| 肖艳林,池再香,夏阳,严锐,孙翔,毛春旭,陈金梅.云贵高原中部倒春寒特征及其极端类型大气环境场分析[J].沙漠与绿洲气象,2024,18(2):123~131 |
| 云贵高原中部倒春寒特征及其极端类型大气环境场分析 |
| Analysis of Characteristics of?Late?Spring?Cold and Atmospheric Environment with extreme?types in The Central of Yunnan-Guizhou Plateau |
| 投稿时间：2022-03-25 修订日期：2023-04-11 |
| DOI： |
| 中文关键词: 倒春寒标准化指数 极端类型 云贵准静止锋 环流 海温 |
| 英文关键词:standardized index of late?spring?cold extreme?type Yunnan-Guizhou quasi-stationary front circulation sea surface temperature. |
| 基金项目:六盘水市科技计划项目（52020-2021-NK-03）、中国气象局预报员专项项目（CMAYBY2016-066)、贵州省气象局科研业务登记项目（黔气科登[2020]06-19号) |
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| 中文摘要: |
| 利用1981—2021年云贵高原中部45个气象观测站逐日平均气温资料,以及NCEP2.5°×2.5°再分析日资料，采用倒春寒指数计算、分级以及合成分析等方法，分析云贵高原中部倒春寒天气年际、年代际变化特征，并确定特重级倒春寒年和无倒春寒年为倒春寒极端类型年，对比分析其环流特征，以期找出其预报指标。结果表明：（1）1981—2021年云贵高原中部区域年度倒春寒标准化指数总体呈下降趋势,且在1998年前后具有一个十分明显的突变（α=0.01）。特重级和重级倒春寒年基本发生在20世纪80年代和90年代，进入21世纪后，以轻级倒春寒年和无倒春寒年为主。（2）在特重级倒春寒年，500 hPa极涡偏强，亚洲中高纬呈现出西高东低的异常环流型，有利于东亚地区环流径向度加大，同时50°N以南温度基本呈负距平分布，表明冷空气活动异常活跃，从而造成地面云贵准静止锋偏强。与此同时，700 hPa上，云贵高原受异常气旋式环流东侧的偏东气流控制，与华北异常反气旋式环流底部的偏东气流在云贵高原上空辐合，将南海和东海的水汽向云贵高原上空输送，从而有利于低温和降水天气的形成。在无倒春寒年，上述形势相反。（3）在特重级倒春寒年，前期夏季、秋季、冬季和同期春季中东太平洋海温均表现为东部型厄尔尼诺；而在无倒春寒年，均表现为中部型厄尔尼诺。 |
| 英文摘要: |
| Based on the data of 45 Conventional daily average temperature data, and reanalysis data ( 2.5° × 2.5° ) in the central of Yunnan-Guizhou Plateau from 1981 to 2021. Using the calculation and classification of late Spring cold index, composite analysis and so on, to analyze the interannual and interdecadal variation characteristics of cold late spring in the central Yunnan-Guizhou Plateau. In order to explore forecast indicators, selected the extremely heavy grade and non-grade late of spring cold years as extreme types, then contrastive analysis the circulation characteristics. Results are showed, firstly, the regional annual standardization index of late Spring cold in the central of Yunnan-Guizhou Plateau showed a downward trend from 1981 to 2021, and it has a very obvious mutation of late spring cold index in the central of Yunnan-Guizhou Plateau around 1998（α=0.01）. The extremely heavy grade and heavy grade of late spring cold years basically occurred in the 1980s and 1990s. The light grade and no grade late spring cold years are mainly occurred in the 21st century. Secondly, the polar vortex is above-normal on 500 hPa in extremely heavy grade years. It presents a abnormal circulation pattern with high in the west and low in the east. It is profit for increasing the circulation radial degree in East Asia. The temperature in the south of 50 ° N is basically negative anomaly distribution, indicating that the cold air activity is extremely active, resulting in a strong quasi-static front on the ground. At the same time, it is controlled by the easterly airflow at the east side of the anomalous cyclonic circulation on Yunnan-Guizhou Plateau at 700 hPa, and it converges with the easterly airflow at the bottom of the anomalous anti-cyclonic circulation in North China over the Yunnan-Guizhou Plateau, it is profit for transferring water vapor from the South China Sea and the East China Sea to the Yunnan-Guizhou Plateau, thus facilitating the formation of low temperature and precipitation weather. While in the year of non-grade late spring cold years, the above situation is opposite. Finally, it is all the eastern type of El Nino phenomenon in the early summer, autumn, winter and the same period of spring in the extremely heavy grade late spring cold year, while it is all the central type of El Nino phenomenon in the early summer, autumn, winter and the same period of spring in the non-grade late spring cold year. |
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