Description

Forests, though very critical for life on Earth, are threatened by various factors and the frequently occurring forest fires are one of the significant causes. Forest fires drastically contribute to climate change on both regional and global scales. Forest fires-of both natural and anthropogenic origins-induce aerosols in the atmosphere and have a significant impact on the health and climate of the region. In this study, we simulate the Uttarakhand (29-31° N, 78-80° E) fire event in India, which occurred in April 2016, using the Weather Research and Forecasting with Chemistry (WRF-Chem) model to estimate the radiative impact of the aerosols emitted due to this fire event and probe into the extent of their transport into the atmosphere. Multiple data from ground-based and satellite observations are used to access the model performance. Our analysis showed that the high values of aerosol optical depths (AODs) during the fire event simulated by WRF-Chem compared very well with MODIS AODs over the Uttarakhand region. The model simulations of the vertical profile of BC corroborate with elevated smoke aerosols derived from CALIPSO. An enhancement of smoke aerosols is observed up to 5-km altitude during the fire event both in the model simulations and observations. The fire has increased the near-surface air temperatures by 1-3 °C and decreased the relative humidity by ~ 10% over the affected areas. The NET (shortwave + longwave) atmospheric radiative forcing due to fire varied between ~ 10 and ~ 40 Wm−2 in the entire affected areas, with the highest values over the source region. The fire-induced atmospheric heating rate varied between 0.5 and 1.4 K/day over the Uttarakhand region.