With the National Oceanic and Atmospheric Administration (NOAA) set to shut down a key satellite data stream used in US hurricane forecasting, a group of amateur radio enthusiasts has stepped in with a decoder they say could fill the gap.
In June, the US Department of Defense (DoD) decided to remove access to data collected by the Special Sensor Microwave Imager Sounder (SSMIS) instrument for the Defense Meteorological Satellite Program (DMSP).
Although the end of the service was put back until August, the data loss is set to hinder hurricane forecasting by scientists in the US. One told The Register: “The SSMIS satellite [data] is extremely important; as a forecaster, I use them constantly. The microwave satellite imagery allows us to peer under the overcast of a storm, probing the inner structure of a tropical cyclone. It’s especially important at night.”
However, a group of amateur satellite and radio ham enthusiasts have pointed out that the data is still available, for those who know where to look. The community SatDump provides tools and data allowing users to access publicly available satellite streams. Lead developer and ham radio operator Alan Antoine said the US authorities were turning off the online distribution of real time data while the satellite passes over the US stations at Wallops Island, Virginia, and Fairbanks, Alaska.
However, with the correct receiver – a guide to the hardware is available online – anyone in the US can pull the data directly off the satellite. Although it is encrypted over the rest of the world, the data is not encrypted over the US and the poles, according to Antoine.
The only problem is using the data. Antoine said that with previously online, publicly available documents, and a bit of trial and error, it is possible to decode the data.
“Since we saw – like everyone else – the NOAA said that the SSMIS data would get cut off, and I knew you could still get it directly from the satellite, I decided to write the decoder so that if somebody wanted to still use it, they could,” he said.
The decoder is now publicly available via SatDump’s GitHub repository in the “verywip” branch, although users wanting to take advantage of the download might want to contact SatDump directly for more information.
However, not all the data NOAA once distributed can be accessed using the decoder, Antoine said. Thermal data is missing due to a lack of reference material needed to decode the signal.
“I don’t have an actual documentation for SSMIS, so it’s mostly reverse-engineered, which I can do. It’s not perfect, but it’s better than nothing. I don’t know if anyone is actually using it yet, because I just published it, but it’s pretty likely that at least some of them are going to be doing so, considering how much of an issue the lack of data is,” he said.
The Register asked NOAA to comment. ®