Category Archives: Haze Review

Review of Regional Haze Situation for April 2020

1.1 Northeast Monsoon conditions prevailed over most parts of the ASEAN region in April 2020. The prevailing winds blew mainly from the east or southeast over the eastern half of the Mekong sub-region, and from the southeast or south in the western half of the sub-region. In early April 2020, there was a gradual increase in shower activities over the eastern half of the sub-region. By the latter half of the month, an increase in shower activities were also observed over the western half of the sub-region. In the southern ASEAN region, scattered showers fell over most parts of the region. The prevailing winds blew mainly from the northeast or east over areas north of the equator and remain light and variable in direction over areas to the south.

Figure 1: Average Daily Rainfall for Apr 2020. (Source: JAXA GsMaP)

1.2 In April 2020, hotspot activities continued to remain elevated in the Mekong sub-region, but the overall hotspot count was lower compared to that of past years. In the southern ASEAN region, the hotspot activities continued to remain subdued.

Figure 2: Hotspot count for the northern ASEAN region for Apr 2013 – 2020. [Note: Hotspot count from year 2019 onward is based on the NOAA-20 satellite, and for the period from year 2013-2018 is based on the Suomi-NPP satellite.]

Figure 3: Hotspot count for the southern ASEAN region for Apr 2013 – 2020. [Note: Hotspot count from year 2019 onward is based on the NOAA-20 satellite, and for the period from year 2013-2018 is based on the Suomi-NPP satellite.]

1.3 In April 2020, hotspot clusters were detected mostly in the northern Mekong sub-region, particularly in Myanmar and northern Lao PDR. These hotspot activities persisted for more than two to three weeks. Isolated hotspot activities were also detected in Cambodia and southern Lao PDR on many days. In the southern ASEAN region, isolated hotspots were detected on some days and were mostly short-lived.

Figure 4: Distribution of hotspots detected based on NOAA-20 satellite surveillance for Apr 2020.

1.4 In terms of fire intensity, the hotspot activities in northern Lao PDR, as well as in several parts of Myanmar recorded higher intensities as compared to other parts of the ASEAN region.

Figure 5: Maximum fire intensity based on NOAA-20 satellite surveillance in Apr 2020.

1.5 The smoke haze observed in the Mekong sub-region was less extensive in April 2020 as compared to March 2020. In April 2020, persistent smoke haze was observed mainly over the northern parts of the sub-region, particularly over Myanmar, northern Lao PDR, and northern and central Thailand. Over these areas, dense smoke haze was observed on many days during the first fortnight of the month, but an increase in shower activities brought a gradual improvement to the haze situation in the second half of the month. The air quality readings in northern and central Thailand improved from the Unhealthy to Very Unhealthy levels to the Excellent to Satisfactory levels by end-April 2020. Showers in the later part of the month had also brought an improvement to the haze situation in northeastern Cambodia and southern Lao PDR. In the southern ASEAN region, no significant smoke haze was observed except for localized smoke plumes emanating from some hotspots in Riau, Sumatra and the east coast of Peninsular Malaysia.

Figure 6: Number of days with moderate to dense smoke haze observed over an area based on satellite imageries, ground observations and air quality reports in Apr 2020.

Review of Regional Haze Situation for March 2020

1.1 While Northeast Monsoon conditions continued to prevail over the ASEAN region in March 2020, the prevailing winds over the Mekong sub-region during the month were mostly blowing from southeast or southwest. Despite an increase in isolated showers over the eastern parts of the Mekong sub-region, the weather over the sub-region remained largely dry during this period. In contrast, scattered showers fell over the southern ASEAN region, particularly over areas south of the equator.

Figure 1: Average Daily Rainfall for Mar 2020. (Source: JAXA GsMaP)

1.2 Scattered hotspots were detected in the Mekong sub-region, while hotspot activities remained subdued in the southern ASEAN region. In terms of the hotspot count, Lao PDR recorded one of the highest number of hotspots in March 2020 in comparison with previous years. Elsewhere in the region, there was no significant trend observed during the review period.

Figure 2: Hotspot count for the northern ASEAN region for Mar 2013 – 2020. [Note: Hotspot count from year 2019 onward is based on the NOAA-20 satellite, and for the period from year 2013-2018 is based on the Suomi-NPP satellite.]

Figure 3: Hotspot count for the southern ASEAN region for Mar 2013 – 2020. [Note: Hotspot count from year 2019 onward is based on the NOAA-20 satellite, and for the period from year 2013-2018 is based on the Suomi-NPP satellite.]

1.3 In March 2020, persistent hotspots were detected in many parts of the Mekong sub-region, particularly in Myanmar, northern and southern Lao PDR, parts of northern and central Thailand, northern Cambodia, as well as a few areas in southern Viet Nam. In the southern ASEAN region, hotspots were detected on occasions and these were mostly short-lived.

Figure 4: Distribution of hotspots detected based on NOAA-20 satellite surveillance for Mar 2020.

1.4 Over the aforementioned areas in the Mekong sub-region with persistent hotspots, the intensity of fires was also high relative to the other parts of the ASEAN region.

Figure 5: Maximum fire intensity based on NOAA-20 satellite surveillance in Mar 2020.

1.5 March 2020 saw a further deterioration in the haze situation over the Mekong sub-region, where many areas were enveloped in widespread smoke haze. In particular, dense haze was observed over eastern Myanmar, parts of northern and central Thailand, as well as the northern parts of Lao PDR and Viet Nam, where there were occurrences of transboundary smoke haze. On some days, transboundary smoke haze also affected southern Lao PDR, southern Viet Nam and northern Cambodia. The air quality levels in northern Thailand remained in the Unhealthy to Very Unhealthy range on most days in March 2020. Smoke haze in the Mekong sub-region also contributed to reduced visibility readings across several parts of the sub-region. In the southern ASEAN region, no significant smoke haze was observed except for localized smoke plumes from the short-lived hotspots in central Sumatra.

Figure 6: Number of days with moderate to dense smoke haze observed over an area based on satellite imageries, ground observations and air quality reports in Mar 2020.

Review of Regional Haze Situation for February 2020

1.1 In February 2020, Northeast Monsoon conditions prevailed over the ASEAN region. During this period, which is also traditional dry season in the northern ASEAN region, dry weather persisted over the Mekong sub-region. In the southern ASEAN region, there were scattered showers on most days. However, brief periods of dry weather were experienced in Malaysia, and northern and central Sumatra (Figure 1).

Figure 1: Average Daily Rainfall for Feb 2020. (Source: JAXA GsMaP)

1.2 In the northern ASEAN region, dry weather gave rise to scattered hotspot activities in the Mekong sub-region. Based on surveillance by the NOAA-20 satellite, the highest number of hotspots was detected in Cambodia and Myanmar. In Lao PDR, Thailand and Viet Nam, the hotspot count in February 2020 was comparable to the same period in 2019 (Figure 2).

Figure 2: Hotspot count for the northern ASEAN region for Feb 2013 – 2020. [Note: Hotspot count from year 2019 onward is based on the NOAA-20 satellite, and for the period from year 2013-2018 is based on the Suomi-NPP satellite.]

1.3 In the southern ASEAN region, hotspot activities were generally subdued in February 2020. The number of hotspots detected was slightly lower than the same period in 2019 (Figure 3).

Figure 3: Hotspot count for the southern ASEAN region for Feb 2013 – 2020. [Note: Hotspot count from year 2019 onward is based on the NOAA-20 satellite, and for the period from year 2013-2018 is based on the Suomi-NPP satellite.]

1.4 During February 2020, there were persistent hotspot activities in parts of the Mekong sub-region. In particular, significant clusters of hotspots were detected in Cambodia. In Thailand, clusters of hotspots were occasionally detected in its northern, northeastern and central regions. Hotspots were detected frequently in central and eastern Myanmar, and northern and southern Lao PDR during the month. In the southern ASEAN region, occasional isolated hotspots were detected mostly in Sumatra, Malaysia and Kalimantan.

Figure 4: Distribution of hotspots detected based on NOAA-20 satellite surveillance for Feb 2020.

1.5 Based on NOAA-20 satellite surveillance, hotspots with moderate to high fire intensity were detected mainly in Cambodia, southern Lao PDR and parts of Thailand and Myanmar.

Figure 5: Maximum fire intensity based on NOAA-20 satellite surveillance in Feb 2020.

1.6 In February 2020, hazy conditions were observed on many days in northern, northeastern and central Thailand, northern Cambodia and eastern Myanmar. Slight haziness was detected in northern Myanmar and southern Lao PDR on some days. There were also occasions of transboundary smoke haze when the prevailing winds transported the smoke haze from northern Thailand to northern Lao PDR, and from Cambodia to eastern Thailand.

Figure 6: Number of days with moderate to dense smoke haze observed over an area based on satellite imageries, ground observations and air quality reports in Feb 2020.

Review of Regional Haze Situation for January 2020

1.1 In Jan 2020, Northeast Monsoon conditions prevailed over the ASEAN region. During this period, which is the traditional dry season of the Mekong sub-region, persistent dry weather prevailed. In the southern ASEAN region, there were scattered rain showers on most days but there were also occasional dry periods in some areas, including Peninsular Malaysia, northern and central Sumatra (Fig. 1).

Figure 1: Average Daily Rainfall for Jan 2020. (Source: JAXA GsMaP)

1.2 In Jan 2020, the number of hotspots detected in the Mekong sub-region was higher than the same period in 2019 (Fig. 2).

Figure 2: Hotspot count for the northern ASEAN region for Jan 2013 – 2020. [Note: Hotspot count from year 2019 onward is based on the NOAA-20 satellite, and for the period from year 2013-2018 is based on the Suomi-NPP satellite.]

1.3 In the southern ASEAN region, hotspot activities remained generally subdued (Fig. 3).

Figure 3: Hotspot count for the southern ASEAN region for Jan 2013 – 2020. [Note: Hotspot count from year 2019 onward is based on the NOAA-20 satellite, and for the period from year 2013-2018 is based on the Suomi-NPP satellite.]

1.4 There were persistent hotspots detected in Cambodia, particularly in the northern and western provinces. Clusters of hotspots were also detected in northern, northeastern and central Thailand, eastern Myanmar, and southern parts of Lao PDR and Viet Nam (Fig. 4). In the southern ASEAN region, there were occasional isolated hotspots detected mainly in Peninsular Malaysia, Sumatra and Kalimantan.

Figure 4: Distribution of hotspots detected based on NOAA-20 satellite surveillance for Jan 2020.

1.5 Based on NOAA-20 satellite surveillance, hotspots with moderate to high fire intensity were detected mostly in northern Cambodia, central Thailand, eastern Myanmar, Lao PDR and southern Viet Nam. Some of these hotspots in northern and central Thailand and Cambodia emitted significant smoke haze on a number of days in Jan 2020.

Figure 5: Maximum fire intensity based on NOAA-20 satellite surveillance in Jan 2020.

1.6 Persistent hazy conditions were observed mainly in northern and central Thailand, and Cambodia. In eastern Myanmar, northern Lao PDR and southern Viet Nam, smoke haze was observed on some days. Blown by the prevailing winds, transboundary transport of smoke haze was observed on a few days from northern Thailand to northern Lao PDR, and from Cambodia to eastern Thailand.

Figure 6: Number of days with moderate to dense smoke haze observed over an area based on satellite imageries, ground observations and air quality reports in Jan 2020.

Review of Land Fires and Smoke Haze Situation for First Fortnight of December 2019

1.1 Following the onset of the dry season in the Mekong sub-region, there has been a gradual increase in the hotspot activities. Isolated hotspots with localised smoke plumes were detected in many areas in the Mekong sub-region. In Thailand, smoke haze from persistent hotspots in central Thailand was blown towards the southwest by the prevailing winds. Air quality at “Very Unhealthy” levels were reported in the Samut Sakhon and Saraburi provinces on occasions.

1.2 In the southern ASEAN region, hotspot activities were largely subdued due to the rainy weather.

Figure 1: Hotspots detected in many parts of the Mekong sub-region during the period of review. There were persistent hotspots detected in central Thailand.

Figure 2: Image from Himawari-8 satellite showing smoke haze from persistent hotspots in central Thailand and localised plumes from isolated hotspots in Cambodia, Myanmar and northeastern Thailand