5. Summary and conclusions
ISS LIS has completed more than three years on orbit. During that time,
it has met all of its major science objectives, including detection of
lightning during day and night, at storm-scale (~4-km)
spatial resolution, with millisecond timing and reasonably high flash
detection efficiency (64% relative to a comparable optical sensor)
without a land/ocean bias. ISS LIS also measures radiant energy, which
though not discussed in depth in this paper is relevant to many studies
such as NOx generation by lightning [e.g.,Pickering et al. , 2016] and differences in land/ocean flash
characteristics [e.g., Nag and Cummins , 2017]. ISS LIS also
provides background images/intensity, and delivers near-realtime
lightning data. In addition, it has produced a lightning climatology
that is fundamentally consistent with previous lightning climatologies,
while also enabling the extension of the climatologies into the current
era as well as to higher latitudes (± 55°). Global-scale flash rates
(3-year average: ~44 s-1) are within
5-10% of previous datasets [e.g., Cecil et al. , 2014], and
the spatial and diurnal distributions of global lightning are consistent
with expectations [e.g., Blakeslee et al. , 2014]. ISS LIS has
demonstrated its value as a calibration/validation tool for current and
future spaceborne lightning datasets. The near-realtime ISS LIS data
have opened up applications within operational weather forecasting and
related applications, including public safety. Finally, ISS LIS is
demonstrating utility as part (or potential part) of cross-platform
studies examining a diverse array of topics, including lightning
physics, thunderstorm processes, convective precipitation, and
atmospheric composition.