Abstract:
In order to better understand the relationship between lightning activities and nitrogen oxide (LNO
x) in the troposphere, and estimate the lightning-generated NO
x production in China more precisely, monthly means of lightning density and tropospheric NO
2 vertical column densities (VCD) from the Tibetan Plateau, where there is a sparse population and underdeveloped industrial activity, are analyzed in terms of their distribution and correlation. The data are obtained from LIS (Lightning Imaging Sensor) measurements and GOME-2 (the Global Ozone Monitoring Experiment-2) from January 2009 to February 2012. The LNO
x production in inland China is estimated based on Beirle's LNO
x estimation method. The results show that the tropospheric NO
x over the selected region of inland China is influenced little by anthropogenic sources. Lightning densities over the region are in reasonable agreement with tropospheric NO
2 in terms of annual, spatial and seasonal variations. Combined with the correlation coefficient of 0.84 calculated by linear fitting, LNO
x production in inland China is evaluated as 0.15 (0.03-0.38) Tg(N) a
-1. It is indicated that the Tibetan Plateau is an ideal area to study LNO
x. The conclusion further reduces the estimation uncertainty range of LNO
x production in previous work, helping us to more clearly recognize the important role of lightning in climate change in China.