@article{Agarwal:2024:10.5194/acp-24-2239-2024,
author = {Agarwal, P and Stevenson, DS and Heal, MR},
doi = {10.5194/acp-24-2239-2024},
journal = {Atmospheric Chemistry and Physics},
pages = {2239--2266},
title = {Evaluation of WRF-Chem-simulated meteorology and aerosols over northern India during the severe pollution episode of 2016},
url = {http://dx.doi.org/10.5194/acp-24-2239-2024},
volume = {24},
year = {2024}
}

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TY  - JOUR
AB  - We use a state-of-the-art regional chemistry transport model (WRF-Chem v4.2.1) to simulate particulate air pollution over northern India during September-November 2016. This period includes a severe air pollution episode marked by exceedingly high levels of hourly PM2.5 (particulate matter having an aerodynamic diameter≤2.5μm) during 30 October to 7 November, particularly over the wider Indo-Gangetic Plain (IGP). We provide a comprehensive evaluation of simulated seasonal meteorology (nudged by ERA5 reanalysis products) and aerosol chemistry (PM2.5 and its black carbon (BC) component) using a range of ground-based, satellite and reanalysis products, with a focus on the November 2016 haze episode. We find the daily and diurnal features in simulated surface temperature show the best agreement followed by relative humidity, with the largest discrepancies being an overestimate of night-time wind speeds (up to 1.5ms-1) confirmed by both ground and radiosonde observations. Upper-air meteorology comparisons with radiosonde observations show excellent model skill in reproducing the vertical temperature gradient (r>0.9). We evaluate modelled PM2.5 at 20 observation sites across the IGP including eight in Delhi and compare simulated aerosol optical depth (AOD) with data from four AERONET sites. We also compare our model aerosol results with MERRA-2 reanalysis aerosol fields and MODIS satellite AOD. We find that the model captures many features of the observed aerosol distributions but tends to overestimate PM2.5 during September (by a factor of 2) due to too much dust, and underestimate peak PM2.5 during the severe episode. Delhi experiences some of the highest daily mean PM2.5 concentrations within the study region, with dominant components nitrate (1/425%), dust (1/425%), secondary organic aerosols (1/420%) and ammonium (1/410%). Modelled PM2.5 and BC spatially correlate well with MERRA-2 products across the whole domain. High AOD at 550nm across the IGP is als
AU  - Agarwal,P
AU  - Stevenson,DS
AU  - Heal,MR
DO  - 10.5194/acp-24-2239-2024
EP  - 2266
PY  - 2024///
SN  - 1680-7316
SP  - 2239
TI  - Evaluation of WRF-Chem-simulated meteorology and aerosols over northern India during the severe pollution episode of 2016
T2  - Atmospheric Chemistry and Physics
UR  - http://dx.doi.org/10.5194/acp-24-2239-2024
VL  - 24
ER  - 

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