Which radar technology allows forecasters to differentiate between rain and hail and detect airborne debris of tornadoes even at night?

Which radar technology allows forecasters to differentiate between rain and hail and detect airborne debris of tornadoes even at night?

• A. Pulse radar
• B. Single polarization
• C. Dual polarization
• D. Phased-array radar

Answer: (C)

Using dual-polarization radar, which sends energy in both horizontal and vertical orientations, lets forecasters distinguish different types of precipitation and debris. By comparing how shapes scatter energy in the two polarizations, they can tell rain from hail: raindrops are typically flattened and produce stronger horizontal returns, while hailstones are more irregular or spherical and show different polarization signatures, making the difference clearer through metrics like differential reflectivity. Another key signal is the correlation between the two polarizations; when tornadoes loft debris, the returns come from a mix of different objects, lowering this correlation and creating a debris signature that stands out even in the dark. Traditional single-polarization radars lack this extra information, so they’re much less reliable for telling rain from hail and for detecting debris.

Using dual-polarization radar, which sends energy in both horizontal and vertical orientations, lets forecasters distinguish different types of precipitation and debris. By comparing how shapes scatter energy in the two polarizations, they can tell rain from hail: raindrops are typically flattened and produce stronger horizontal returns, while hailstones are more irregular or spherical and show different polarization signatures, making the difference clearer through metrics like differential reflectivity. Another key signal is the correlation between the two polarizations; when tornadoes loft debris, the returns come from a mix of different objects, lowering this correlation and creating a debris signature that stands out even in the dark. Traditional single-polarization radars lack this extra information, so they’re much less reliable for telling rain from hail and for detecting debris.