The first complete dropsonde observation of a tropical cyclone over the South China Sea by the Hong Kong Observatory

Abstract

For the first time, Hong Kong Observatory conducted a full scale dropsonde observation of the circulation of a tropical cyclone, namely, Tropical Storm Aere, on 7 October 2016, over the northern part of the South China Sea. This paper documents the observations and their use in the prediction of the track and strength of the tropical cyclone in a numerical weather prediction model. In addition to the model analysis fields, the dropsonde observations are found to provide further information about the structure of Aere. The quality of the dropsonde data was found to be satisfactory in comparison with the radiosonde data nearby. The dropsonde data were found to have a positive impact on the prediction of the track of the tropical cyclone, improving track location accuracy by about 13%. The prediction of the strength of Aere was found to have a higher dependence on the assimilation of the wind field than the assimilation of the humidity field.