantaneous occlusion of the three key areas in Eurasia increased to some extent, of which the instantaneous occlusion in the Sea of Okhotsk was mostly the most, reaching 55% The average duration of the increase of 18.2%; In the LN Modoki event, the Ural Mountains occured more than 15% for instantaneous occlusion and the average duration of occlusion events by 25%, while the transient blockage in the Sea of Okhotsk was 29% less than that for the Sea of Okhotsk and 10.6% less for the average duration of occlusion events. The two types of ENSO events have a small impact on the resistance of the Baikal region, and the direct impact of the two ENSO events on the drag height is that they have different effects on the atmospheric circulation.From the 500 hPa geopotential height field and the wind field configuration, , When the EN event occurred, the cyclones in the Ural Mountains and the Sea of Okhotsk had a cyclonic circulation anomaly with negative anomalies of the geopotential height field, which resulted in a decrease of the resistance height. In the event of LN, the Ural Mountains and the western part of Lake Baikal are northerly , There is a wide range of anomalous anticyclone circulation anomalies with a 500 hPa geopotential height and a high resistance level. In the event of EN Modoki event, the geopotential height at 500 hPa in the three key areas of Eurasia is different to some extent In the case of LN Modoki, the high altitude in the Ural Mountains and the northern part of Lake Baikal is favorable to the high resistance in both areas, which is not conducive to the development of the Okhotsk Kehai area high resistance to the formation.