Investigation of Atmospheric Dynamic and Thermodynamic Structures of Typhoon Sinlaku (2020) from High-Resolution Dropsonde and Two-Way Rawinsonde Measurements

Abstract

Profiling the vertical atmospheric structure for typhoons remains challenging. Here, the atmospheric dynamic and thermodynamic structures were investigated during the passage of Typhoon Sinlaku (2020) over Xisha Islands in the South China Sea for the period 28 July to 2 August 2020, mainly based on two-way rawinsonde and dropsonde measurements in combination with surface-based automatic weather station observations, disdrometer measurements, and Himawari-8 geostationary satellite images. The study period was divided to three stages: the formation stage of tropical depression (pre-TD), tropical depression (TD), and tropical storm (TS). The wind speed and local vertical wind shear reached the maximum value at 3 km above mean sea level (AMSL) before the typhoon approached the Xisha islands. Pseudo-equivalent potential temperature (θse) was found to decrease with the altitude below 2 km AMSL; temperature inversions occurred frequently within this altitude range, particularly during the TS stage. This seemed a typical capping inversion that indicated a downward motion above 2 km AMSL. The temperature increased slightly with the development of Typhoon Sinlaku (2020) at altitudes of 8–10 km AMSL. This indicated that our observations presumably captured the air mass warmed by the condensation, which was a good signature of an upper air in the tropical cyclone. In addition, wind speed (particularly in the lower stratosphere), specific humidity, and equivalent potential temperature escalated significantly when the tropical depression strengthened into Typhoon Sinlaku (2020), which indicated that the typhoon constantly obtained energy from the sea surface during its passage over the study region. The thermodynamic and dynamic structures of atmosphere advance our understanding of the inner structure of typhoons during the different evolutionary stages.

An Appraisal of the Progress in Utilizing Radiosondes and Satellites for Monitoring Upper Air Temperature Profiles

“…RS instruments measure temperature, pressure, altitudes, wind (both speed and direction), relative humidity, and cosmic ray readings at high altitudes [33,55]. There are other classes of radiosondes such as rawinsondes and dropsondes [58]. A rawinsonde is a class of radiosondes whose position is tracked as it ascends in the atmosphere to provide wind speed and direction, although, in practice, radiosonde and rawinsonde are frequently used interchangeably [33,53].…”

“…Meanwhile, ref. [58] studied the relationship between the temperature inversion layer and the ABL and their aerosol capture capabilities with the aid of RS and micropulse lidar data in the United States of America.…”

A Fast Calibration Method for Sensors of Atmospheric Detection System

“…The high demand for atmospheric sounding requires systems to ensure the high performance of each sensor while keeping costs low [6][7][8]. The ADS integrates several different sensors to obtain in situ data on all aspects of atmospheric detection [9,10]. As one of the most critical sensors in system integration, the temperature sensor can not only solve the temperature information of the environment in real-time but also improve the accuracy of sensors such as pressure and humidity through temperature compensation [11][12][13].…”