Lightning Nitrogen Oxides (LNOx) Vertical Profile Quantification and 10 Year Trend Analysis using Ozone Monitoring Instrument (OMI) Satellite Measurements, Air Quality Station (AQS) Surface Measurements, The National Lightning Detection Network (NLDN), and Simulated by Cloud Resolving Chemical Transport Model (REAM Cloud)

Abstract:

Vertical profiles and emission lifetimes of lightning nitrogen oxides (LNO_x) are derived using the Ozone Monitoring Instrument (OMI). Approximately 200 million flashes, over a 10 year climate period, from the United States National Lighting Detection Network (NLDN), are aggregated with OMI cloud top height to determine the vertical LNO_x structure. LNO_x lifetime is determined as function of LNO_x signal in a 36 kilometer vertical column from the time of the last known flash to depletion of the LNO_x signal. Environmental Protection Agency (EPA) Air Quality Station (AQS) surface data further support these results by demonstrating as much as a 200% increase in surface level NO2 during strong thunderstorm events and a lag as long as 5 to 8 hours from the lightning event to the peak surface event, indicating a evolutional process. Analysis of cloud resolving chemical transport model (REAM Cloud) demonstrates that C-shaped LNO_x profiles, which agree with OMI vertical profile observations, evolve due to micro-scale convective meteorology given inverted C-shaped LNO_x emission profiles as determined from lightning radio telemetry. It is shown, both in simulations and in observations, that the extent to which the LNO_x vertical distribution is C-shaped and the lifetime of LNO_x is proportional to the shear-strength of the thunderstorm. Micro-scale convective meteorology is not adequately parameterized in global scale and regional scale chemical transport models (CTM). Therefore, these larger scale CTMs ought to use a C-shape emissions profile to best reproduce observations until convective parameterizations are updated. These findings are used to simulate decadal LNO_x and lightning ozone climatology over the Continental United States (CONUS) from 2004-2014.