摘要：Space‐based optical lightning sensors including the lightning imaging sensor (LIS) and geostationary lightning mapper (GLM) are pixelated imagers that detect lightning as transient increases in cloud top illumination. Detection requires optical emissions to escape the cloud top to space with sufficient energy to trigger a pixel on the imaging array. Through scattering and absorption, certain clouds are able to block most light from reaching the instrument, causing a reduction in detection efficiency (DE) and possibly location accuracy (LA). Radiant lightning emissions that illuminate large cloud top areas are used to examine scenarios where clouds block light from reaching orbit. In some cases, these anomalies in the spatial radiance distribution from the lightning pulse lead to “holes” in the optical lightning flash where certain pixels fail to trigger. Such holes are identified algorithmically in the Tropical Rainfall Measuring Mission satellite LIS record and the microphysical properties of the coincident storm region are queried. We find that holes primarily occur in tall (IR T b < 235 K) convection (87%) and overhanging anvil clouds (10%). The remaining 3% of holes occur in moderate‐to‐weak convection or in clear air breaks between stormclouds. We further demonstrate how an algorithm that assesses the spatial radiance patterns from energetic lightning pulses might be used to construct an optical transmission gridded stoplight product for GLM that could help operators identify clouds with a potentially reduced DE and LA. Plain Language Abstract Lightning sensors on satellites detect lightning by looking at how they illuminate the surrounding clouds. These instruments register lightning events by comparing high‐speed movies of cloud top brightness with the comparably steady‐state background. However, there are some cases where the cloud is able to block the light produced by lightning from passing through. If too little energy makes it to the top of the cloud, the instrument will not be able to differentiate the lightning illumination from the background—and the lightning will not be detected. This study examines how clouds are illuminated by lightning to identify scenarios where light is blocked from reaching the LIS instrument. LIS “holes” are compared with the meteorological measurements from the other sensors on the Tropical Rainfall Measuring Mission satellite to investigate what types of clouds can inhibit lightning detection. We find that it is not just the tall thunderclouds that are responsible for holes in optical flashes, but also overhanging anvil clouds, and even breaks in the clouds surrounding the thunderstorm. These insights might be used to construct a gridded stoplight product that can alert end users to issues with optical transmission.
