The First Stereo Views of Lightning from Space: Double the GLMs, Double the Fun

GOES-17, the second in the GOES-R series of NOAA geostationary weather satellites, launched on March 1^st, 2018 carrying the second Geostationary Lightning Mapper. The stereo view provided by two satellites gives us the opportunity to better determine navigation accuracy and compare the lightning detection performance of the two instruments in concert with their ground processing algorithms. The varying heights of the lightning emission can cause parallax errors in the reported geolocation of GLM lightning groups; we characterize these errors across the overlapping field of view. We also compare the lightning detection performance of the two instruments using a data set of several million flashes. Once GOES-17 is moved to the GOES-West location, the area of overlap between the two fields of view will be greatly reduced, making the post launch test period a unique opportunity to view lightning in stereo.