The Lightning Imaging Sensor (LIS) is a space-based instrument used to detect the distribution and variability of total lightning (cloud-to-cloud, intra-cloud, and cloud-to-ground lightning). It measures the amount, rate, and radiant energy of lightning during both day and night. LIS data are used to study mesoscale phenomena such as storm convection, dynamics, and microphysics. These are related to global rates and amounts and distribution of convective precipitation, as well as to the release and transport of latent heat, which are all influenced by global scale processes. An LIS was aboard NASA's Tropical Rainfall Measuring Missing (TRMM) spacecraft (operational 1997 to 2015) and an LIS was installed on the International Space Station in February 2017.

LIS data are used to study mesoscale phenomena such as storm convection, dynamics, and microphysics. These are related to global rates and amounts and distribution of convective precipitation, as well as to the release and transport of latent heat, which are all influenced by global scale processes. LIS data are vital to our understanding of global lightning and thunderstorm climatology.

LIS consists of a collection of instrumentation centered around a staring imager that is optimized to locate and detect lightning at millisecond timing with storm-scale resolution over a large region of the Earth's surface. Resolution of measurement and region of coverage varies depending on the orbit and altitude (whether on TRMM in a semi-equatorial orbit or on the ISS.)

LIS is a calibrated lightning sensor which uses a wide field-of-view expanded optics lens with a narrow-band filter (at 777nm) in conjunction with a high speed charge-coupled device (CCD) detection array. A Real Time Event Processor (RTEP) inside the electronics unit is used to determine when a lightning flash occurs, even in the presence of bright sunlit clouds. Weak lightning signals that occur during the day are hard to detect because of background illumination. The RTEP will remove the background signal, thus enabling the system to detect the weak lightning signal and achieve up to a 90% detection efficiency. The efficiency with which lightning detection occurs varies depending on time of day and the intensity of the lightning. The instrument records the time of occurrence of a lightning flash, measures the radiant energy, and determines the location of flashes within its field-of-view.