Hazardous thunderstorm intensification over Lake Victoria

Area of Science:

• Climatology
• Meteorology
• Environmental Science

Background:

• Extreme weather events, particularly intense night-time thunderstorms, pose severe risks to communities around Lake Victoria, leading to numerous fatalities among fishermen annually.
• The impact of a warming climate on the future evolution of these severe thunderstorms over Lake Victoria remains largely unknown.

Purpose of the Study:

• To investigate the projected changes in extreme precipitation intensification over Lake Victoria in a future warmer climate.
• To identify the key factors influencing the occurrence and intensity of night-time thunderstorms on the lake.

Main Methods:

• Utilized new satellite-based observations.
• Employed a high-resolution climate projection model specifically for the African Great Lakes region.
• Incorporated coarser-scale ensemble climate projections for comparative analysis.

Main Results:

• Lake Victoria is identified as a projected hotspot for future extreme precipitation intensification.
• Preceding day's land precipitation significantly influences night-time lake extremes by enhancing atmospheric convergence (74%) and moisture availability (26%).
• Under a high-emission scenario, projected increases in extreme precipitation over Lake Victoria are approximately double those over surrounding land areas, driven by sufficient over-lake moisture advection to support Clausius-Clapeyron scaling.

Conclusions:

• Climate change is projected to significantly increase extreme weather hazards over Lake Victoria.
• The findings underscore the critical need for high-resolution climate projections to accurately assess localized climate change impacts in East Africa.
• Enhanced understanding of atmospheric dynamics is crucial for predicting and mitigating the risks of extreme weather events in vulnerable regions.