Aerospace Information Research Institute, Chinese Academy of Sciences has monitored the crop conditions affected by drought in the Mekong River Basin from February to April of 2020 through its Global Drought and Crop Monitoring Systems (DroughtWatch and CropWatch) based on the remote-sensing technology. The data sources used also include the multiple remote sensing data such as optical, thermal infrared satellite data (MODIS) and the reanalysis data of the National Center for Environmental Prediction (CFSv2) of the United States in the period between February 1 and April 20. The institute has obtained comprehensive monitoring results for the region, including Cambodia, Laos, Myanmar, Thailand, Vietnam and the Yunnan Province of China.

    The results indicated that the five countries of the Mekong River Basin and the Yunnan Province of China had severe deficits of precipitation from February to April 2020, and a meteorological drought occurred in varying degrees (Figure 1). The precipitation deficits mainly occurred in the lower Mekong region in February, in Cambodia in March, and along the borders of Myanmar, Thailand and Laos in April.

Figure 1. Distribution and changes of Standardized Precipitation Index (SPI-3) in the Mekong River Basin in early February, early March and early April 2020

    Since it is the dry season of the Mekong and Lancang Jiang Rivers in February and March and it is not a main season for crop planting, the severe meteorological drought had not produced a significant impact on agriculture (Figure 2). Table 1 showed the drought situations since February in terms of the proportion of drought-affected area to crop planting area. Laos was hit the hardest: its average proportion reached 38.3% with a peak value of 58.5% in early March. Laos is followed by Cambodia (27.7%), Myanmar and Thailand (18.3% and 17.1%, respectively). The drought impact on Vietnam and the Yunnan Province of China was relatively low, about 13.1% and 11.0% respectively (Table 1).

Figure 2. Spatial distribution and changes of drought in the Mekong River Basin in mid-February, mid-March and mid-April 2020

Table 1. Dekadal crop drought proportion from February to April 2020

There were differences in the temporal and spatial distribution of drought impact in the countries. The drought occurred mainly in the north of Laos and in the central and western regions of Cambodia (February). The southern and central and eastern regions in Myanmar were heavily affected by drought (February-March). The central and western Thailand (February) and the southern region (March) were relatively hard hit. The Mekong Delta and central Vietnam (February-March) and central and southern Yunnan Province of China (March) also suffered a rather serious drought. By mid-April, the drought situation in the Mekong River Basin had eased as a whole. However, the trend of drought still warrants continuous monitoring, and special attention should be paid to the drought impact as the main crop growing season starts.