Indonesian authorities have taken to the skies with tonnes of dry ice in an attempt to disperse thick haze from forest and land fires blanketing South Sumatra.
BNPB, Indonesia’s government agency for natural disaster management, initially deployed 2.4 tonnes of dry ice over 15 and 16 Oct, as poor visibility disrupted flights at Palembang’s Sultan Mahmud Badaruddin II International Airport and raised health concerns for residents.
The operation has since been extended, with weather modification efforts expected to continue until 25 Oct.
During the initial two-day operation, BNPB aircraft completed three deployments totalling seven hours and three minutes of flying time.
Flights departed from Raden Inten II Airport in Bandar Lampung before heading towards Palembang.
Each deployment carried around 800kg of dry ice, with the first batch dispersed around Sultan Mahmud Badaruddin II Airport.
Source: deTik
According to Indonesia’s agency for Meteorology, Climatology, and Geophysics, visibility at the airport stood at around 1km at 1pm following the first operation.
It later improved to between 1.5km and 2km, before stabilising at around 2.8km after subsequent deployments.
Two hours later, visibility reached about 3km and remained around that level until 8.30pm.
South Sumatra’s disaster management agency said the improvement was also accompanied by better air quality.
The dry-ice operation continued on 17 Oct, with another deployment carrying approximately 800kg over the Palembang area.
A separate flight also dispersed sodium chloride, or salt, over areas where conditions were suitable for cloud and rain formation.
This brought the reported amount of dry ice deployed since the initial operation began to at least 3.2 tonnes.
Source: Sumatra Business
Indonesia’s Forestry Ministry said the wider weather modification operation would run for 10 days, from 16 to 25 Oct, with flights adjusted according to changing atmospheric conditions.
Unlike conventional cloud seeding aimed primarily at encouraging rainfall, the dry ice is being used to tackle an atmospheric inversion.
An inversion occurs when warmer air sits above cooler air near the ground, preventing air from rising normally and trapping smoke and pollutants close to the surface.
Source: Jakarta Daily
Officials hope that dispersing solid carbon dioxide into the atmosphere can weaken this layer, allowing trapped smoke to disperse and improving visibility.
When the inversion weakens and suitable rain clouds develop, authorities can switch to or combine the method with salt seeding to encourage rainfall.
Palembang has been grappling with severe haze from forest and land fires throughout October.
On 8 Oct, BNPB reported that visibility in the city had fallen to as low as 400m, resulting in flight delays at Sultan Mahmud Badaruddin II Airport.
Three civilian flights had already experienced disruptions the previous day.
Source: GO Kompas
Authorities have identified Ogan Komering Ilir Regency as one of the main areas contributing smoke to Palembang and made it a priority for firefighting operations.
Ground crews and aerial teams are continuing to tackle the fires themselves, while weather modification is being used to mitigate the resulting haze.
Despite the improvement in visibility following the flights, BNPB has cautioned against attributing the change entirely to the dry ice.
Berton Panjaitan, acting head of BNPB’s Disaster Data, Information and Communication Centre, said further evaluation and research are needed to determine how much of the improvement resulted from the intervention and how much may have been influenced by other weather conditions.
South Sumatra Governor Herman Deru nevertheless said conditions in Palembang appeared clearer following the trial and called for the pilot project to continue.
Also read: NEA sends legal notices to 7 companies in Indonesia whose lands hosted haze-causing fires
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Featured image adapted from Jakarta Daily and Sumatra Business.