Higher risk of haze in southern ASEAN region between June and October 2023
The dry season is expected to be more intense and prolonged compared to recent years, said the ASEAN Specialised Meteorological Centre.
SINGAPORE: Weather and climate authorities on Monday (May 29) flagged a higher risk of haze in the southern ASEAN region between June and October this year amid expectations of a more intense and prolonged dry season.
The ASEAN Specialised Meteorological Centre (ASMC) made this announcement as it issued Alert Level 1, indicating the start of the dry season associated with the Southwest Monsoon in the southern ASEAN region.
“Persistent drier weather has been observed over most parts of Brunei, Indonesia, Malaysia, Singapore and southern Thailand in recent days, as the monsoon rain band moves north of the equator.
“With a high likelihood of El Nino conditions developing in the coming months, the dry season is expected to be more intense and prolonged compared to recent years, and extend into October 2023,” it said.
Hotspot activities in the southern ASEAN region are presently still subdued, with 14 and 13 hotspots detected in the southern ASEAN region on May 27 and May 28 respectively, said ASMC.
A few localised smoke plumes were detected in parts of the region on some days in May, but no transboundary smoke haze occurrence has been observed so far.
El Nino and Indian Ocean Dipole
According to the ASMC, El Nino is a naturally occurring climate pattern associated with changes in both the ocean and atmosphere in the equatorial Pacific Ocean, including an abnormal warming of the surface waters in the eastern equatorial Pacific.
Typically lasting nine to 12 months and occurring every three to five years, it produces widespread and at times severe changes in the global climate.
The Indian Ocean Dipole (IOD) is similar to the El Nino, but occurs in the equatorial Indian Ocean and is of shorter duration, typically ending by December to January. The IOD varies between three phases – positive, negative and neutral.
Both La Nina and negative IOD events tend to bring wetter conditions to most parts of the ASEAN region.
Since earlier this year, warmer subsurface ocean temperatures have been observed in the eastern tropical Pacific. This is an early sign that supports El Nino conditions developing in the next few months.
A positive Indian Ocean Dipole, which suppresses cloud formation over certain parts of the tropical Indian Ocean, may also develop in the next one to two months.
Both climate phenomena typically bring drier and warmer conditions to many parts of the southern ASEAN region.
Based on these observations, ASMC said it assessed a higher risk of escalated hotspot activities and transboundary smoke haze occurrence in the southern ASEAN region between June and October 2023.
This is compared to the last three years when the dry season was moderated by prolonged La Nina conditions.
“Early precautionary and mitigation measures are advised to prevent the occurrence of fires and transboundary haze in the region,” it said.
Further updates on the regional weather and smoke haze situation are available on the ASMC website.