Identification of Tropopause Height with Atmospheric Refractivity

Abstract

AbstractInvestigation of the structure and variation of the tropopause is crucial for the development of an in-depth understanding of water-vapor exchange processes, the concentrations and nature of chemicals within the tropopause, and their role in climate change and the ecosphere. At present, the common methods used for the estimation of tropopause height are limited by their reliance on area, an overdependence on atmospheric temperature, and the use of many different data types, and thus lack strong generality. Therefore, this study used atmospheric refractivity data from multiple sources to determine the tropopause height. An objective covariance transform method was applied to identify transitions in a refractivity profile. The refractivity tropopause height was compared with the bending angle tropopause (BAT)/cold point tropopause (CPT)/lapse rate tropopause (LRT) height derived from radio occultation (RO) and radiosonde data and revealed a good agreement. An initial analysis of tropopause structure and seasonal changes derived from refractivity method afforded results that were consistent with existing research results, which proved the validity of the method. The refractivity method was also used to analyze various types of data downloaded from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) Data Analysis and Archive Center (CDAAC), and show that this method is suitable for the analysis of RO data, radiosonde, reanalysis and analysis/forecast data. A series of experiments were used to verify the generality and utility of the refractivity covariance transform method to determine tropopause height, which will be useful for the analysis of long-term variations in tropopause height.