In April and early May 2023, the Indo-China Peninsula was hit by sustained heat waves, areas heavily affected by heat waves were mainly located in northern Thailand, Laos and Vietnam. Heatwaves with temperature more than 40℃ lasted more than 10 days in many places in Thailand, Laos, Vietnam and Myanmar, and the daily maximum high temperature in many stations broke its historical records, the extreme maximum temperature reached 44.1℃at HoiXuan Station in Vietnam. AOD and NO2 in Indo-China Peninsula were significantly higher than that in the same period of last year and close to the historical high value in early and middle April. Droughts occurred in most peninsula, and areas affected by moderate drought was 83,982 km² in Thailand and 30,209 km² in Vietnam. The soil moisture in sugarcane growing areas in central and northern Thailand was as low as 0.2 m³/m³ in early April.

Under the influence of the latest El Nino, the Indo-China Peninsula was controlled by the Subtropical High for a long time from April to early May, air became warm due to adiabatic compression in the downdraft and the continuous hot and sunny weather appeared frequently.

Editor: Liuyi, Meng Qingtao, Yuan Fang, Zhou Yike, Zhang Tao, Gao Hao

Drought index of Indo-China Peninsula in early April 2023