Assessing Eight Years of Monsoon Rainfall Patterns in Karachi, Pakistan: Study of the Intense Rainfall Events

Safeera Zaineb; Muzaffar Bashir

Authors

Safeera Zaineb Smart Computing and Applied Sciences group, Department of Physics, University of the Punjab, Lahore, Pakistan.
Muzaffar Bashir Smart Computing and Applied Sciences group, Department of Physics, University of the Punjab, Lahore, Pakistan.

Keywords:

Flood inundation, Rainfall, Cumulative rainfall, Monsoon, Precipitation, Linear regression coefficient.

Abstract

Rainfall plays a pivotal role in regulating water levels in reservoirs, which can lead to overflow or drought, depending on the unpredictability of rainfall patterns. In 2020 and 2022, Sindh experienced seven episodes of normal to heavy rains, causing flooding and disrupting major highways such as Gwadar-Karachi. This study evaluates daily and cumulative rainfall data in Karachi for the months of June, July, and August from 2016 to 2023. The rainfall data is divided, focusing on the monsoon rains over the eight-year period. Among these years, the highest recorded rainfall of 93.099mm occurred on August 11, 2019, while the lowest rainfall of 0.001mm was noted on July 26, 2016, and June 18, 2017. The yearly (2016-2023) cumulative rainfall for the study period was 114.6mm, 187.0mm, 34.9mm, 310.5mm, 347.9mm, 285.3mm, 761.4mm, and 167.6mm respectively. Notably, the cumulative rainfall and the frequency of rain events were highest in August 2020 and 2022. The monthly data revealed that Karachi experienced exceptionally heavy rainfall in August 2020 and 2022, resulting in significant disruption and chaos in the city. Moreover, when considering the data across the years, it becomes evident that Karachi faced unprecedented rainfall in 2020 compared to the preceding years. This research represents the first comprehensive analysis of the intense rainfall events in August 2020 and 2022 in Karachi. It identifies trends in rainfall patterns that led to flood-like conditions in the city. This study provides a detailed and quantitative understanding of rainfall occurrences during the monsoon season. Such insights are invaluable for assessing flood risks in Karachi, Pakistan.

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