We are, as everyone knows by now, huge volcano stans. And the last month has been amazing for all the volcano watchers around the world. We have had our fill of lava pouring out of a cinder cone and fissure in Iceland, as well as some scarier, explosive eruptions at La Soufriere in the Caribbean. But we’re not the only ones keeping an eye on volcanoes these days, and no, I’m not talking about all the webcams around the world. I’m talking about the Volcanic Cloud Analysis Toolkit or VOLCAT.

VOLCAT is a complex set of software that scientists use to process data from remote sensing satellites in near-real-time, and with that software, they can detect and track the volcanic ash clouds that rise up into the atmosphere. For the most part, this analysis lends itself to mitigating ash-related hazards for aircraft, since the ash particles will destroy engines, so planes need to be redirected around the ash clouds.

The VOLCAT software was the brainchild of NOAA scientist Mike Pavolonis, who has spent his career watching clouds, and he realized about fifteen years ago that analysts could not integrate all of the data coming in. And now, his project uses five low Earth orbit satellites and four geostationary satellites to track more than 1,500 volcanoes around the world. The satellites have amazing sensors that help identify the radiation signatures specific to ash separate from regular, water-rich clouds. But it’s not always that easy to differentiate the two types of cloud. As Pavolonis explains: …they’re a mixture of volcanic ash, ice, liquid water, and volcanic gases.

When there is no clear distinction between ash cloud and water cloud, VOLCAT tracks the cooling speed of the clouds instead. A volcanic eruption, and this should not come as a surprise, is very hot. And the ash clouds are also hot and get injected by the eruption in the cold upper levels of the atmosphere, and those clouds then cool rapidly compared to thunderstorm clouds. That’s where the geostationary satellites come in as they can stay focused on a single swath of our planet and track the changes over time, observing volcanoes in their surveillance region every fifteen minutes or so. In fact, they can take those images even more often, and La Soufriere was being imaged every minute during the height of its recent eruption.

Of course, VOLCAT is only one piece of the volcano observing puzzle. We still need human experts to filter through the alerts from the system and check for any false notifications. It turns out that it’s hard for even an automated system to process more than a terabyte of data per day. VOLCAT, however, makes it much easier for scientists to focus on where the ash clouds might be, and this means those one-minute images become alerts in less than two minutes. Pavolonis sums up the advancement: We are in a golden era because it was only less than 10 years ago [that] we were happy to get an image every 15 minutes. We [imaged Soufrière St. Vincent’s] clouds when they were on their way up [and] that type of capability is really important.

It’s amazing how quickly technology can improve.

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