中国南方持续性低温雨雪冰冻事件环流分型特征
发布时间：2018-09-11 17:52
【摘要】：针对1980年以来南方持续性低温雨雪冰冻事件的8次过程及其相关降水温度观测资料和大气环流再分析资料,利用客观分析方法进行环流分型并分析其关键分型特征。结果表明,我国南方持续性低温雨雪冰冻事件至少有两种大尺度环流分型,具体表现为:1)单阻型:500 hPa阻塞高压位于贝加尔湖地区,东亚大槽位置偏东,高度场上中亚以及我国大部分地区以负异常为主,事件极有可能发生在AO正位相背景下;高层(200hPa)副热带急流位于青藏高原西侧部分异常增强;低层(850 hPa)冷空气经我国东北部向西南方向输送;低层(850 hPa)水汽输送主要为两条,分别为经孟加拉湾的西南低空急流和来自南海的偏南气流;多数个例对流层低层具有逆温结构;2)双阻型:500 hPa阻塞高压位于乌拉尔山地区和鄂霍茨克海地区,东亚大槽比单阻型事件期间的东亚大槽强度更强,位置偏西,极地位势高度场主要处于正异常,事件多半可能发生在AO负位相背景下;高层(200 hPa)副热带急流主要在东亚中纬度区域异常增强,并且急流正异常中心相较于单阻型更偏北;低层(850 hPa)冷空气经贝加尔湖南下影响我国;低层(850 hPa)水汽输送主要为西南低空急流;对流层下层大气没有明显逆温层。此外,通过对事件期间行星尺度罗斯贝波能量频散诊断分析,揭示了行星尺度罗斯贝波能量频散对于事件期间大尺度异常环流的稳定维持以及南支槽的活动有着重要作用。2016年1月21日至25日,我国大部分地区遭受强寒潮事件。此次大范围强寒潮事件发生较快,持续时间短。从大尺度环流背景角度分析此次事件的特征及成因,并与2008年持续性低温雨雪冰冻事件作比较,经过研究发现:1)阻塞高压区域有较强的能量频散,而其上游并未有明显能量输送到阻塞区域,从而使阻塞高压演变快速并崩溃,而2008年持续性低温雨雪冰冻雪事件则是由于阻塞区域上游不断有能量输送至阻塞区,使得阻塞高压不断维持,形成稳定的阻塞形势;2)地面西伯利亚高压比2008年持续性低温雨雪冰冻事件异常偏强,冷空气也异常偏强,不利于降水的发生;3)中低纬度低槽系统不活跃,使得水汽输送较弱,而2008年中低纬度低槽系统较强且活跃,为2008年事件提供充足的水汽;4)西太平洋副热带高压相较于2008年事件期间位置偏东偏南,自南海水汽输送较弱;5)冷空气路径与双阻型持续性低温雨雪冰冻事件相同。
[Abstract]:Based on the 8 processes of the continuous low temperature rain and snow freezing events in southern China since 1980 and the related precipitation temperature observation data and the atmospheric circulation reanalysis data, the circulation classification and its key classification characteristics are analyzed by objective analysis method. The results show that there are at least two types of large-scale circulation patterns for the persistent low temperature, rain and snow freezing events in southern China, which are manifested as: 1) the single resistance type of the 500 hPa blocking high is located in Baikal Lake region, and the East Asian trough is located eastward. In Central Asia and in most parts of China, the events may occur in the background of AO positive phase, the 200hPa subtropical jet is located in the west of Qinghai-Xizang Plateau, and the subtropical jet is enhanced in the west of Qinghai-Xizang Plateau. The cold air in the lower layer (850 hPa) is transported to the southwest through the northeast of China, and the vapor transport in the lower layer (850 hPa) is mainly in the southwest of the Bay of Bengal and the southerly stream from the South China Sea. In most cases, the tropospheric lower layer has a temperature inversion structure 2) the double resistance type hPa blocking high is located in the Ural Mountains and the Okhotsk Sea. The East Asian trough is stronger in intensity and westward than the East Asian trough during the single resistive event. The polar geopotential height field is mainly in positive anomaly, most of the events may take place in the AO negative background, the upper (200 hPa) subtropical jet is mainly anomalous in the mid-latitude region of East Asia, and the center of the positive anomaly of the jet is farther north than that of the single-resistive type. The cold air in the lower layer (850 hPa) affects China south of Baikal Lake, the vapor transport in the lower layer (850 hPa) is mainly in the southwest low level jet stream, and there is no obvious inversion layer in the lower troposphere atmosphere. In addition, through the diagnosis and analysis of the energy dispersion of the planetary scale Rossberg wave during the event, It is revealed that the energy dispersion of the planetary Rossby wave plays an important role in maintaining the large scale anomalous circulation and the activity of the southern branch trough during the event. From January 21 to 25, 2016, most areas of China suffered from strong cold wave events. The large-scale strong cold wave events occurred quickly, the duration of a short period. The characteristics and causes of the event are analyzed from the point of view of large-scale circulation background, and compared with the persistent low temperature, rain, snow and freezing events in 2008. It is found that there is a strong energy dispersion in the blocking high pressure region of 1: 1. However, there is no obvious energy flowing upstream to the blocking area, which causes the blocking high to evolve rapidly and collapses. However, the persistent low temperature, rain, snow and frozen snow events in 2008 are due to the continuous energy transfer from the upstream of the blocking area to the blocking area. This makes the blocking high constantly maintained and forms a stable blocking situation. 2) the Siberian high on the ground is unusually stronger than the persistent low temperature, rain, snow and freezing events in 2008, and the cold air is also unusually strong. The low trough system in middle and low latitudes is not active, which makes the water vapor transport weaker, while in 2008, the low trough system in middle latitude and low latitude is stronger and more active. To provide sufficient water vapor for the 2008 event) the position of the Western Pacific subtropical high is eastward and southward during the 2008 event, and the water vapor transport from the South China Sea is weaker than that of the South China Sea. 5) the cold air path is the same as the double resistive persistent low temperature rain and snow freezing event.
【学位授予单位】：中国气象科学研究院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P434;P429
[Abstract]:Based on the 8 processes of the continuous low temperature rain and snow freezing events in southern China since 1980 and the related precipitation temperature observation data and the atmospheric circulation reanalysis data, the circulation classification and its key classification characteristics are analyzed by objective analysis method. The results show that there are at least two types of large-scale circulation patterns for the persistent low temperature, rain and snow freezing events in southern China, which are manifested as: 1) the single resistance type of the 500 hPa blocking high is located in Baikal Lake region, and the East Asian trough is located eastward. In Central Asia and in most parts of China, the events may occur in the background of AO positive phase, the 200hPa subtropical jet is located in the west of Qinghai-Xizang Plateau, and the subtropical jet is enhanced in the west of Qinghai-Xizang Plateau. The cold air in the lower layer (850 hPa) is transported to the southwest through the northeast of China, and the vapor transport in the lower layer (850 hPa) is mainly in the southwest of the Bay of Bengal and the southerly stream from the South China Sea. In most cases, the tropospheric lower layer has a temperature inversion structure 2) the double resistance type hPa blocking high is located in the Ural Mountains and the Okhotsk Sea. The East Asian trough is stronger in intensity and westward than the East Asian trough during the single resistive event. The polar geopotential height field is mainly in positive anomaly, most of the events may take place in the AO negative background, the upper (200 hPa) subtropical jet is mainly anomalous in the mid-latitude region of East Asia, and the center of the positive anomaly of the jet is farther north than that of the single-resistive type. The cold air in the lower layer (850 hPa) affects China south of Baikal Lake, the vapor transport in the lower layer (850 hPa) is mainly in the southwest low level jet stream, and there is no obvious inversion layer in the lower troposphere atmosphere. In addition, through the diagnosis and analysis of the energy dispersion of the planetary scale Rossberg wave during the event, It is revealed that the energy dispersion of the planetary Rossby wave plays an important role in maintaining the large scale anomalous circulation and the activity of the southern branch trough during the event. From January 21 to 25, 2016, most areas of China suffered from strong cold wave events. The large-scale strong cold wave events occurred quickly, the duration of a short period. The characteristics and causes of the event are analyzed from the point of view of large-scale circulation background, and compared with the persistent low temperature, rain, snow and freezing events in 2008. It is found that there is a strong energy dispersion in the blocking high pressure region of 1: 1. However, there is no obvious energy flowing upstream to the blocking area, which causes the blocking high to evolve rapidly and collapses. However, the persistent low temperature, rain, snow and frozen snow events in 2008 are due to the continuous energy transfer from the upstream of the blocking area to the blocking area. This makes the blocking high constantly maintained and forms a stable blocking situation. 2) the Siberian high on the ground is unusually stronger than the persistent low temperature, rain, snow and freezing events in 2008, and the cold air is also unusually strong. The low trough system in middle and low latitudes is not active, which makes the water vapor transport weaker, while in 2008, the low trough system in middle latitude and low latitude is stronger and more active. To provide sufficient water vapor for the 2008 event) the position of the Western Pacific subtropical high is eastward and southward during the 2008 event, and the water vapor transport from the South China Sea is weaker than that of the South China Sea. 5) the cold air path is the same as the double resistive persistent low temperature rain and snow freezing event.
【学位授予单位】：中国气象科学研究院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P434;P429
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