124
124 – Evaluating Potential for Satellite Observations to Improve Soil NOx Emissions Estimates by Satellite/Emissions/Photochemical Model Intercomparison
Principal Investigator(s): S. Ehrman
Soil NOx emissions contribute to the tropospheric NO2 column. Soil bacteria produce NO through the processes of nitrification and denitrification. Field experiments, model simulations [e.g., Davidson et al., 1998] and satellite observations indicate that NO emissions pulse following rain on dry soils, particularly after recent application of fertilizer. Satellite-based observations have been instrumental in determining the magnitude of soil NOx emissions. Globally, soil emissions of NO contribute perhaps 5-10 Tg N per year to the global NOx budget. Jaeglé et al. [2004, 2005] and Bertram et al. [2005] estimated the soil NOx source using top-down approaches based on satellite data from the GOME and SCIAMACHY instruments, respectively. Their results suggest that biospheric models underestimate soil NOx emissions by a factor of 2. The increasingly high resolution of satellite data makes it possible to constrain emission sources over smaller and smaller regions. Reducing uncertainties in this source is an active area of research.