We have been producing maps of global lighting activity derived from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) sensor. Initially, we used the analog film strips archived at the National Snow and Ice Data Center (NSIDC) located at the Cooperative Institute for Research In Environmental Sciences (CIRES)/University of Colorado. Lightning signatures appear as horizontal streaks in the smoothed (2.5 km) nighttime visible band imagery. A human analyst would hand digitize these streaks and record the latitude, longitude, and time of the lightning discharge. 

For example, the 1986 annual lightning distribution is derived from more than 40,000 orbits (film strips). (Reference: Goodman, S. J. and H. J. Christian, 1993: Global Observations of Lightning, in "Atlas of Satellite Observations related to Global Change," Gurney, Foster, and Parkinson, ed., Cambridge University Press, 191-219). In 1991-1992 the film archive transitioned to a digital archive, also located at the University of Colorado and the National Geophysical Data Center (NGDC). We have recently succeeded in developing and implementing a neural network and pattern recognition algorithm that automatically extracts the lightning discharge time and location (primarily from the F10 and F12 satellites). We are using these data bases to extend our observations into the mid 1990s. We are also inter-comparing these lightning distributions to those derived from observations made by the NASA Optical Transient Detector. 

This instrument was a prototype for the EOS Lightning Imaging Sensor (LIS) that was launched on the Tropical Rainfall Measuring Mission (TRMM). In addition, we can compare the occurrence of lightning with the Special Sensor Microwave/Imager (SSM/I) indications of rainfall and precipitation sized ice using the multispectral passive microwave frequencies. These data sets have been requested and used by atmospheric chemists studying NOx budgets and transport (lightning is a significant natural source of NOx) and by atmospheric physicists and meteorologists interested in the natural variability of thunderstorms. This system was only capable of detecting lightning during night.