Simulations over south Asia using the Weather Research and Forecasting Model with Chemistry (WRF-Chem): Chemistry evaluation and initial results

The evaluation results indicate large uncertainties in anthropogenic and biomass burning emission estimates, especially for NOx. The model results indicate clear regional differences in the seasonality of surface ozone over South Asia, with estimated net ozone production during daytime (1130--1530 h) over inland regions of 0--5 ppbv h⁻¹ during all seasons and of 0--2 ppbv h#8315;¹ over marine regions during outflow periods.

The model results indicate that ozone production in this region is mostly NOx-limited. This study shows that WRF-Chem model captures many important features of the observations and gives confidence to using the model for understanding the spatio-temporal variability of ozone over South Asia. However, improvements of South Asian emission inventories and simulations at finer model resolution, especially over the complex Himalayan terrain in northern India, are also essential for accurately simulating ozone in this region.