A High-Resolution Tropopause Folding Dataset over China from 2014–2023

Abstract. Tropopause folds are a primary mechanism for stratosphere-to-troposphere transport (STT), significantly influencing tropospheric ozone, air quality, and regional weather. However, a multi-year, high-resolution folding dataset for China has been lacking. To address this gap, we developed a comprehensive tropopause folding dataset for China and its surrounding regions using the ERA5 reanalysis data and a three-dimensional labeling method for the period 2014–2023. This dataset is distinguished by its decade-long coverage (2014–2023) and an unprecedented combination of high spatial (0.25°×0.25°) and temporal (hourly) resolutions across 37 vertical levels, which collectively facilitate a detailed analysis of the spatiotemporal characteristics of folds in these regions. We validated the dataset's accuracy and its capability to capture the full evolution of folding events by comparing it with global datasets and multiple case studies of stratospheric intrusions. The high-resolution dataset not only aligns with large-scale climatology from previous studies but also resolves finer details that were previously smoothed out. Furthermore, this dataset reveals the distinct spatiotemporal distribution of tropopause folds over China. Folding events over China were found to occur predominantly in winter and spring, with significantly lower frequencies in summer and autumn. Spatially, shallow folds are concentrated along the subtropical jet stream, while medium folds peak over the Tibetan Plateau and Sichuan Basin in winter. Deep folds, though less frequent, have a notable impact on southwestern China, including the Tibetan Plateau, where they can substantially affect surface ozone levels. This dataset provides a solid foundation for in-depth investigations of STT mechanisms and the subsequent impacts of tropopause folds on near-surface atmospheric composition and extreme weather events, thereby serving as a valuable resource for the atmospheric science community.