ERA5-based database of Atmospheric Rivers over Himalayas

Abstract. Atmospheric Rivers (ARs) – long and narrow transient corridors of large horizontal moisture flux in the lower troposphere – are known to shape the hydrology of many regions around the globe. Heavy precipitation and flooding are often observed over many mountainous regions when the moisture-rich filaments impinge upon the elevated topographies. Although ARs and their impacts over many mountainous regions are well documented, their existence over the Himalayas and importance to the Himalayan hydrology have received negligible attention in the scientific literature. The Himalayas support more than a billion population in the Indian subcontinent, sustain the region's biodiversity, and play important roles in regulating the global climate. In this study, we develop a comprehensive database of ARs over the Himalayas using the European Reanalysis fifth-generation (ERA5) fields of humidity and winds. The AR database consists of the dates and times of ARs from 1982 to 2018, their duration, major axes, and intensities and categories. We find that majority of intense ARs are associated with extreme precipitation widespread over the Ganga and Indus basins of the Himalayas, suggesting that ARs have profound impacts on the hydrology of the region. The AR database developed here is envisioned to help in exploring the impacts of ARs on the hydrology and ecology of the Himalayas. For this, we provide a few brief future perspectives on AR-Himalayas relationships. The data developed in this study has been uploaded to the Zenodo repository at https://doi.org/10.5281/zenodo.4451901 (Nayak et al., 2021). The data is also included in the Supplemental Information for easier access.