冬季云贵准静止锋的气候类型特征研究
网络出版日期: 2025-05-20
基金资助
中国气象局创新发展专项(CXFZ2023J086);贵州省科技计划项目(黔科合支撑[2023]一般165);贵州省气象局省市联合科研基金项目(黔气科合 SS[2023]01号);贵州省科技厅基础研究面上项目(黔科合基础MS[2025]318)
Climatic Type Characteristics of the Winter Yunnan-Guizhou Quasi-Stationary Front
Online published: 2025-05-20
利用 24年(2000-2023年)逐 6 h的 FNL(Final Operational Global Analysis)大气再分析资料,基于云贵高原的地形特征,定义了评估冬季云贵准静止锋强度的客观标准指数,并依据此指标筛选出强云贵准静止锋事件,对强准静止锋事件的温湿和风场结构进行了深入研究,并对比分析了不同类型强准静止锋事件的锋区特征。结果表明:(1)冬季云贵准静止锋的特征在于对流层中低层出现密集的等θse线,且该锋区随着高度向东侧倾斜,梯度呈南北向带状分布;强准静止锋事件多集中于 1 月(39%)和 2 月(33%),而且发生频次存在显著的年际波动;(2)强云贵准静止锋事件在云南与贵州交界区域形成明显的等 θse线密集带,锋区内风场表现为东北风和西南风的辐合,湿度大值区域位于锋区以东的贵州中西部;700 hPa以下呈现西部显著偏暖,东部显著偏冷的强烈对比;800 hPa以下东部地区出现异常东风,并在750 hPa左右转变为上升运动,由此向上的水分输送异常加强,从而促进了锋区以西上湿下干的异常结构;(3)根据静止锋锋区两侧冷暖空气的强弱情况,将强准静止锋事件分为东冷异常型(CE,75%)和西暖异常型(WW,13%);地面场上WW型事件的锋线位置相较于CE型事件略有东移;在CE型中较强的冷异常向西扩展至 104°E,向上扩展至 750 hPa,而 WW 型较强的暖异常向东扩展,冷异常仅限于106°E 以东,向下收缩至 850 hPa 以下;800 hPa 以下 CE 型事件的异常东风比 WW 型事件更强、延伸更高,促进了更多的水汽沿地形进行爬升并向西输送,使得相比于 CE型事件,WW 型事件中相对湿度正异常中心更偏东。
任曼琳, 白 慧, 严小冬, 夏 阳, 李忠燕, 郑 蓓 . 冬季云贵准静止锋的气候类型特征研究[J]. 高原气象, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2025.00055
Based on the topographic characteristics of the Yunnan-Guizhou Plateau,the objective standard index of the intensity of the Yunnan-Guizhou quasi-stationary front in winter is defined by using the FNL atmospheric reanalysis data of 24 years(2000-2023),According to this index,the strong quasi-stationary front events are selected,the temperature,humidity and wind structure of the strong quasi-stationary front events were studied, and the characteristics of different types of strong quasi-stationary front events are compared and analyzed. The results show that:(1)the Yunnan-Guizhou Quasi-Stationary Front manifests as a dense band of isentropic lines (θse)in the mid-to-lower troposphere,with the frontal zone tilting eastward with increasing altitude and the gradient distributed in a north-south band. Strong quasi-stationary front events occur most frequently in January (39%) and February (33%),and their occurrence frequency shows significant interannual variability. (2)Strong Quasi-Stationary Front is characterized by a dense band of isentropic lines(θse)at the junction of Yun‐ nan and Guizhou. Within the frontal zone,the wind exhibits convergence between northeastern and southwestern winds,with high humidity areas located in the central and western parts of Guizhou to the east of the front. Be‐ low 700 hPa,there is a stark contrast between the notably warmer western region and the significantly cooler eastern region. Below 800 hPa,abnormal easterly winds appear in the eastern area and transition into upward motion around 750 hPa,leading to an enhanced upward transport of moisture. This,in turn,promotes an abnormal structure with upper-level moisture and lower-level dryness to the west of the front.(3)Based on the strength of the cold and warm air on either side of the stationary front,strong quasi-stationary front events are classified into two types:the Cold Anomaly in the East(CE,75%)and the Warm Anomaly in the West(WW,13%). On the surface,the frontal position of WW-type events shifts slightly eastward compared to CE-type events. In CE-type events,the stronger cold anomaly extends westward to 104° E and upward to 750 hPa,while in WW-type events,the stronger warm anomaly extends eastward,with the cold anomaly limited to the east of 106°E and contracting downward below 850 hPa. Below 800 hPa,the abnormal easterly winds in CE-type events are stronger and extend higher than those in WW-type events,promoting more moisture to ascend along the terrain and be transported westward. As a result,the center of positive relative humidity anomalies in WW-type events is located further east compared to CE-type events.
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