Non-detection of impulsive radio signals from lightning in Martian dust storms using the radar receiver on the Mars Express spacecraft

• Published in: Geophysical research letters Vol. 37; no. 17
• Main Authors: Gurnett, D. A., Morgan, D. D., Granroth, L. J., Cantor, B. A., Farrell, W. M., Espley, J. R.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01-09-2010; American Geophysical Union; John Wiley & Sons, Inc
• Subjects: Altitude; Atmospheric sciences; Dust; Dust storms; Earth sciences; Earth, ocean, space; electrostatic discharges; Exact sciences and technology; Lightning; Mars; Mars dust; Meteorology; Radar; Radio signals; Searching; Spacecraft; Storms; altitude; detection; time resolution; aerosols; frequency; intensity; dust storms; Mars Express space probe; Lightning; Radar observation; Detection threshold; discharge; radar methods; Atmospheric electricity
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2010GL044368

Here we report the results of a nearly five‐year search for impulsive radio signals from lightning discharges in Martian dust storms using the radar receiver on the Mars Express spacecraft. The search covered altitudes from 275 km to 1400 km and frequencies from 4.0 to 5.5 MHz with a time resolution of 91.4 μs and a detection threshold of 2.8 × 10−18 Watts m−2 Hz−1. At comparable altitudes the intensity of terrestrial lightning is several orders of magnitude above this threshold. Although two major dust storms and many small storms occurred during the search period, no credible detections of radio signals from lightning were observed.