Abstract and subjects
The Radio Frequency Sensor (RFS), a new radio frequency lightning detector, was launched into geosynchronous orbit in December 2021, and first collected data in January 2022. RFS is a specialized software‐defined radio receiver that detects, records, and reports impulsive broadband radio‐frequency (RF) signatures from lightning in the very high frequency (VHF; 30–300 MHz) range. Its vantage point from a Western hemisphere geosynchronous orbit provides unique opportunities to study evolution of RF lightning signatures over the durations of thunderstorms over the Americas and Pacific Ocean. Its overlapping view with the Geostationary Lightning Mappers (GOES‐16 & 17) enables additional comparisons between the sources of optical emissions and associated VHF emissions that were not possible with previous sensors. We find that RFS preferentially detects bright VHF signals called transionospheric pulse pairs (trans‐ionospheric pulse pairs (TIPPs)). It is estimated that more than 85% of the RFS‐detected lightning events are TIPPs. This paper presents initial results from the first year and a half of on‐orbit operation.
Plain Language Summary
A new lightning‐detection instrument, called the Radio Frequency Sensor (RFS), was launched in December 2021 and has been providing measurements of lightning signals since January 2022. RFS detects radio‐frequency emissions from lightning that are in the very high frequency (VHF; 30–300 MHz) and high frequency (HF; 3–30 MHz) range. It is in geostationary orbit over the Western hemisphere and is well‐positioned to compare the RF lightning signatures from the same thunderstorms with optical measurements of lightning from geostationary National Oceanic and Atmospheric Administration (NOAA) satellites. It is found that RFS preferentially detects a particular in‐cloud type of lightning that emits a strong signal in the VHF. It is estimated that 85% of RFS detections are of this type of lightning. We present initial results from the first year of measurements taken by this instrument.
Key Points
The Radio Frequency Sensor (RFS) provides new RF lightning measurements from geosynchronous orbit
RFS primarily detects trans‐ionospheric pulse pairs (TIPPs), and a much smaller fraction of cloud‐to‐ground lightning discharges
TIPP‐derived altitudes allow tracking the altitude evolution of the convective region of a storm over time