Simulation and evaluation of dust emissions with WRF-Chem (v3.7.1) and its relationship to the changing climate over East Asia from 1980 to 2015

Abstract

Dust particles have been long recognized to affect the atmospheric radiative balance and are influenced by climate change. Impacts of climate change on dust emissions in East Asia, however, are not well understood. In this work, we conduct an evaluation of meteorological variables and dust emissions using the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) and examine the relationships between dust emissions and meteorological variables (wind speed, precipitation, and temperature) over East Asia during the period of 1980–2015. Model simulated surface meteorological variables compared well overall with surface-based observations, consistent with other WRF studies. Compared to observations, the coarse particulate matter (PM10-2.5) concentrations were underpredicted for most dust source regions of East Asia with a domain-wide mean bias and correlation of −40.2 μg m−3 and 0.5 against observations, respectively. Dust particulate concentrations simulated by WRF-Chem were found to reproduce the observed spatial variability in surface dust particulates over East Asia. The average annual dust emission (0 < r < 20 μm) is around 67.4 Tg yr−1 and the dust emission increased with the trend of 0.173 Tg yr−1 (R2 = 0.03, P = 0.32) in China and Mongolia over the past four decades. The spatial and temporal variations of dust emissions in China and Mongolia indicate that the annual dust flux has increased in desert areas of China and Mongolia, but decreased in most Gobi regions of China. Dust emission is significantly positively and negatively correlated with wind velocity and precipitation at the regional scale. Spatial patterns of seasonal correlations between dust flux and climate varies greatly during the period of 1980–2015.