基于ECMWF细网格模式在2018年11月乌鲁木齐机场一次大风降雪天气过程中的释用分析

Interpretation Analysis Based on ECMWF Fine Grid Model during a Gale and Snowfall in Urumqi Airport in November 2018

摘要: 本文应用美国环境预报中心(NCEP) FNL全球分析0.25 × 0.25再分析资料及ECMWF细网格(0.25 × 0.25)数值预报产品，对2018年11月24日至25日发生在乌鲁木齐地窝堡机场的一次大风降雪天气过程进行分析及预报释用，结果表明：1) 高空槽东移，强冷空气南下，高空风温转变，充足的水汽，地面形势场配合，导致了此次大风降雪天气过程的出现；2) 此次东南大风是明显的锋前减压加回流型。当700 hPa与850 hPa的温度在6小时内出现明显的剧烈上升后剧烈下降的趋势，东南大风使得地面温度升高、气压降低，冷空气临近时，地面也出现了强烈的温度梯度和气压梯度变化，预报要考虑东南大风急转西北大风的可能性；3) EC细网格数值模式针对此次天气的降雪过程，提前24小时初始场对整个降雪时段预报的更为精准，但对于中雪时段，提前48小时的预报场预判更为准确，前三小时总降水量及前三小时降雪量也是提前48小时的预报场预计更为准确。

Abstract: In this paper, the FNL global analysis 0.25 × 0.25 reanalysis data of the US Center for Environmental Prediction (NCEP) and the ECMWF fine grid (0.25 × 0.25) numerical forecast products are used to analyze the occurrence of the incident at Diwopu Airport in Urumqi from November 24 to 25, 2018 of the analysis and forecast interpretation of a strong wind and snowfall weather process. The results show that: 1) The high-altitude trough moves eastward, the strong cold air moves southward, the high-altitude wind temperature changes, sufficient water vapor, and the coordination of the ground situation and field lead to the occurrence of this strong wind and snowfall weather process; 2) The southeast gale is of obvious frontal decompression and backflow type. When the temperature of 700 hPa and 850 hPa showed a trend of sharply rising and then falling sharply within 6 hours, the southeast strong wind made the ground temperature rise and the air pressure drop, and when the cold air approached, the ground also showed a strong temperature gradient and pressure gradient change. The forecast should consider the possibility that the southeast gale will turn sharply to the northwest gale; 3) For the snowfall process of this weather, the EC fine grid numerical model predicts the entire snowfall period more accurately with the initial field 24 hours in advance, but for the medium snow period, the forecast field forecast 48 hours in advance is more accurate. The three-hour total precipitation and the first three-hour snowfall are also more accurate forecast fields 48 hours in advance.