| 摘要: |
| 以中国气象局南海（博贺）海洋气象野外科学试验基地的Ka波段毫米波云雷达为主，结合基地及周边的多源观测资料，分析了茂名沿海两次暖海雾过程（一次强海雾过程和一次弱海雾过程）的结构和演变特征，主要结论如下：（1）总体上看，强海雾过程和弱海雾过程在回波强度、水平覆盖范围和雾顶高度等方面存在明显差异：一是强海雾过程的云雷达回波强度可以达到-5 dBZ，弱海雾过程只能达到-20 dBZ左右；二是强海雾过程的水平范围可达20 km，弱海雾过程的只是10 km左右；三是强海雾过程雾顶高度平均值为426.7 m，最高为657.5 m，而弱海雾过程平均值为262.7 m，最高为590.0 m。两次暖海雾过程也呈现出一些共性的特征：一是海雾首先在岸边生成，然后逐渐向海上发展；二是海雾在近岸的回波始终相对海上要强一些。（2）强海雾过程的水平回波特征表明，在海雾发展阶段，强回波有条索状特征。在海雾消散阶段，水平回波覆盖范围迅速减小，连续雾区快速破碎。垂直回波特征表明，雾层首先在近岸增厚并向海上延伸；在雾层里面出现从海面到雾顶的丝缕状回波，随着海雾的发展而持续增强；丝缕状回波反映出雾内的垂直混合较小，表现为偏向于层状云的特性。在海雾消散阶段，中上层的雾体首先消散。（3）弱海雾过程的水平和垂直回波比强海雾过程要弱得多，只是维持低层的热力稳定结构，原因是暖湿平流输送偏弱，导致雾层无法继续向上发展。 |
| 关键词: 茂名沿海 海雾 多源观测 结构特征 演变特征 |
| DOI： |
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| 基金项目:国家自然科学基金,42275083号；广东省气象局科学技术研究项目,GRMC2025M05和GRMC2024M16号；广东省海洋气象科学数据中心,2024B1212070014号；广东省气象局创新团队,GRMCTD202201号。麦宗鉴,工程师,E-mail:149619750@qq.com |
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| The structure and evolution characteristics of two warm sea fog processes off the coast of Maoming based on multi-source observational data |
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Mai Zongjian1, Huang Huijun2, Li Zhiping1, Liu Xiantong1, Xie Shao1, Che Fenghua1, Zhou Siying1, Luo Guanzhu1, Zhou Mingsen2
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1.Maoming Meteorological Bureau,Maoming;2.Guangzhou Institute of Tropical and Marine Meteorology,CMA/GBA Academy of Meteorological Research/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction
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| Abstract: |
| Based on the Ka-band millimeter-wave cloud radar at the South China Sea (Bohe) Marine Meteorological Field Science Experiment Base, and integrating the multi-source observational data from the base and its surrounding areas, this study analyzed the structure and evolution characteristics of two warm sea fog processes (a strong sea fog process and a weak sea fog process) in the coastal area of Maoming. The main conclusions are as follows: (1) Generally speaking, there are significant differences in echo intensity, horizontal coverage range, and fog top height between the strong sea fog process and the weak sea fog process: First, the cloud radar echo intensity of the strong sea fog process can reach -5 dBZ, while that of the weak sea fog process is only about -20 dBZ; second, the horizontal range of the strong sea fog process can reach 20 km; while that of the weak sea fog process is only about 10 km; third, the average fog top height of the strong sea fog process is 426.7 m, with the highest reaching 657.5 m, while the average height of the weak sea fog process is 262.7 m, with the highest reaching 590.0 m. The two warm sea fog processes also exhibit some common characteristics: First, sea fog initially forms on the coast and then gradually develops towards the sea; second, the echo at the nearshore area is always relatively stronger than that in the sea area. (2) The horizontal echo characteristics of the intense sea fog process indicate that during the development stage of sea fog, the strong echoes have a ribbon-like feature. During the dissipation stage of sea fog, the horizontal echo coverage area decreases rapidly, and the continuous fog zone breaks up rapidly. The vertical echo characteristics indicate that the fog layer initially thickens near the coast and then extends towards the sea; within the fog layer, filamentous echoes from the sea surface to the fog top appear and continuously intensify as the sea fog develops; the filamentous echoes reflect that the vertical mixing within the fog is relatively small, presenting a characteristic similar to stratiform clouds. During the stage of sea fog dissipation, the upper and middle layers of sea fog are the first to dissipate. (3) The horizontal and vertical echoes of the weak sea fog process are much weaker than those of the strong sea fog process. It only maintains the thermal stable structure of the lower layer, because the warm moist advection continues to be weak, resulting in the inability of the fog layer to continue to develop upward. |
| Key words: Coastal areas of Maoming Sea fog Multi-source observation Structural characteristics Evolution characteristics |