Utilizing the Geostationary Lightning Mapper for Lightning Safety

The Geostationary Lightning Mapper (GLM) offers several capabilities to enhance lightning safety. First and foremost is the instrument’s field of view. With near hemispheric coverage, the GLM provides the ability to observe total lightning (intra-cloud and cloud-to-ground observations) with relatively similar detection efficiencies across the field of view. This provides GLM observations for locations that typically would have limited coverage due to few, if any, ground sensors or extreme distance from any given ground sensor. Secondly, as mentioned, GLM observes intra-cloud lightning. This ability is generally superior to existing ground-based networks aside from the short-ranged lightning mapping arrays. Although the instrument cannot distinguish between intra-cloud and cloud-to-ground flashes, is has been shown that the first intra-cloud flash typically precedes the first cloud-to-ground flash. Since GLM observes intra-cloud lightning, it can provide an initial alert that a storm is becoming electrified or remains electrified. Lastly, but significantly, the GLM can observe the spatial extent of a lightning flash. It is important to be able to observe intra-cloud centroids or where a cloud-to-ground flash comes to ground. However, it is vital to be able to observe the full extent of a flash, which can often exceed 100 kilometers from its origin.

Each of these features is important to have, but the information is useless if it cannot be provided to, and visualized by, an end user. As part of a collaboration with local National Weather Service forecast offices and nearby emergency managers, NASA’s Short-term Prediction Research and Transition (SPoRT) Center has developed a basic GLM visualization to aid lightning safety. This product shows 30 minutes of data and color codes the observations by age in bins of 0-10 minutes, 11-20 minutes, and 20-30 minutes. Able to be viewed as an animation or still image, the product provides emergency managers a way to quickly identify where lightning has been, where it is developing, and the general motion of the parent storm. Since the product displays 30 minutes of data, even a single frame provides details of the storm evolution, which will be vital for users who may have limited bandwidth.

This presentation will focus on the initial assessment of this lightning safety product by several end users in the southeastern portion of the United States. In addition to the safety product and the results of the SPoRT-led assessment, additional details on the time between flashes in an area and flash area observations relevant to lightning safety will be discussed.