The mesoscale structure of a polar low: airborne lidar measurements and simulations
The mesoscale structure of a polar low: airborne lidar measurements and simulations
复制标题
DOI：
10.1002/qj.857
复制
发表时间：
2011-07
影响因子：
8.9
通讯作者：
Johannes Wagner;A. Gohm;A. Dörnbrack;A. Schäfler
中科院分区：
文献类型：
--
作者：
Johannes Wagner;A. Gohm;A. Dörnbrack;A. Schäfler
一个成熟的极地低压的中尺度结构是根据高分辨率的空中测量和数值模拟研究的。2008年3月3日和4日，通过光探测和测距（激光雷达）和投下式探空仪观测，在挪威海上空测量到一个极地低压。激光雷达观测提供了极地低压周围和通过其中心的水蒸气混合比，后向散射比和水平风速的横截面。中尺度结构，如冷空气爆发中的浅对流，气旋眼状中心的干侵入和周围的深对流都可以被识别出来。使用欧洲中期天气预报中心（ECMWF）集成预报系统（IFS）和高分辨率极区版本的天气研究和预报（WRF）模型进行了数值模拟。WRF模拟重现了这些结构，并显示极地低气压有一个温暖的上层核心，并有下降运动。眼状中心直径约100-150公里，具有相当稳定的层结，水平恒定的位温和平静的风。在中心之外，风速迅速增加。观测到的径向风和温度廓线支持以前的理想化模拟。几个WRF敏感性测试显示了初始化时间和来自地面的感热和潜热通量对模拟极地低气压发展的影响。极低模拟在成熟阶段开始的运行中更准确。来自地表的热通量对于极低能量很重要，特别是在最后阶段。皇家气象学会
The mesoscale structure of a mature polar low was studied on the basis of high‐resolution airborne measurements and numerical modelling. A polar low was measured by light detection and ranging (lidar) and dropsonde observations over the Norwegian Sea on 3 and 4 March 2008. Lidar observations provided cross‐sections of water‐vapour mixing ratio, backscatter ratio and horizontal wind speed around the polar low and through its centre. Mesoscale structures, such as shallow convection in a cold‐air outbreak, a dry intrusion in the eye‐like centre of the cyclone and deep convection surrounding it could be identified. Numerical simulations were performed with the European Centre for Medium‐Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS) and a high‐resolution, polar version of the Weather Research and Forecasting (WRF) model. WRF simulations reproduced these structures and showed that the polar low had a warm, upper‐level core with descending motions. The eye‐like centre had a diameter of about 100–150 km and was characterized by rather stable stratification, horizontally constant potential temperatures and calm winds. Beyond the centre, wind speeds increased rapidly. The observed radial wind and temperature profiles support previous idealized simulations. Several WRF sensitivity tests showed the influence of the initialization time and sensible and latent heat fluxes from the surface on the simulated polar‐low development. The polar‐low simulations were more accurate in runs starting at the mature stage. Heat fluxes from the surface were important for the polar‐low energetics, especially at the final stages. Copyright © 2011 Royal Meteorological Society