Ghdue, Sachin D., Indian Institute of Tropical Meteorology, Pune,
India and Gabriele G. Pfister, NCAR/ACD
IndiaÕs emission
inventories for NOx are considered to be highly uncertain, due to lack of
accurate statistics and emission factors. It is, therefore, imperative that
more efforts are needed to reduce the uncertainty in the regional NOx
emissions. Vertical column densities (VCDs) of tropospheric nitrogen dioxide
(NO2) retrieved from space allow deriving top-down estimates of NOx
emissions. This study presents an
inversion based approach to estimate emissions of NOx for the Indian region on
0.5 x 0.5 grid resolution, using the Ozone Monitoring Instruments (OMI) DOMINO
tropospheric NO2 retrieval product. The Weather Research and Forecasting model
coupled with Chemistry (WRF-CHEM) is used to simulate tropospheric column NO2
over this region. The model uses MOZART gas phase chemistry and GOCART aerosol
schemes. The anthropogenic emissions of NOx for India are taken from the
emissions inventory prepared for the Intercontinental Chemical Transport
Experiment – Phase B (INTEX-B). The inversion is done grid box by grid
box and iterated until convergence is achieved. Significant differences are seen between the INTEX-B and the
top-down emissions inferred from the OMI observations. Our top-down inventory
for NOx captures many localized point sources in India, which are not
represented well in the INTEX-B inventory. Top-down NOx emissions are increased for many cities and
Thermal Power Plant locations compared to the INTEX-B emissions.