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Rain

Insights into Rainfall Trends and Extremes in Bangladesh

Strategic Insights

— 2 min read

Researchers at the University of Dhaka have analyzed rainfall patterns in Bangladesh's southeastern Chittagong region, which is prone to significant hydrometeorological hazards, including floods and landslides. The study used data from 35 years, spanning from 1988 to 2023, and employed various statistical approaches to understand rainfall variability and extremes. The research concluded that the Generalized Extreme Value (GEV) distribution was the most appropriate for frequency analysis in the region and provided crucial insights for predicting future hydrometeorological extremes.

Key Takeaways:

  • The study analyzed yearly maximum rainfall data from nine stations over 35 years, from 1988 to 2023.
  • The Mann-Kendall, modified Mann-Kendall trend model, and Sen's slope estimator were applied for trend analysis.
  • Different probability distribution functions (PDFs), including Normal, Log-Normal, and Generalized Extreme Value (GEV), were applied to estimate return periods (RPs).
  • Every station demonstrated a decreasing trend, except for Patia-CL325, which showed an increasing trend.
  • The Generalized Extreme Value (GEV) distribution was the best fit for five stations, while the Log-Normal distribution was the best fit for two stations.
  • The Normal distribution best fitted Rangunia-CL301, and the Log Pearson Type-III best fitted for Fatikchhari-CL301.
  • The study's outcomes will improve the understanding of present rainfall trends and offer crucial insights for predicting future hydrometeorological extremes in the region.
  • The research identified a larger variation in rainfall at Patia-CL325, with a 906 mm difference, while Anowara-CL302 showed a smaller variation, with a 66 mm difference.
  • The study's outcomes will improve the understanding of present rainfall trends and offer crucial insights for predicting future hydrometeorological extremes in the region.

Statistics:

  • 35 years of rainfall data were analyzed, spanning from 1988 to 2023.
  • 9 stations were studied in the southeastern Chittagong region.
  • Every station demonstrated a decreasing trend, except for Patia-CL325, which showed an increasing trend.
  • 5 stations were best fitted by the Generalized Extreme Value (GEV) distribution.
  • 2 stations were best fitted by the Log-Normal distribution.
  • 1 station (Rangunia-CL301) was best fitted by the Normal distribution.
  • 1 station (Fatikchhari-CL301) was best fitted by the Log Pearson Type-III distribution.
  • A 906 mm difference was identified in rainfall variation at Patia-CL325.
  • A 66 mm difference was identified in rainfall variation at Anowara-CL302.

Sources:

  • "Assessment of rainfall trends and extremes in the southeastern Chittagong region of Bangladesh using multiple statistical approaches." Discover Sustainability, 2025, 6(1): 1-27.
  • https://doi-org.sdpl.idm.oclc.org/10.1007/s43621-025-01624-9
  • University of Dhaka.

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