The effects of gravity waves on ozone over the Tibetan Plateau
The effects of gravity waves on ozone over the Tibetan Plateau
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DOI：
10.1016/j.atmosres.2023.107204
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发表时间：
2023-12
影响因子：
5.5
通讯作者：
Shujie Chang;Haotian He;Dong Huang
中科院分区：
文献类型：
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作者：
Shujie Chang;Haotian He;Dong Huang
青藏高原上空的臭氧层对全球天气和气候有重要影响。作为大气重力波(GWS)的重要来源，TP也是全球平流层-对流层交换(STE)的关键区域，但从GW的角度探讨TP上空臭氧含量低的原因一直很少。本文利用高光谱大气红外探测仪(AIRS)资料，提取了青藏高原上空的GW和深对流，并分析了相应事件的臭氧统计特征。结果表明：(1)AIR观测到的GWS主要出现在中纬度地区，最大出现频率为>；10%，且强度随经度变化。在东南亚、中美洲和中非的海岸已经确定了三个大价值区域。(2)热带辐合区(ITCZ)是最大的深部对流区域，东亚季风区、中美洲和中非是三个较大的数值中心。其中，印度季风区、菲律宾以东的西北太平洋区、南海西侧中国海是东亚季风区内的大值区，最大出现频率超过15%。(3)TP是对流重力波的高频区。在青藏高原南麓的大部分地区，与对流有关的GWS出现的频率为30%-50%。青藏高原及其邻近地区的深对流几乎都伴随有GWS，出现频率为60-90%。(4)综合分析结果表明，GWS或深对流的发生伴随着TP南麓大部分地区的臭氧负异常，表明臭氧积分柱数量减少。(5)分析了云量、云顶高度、对流层顶高度、长波辐射(OLR)等气象要素的异常分布，结果表明，GWS或深对流的存在具有双重效应。这种影响不仅增加了云的生成，有利于对流，而且还抬高了云顶高度，促进了高云的形成，有些甚至超过了对流层顶。此外，GW或深对流的发生也会影响对流层顶高度，加强对流活动，促进低浓度臭氧从下层向上输送到上层，从而导致臭氧积分柱量的减少。
The ozone valley over the Tibetan Plateau (TP) has an important effect on global weather and climate. As a significant source of atmospheric gravity waves (GWs), TP is also a key area of global stratosphere-troposphere exchange (STE), yet the exploration of the causes of low ozone values over the TP has been scarce from the perspective of GW. In this paper, we used the hyperspectral Atmospheric Infrared Sounder (AIRS) data to extract GWs and deep convection over the TP and analyzed the statistical characteristics of ozone for corresponding events. The results show that: (1) The GWs observed by AIRS mainly occur in the mid-latitude region, with a maximum frequency of >10%, and their intensity varies with longitude. Three large-value regions have been identified on the coast of Southeast Asia, Central America, and Central Africa. (2) Most deep convection occurs in the Intertropical Convergence Zone (ITCZ), with three large value centers in the East Asian monsoon region, Central America and Central Africa. Among them, the Indian monsoon region, the Northwest Pacific region to the east of the Philippines, and the western side of the South China Sea (SCS) are the large-value areas within the East Asian monsoon region, with the maximum occurrence frequency exceeding 15%. (3) TP is a region with a large frequency of convective gravity waves. In most areas of the southern foothills of the TP, the frequency of GWs related to convection is 30%–50%. Almost all deep convection over the TP and its adjacent areas are accompanied by GWs, with a frequency of 60–90%. (4) The composite analysis results show that the occurrence of GWs or deep convection is accompanied by negative anomalies of ozone in most areas of the southern foothills of the TP, indicating a decrease in the integrated column amount of ozone. (5) By analyzing the anomaly distribution of meteorological elements such as cloud fraction, cloud top height, tropopause height, and outgoing longwave radiation (OLR), the results show a dual effect in the presence of GWs or deep convection. The effect involves not only an increased generation of clouds, conducive to convection but also elevated cloud top height, promoting the formation of high clouds, some even beyond the tropopause. In addition, the occurrence of GW or deep convection can also affect the tropopause height, strengthen convective activity, and facilitate the upward transfer of low-concentration ozone from the lower layer to the upper layer, thereby causing a decrease in the integrated column amount of ozone.