APPLICABILITY OF GEOGRAPHICAL INFORMATION SYSTEM AND REMOTE SENSING TECHNIQUES IN INVESTIGATING THE OCCURRENCE OF HEAT WAVES: A CASE STUDY OF NGABU

Interest in heatwaves and extreme heat events have increased globally over the past few years following the high profile of heat events across the globe. Heatwaves historically received little attention but with the rising temperatures on average, they are becoming more variable and extreme coupled with the increase in the concentration of greenhouse gases in the atmosphere. Several studies have been conducted worldwide addressing the phenomena with different approaches. In this research, the occurrence of heatwaves at Ngabu was investigated using remote sensing techniques and geographical information systems. The study examined the changes in land surface temperature for Ngabu from 2000 to 2020 and determined the occurrence of heatwaves using a percentile-based threshold justified by literature and study area climatology. The United States Geological Survey and Malawi meteorological department provided data used in the study. The results revealed that there are significant changes in LSTs between 2000 and 2020 and heatwaves are occurring of events influenced by high temperatures. The changes in LSTs can be attributed to reduction in vegetation and land use/ landcover change. Future climate trends is predicted to increase the magnitude of heatwave events; therefore, it is recommended to develop adequate adaptation, preventive strategies for societal vulnerability reducing and creating a culture of safety.

Interest in heatwaves and extreme heat events have increased globally over the past few years following the high profile of heat events across the globe. Heatwaves historically received little attention but with the rising temperatures on average, they are becoming more variable and extreme coupled with the increase in the concentration of greenhouse gases in the atmosphere. The study examined the changes in land surface temperature for Ngabu from 2000 to 2020 and determined the occurrence of heatwaves using a percentile-based threshold justified by literature and study area climatology. Future climate trends is predicted to increase the magnitude of heatwave events; therefore, it is recommended to develop adequate adaptation, preventive strategies for societal vulnerability reducing and creating a culture of safety.

Ngabu is located in the southern region of Malawi in Chikwawa district. It has a population of about 157, 742 and is the largest traditional authority in Chikwawa.
Southern Malawi is mostly low-lying and drier than central and northern regions and experiences only one short rainy season between December and February (Future Climate for Africa, 2017). The altitude drops to sea level and consequently, characterized by higher temperatures, which range from 90c to 390c on average. The highest maximum temperatures far reach 490c during the summer months between October and November in the Lower Shire Valley and it becomes extensive. The only months when the temperatures are bearable is June, July and August. The Shire Valley, Nsanje and Chikwawa districts in the south, are most at risk to climatological hazards such as floods, dry spells, droughts, pest and disease and heat waves(In, 2019). Ngabu was chosen for this specific study because of notoriously high summer temperatures that make it prone to heat waves. It also often experiences high humidity and low wind speed and when such conditions coincide with high temperatures, the frequency of casualties due to heat stress increase. The fact that Ngabu is a location where increased temperatures may have dramatic impact emphasizes the importance of understanding the trend of occurrence of heat waves in the area.

Traditional authority: TA Ngabu

District: Chikwawa

Coordinates: -16.477, 34.83805