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Forecasting tropical cyclone track and intensity is a great challenge for the meteorological community, and safeguarding the life and property of people living near the coast is an important issue. One major reason for challenging forecasts is the lack of observations over the vast oceans. During tropical cyclone Mulan between 8 and 10 August 2022 over the northern part of the South China Sea, the meteorological authority and research institutes of Chinese mainland collaborated with the meteorological service in Hong Kong on conducting the first-ever ground-space-sky observing system experiment on tropical cyclone Mulan. The enhanced targeted observations collected during the experiment include Geostationary Interferometric Infrared Sounder, round-trip radiosondes, and aircraft-launched dropsondes. This paper describes the campaign, technical details of the meteorological models used, and impact of the additional targeted observation data on the tropical cyclone forecast. Ideally, similar enhanced observation campaigns could be conducted in the future, not only in the northern part of the South China Sea, but also in other ocean basins. [ABSTRACT FROM AUTHOR]

The invaluable meteorological observations for a late autumn tropical cyclone that came very close to Hong Kong, namely, Nalgae in November 2022, are documented in this article. In particular, the dropsonde data for two consecutive days for this late season storm close to Hong Kong are presented. Meteorological data revealed that while Nalgae appeared to be rather weak from the meteorological satellite image under the cool sea surface water and the cool and dry northeast monsoon, it still maintained considerable intensity near the lower-boundary layer and managed to bring gale to storm force 10 min mean winds over many places in Hong Kong, necessitating the issuance of a gale or storm wind signal in November since 1972. The consideration in the issuance of the warning signal in Hong Kong and the difficulty in numerical weather prediction (NWP) model in forecasting Nalgae are also discussed in this article. [ABSTRACT FROM AUTHOR]

Extensive surface and upper air measurements of a typhoon over the northern part of the South China Sea, namely, Typhoon Talim in July 2023, are documented and analysed in this paper. A number of features have been observed from the upper air measurements. First, the log law and the power law were found to be appropriate in fitting the wind profiles of the typhoon in the first 1000 m or so above the sea surface. Second, a low-level jet with the height of the maximum wind speed of around 1000 m was observed in the lower troposphere from the observations of the radar wind profilers. This paper is also novel from the perspectives that the vertical wind profile from a Doppler LIDAR on an offshore platform over the northern part of the South China sea and ocean radar data are used to analyse the surface wind observations of a typhoon in the region. The results of this paper would be useful in understanding the structure of tropical cyclones, e.g., in wind engineering applications. [ABSTRACT FROM AUTHOR]