Temporal and spatial characteristics of lightning-produced nitrogen oxides in China.

Tropospheric NO 2 vertical column densities (NO 2 VCDs) retrieved from the Global Ozone Monitoring Experiment-2 satellite spectrometer, as well as lightning flashes measured by an Optical Transient Detector and Lightning Image Sensor from 1997 to 2013 are used to investigate spatial and temporal characteristics of lightning-produced nitrogen oxides (LNO X ) under the recent period of rapid and locally-unbalanced economic development in China. Correlations between spatial distributions of lightning flashes and monthly mean tropospheric NO 2 VCDs were analyzed over this period. Mean production of LNO X per flash is 330 mol[N]/flash which was estimated using the correlation between lightning flashes and monthly mean tropospheric NO 2 VCD for the Tibetan Plateau. Using this correlation, the spatial and temporal characteristics of the ratio of LNO X to tropospheric NO X in China were determined. Results show that the ratio of LNO X to the tropospheric NO X is small in eastern regions, having a developed industrial sector and dense population, but relatively large in western regions, with a developing industrial sector and sparser population. The annual mean value of LNO X contributing to tropospheric NO X is 7.5% in China, which is lower than global averages (10–20%). The difference in interannual variability of LNO X production contributing to tropospheric NO X in different areas is distinct, ranging from high to low values for the Tibetan Plateau, Pearl River Delta, Yangtze River Delta and Beijing–Tianjin–Hebei regions, respectively. This indicates that lightning had a large influence on the column density of tropospheric NO X on the Tibetan Plateau, a region typically used as a sensitivity indicator for climate change. Lightning had less influence on atmospheric environments of the Pearl River Delta, Yangtze River Delta and Beijing–Tianjin–Hebei regions. [ABSTRACT FROM AUTHOR]