Rising Global Temperatures Could Affect Military Sensors, Comms Systems (Updated)

By Cambrie Eckert

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ARLINGTON, Virginia — Climate change isn’t just contributing to unprecedented flooding in New England and record temperatures experienced around the world this summer, it could also degrade critical defense technologies, according to the findings of a research team.

Scientists at John Hopkins Applied Physics Laboratory in Laurel, Maryland, studied the effects of climate change on radio wave propagation, including how rising temperatures can degrade other defense technologies across various marine climates.

The changes could be significant enough to affect next-generation communication systems, navigation and surveillance radars, Jonathan Gehman, lead researcher and applied physicist at the lab, said in an interview.

The team discovered that higher temperatures and increased humidity would likely affect the way radio waves travel, degrading certain bands, like X-band, by 10 to 20 percent. This means engineers might need to consider the environment as an “evolving design factor” when outlining future defense technologies and systems, he said.

“Today, when you’re designing these systems, one of the choices you often have to make is between S- and X-band, which are around three and 10 gigahertz, respectively. The trade-off is that with S-band, you can see farther through the atmosphere, but with X-band and other high-frequency bands, you get better resolution, more bandwidth and a less crowded spectrum,” he said in a release.

Global temperatures will likely rise 2 to 4 degrees Celsius higher than current levels in the next 50 to 100 years if carbon emissions continue to rise, APL researchers said, citing U.S. government statistics.

“What we found was that, over the next 50 years, in the severe scenario, differentiation is likely to become more pronounced. The longer-range advantage of S-band will improve, and X-band and higher frequencies will degrade as a result of increasing moisture in the atmosphere,” he said in the release.

Gehman said the team conducted the study by extrapolating each location across two future climate scenarios, moderate and severe, after downloading and analyzing data from the World Climate Research Programme’s Coupled Model Intercomparison Project. The data was used to help predict how rising moisture in the atmosphere and warmer seas from increasing carbon emissions could potentially impact communications and remote sensing systems, like radar.

This impact might require more power for the systems, Gehman said. As a signal transmits through more water molecules or pollutants in the atmosphere, energy is lost. To use more power, costs will increase, he added.

It is yet to be determined what kind of impact other aspects of climate change — changing rainfall, cloud cover and aerosols — could have on sensor and missile defense systems, Gehman said. “If you only use what we now know about today’s environment for that part of the budget, and then you go into the real world, the real world might be taking up more of that. So, you want to add some margin to that part of your power budget,” he continued.

Aerosols are an important piece of the puzzle, since they make it hard to have a clear view, interfering with infrared and optics, Gehman said. “It’s very hard to predict what the future aerosol contents would look like. That has as much to do with technology developments and policy and emissions as it does with scientific equations that you can code up and solve.” ND

Correction: A previous version of this story suggested that infrared bands were radio bands and failed to cite government statistics as the source of the rising global temperatures statistic.

Topics: Battlefield Communications

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