| 滇黔静止锋减弱北抬期间环流特征分析 |
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| 引用本文： | 李刚,杨林,汤天然,谯勋,刘健平.滇黔静止锋减弱北抬期间环流特征分析[J].热带地理,2022,42(6):1018-1026. |
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| 作者姓名： | 李刚 杨林 汤天然 谯勋 刘健平 |
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| 作者单位： | 1.贵州省气象台，贵阳 550002;2.毕节市气象局，贵州 毕节 551700 |
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| 基金项目： | 中国气象局公共气象服务中心2021年度创新基金项目(M2021014);2021年度泛珠三角科技创新开放基金项目(FZSJ202107);毕节市登记制项目(BJKD［2021］03-08) |
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| 摘 要： | 采用2010—2021年深秋初冬时节（11—12月）ECMWF细网格2 m温度预报资料，以及实况地面气压场、综合观测资料、卫星资料与NCEP/NCAR提供的FNL再分析资料，对滇黔静止锋减弱北抬期间贵州境内84个国家观测站72 h内逐日最高温、最低温进行检验评估。结果发现，滇黔静止锋活动期间相对于平均状态，其预报准确率均显著降低而平均均方根误差明显增加，其中2014年ECMWF预报准确率不足20%，几乎丧失预报能力。为此，以2014年发生的19次滇黔静止锋减弱北抬个例进行合成分析，发现各层环流和要素场特征较平均状态均发生了明显变化。主要表现为：200 hPa上，静止锋摆动期间较平均状态急流入口有所东移，其南北界区域总体变窄，急流中心平均强度由65.0 m/s下降到60.0 m/s；500 hPa上，中高纬两槽一脊形势变得更加不明显，冷空气势力减弱，环流纬向度增大；要素场上，相对平均状态，0℃线均位于600 hPa附近，中低层气温呈现明显增温状态，700~850 hPa逆温状态变弱甚至消散，在低层风场上表现为南风增强、涡度增大。因此，当滇黔静止锋发生减弱北抬时，其环流和要素场特征相对平均状态均发生强度和位置上的变化，在预报工作中，可以此特征判断静止锋是否减弱北抬，更好地进行地方预报与服务。
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| 关 键 词： | 滇黔静止锋 预报准确率 环流形势 温度场 |
| 收稿时间： | 2022-01-06 |
Analysis of Temperature Difference and Circulation Characteristics during the Weakened Northward Lift of Dian-Qian Quasi-Stationary Front |
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| Gang Li,Lin Yang,Tianran Tang,Xun Qiao,Jianping Liu.Analysis of Temperature Difference and Circulation Characteristics during the Weakened Northward Lift of Dian-Qian Quasi-Stationary Front[J].Tropical Geography,2022,42(6):1018-1026. |
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| Authors: | Gang Li Lin Yang Tianran Tang Xun Qiao Jianping Liu |
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| Institution: | 1.Guizhou Meteorological Observatory, Guiyang 550002, China;2.Bijie Meteorological Bureau of Guizhou Province, Bijie 551700, China |
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| Abstract: | As an important weather system, domestic and international scholars have studied the front for a long time. The Dian-Qian quasi-stationary front is also called the Yun-Gui quasi-stationary front, and many scholars call it the Southwest quasi-stationary front. It refers to the phenomenon that in East Asia, cold air outbreaks that spread southward cannot cross the plateau because they are obstructed by the topography of the plateau. The frontal system is formed when the cold air and the warm, wet air from the southwest of the Bay of Bengal meet. Every year, weak quasi-stationary fronts frequently affect Guizhou Province in late autumn and early winter. The appearance of such a stationary front is less obvious than that of winter, and is generally difficult to predict or forecast. However, when it appears, it is not only difficult to grasp the weather phenomenon, but also to forecast the temperature due to its influence. Moreover, the relative error of some observation sites can even reach 10.0℃ or higher. It has greatly affected forecasting services, production, and people's activities. Therefore, this study used the ECMWF fine-grid 2 m temperature forecast and ground comprehensive observation data from November to December 2010 to 2021, and the daily maximum and minimum temperature forecasts within 72 hours from 84 national observation stations in Guizhou were examined and evaluated. The results showed that the prediction accuracy was significantly reduced, whereas the mean root square error was significantly increased during the quasi-stationary front activity relative to the mean state. Furthermore, the forecast accuracy was less than 20% in 2014, nearly erasing the forecasting ability. Therefore, 19 cases of stationary front weakening and moving northward in 2014 were synthesized and their circulation characteristics were compared with the mean state. The results were as follows: at 200 hPa, compared with the mean state, the inlet of the jet stream moved eastward during the activity of the quasi-stationary front, the northern and southern boundary became narrower, and the average intensity of the jet stream center decreased from 65.0 m/s to 60.0 m/s; at 500 hPa, the characteristic of trough and ridge in the middle and high latitudes became less obvious, the cold air force weakened, and the latitude direction of circulation increased. In terms of factor characteristics, the temperature in the middle and lower layers showed a significant warming state relative to the average state, the inversion state of 700-850 hPa weakened or even dissipated, and the lower southerly wind strengthened and the vorticity increased. In conclusion, through the abnormal analysis of the circulation situation and the element field, when the Dian-Qian quasi-stationary front weakened and moved northward, the intensity and location characteristics of the circulation and the element field changed relative to the average state. Therefore, in our forecast, we can assess whether the Dian-Qian quasi-stationary front weakens the northward movement based on various characteristics of intensity and position. It can provide insights into the forecast and service work of temperature, as well as weather phenomena and other factors in our daily lives. |
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| Keywords: | Dian-Qian quasi-stationary front forecast accuracy rate circulation situation temperature field |
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