| 摘要: |
| 利用新一代GPM IMERG卫星遥感反演降水数据产品以及NCEP提供的海表温度（SST）、海（陆）-气界面热通量和风场等资料，对超强台风“利奇马”（1909）强度变化和降水结构特征进行分析。结果表明：①2019年8月4日14:00至9日02:00，显著减弱的环境垂直风切变、SST为29.6～30.4℃的海域为“利奇马”提供的感热和大量潜热以及“利奇马”环流东侧极为强盛的偏南风低空急流向其输送充足的水汽和能量，使“利奇马”强度呈显著增强的趋势。2019年8月9日08:00至13日08:00，随着“利奇马”逐渐靠近陆地并登陆，显著增强的垂直风切变、“利奇马”从海洋（陆地）获得的潜热显著减小并且同时失去感热、“利奇马”环流东侧偏南风低空急流的显著减弱、对流层中低层干冷空气侵入“利奇马”环流以及“利奇马”登陆后受到陆面摩擦，使“利奇马”强度显著减弱。②当“利奇马”处于中等强度以上的垂直风切变环境中时（垂直风切变≥5 m/s），无论其移动缓慢（移速＜5 m/s），还是移动快速（移速≥5 m/s），垂直风切变对其内（距台风中心100 km半径范围）、外雨带（距台风中心100～300 km半径范围）上的降水分布起决定性作用，“利奇马”内、外雨带上的强降水均位于顺垂直风切变方向及其左侧。当“利奇马”处于较弱的垂直风切变环境中时（垂直风切变＜5 m/s），无论其移动缓慢，还是移动快速，内雨带上的降水分布由垂直风切变和“利奇马”移动共同决定，强降水分别出现在顺垂直风切变方向及其左侧以及移动的前方，而外雨带上的降水分布由垂直风切变起主导作用，即强降水位于顺垂直风切变方向。总的来看，与“利奇马”移动速度和方向相比，环境垂直风切变对“利奇马”内、外雨带上降水非对称分布的影响要重要得多。 |
| 关键词: 海洋气象学 超强台风“利奇马” 强度变化 降水结构 SST 海（陆）气热通量 垂直风切变 |
| DOI：10.3969/J.ISSN.2095-4972.2022.01.017 |
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| 基金项目:山东省自然科学基金资助项目（ZR2021MD012）;中国气象局预报员专项资助项目（CMAYBY2019 063）;济南市气象局面上课题资助项目（2019jnqx01） |
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| Intensity change and precipitation structure of super typhoon Lekima (2019) |
| LI Rui,GAO Fan,YIN Chengmei,HU Peng,CHU Yingjia |
| (Ji'nan Meteorological Bureau, Ji'nan 250102, China) |
| Abstract: |
| Using the latest-generation GPM (Global Precipitation Measurement) IMERG (Integrated Multi-satellitE Retrievals for GPM) satellitebased precipitation data as well as sea surface temperature (SST) , air-sea (land surface-atmosphere) heat flux and wind date supplied by NCEP, the intensity changes and precipitation structure characteristics during super typhoon Lekima (2019) were analyzed. As results firstly From 14:00 BST 4 to 02:00 BST 9 August 2019, Lekima intensified obviously due to significantly weakened environmental vertical wind shear (VWS), sensible heat and abundant latent heat which gained from the warm ocean in conditions of SST 29.6-30.4℃, sufficient vapor and energy provided by extremely strong southerly low-level jet in the east of Lekima. From 08:00 BST 9 to 08:00 BST 13 August 2019, when Lekima was approaching the land and landed, it weakened obviously due to significantly intensified environmental VWS, significantly decreased latent heat, loss of sensible heat, significantly weakened southerly lowlevel jet in the east of Lekima, the intrusion of cold dry air in the middle and low troposphere in its circulation and the land surface friction after its landfall. secondly, when the environmental VWS ≥ 5 m/s, whether Lekima moved slowly (motion speed ＜5 m/s ) or fast (motion speed ≥ 5 m/s), the environmental VWS was a dominant factor for the rainfall asymmetry in both the inner (defined as the inner 100 km) and outer rainband region (r = 100-300 km) of Lekima. The Lekima's heavy rainfall occurred downshear to downshear-left of the environmental VWS vector in both the inner and outer rainband region. When the environmental VWS ＜5 m/s, whether Lekima moved slowly or fast, the rainfall asymmetry in the inner rainband region depended on both the environmental VWS and the Lekimas motion, while in the outer rainband region, the environmental VWS was still a dominant factor for the rainfall asymmetry. That is to say, in the inner rainband region, heavy rainfall occurred along with downshear to downshearleft of the environmental VWS or ahead of Lekima, while in the outer rainband region, heavy rainfall was dominated by VWS and distributed in the direction along the downshear of the environmental VWS vector. In general, the influence of environmental VWS on rainfall asymmetry in both the inner and outer rainband regions of Lekima was much stronger than that of the Lekimas motion. |
| Key words: marine meteorology super typhoon Lekima intensity change precipitation structure SST air-sea(land surface-atmosphere) heat flux vertical wind shear |
