Analyzing Extreme Precipitation during the Prolonged Summer Monsoon of 2022 in Nepal: Insights from Hourly Observational Data

Authors

  • Smriti Adhikari Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Pooja Lamichhane Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Jayanti Karki Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Sangya Mishra Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Darwin Rana Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Akash Mandal Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Sandesh Tamang Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Him Kiran Paudel Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal https://orcid.org/0009-0002-3910-9049
  • Sumana Regmi Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Anuja Bohora Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Santhosh Parajuli Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Ashmita Pangeni Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Earina Sthapit Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Shankar Sharma Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal; Climate Change Research Centre, University of New South Wales, Sydney, Australia https://orcid.org/0000-0001-7008-5757
  • Deepak Aryal Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal https://orcid.org/0000-0002-7042-3135
  • Tek Bahadur Chhetri Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal
  • Vishnu Prasad Pandey Department of Civil Engineering, Pulchowk Campus, Institute of Engineering, Tribhuvan University, Lalitpur, Nepal https://orcid.org/0000-0001-5258-7446
  • Binod Pokharel Central Department of Hydrology and Meteorology, Institute of Science and Technology, Tribhuvan University, Kirtipur, Nepal https://orcid.org/0000-0002-6369-7525

DOI:

https://doi.org/10.3126/jist.v30i1.70014

Keywords:

Extreme precipitation, diurnal variation, monsoon, Nepal, station data

Abstract

The South Asian Summer Monsoon is a vital part of the broader Asian monsoon system, heavily influencing atmospheric circulation, regional climate, and water resources across South Asia. Nepal, located on the southern slopes of the Himalayas, receives approximately 80% of its annual rainfall during the summer monsoon (June-September), which significantly impacts agriculture, water availability, and disaster risks. This study focuses on analyzing the diurnal variation, spatial distribution, and intensity of extreme precipitation events in Nepal during the 2022 monsoon season. Using hourly precipitation data from 63 meteorological stations across Nepal, the study investigates rainfall patterns from June to September 2022. The monsoon season of 2022 began earlier than usual on June 5th, extending for 134 days, the longest on record in Nepal. Despite its extended duration, the total rainfall was not significantly higher than average, with western Nepal experiencing below-normal precipitation and eastern regions receiving slightly above-normal rainfall. The analysis of spatial variation revealed considerable disparities in rainfall distribution, with the Lumle area recording the highest precipitation (3133 mm) and several western districts observing minimal rainfall. Diurnal analysis highlighted a consistent pattern of nighttime precipitation dominance, with the highest rainfall occurring around 9 PM and the lowest around 6 AM. Approximately 60% of the total monsoon rainfall occurred during nighttime hours. This diurnal cycle was consistent across Nepal’s major regions, suggesting large-scale atmospheric influences like monsoon troughs and southwesterly winds. The study also assessed extreme precipitation events, defined as rainfall exceeding 40 mm/h. These events were widespread across Nepal, with central and eastern regions experiencing a higher frequency of extreme rainfall compared to western areas. The findings emphasize significant spatial variability in precipitation intensity and duration, critical for understanding regional monsoon dynamics and improving disaster preparedness.

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Published

2025-06-15

How to Cite

Adhikari, S., Lamichhane, P., Karki, J., Mishra, S., Rana, D., Mandal, A., … Pokharel, B. (2025). Analyzing Extreme Precipitation during the Prolonged Summer Monsoon of 2022 in Nepal: Insights from Hourly Observational Data. Journal of Institute of Science and Technology, 30(1), 179–188. https://doi.org/10.3126/jist.v30i1.70014

Issue

Vol. 30 No. 1 (2025)

Section

Research Articles

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