Initial Results from the Lightning Imaging Sensor (LIS) on the International Space Station (ISS) and Comparison with Observations from the Tropical Rainfall Measuring Mission (TRMM) LIS

Lightning observations over the tropics were obtained from over 17 years of from the Lightning Imaging Sensor (LIS) onboard the Tropical rainfall Measuring Mission (TRMM). A spare LIS instrument originally built as a backup for the TRMM mission has been operating onboard the International Space Station (ISS) since 27 February 2017. The ISS LIS observes lightning on the earth between the latitudes of 54S-54N compared to the 38S-38N observed by TRMM LIS, extending the latitudinal coverage of lightning observations. In August 2001, the TRMM orbit was boosted from 350 km to 402.5 km. The nominal altitude of the ISS LIS orbit (405 km) is very similar to that of post boost TRMM LIS (402.5 km).

Preliminary comparisons between TRMM and ISS LIS observed lightning event, group, and flash distributions are examined. The lightning flash climatology for the initial year of ISS LIS observations compares favorably to that obtained from TRMM LIS observations. The global lightning flash rates obtained by ISS LIS (41.1 fl/s) are very similar to TRMM LIS (40.7 fl/s) results. Similar diurnal distribution patterns of lightning are also observed from TRMM and ISS LIS observations.