Heat Wave Trends in Southeast Asia: Comparison of Results From Observation and Reanalysis Data

Abstract

Southeast Asia (SEA), a region climatologically important but limited by data availability, is suffering from serious scarceness of heat wave (HW) research. Using the observational and reanalysis data, we find that in most parts of SEA, HWs are becoming more frequent, longer-lasting, and stronger, and affect more land areas. The increasing trends of HW characteristics defined by minimum temperatures are larger than those by maximum temperatures, alarming a situation of anomalously warm night. Magnitude of yearly hottest HW event increases faster, and duration of yearly longest HW shows significant trends in more areas than their average counterparts. ERA5 reproduces well the HW trends defined by daily minimum temperatures, but underestimate those by maximum temperature. The data set CHIRTS improves on daily maximum temperature and associated HW trends, but deteriorates on daily minimum temperature. This study highlights the importance of high-quality data, either observational or reanalysis, on the HW study in SEA.