Measurements of NOX produced by rocket‐triggered lightning

We present the first direct measurements of NOX generated by specific lightning sources. In July 2005, three negative lightning flashes were triggered using the rocket‐and‐wire technique at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida. The NOX produced by these three rocket‐triggered flashes was measured. The NOX production per unit charge was between 2 and 3 · 1020 molecules per meter per coulomb. The data show that the NOX production is primarily from long‐duration, steady currents, as opposed to microsecond‐scale impulsive return stroke currents. This observation implies that cloud discharges, which transfer, via a steady current of the order of 100 A, larger charges than ground discharges, but do not contain return strokes, are as efficient as (or more efficient than) cloud‐to‐ground discharges in producing NOX.