Category Archives: Haze Review

Review of Regional Haze Situation for September 2022

1.1 Southwest Monsoon conditions continued to be observed over the ASEAN region in September 2022, with the prevailing low-level winds blowing from the southeast for areas south of the Equator and mainly from the south to southwest for areas north of the Equator (Figure 1).

1.2 The weather over the ASEAN region in September 2022 was mostly rainy, except for parts of Java, Sulawesi, and the Lesser Sunda Islands where there were periods of drier conditions. During the last two weeks of the month, Typhoon Noru brought increased rainfall and strong winds to the northern part of the Philippines and the eastern and central parts of the Mekong sub-region, as it made landfall over Viet Nam on 28 September 2022 (Figure 1).

1.3 Hotspot activity in the ASEAN region was mostly subdued in September 2022 due to widespread shower activities. For the Mekong sub-region, hotspot counts were generally lower or comparable to previous years, with a majority of the hotspots detected in Viet Nam (Figure 3). Over the southern ASEAN region, despite this period of the year being its traditional dry season, hotspot counts were significantly lower compared to the same period in previous years (Figure 2).

1.4 During the review period, few to isolated hotspots were detected mainly in parts of Viet Nam, Kalimantan, Sulawesi, and the Lesser Sunda Islands on several days. In term of persistency, these hotspots were mostly short-lived and did not contribute to any significant smoke haze in September 2022 (Figure 4).

1.5 The overall fire intensity of hotspots detected over the ASEAN region was low in September 2022. No significant smoke haze was observed from satellite imageries and ground reports (Figure 5).

Review of Regional Haze Situation for August 2022

1.1 The monsoon rainband remained north of the Equator in August 2022, as Southwest Monsoon conditions persisted over the ASEAN region. The prevailing low-level winds blew mainly from the east or southeast for areas south of the Equator and from the southeast or southwest over areas north of the Equator.

1.2 For the southern ASEAN region, shower activities were observed across many areas despite the ongoing traditional dry season. Rainfall was most intense in Luzon, Philippines contributed by Severe Tropical Storm Ma-on which made landfall on August 23, 2022. Persistent dry weather conditions developed in Java and the Lesser Sunda Islands during the month. In addition, intermittent periods of drier weather were observed in Sumatra, Borneo, Peninsular Malaysia and Singapore in early to mid-August. The traditional wet season for the northern ASEAN region persisted in August 2022 and shower activities were observed over the region on most days of the month (Figure 1).

1.3 There was an increase in hotspot activity in the southern ASEAN region during brief periods of drier weather in the first half of August 2022. For the northern ASEAN region, continued showers helped to keep the hotspot counts low. The hotspot count for most parts of the ASEAN region were comparable or lower to previous years, except for Kalimantan where hotspot counts were higher compared to 2020 and 2021 (Figure 2 and 3).

1.4 4. Dry periods in early to mid-August 2022, contributed to an escalation in hotspot activity in the southern ASEAN region (Figure 4). In particular, clusters of hotspots with high intensity were detected in West Kalimantan on several days during this period. Increased hotspot activity was also detected in parts of Viet Nam and Sumatra. (Figure 5). Moderate smoke haze was observed in the vicinity of the hotspot clusters in West Kalimantan on several days in the first half of August 2022, but the haze was generally localized. (Figures 6 and 7).

Review of Regional Haze Situation for July 2022

1.1 In July 2022, the Southwest Monsoon conditions prevailed with the low-level winds blowing mainly from the southeast or south over areas south of the Equator and blowing mainly from the southwest or west over areas north of the Equator.

1.2 With the monsoon rainband located north of the Equator, the traditional wet season set-in for the northern ASEAN region during the review period. Shower activities were observed over the region on most days, except for the southern parts of Myanmar where it was drier. In the southern ASEAN region, the traditional dry season became established and drier conditions were observed over most parts of the region except for the eastern parts Sulawesi and the northern parts of Sumatra, as well as the northeastern and southwestern parts of Borneo where conditions were relatively wetter (Figure 1).

Figure 1: Average Daily Rainfall and Mean Winds for July 2022. (Source: JAXA GsMaP and GFS, respectively)

1.3 The hotspot activity in the ASEAN region was generally subdued in July 2022 under continued wet weather conditions with the total hotspot counts lower or comparable to the same month in previous years, except for Thailand where there was a slightly higher total hotspot count compared to 2020 and 2021 (Figure 2 and 3).

Figure 2: Hotspot counts for the southern ASEAN region for the month of July (2018 – 2022). [Note: The hotspot counts from 2019 onwards are based on the NOAA-20 satellite, while those from 2018 are based on the Suomi-NPP satellite.]

Figure 3: Hotspot counts for the northern ASEAN region for the month of July (2018 – 2022). [Note: The hotspot counts from 2019 onwards are based on the NOAA-20 satellite, while those from 2018 are based on the Suomi-NPP satellite.]

1.4 During the review period, isolated to scattered hotspots were detected mostly in Sumatra, the Lesser Sunda Islands, western parts of Borneo and the central parts of Viet Nam during brief periods of drier weather (Figure 4). In particular, some of the detected hotspots in Sumatra, West Kalimantan and the central parts of Viet Nam were intense (Figure 5). Towards the end of the month, localised smoke plumes were observed to emanate from the hotspots in Sumatra, Sarawak, West Kalimantan and the central parts of Viet Nam (Figure 6).

Figure 4: Distribution of hotspots detected in July 2022 based on NOAA-20 satellite surveillance.

1.5 The overall fire intensity of hotspots detected over the ASEAN region was low during the review period of July 2022. There was no significant smoke haze observed via satellite imagery and ground reports (Figure 5).

Figure 5: Maximum fire intensity in July 2022 based on NOAA-20 satellite surveillance.

Figure 6: True Color RGB image (left) and False Color RGB image (right) showing localised smoke plumes emanating from some hotspots located in West Kalimantan on 21 July 2022.

Review of Regional Haze Situation for June 2022

1.1 Southwest Monsoon conditions persisted over the ASEAN region in June 2022. Over the Philippines and much of the southern ASEAN region, the prevailing winds blew mainly from the southeast. Regions close to the Equator experienced winds that were light and variable in direction. Over the Mekong sub-region, the prevailing winds were mostly southwesterly (Figure 1).

1.2 During the review period, rainy weather prevailed over most parts of the ASEAN region. In particular, moderate to heavy showers fell on several days over western Borneo, as well as central and northern Sumatra, southern Sulawesi, northern Viet Nam, and northern Philippines. Drier conditions were observed over the Lesser Sunda Islands, coastal Viet Nam, central Myanmar, as well as northern parts of Thailand and Lao PDR (Figure 1).

Figure 1: Average Daily Rainfall and Mean Winds for June 2022. (Source: JAXA GsMaP and GFS, respectively)

1.3 Hotspot activity in the ASEAN region was mostly subdued in June 2022 due to the prevailing wet weather conditions. The total number of hotspots was lower or comparable to previous years for the same period (Figure 2 and 3), except in Lao PDR where a slightly higher number of hotspots was detected.

Figure 2: Hotspot counts for the southern ASEAN region for the month of June (2018 – 2022). [Note: The hotspot counts from 2019 onwards are based on the NOAA-20 satellite, while those from 2018 are based on the Suomi-NPP satellite.]

Figure 3: Hotspot counts for the northern ASEAN region for the month of June (2018 – 2022). [Note: The hotspot counts from 2019 onwards are based on the NOAA-20 satellite, while those from 2018 are based on the Suomi-NPP satellite.]

1.4 In June 2022, isolated to scattered hotspots were detected in parts of Viet Nam and Cambodia while few to isolated hotspots were detected in most parts of the southern ASEAN region on some days. However, these hotspots were short-lived and did not contribute to any significant smoke haze. During a brief period of drier weather toward the end of the review period, a slight increase in hotspots was detected in Sumatra and Borneo (Figure 4).

Figure 4: Distribution of hotspots detected in June 2022 based on NOAA-20 satellite surveillance.

1.5 The overall fire intensity of hotspots detected over the ASEAN region was low during the review period of June 2022. There was no significant smoke haze observed via satellite imagery and ground reports (Figure 5).

Figure 5: Maximum fire intensity in June 2022 based on NOAA-20 satellite surveillance.

Review of Regional Haze Situation for May 2022

1.1 Inter-monsoon conditions started to give way to Southwest Monsoon conditions through May 2022 as the monsoon rainband continued to move northwards over the northern ASEAN region. The prevailing winds over the ASEAN region blew generally from the southeast or southwest, except for regions close to the Equator where winds were light and variable in direction (Figure 1).

1.2 Rainy weather was observed over most of the ASEAN region in May 2022 although drier conditions prevailed over the Lesser Sunda Islands and the northernmost parts of the Mekong sub-region. Heavy rainfall was observed in parts of southern Philippines, as well as the southern parts of both Myanmar and Thailand (Figure 1).

1.3 For May 2022, the total number of hotspots were lower or comparable to previous years for the same period (Figures 2 and 3), except in Sumatra and Kalimantan where a slightly higher number of hotspots were detected in May 2022 compared to previous years.

1.4 Isolated to scattered hotspots (Figures 4 and 5) and moderate smoke haze (Figure 6) were observed in the first week of May 2022 over northern parts of the Mekong sub-region. However, the onset of wetter conditions over the northern ASEAN region in subsequent weeks helped to suppress hotspot and smoke haze activities here. As wet conditions became established, the Alert Level over the Mekong sub-region was downgraded to Alert Level 1 on 10 May 2022, and the End of Dry Season (Alert Level 0) was declared on 19 May 2022.

1.5 The hotspot and smoke haze situation in the southern ASEAN region remained subdued as rainy conditions continued to prevail. Isolated hotspots were detected (Figures 4 and 5) and localised smoke plumes were observed to emanate from some of these hotspots in Borneo and the central Sumatra on some days.

Review of Regional Haze Situation for April 2022

1.1 The Northeast Monsoon gradually transitioned to inter-monsoon conditions in April 2022 as the monsoon rainband moved northwards over the equator. The prevailing winds over most parts of the ASEAN region were light and variable in direction on most days, except for the Philippines where winds blew mostly from the northeast or east (Figure 1).

1.2 Most parts of the Mekong sub-region experienced prolonged dry weather in April 2022, except for southern Cambodia and northern Myanmar where showers were observed on some days. Rainy weather conditions were observed elsewhere in the ASEAN region on most days during this period, although drier conditions prevailed over northern Philippines and the Lesser Sunda Islands. Heavy rainfall was observed in parts of central and southern Philippines, contributed by the passage of Tropical Storm Megi in the second week of April 2022 (Figure 1).

1.3 For April 2022, the total number of hotspots were lower or comparable to previous years for the same period (Figures 2 and 3), except for Lao PDR where significantly higher numbers of hotspots were detected in April 2022 compared to previous years. Slightly more hotspots were detected in Sumatra compared to previous years.

1.4 Under the prevailing dry weather in April 2022, scattered to widespread hotspots were detected in most parts of the Mekong sub-region on many days. In particular, persistent clusters of high intensity hotspots, were detected in northern and central Lao PDR, as well as western and northeastern Myanmar during the month (Figures 4 and 5). Widespread moderate to dense smoke haze was observed to emanate from these hotspots on several days in early to mid- April, with transboundary haze observed to drift from Lao PDR into Thailand, Viet Nam and Cambodia on several days (Figures 6 and 7). As a result, Alert Level 3 was issued on 11 April 2022. As shower activities returned later in the month, the overall hotspot and smoke haze situation improved and a downgrade to Alert Level 2 was issued on 29 April 2022.

1.5 The hotspot and smoke haze situation in the southern ASEAN region remained comparatively subdued as rainy conditions prevailed. Isolated hotspots were detected and localised smoke plumes were observed to emanate from some of these hotspots in West Kalimantan and the western coastal areas of central Sumatra on some days (Figure 8).

Review of Regional Haze Situation for March 2022

1.1 In March 2022, Northeast Monsoon conditions prevailed over the ASEAN region. While the prevailing winds over the areas north of the Equator blew mostly from the northeast or east, the winds over the Mekong sub-region were light and variable in direction. The prevailing winds over the areas south of the Equator blew mostly from the west or northwest. As the Northeast Monsoon conditions gradually weakened in the second half of the month, the prevailing winds over most of the ASEAN region were light and variable in direction on several days during the review period (Figure 1).

1.2 The dry conditions over the Mekong sub-region continued in March 2022, even though isolated showers were observed over the sub-region on some days. In the rest of the ASEAN region, generally wet conditions were observed but brief periods of drier weather were experienced in Sumatra and West Kalimantan (Figure 1).

1.3 For March 2022, the total number of hotspots were lower or comparable compared to previous years for the same period (Figure 2 & 3).

1.4 Scattered to widespread hotspots were detected during the continued dry weather conditions over the Mekong sub-region. Clusters of hotspots were more intense and persistent in Myanmar, Lao PDR and northeastern Cambodia, with smoke haze observed to emanate from these hotspots on several days. In particular, smoke haze was observed to be denser over parts of Myanmar and northern Lao PDR.

1.5 Elsewhere in the ASEAN region, isolated to scattered hotspots were observed mostly in the Philippines, central Sumatra, West Kalimantan and Sulawesi. Localised smoke plumes were observed to emanate from the hotspots detected in West Kalimantan and the western coastal areas of central Sumatra on some days in the second half of the month.

Review of Regional Haze Situation for February 2022

1.1 The ASEAN region continued to be influenced by Northeast Monsoon conditions in February 2022. Over areas north of the equator, the prevailing winds blew mainly from the northeast even though the winds were relatively weaker and more variable in direction over the Mekong sub-region. For areas south of the equator, the prevailing winds blew mostly from the west or northwest (Figure 1).

1.2 Dry conditions persisted over the Mekong sub-region throughout the review period of February 2022, except for isolated shower activities in the southern parts of the sub-region on some days. Elsewhere in the ASEAN region, rainy weather was observed in many areas. However, parts of Sumatra, Borneo, and the Philippines experienced brief periods of drier weather.

1.3 Prolonged dry conditions over the Mekong sub-region led to an increase in overall hotspot activity in February 2022. While isolated to scattered hotspots were detected in most parts of the sub-region on several days, the hotspot counts were generally lower this year compared to previous years (Figure 2). In the southern ASEAN region, hotspot activity was generally subdued, with only isolated hotspots detected in Sumatra and Kalimantan. The hotspot counts were also lower compared to previous years (Figure 3).

1.4 In view of the increase in hotspots and escalating smoke haze situation in the Mekong sub-region, ASMC activated Alert Level 2 for the sub-region on 11 February 2022. From the middle of the month, persistent hotspots and a few localised smoke plumes were detected in many parts of the Mekong sub-region, particularly over Myanmar, northern Cambodia, and southern Lao PDR (Figures 4 and 5). By the end of the month, moderate to dense smoke haze was observed to emanate from persistent hotspot clusters in Myanmar, northern Thailand, northern Cambodia, and southern Lao PDR (Figures 6 and 7).

Review of Regional Haze Situation for January 2022

1.1 Northeast Monsoon conditions persisted over the ASEAN region in January 2022. This month, the prevailing low-level winds over regions north of the Equator blew mostly from the northeast or east while the prevailing low-level winds over regions south of the Equator blew mainly from the west or northwest. Under the influence of the Northeast Monsoon, persistent dry conditions were observed over the Mekong sub-region. Relatively dry weather was also observed over parts of Peninsular Malaysia, Singapore, the Philippines and Sumatra in January 2022. Wetter conditions were observed over regions south of the Equator during the review period in line with the monsoon rainband’s position south of the Equator.

1.2 In January 2022, hotspot activities started to increase in the Mekong sub-region as dry conditions prevailed, while wet conditions helped subdue hotspot activities in the southern ASEAN region. The hotspot counts for the Mekong sub-region in January 2022 were mostly lower compared to previous years, while the hotspot counts over the southern ASEAN region were generally similar to previous years (Figures 2 and 3).

1.3 The Mekong sub-region remained at Alert Level 1 for the month as the risk of transboundary haze remained low. However, there was an increase in hotspot activities with localized smoke plumes in persistently dry areas of the sub-region. In particular, clusters of scattered hotspots with visible smoke plumes were detected in northeastern Cambodia on several days. Elsewhere in the ASEAN region, hotspot activities remained mostly subdued (Figures 4 and 5).