Global measurements of tropospheric nitrogen dioxide (NO2) have been derived for the period 1996-2005 based on the satellite instruments GOME on ERS-2 and SCIAMACHY on Envisat. The time series of the monthly NO2 columns for these ten years have been modeled fitted with a linear function superposed on an annual seasonal cycle on a grid of 1º by 1º. A statistical analysis is applied to derive trends and seasonal variability for this period on a global scale. We see significant reductions in NO2 in Europe and parts of the eastern USA, but a strong increase in Asia, most particularly in China but also in Iran and Russia. The seasonal variability often shows a strong cycle that correlates well with the seasonal cycle of specific NO2 sources like biomass burning. The seasonal variability has been used to distinguish between the dominant sources of NOx emissions: anthropogenic (fossil fuel and biofuel), biomass burning and soil emissions. By comparing the data with the cloud information derived from the same satellite observations the contribution of lightning to the total column of NO2 is estimated. The relationship between the tropospheric NO2 and the NOx emissions is derived from simulations with a chemistry-transport model for a case study for China. This allowed us to derive a top-down emission inventory for China in the period 1996-2005.
RJ. van der A, HJ. Eskes, KF. Boersma, TPC. van Noije, M. Van Roozendael, I. De Smedt, DHMU. Peters, JJP. Kuenen, EW. Meijer. Trends, seasonal variability and dominant NOx source derived from a ten year record of NO2 measured from space.
J. Geophys. Res., 1, 2008, 113, 10.1029/2007JD009021.