浦东机场低跑道视程变化特征及其影响机制分析

Change Characteristics and Its Influence Mechanism of Low RVR at Shanghai Pudong Airport

运用数理统计方法分析浦东机场2000—2014年低跑道视程（RVR,RVR〈1 000 m）变化特征及其影响机制,并建立低RVR预报试验的逻辑回归（Logit）模型。结果表明,上海浦东机场近15 a低RVR日数呈明显下降趋势;低RVR日多出现在冷季,主要集中在11月—次年2月,2月出现频率最多;06：00—08：00出现最多,开始时刻主要集中在06：00—08：00;结束时刻主要在09：00—10：00;持续时间大部分在3 h以内,其中1 h频率最高;低RVR伴随的天气现象绝大部分与视程障碍有关,冷季时视程障碍比重更高,暖季强降水贡献更多;气温在0-10℃频率最高,相对湿度主要集中在90%以上,风速大多在5 m·s-1以下,风向冷季多发生在260°-360°,暖季多发生在120°-170°;低RVR的发生与08：00相对湿度呈正相关,与气温、风速呈负相关,其中与相对湿度的相关系数最高。在预报模型试验中较好地建立了Logit预报方程,历史回报的TS评分达到一定水平。

The change characteristic and influence mechanism of low RVR（ RVR 1 000 m） during 2000-2014 at Pudong airport were analyzed by using the method of mathematical statistics,and the low RVR prediction test of Logit model was established. The results show that the low RVR days decreased significantly in the last 15 years. Low RVR appeared in cold seasons,it mainly occurred from November to next February and peaked in February. The low RVR occurred frequently during 06： 00-08： 00,and it mainly started during 06： 00-08： 00,while ended during 09： 00-10： 00. The duration of low RVR was mainly within 3 hours,and the duration of 1 hour was highest. The weather phenomenon coming with the low RVR was usually related with obstruction to vision,and the frequency of obstruction to vision was higher in cold seasons,while it was a much higher proportion of heavy precipitation in warm seasons. The highest frequency of low RVR appeared when temperature was during 0-10 ℃,relative humidity mainly concentrated in more than 90% and wind speed was mostly below 5 m·s-1. In cold seasons,wind direction was mainly 260°-360°,while in warm seasons it was mainly 120°-170°. The occurrence of low RVR was positively correlated with relative humidity at 08： 00,and negatively correlated with air temperature and the wind speed,and the correlation coefficient between low RVR and relative humidity was the highest. The low RVR prediction test of Logit model was well established and the TS score of historical returns reached a certain level.These quantitative summaries increased our understanding and mastering of low RVR events,which was benefit to the safety,normal and efficiency of civil aviation.