Category Archives: Haze Review

CR58

March 8, 2023

Review of Regional Haze Situation for February 2023

1.1 The ASEAN region continued to experience Northeast Monsoon conditions in February 2023. Over areas north of the equator, the prevailing winds blew mainly from the northeast even though the winds were mostly light and 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 2023, 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 Peninsular Malaysia and the northern Philippines experienced brief periods of drier weather. (Figure 1).

Figure 1: Average Daily Rainfall and Mean Winds for February 2023. (Source: JAXA GsMaP and GFS, respectively)

1.3 Prolonged dry conditions over the Mekong sub-region led to an increase in overall hotspot activity in February 2023 and the hotspot counts in the Mekong sub-region were higher or comparable to previous years (Figure 2). In particular, the highest hotspot activity was detected in Myanmar, and the hotspot counts for both Myanmar and Lao PDR were the highest in 5 years. For the southern ASEAN region, hotspot activity remained generally subdued and the hotspot counts were generally lower than in previous years (Figure 3).

Figure 2: Hotspot counts for the northern ASEAN region for the month of February (2019 – 2023) based on NOAA-20 satellite surveillance.

Figure 3: Hotspot counts for the southern ASEAN region for the month of February (2019 – 2023) based on NOAA-20 satellite surveillance.

1.4 Hotspot activity was widespread and persistent over the Mekong sub-region during the review period of February 2023. On many days, clusters of hotspots were detected in parts of Lao PDR, northern and eastern Cambodia, northern and central Myanmar, and northern Thailand. Isolated hotspots were also detected in northern Viet Nam. Over the southern ASEAN region, few hotspot activities were detected but most of them was short-lived (Figure 4).

Figure 4: Distribution of hotspots detected in February 2023 based on NOAA-20 satellite surveillance.

1.5 The overall fire intensity in the Mekong sub-region had increased in February 2023, particularly over the fire-prone areas in Lao PDR, northern and central Myanmar, northern and eastern Cambodia, and northern Thailand (Figure 5). As a result, moderate to dense smoke haze was observed in the vicinity of the hotspot clusters in Myanmar, Thailand, and Cambodia (Figure 6, 7, 8 and 9) on many days. Localised smoke plumes and occasional hazy conditions were also observed in northern Viet Nam on some days.

Figure 5: Maximum fire intensity in February 2023 based on NOAA-20 satellite surveillance.

Figure 6: Number of days with moderate to dense smoke haze observed in February 2023 based on satellite imagery, ground observations, and air quality reports.

Figure 7: Moderate to dense smoke haze observed over northern and central Myanmar on 24 February 2023, based on NOAA-20 satellite surveillance.

Figure 8: Moderate to dense smoke haze emanated from the hotspot clusters detected in northern and central Thailand on 24 February 2023, based on NOAA-20 satellite observation.

Figure 9: Moderate smoke haze emanated from the hotspot clusters detected in northern and eastern Cambodia on 20 February 2023, based on NOAA-20 satellite observation.

February 6, 2023

Review of Regional Haze Situation for January 2023

1.1 Northeast Monsoon conditions continued to be observed over the ASEAN region in January 2023, with the prevailing low-level winds blowing predominantly from the northeast or east over areas north of the Equator and mainly from the west or northwest for areas south of the Equator (Figure 1). The strengthening of high-pressure systems over the northern Asian continent also brought a surge of strong northeasterly winds or monsoon surge over the South China Sea during the last week of January 2023.

1.2 In January 2023, dry weather prevailed over much of the Mekong sub-region under the influence of the Northeast Monsoon. As a result of the persistent dry conditions, an escalation in hotspot activity and development of smoke haze was observed in many parts of the sub-region from the second half of the month. On 27 January 2023, Alert Level 2 was activated for the Mekong sub-region as hotspot counts were persistently high and there was an increasing risk of transboundary haze. Elsewhere, rainy weather prevailed over the southern ASEAN region and the Philippines on most days of the month. In particular, monsoon surges contributed to increased rainfall over southern Peninsular Malaysia, Singapore, western Borneo, central Sumatra, and southern Philippines (Figure 1).

Figure 1: Average Daily Rainfall and Mean Winds for January 2023. (Source: JAXA GsMaP and GFS, respectively)

1.3 For January 2023, hotspot counts in the Mekong sub-region were slightly elevated compared to the same review period in 2022 (Figure 2). In particular, the highest hotspot activity was detected in Cambodia, and the hotspot count for Lao PDR and Viet Nam was slightly higher than the past 5 years. For the southern ASEAN region, hotspot activity remained generally subdued and the hotspot counts were lower or comparable to those in previous years (Figure 3).

Figure 2: Hotspot counts for the northern ASEAN region for the month of January (2019 – 2023) based on NOAA-20 satellite surveillance.

Figure 3: Hotspot counts for the southern ASEAN region for the month of January (2019 – 2023) based on NOAA-20 satellite surveillance.

1.4 During the review period, hotspot activity was widespread over the Mekong sub-region. On many days, clusters of hotspots were detected in northern and eastern Cambodia, as well as central Myanmar. Persistent hotspots were also detected in northern Viet Nam, as well as the northern and northeastern regions of Thailand. Over the southern ASEAN region, few hotspots were detected but most of them were short-lived (Figure 4).

Figure 4: Distribution of hotspots detected in January 2023 based on NOAA-20 satellite surveillance.

1.5 The overall fire intensity in the Mekong sub-region had increased in January 2023, particularly over the fire-prone areas in central Myanmar, and northern and eastern Cambodia (Figure 5). As a result, persistent and moderate smoke haze was observed in the vicinity of the hotspot clusters in Myanmar and Cambodia (Figure 6, 7, and 8). Localised smoke plumes and occasional hazy conditions were also observed in northern Thailand, northern Viet Nam, and parts of Lao PDR.

Figure 5: Maximum fire intensity in January 2023 based on NOAA-20 satellite surveillance.

Figure 6: Number of days with moderate to dense smoke haze observed in January 2023 based on satellite imagery, ground observations, and air quality reports.

Figure 7: Moderate smoke haze observed over central Myanmar on 22 January 2023, based on NOAA-20 satellite surveillance.

Figure 8: Moderate smoke haze emanated from the hotspot clusters detected in northern and eastern Cambodia on 31 January 2023, based on NOAA-20 satellite surveillance.

January 11, 2023

Review of Regional Haze Situation for December 2022

1.1 In December 2022, the Northeast Monsoon was well established over the ASEAN region as the predominant low-level winds blew from the northeast over areas north of the Equator and blew from the west or northwest over areas south of the Equator. The northeasterly winds strengthened at times, bringing a monsoon surge over the South China Sea and parts of the Mekong sub-region (Figure 1).

1.2 During the month, dry conditions were experienced over most parts of the Mekong sub-region except for the southeastern parts of the sub-region where some rainfall was observed. Alert Level 1 for the onset of the dry season in the northern ASEAN region was issued on the 15 December 2022. Wet weather was experienced elsewhere in the ASEAN region with the highest rainfall observed over the eastern parts of the Peninsular Malaysia and the southern parts of Thailand and the Philippines (Figure 1), under the influence of the monsoon surge. Floods and landslides were also reported in these areas on several days during the month which resulted in several fatalities and displacement of people from their homes.

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

1.3 1.3 There was an increase in the overall hotspot activities in the Mekong sub-region following the onset of the dry conditions over the sub-region in December 2022 with the highest hotspot activity detected in Cambodia (Figure 2). In the southern ASEAN region, hotspot activities were mostly subdued due to the prevailing wet weather (Figure 3). While the hotspot activities in ASEAN region were mostly comparable to the same month in previous years, there was a noticeable increase in the hotspot activities in Cambodia compared to the last two years.

Figure 2: Hotspot counts for the northern ASEAN region for the month of December (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 southern ASEAN region for the month of December (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 the northern ASEAN region, isolated to scattered hotspots were detected mostly in the Mekong sub-region. The hotspots were more persistent in the northern and eastern parts of Cambodia, the southern parts of Myanmar, the northern parts of Viet Nam and the northern and central parts of Thailand (Figure 4). While the overall fire intensity of hotspots was low, localised smoke plumes were observed to emanate from hotspots in the eastern parts of Cambodia and northern parts of Viet Nam where the fire intensity was slightly higher (Figure 5). In the southern ASEAN region, hotspot activities were subdued due to the wet weather with few hotspots detected in Sumatra, Kalimantan and Sulawesi.

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

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

December 15, 2022

Review of Regional Haze Situation for November 2022

1.1 The inter-monsoon conditions gradually made way for the Northeast Monsoon over the ASEAN region in November 2022. The prevailing low-level winds over the northern ASEAN region blew from the northeast to east while the winds over most parts of the southern ASEAN region were light and variable in direction (Figure 1).

1.2 Most of the ASEAN region experienced wet weather conditions during November 2022, except for the northern, western and central parts of the Mekong sub-region where the conditions were relatively drier. Over the northern ASEAN region, rainfall amount was higher over the southern Mekong sub-region, coastal areas of Viet Nam and the Philippines. Widespread rainfall fell over much of the southern ASEAN region (Figure 1).

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

1.3 For November 2022, overall hotspot activities were mostly subdued due to the prevailing rainy conditions over the ASEAN region. Majority of the hotspots in the northern ASEAN region were detected in Myanmar, but the hotspot counts for the whole ASEAN region were generally lower or comparable to the counts in previous years (Figures 2 and 3).

Figure 2: Hotspot counts for the northern ASEAN region for the month of November (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 southern ASEAN region for the month of November (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 Throughout the November review period, few to isolated hotspots were detected in the ASEAN region. While these hotspots were mostly short-lived, hotspots were relatively more persistent in the southern parts of Myanmar, central and northern Viet Nam, as well as central Thailand (Figure 4). On most days, no discernable smoke plumes were observed.

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

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

1.5 The fire intensity of hotspots detected over the ASEAN region was generally low in November 2022 (Figure 5). No significant smoke haze was observed from satellite imagery.

November 8, 2022

Review of Regional Haze Situation for October 2022

1.1 Southwest Monsoon conditions transitioned to the inter-monsoon in late October 2022 as the monsoon rainband moved over the Equator and the prevailing winds gradually weakened and turned light and variable over the equatorial ASEAN region (Figure 1).

1.2 Rainy conditions prevailed over most parts of the ASEAN region in October 2022, except for parts of northeastern Mekong sub-region. In the 3rd week of October, Typhoon Nesat made landfall in the Philippines and contributed to the heavy rainfall over northern parts of the country. It also brought increased rainfall over central Viet Nam as it weakened into a tropical depression before making landfall (Figure 1). The southern ASEAN region experienced continued shower activities during the review period and Alert Level 0 was issued for the region on 12 October 2022, signaling the end of its traditional dry season.

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

1.3 In October 2022, overall hotspot activity in the ASEAN region was subdued under wet weather conditions. While majority of the hotspots in the Mekong sub-region were detected in Viet Nam, the hotspot counts for northern ASEAN region were generally lower or comparable to the counts in previous years (Figure 2). For the southern ASEAN region, hotspot counts were significantly lower compared to the same period in previous years (Figure 3).

Figure 2: Hotspot counts for the northern ASEAN region for the month of October (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 southern ASEAN region for the month of October (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 For the October 2022 review period, few to isolated hotspots were detected in the ASEAN region on most days. In term of persistency, these hotspots were mostly short-lived and did not contribute to any significant smoke haze in October 2022 (Figure 4).

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

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

1.5 The overall fire intensity of hotspots detected over the ASEAN region was low in October 2022. On most days, no smoke plumes were discernable from satellite imagery (Figure 5).

October 10, 2022

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).

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

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).

Figure 2: Hotspot counts for the southern ASEAN region for the month of September (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 September (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, 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).

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

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

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).

September 15, 2022

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).

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

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).

Figure 2: Hotspot counts for the southern ASEAN region for the month of August (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 August (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 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).

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

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

Figure 6: Number of days with moderate to dense smoke haze in August 2022 based on satellite imagery, ground observations and air quality reports

Figure 7: Himawari-8 satellite imagery showing moderate smoke haze in the vicinity of clusters of hotspots located in West Kalimantan on 9 August 2022 (left) and 18 August 2022 (right).

August 15, 2022

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.

July 8, 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.

June 16, 2022

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).

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

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.

Figure 2: Hotspot counts for the southern ASEAN region for the month of May (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 May (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 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.

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

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

Figure 6: Number of days with moderate to dense smoke haze observed in May 2022 based on satellite imagery, ground observations, and air quality reports.