Characteristics of the dynamical tropopause derived from satellite observations

                                                                                                                             Abstract

As the products of the complicated interactions and the kinematic, chemical and radiative balances between upper troposphere and lower stratosphere, dynamical tropopause is recognized as a key boundary of atmosphere closely related to weather and climate change. In this study, a high-spatio-temporal-resolution dynamical tropopause pressure estimation scheme based on the measurements from the Advanced Geostationary Radiation Imager boarded on the new generation geostationary satellite of China, FengYun-4A, is proposed. The implemented retrieval model is quantitative validated against ERA-Interim reanalysis dataset showing a high accuracy with the correlation coefficient of 0.9603 and root-mean-square-error of 42.96 hPa. The method is applied to a 1-year period starting in January 2018 over the east hemisphere. The geographic distributions and the seasonal cycle show that the dynamical tropopause height is varied with the latitudes and seasons which has the mean pressure of about 50 hPa over low latitudes and about 300 hPa over the high latitudes where the tropopause height reaches the minimum during March-May. Generally, the folds preferentially occur in the subtropics around 20-40º latitude where the upper fronts located. They are found to have potential connection with the rain band splitting during the Mei-Yu season in East Asia.

Keywords：Dynamic tropopause, FengYun-4 geostationary satellite, WV channels