Heatwaves in Peninsular Malaysia: a spatiotemporal analysis

Area of Science:

• Environmental Science
• Climatology
• Public Health

Background:

• Global warming is increasing the frequency and severity of heatwaves worldwide.
• Malaysia, previously less affected, is now experiencing significant heatwave events.
• Understanding heatwave patterns is crucial for developing effective mitigation and adaptation strategies.

Purpose of the Study:

• To develop and apply novel heatwave indices using daily maximum (Tmax) and minimum (Tmin) temperatures.
• To analyze changes in heatwave frequency, severity, and affected population in Peninsular Malaysia (PM) from 1950 to 2022.
• To identify geographical patterns and trends in heatwave characteristics and their societal impact.

Main Methods:

• Utilized daily ERA5 temperature data (0.25° resolution, 1950-2022) and LandScan population data (2000-2020).
• Defined heatwaves based on Tmax exceeding the 95th percentile for three or more consecutive days.
• Employed Sen's slope for trend analysis to distinguish secular trends from oscillatory fluctuations.

Main Results:

• Heatwave patterns in Peninsular Malaysia were reconstructed, with the southwest region identified as most vulnerable to severe events.
• A significant increase in heatwave occurrences was observed after the year 2000 compared to the pre-2000 period.
• The study quantified an increase in heatwave-affected area (8.98 km²/decade) and duration (1.54 days/decade), with the highest population impact in the central south region.

Conclusions:

• Peninsular Malaysia is experiencing a clear upward trend in heatwave activity, frequency, and spatial extent.
• The findings highlight the urgent need for targeted public health interventions and urban planning strategies to address the growing threat of heatwaves.
• Continued monitoring and characterization of heatwave events are essential for effective climate change adaptation in Malaysia.