Enviro News Asia, Jakarta — Indonesia’s National Research and Innovation Agency (BRIN) is evaluating the use of dry ice in weather modification operations as researchers seek to determine whether the technique can weaken atmospheric conditions that trap smoke from forest and land fires near the ground.
The assessment focuses on temperature inversions, a meteorological phenomenon in which a layer of warmer air sits above cooler air, restricting vertical air movement. The stable conditions can prevent smoke from dispersing upward and make it harder for rain clouds to develop.
Florentinus Heru Widodo, a principal engineer at BRIN’s Research Center for Limnology and Water Resources, explained the mechanism during a briefing with the integrated weather modification operations team at Halim Perdanakusuma air base in Jakarta on Sunday.
Under normal atmospheric conditions, air temperature generally decreases with altitude, allowing warm air near the surface to rise through convection and support cloud formation. During a temperature inversion, however, the warmer layer above acts as a barrier, limiting vertical mixing and potentially allowing smoke to accumulate near the surface.
“One can think of the inversion layer as a lid that restricts upward air movement,” Heru said. “As a result, smoke from fires has difficulty dispersing vertically and becomes more concentrated near the ground, while stable atmospheric conditions also hinder rain cloud development.”
The technique being examined involves releasing dry ice, or solid carbon dioxide, into the atmosphere. Unlike conventional cloud seeding, which aims to increase the likelihood of rainfall in suitable clouds, this approach is intended to test whether localized cooling can affect the thermal structure of an inversion layer.
Dry ice has a temperature of about minus 78.5 degrees Celsius. As it sublimates from a solid directly into a gas, it absorbs heat from its surroundings. Researchers are investigating whether this localized cooling could alter temperature differences and air density, trigger localized air movement and encourage vertical mixing.
If the resulting changes are sufficiently strong and atmospheric conditions are favorable, the inversion layer could weaken, potentially allowing greater air movement and improving conditions for cloud development.
However, Heru stressed that the proposed mechanism remains a scientific hypothesis and requires verification through atmospheric observations.
“Dry ice is expected to produce localized cooling and influence atmospheric stability within the inversion layer. But this mechanism remains a scientific hypothesis. We must test whether the changes are actually sufficient to weaken the inversion and support cloud growth,” he said.
The effectiveness of the method may depend on the inversion layer’s geographic extent and stability. A temperature change in one location may not be enough to alter atmospheric conditions across a wider area.
BRIN can help assess the operation using atmospheric observations collected by implementing agencies and the Meteorology, Climatology and Geophysics Agency (BMKG). The data include vertical temperature profiles, humidity, the altitude and thickness of inversion layers, and other indicators of atmospheric stability.
Radiosondes, instruments used to measure atmospheric conditions at different altitudes, can provide temperature and humidity profiles. Temperature measurements taken during flights can also help identify inversion layers and estimate their thickness.
Researchers say observations before, during and after the dry ice release are needed to document changes systematically and distinguish the effects of the intervention from other weather processes.
“We want to ensure that every technology used in disaster response has a strong scientific basis,” Heru said. “Observational data are essential to determine whether the treatment actually affects the inversion layer or whether changes are also driven by other atmospheric dynamics.”
The evaluation comes as authorities continue efforts to address the effects of forest and land fires. BRIN’s assessment is intended to establish whether dry ice can provide a measurable benefit under specific atmospheric conditions, rather than assume that the technique will automatically disperse smoke or produce rainfall. (*)
