LNOx Emission Model for Air Quality & Climate Studies Using Satellite
Lightning Mapper Observations
Abstract
A lightning nitrogen oxides (LNOx) emissions model using
satellite-observed lightning optical energy is introduced for
utilization in Air Quality modeling systems. The effort supports
assessments of air-quality/climate coupling as related to the influence
of LNOx on atmospheric chemistry. The Geostationary Lightning Mapper
(GLM), International Space Station Lightning Imaging Sensor (ISS-LIS),
and the Tropical Rainfall Measuring Mission (TRMM) LIS data are used to
examine the efficacy of the method, extend the previously derived LNOx
record, and demonstrate a path for using ISS-LIS observations to
cross-calibrate regional LNOx estimates from the future global
constellation of geostationary lightning observations. A detailed
evaluation of the GLM dataset is provided to establish the robustness of
observations for LNOx estimates and to make preliminary assessments of
the LNOx emissions model. Seasonal and geographical variation,
land/ocean contrast, and annual fluctuation in the GLM observed
lightning activity and flash optical energy are provided. GLM detection
substantially degrades with the increase in the field of view, resulting
in 44% more flashes and 40% less optical energy observation by GLM-16
(compared to GLM-17) to the east of the middle-longitude between the two
mappers (106.2°W). Regular horizontal striations are found in the
optical energy product. On average, GLM flashes matched to the
cloud-to-ground flashes have ~30% longer duration,
50-70% more extension, and ≥ 100% higher optical energy compared to
the unmatched flashes (assumed to be intra-cloud). The results from
summer-long chemical transport simulations using LNOx generated from the
emission model agrees with previous studies and shows consistency across
the GLM/LIS datasets.