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Extreme precipitation events (EPEs) often bring disastrous consequences, such as floods, urban waterlogging and landslides. Understanding the effects of weather systems on EPEs can help improve the accuracy of weather forecasts. The Tibetan Plateau vortex (TPV) is a mesoscale weather system that is active near the surface of the Tibetan Plateau (TP). Though the crucial role of TPVs on the TP precipitation has been widely known, the influence of TPVs on EPEs is not yet clear. In this study, the quantitative impacts of TPVs on the EPEs over the TP and its surrounding areas are investigated based on the TPV datasets from the ECMWF Reanalysis v5 (ERA5) and four precipitation datasets from the ERA5, NOAA Climate Prediction Center (CPC), Integrated Multi-satllitE Retrievals for the Global Precipitation Measurement (GPM) Mission (IMERG) and in-situ rain gauges. The results show that the TPVs have remarkable positive contribution to the EPEs over the TP and its adjacent regions for all four precipitation datasets. The TPVs induce more than half of the daily EPEs over the central TP, while the number of days influenced by TPVs only accounts for <20% of the total days over this region. A higher frequency of EPEs is identified over the central TP, and a higher ratio of the TPVs tends to be associated with EPEs after they move out of the TP. The EPEs tend to occur near the center and the southeastern quadrant of TPVs. For the TPVs associated with EPEs (EPE-TPVs) and those having no relation to EPEs (NEPE-TPVs), the structure of TPVs and related large-scale circulation are significantly different at the upper- and lower-level of the troposphere. The EPE-TPVs tend to be larger, stronger, thicker, and move farther than the NEPE-TPVs. The TPVs inducing EPEs usually consist of some specific synoptic components, including the southwest monsoon current along the southern side of TPVs, the shear line near the surface of the TP, and the South Asia high in the upper-troposphere. EPE-TPVs related atmospheric circulations and the climatology of circulations are analyzed in detail to provide a better understanding for forecast service. • The contributions of Tibetan Plateau vortices (TPVs) to extreme precipitation events (EPEs) over the Tibetan Plateau and its vicinity are consistent by using different precipitation datasets. • The TPVs contribute to more EPEs with more intense EPEs threshold. • The TPVs associated with EPEs (EPE-TPVs) are relatively larger, stronger, thicker and longer-lived than those having no connection to EPEs (NEPE-TPVs). • The South Asian high is under the western (eastern) mode for EPE-TPVs (NEPE-TPVs). [ABSTRACT FROM AUTHOR]

Highlights • The Evaporative Stress Index was used to represent global extreme dry/wet conditions. • MJO has impacts on global extreme dry/wet conditions particularly over monsoon regions. • The influence of MJO on extreme dry/wet conditions is associated with precipitation, soil moisture and air temperature. Abstract Extreme climate events such as severe droughts and floods have become more frequent and widespread in the 21st Century. Recent studies have revealed the tele-connections between Madden–Julian Oscillation (MJO) and extreme precipitation over different regions such as South America, India and China. This study investigates the influence of MJO on global extreme dry and wet conditions, and how the strength of the relationship changes across the MJO phases over the globe. The Evaporative Stress Index (ESI) calculated from global GLEAM evapotranspiration dataset is used to represent extreme dry and wet conditions. Strong correlations between MJO and extreme dry and wet conditions are found, particularly over monsoon regions such as South Asia, South America and East Africa. The underlying mechanism of the influence of MJO on extreme dry and wet conditions is associated with the variation of precipitation, air temperature and soil moisture modulated by the MJO. The study suggests that MJO impacts on extreme dry and wet conditions should be taken into account in investigation of droughts/floods around the world particularly over monsoon areas. [ABSTRACT FROM AUTHOR]