The Optical Transient Detector (OTD): Instrument Characteristics and Cross-Sensor Validation

Abstract

Lightning data from the U.S. National Lightning Detection Network (NLDN) are used to perform preliminary validation of the satellite-based Optical Transient Detector (OTD). Sensor precision, accuracy, detection efficiency, and biases of the deployed instrument are considered. The sensor is estimated to have, on average, about 20?40-km spatial and better than 100-ms temporal accuracy. The detection efficiency for cloud-to-ground lightning is about 46%?69%. It is most likely slightly higher for intracloud lightning. There are only marginal day/night biases in the dataset, although 55- or 110-day averaging is required to remove the sampling-based diurnal lightning cycle bias.