Ozone variations over the northern subtropical region revealed by ozonesonde observations in Hanoi
Ozone variations over the northern subtropical region revealed by ozonesonde observations in Hanoi
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DOI：
10.1002/jgrd.50348
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发表时间：
2013-04
期刊：
影响因子：
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通讯作者：
S. Ogino;M. Fujiwara;M. Shiotani;F. Hasebe;Jun Matsumoto;Thuy Ha T Hoang;Tan Thanh T Nguyen
中科院分区：
文献类型：
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作者：
S. Ogino;M. Fujiwara;M. Shiotani;F. Hasebe;Jun Matsumoto;Thuy Ha T Hoang;Tan Thanh T Nguyen
利用越南河内（21°N，106°E）连续7年的臭氧探空资料，研究了臭氧混合比（OMR）的季节和亚季节变化。7年的平均季节变化在对流层上部和平流层下部（UTLS）区域（10-18 km）和对流层下部（约3 km）显示出较大的振幅，两个区域的标准偏差均由约30%的年平均值归一化。在UTLS地区，OMR的季节变化表现为冬季最小，春季至夏季最大。这种变化似乎是由水平输送的季节变化引起的。冬季赤道对流层的反气旋气流输送低OMR气团，夏季中纬度平流层的高OMR气团输送可能是UT区Rossby波破碎和LS区青藏高压的反气旋环流共同作用的结果。在对流层低层，春季最大值出现在3 km高度。生物质燃烧和对流层顶折叠的建议，作为可能的原因，这一最大。OMR的亚季节变化在UTLS区域（约15公里）和边界层（1公里以下）显示出较大的振幅，用年平均值归一化的标准差大于40%。冬季UTLS区的OMR变化与纬向风呈负相关。这种关系表明，在河内观测到的低OMR是从赤道地区输送过来的。
Seasonal and subseasonal variations in the ozone mixing ratio (OMR) are investigated by using continuous 7 year ozonesonde data from Hanoi (21°N, 106°E), Vietnam. The mean seasonal variations for the 7 years show large amplitude at the upper troposphere and lower stratosphere (UTLS) region (10–18 km) and at the lower troposphere (around 3 km) with standard deviations normalized by the annual mean value of about 30% for both regions. In the UTLS region, the seasonal variation in the OMR shows a minimum in winter and a maximum in spring to summer. The variation seems to be caused by the seasonal change in horizontal transport. Low OMR air masses are transported from the equatorial troposphere in winter by the anticyclonic flow associated with the equatorial convections, and high OMR air masses are transported from the midlatitude stratosphere in summer possibly due to Rossby wave breakings in the UT region and anticyclonic circulation associated with the Tibetan High in the LS region. In the lower troposphere, a spring maximum is found at 3 km height. Biomass burning and tropopause foldings are suggested as possible causes of this maximum. Subseasonal variations in the OMR show large amplitude in the UTLS region (at around 15 km) and in the boundary layer (below 1 km) with the standard deviations normalized by the annual mean larger than 40%. The OMR variations in the winter UTLS region have a negative correlation with the meridional wind. This relation indicates that the low OMRs observed at Hanoi has been transported from the equatorial region.