The Low-level Wind Structure Characteristics Of Landing Typhoon "Swan" And "Koppu" Revealed By Multi-point Observation Network Of Wind Profilers

Landing typhoon has been the world (especially the countries affected by the typhoon) attach great importance to scientific problems. China is located in the Northwest Pacific and South China Sea coast, where nearly 40% of the typhoon generates. Because the long coastline is likely attacked by the typhoon, China is the world most affected by the typhoon-hit countries.Typhoon boundary layer has a significant impact on the typhoon's generation and development, this is mainly due to the vertical transportation of sensible heat, latent heat and momentum between typhoon and the underlying surface play an important role in typhoon's generation and development. The effect of typhoon boundary layer will change the structure of landing typhoon, and may produce squall lines, tornadoes and other severe small-scale systems to make the landing typhoon structure more complex. Because the observation method and the equipments are imperfect, the landing typhoon boundary layer's research lacks.By using the data from the five windprofilers which are set up in the guangdong coastal, the wind structure of landing typhoon Goni and Koppu is studied. The main conclusions are:(1) In the eye of the typhoon, before the typhoon goes through the windprofiler, wind speed decreases with increasing altitude; after that, air mixed strongly and wind speed significant weaker than before.(2) Out of the eye of the typhoon, the wind structure on the path sides has obvious diversity. On the left side, the wind structure is complex and wind speed is relatively small; on the right side, in the surface layer wind speed increase with the increasing altitude, in the mixed layer wind speed has little change and the wind speed is obviously large than that in the left. This is mainly due to the different underlying surface of the two sides. The right airflow come from the ocean have plenty of energy and less friction, the left airflow come from the land have less energy and greater friction.(3) The maximum wind speed is observed in Zhuhai, the radius of maximum wind is about 60km when the typhoon is landing. (4) When the two typhoons are landing, low-level jet was both observed at 600 meters altitude in Maoming.(5) Out of the eye of typhoon, outflow is obvious, its role is to maintain low pressure within the eye to keep the typhoon's development. The low-level inflow has been present in the"Goni"landing process, it is both caused by its slow moving speed and weak strength, and a important reason to maintain its long history of life. Low-level inflow just be observed before"Koppu"landing, because the intensity decrease rapidly, after that, inflow change into outflow.(6) The height of the mixed layer keep changing during two typhoons are landing, while out of the eye, it remains at the height of 3,500 meters above. At Maoming, it maintains at 5,000 meters high.