Comparison of two different dust emission mechanisms over the Horqin Sandy Land area: Aerosols contribution and size distributions

Multimodel simulations of a springtime dust storm over northeastern China: implications of an evaluation of four commonly used air quality models (CMAQ v5.2.1, CAMx v6.50, CHIMERE v2017r4, and WRF-Chem v3.9.1)

“…According to Equation 13 and its description in Foroutan et al (2017), the verticalto-horizontal dust flux ratio (α), which determines the vertically transportable fraction of emitted dust particles, is calculated via Eq. (24) in Lu and Shao (1999), and parameters in this equation were defined according to Table 2 of Kang et al (2011). The formula is expressed as follows:…”

“…where f is the fraction of fine particles contained in the soil volume, p is plastic pressure in the range of 10 3 -10 7 N m −2 (Gillette, 1977;Callebaut et al, 1985;Rice et al, 1997), ρ b and ρ p are the bulk soil and soil particle densities, respectively, with unit of kilograms per cubic meter (kg m −3 ), g is the gravitational acceleration (m s −2 ), u * is friction velocity (m s −1 ), and C α and C β are constants. Here the formula described in Lu and Shao (1999) is named as LS99 and a version of LS99 modified by Kang et al (2011) and introduced in CMAQ since version 5.2 by Foroutan et al (2017) is called F17. The formula involving p for calculating α according to Shao (2004), namely S04, can be described as…”

“…Note that the fitted c y and p defined above could only be used in S04 and not in LS99 and F17 with different physical parameters. For example, the fitted value of 5000 for p (silty clay loam) in Table 3 of Shao (2004) was used as p of sand in Kang et al (2011). To correct the overestimated p used in the vertical flux calculation of LS99, Kang et al (2011) reported that a modified C α was recalculated based upon c y (which is used in S04).…”

“…Numerical dust models are often used to assess the magnitude of windblown dust emission and to predict its effects on air quality and climate. Several dust schemes to estimate the dust flux into the atmosphere and other relevant parameters have been proposed in the past 20 years; some have been coupled with air quality models, such as WRF-Chem (Kang et al, 2011;Su and Fung, 2015;Flaounas et al, 2017), CMAQ Foroutan et al, 2017), CAMx (Klingmüller et al, 2018), CHIMERE (Menut et al, 2013a;Mailler et al, 2017), ALADIN-SURFEX (Mokhtari et al, 2012), LOTOS-EUROS (Manders-Groot et al, 2016), EMEP MSC-W (Simpson et al, 2012), NAQPMS (Li et al, 2012), and CUACE/Haze . These models are widely used to study the air quality and climate effects of dust emissions.…”

Multi-model simulations of springtime dust storms in East Asia: Implications of an evaluation of four commonly used air quality models (CMAQv5.2.1, CAMxv6.50, CHIMEREv2017r4, and WRF-Chem v3.9.1)

“…. Most importantly, recent studies have suggested that dust emissions by direct aerodynamic entrainment (or convective turbulent dust emission) are about one third of sandblasting dust emissions(Li et al, 2014;Parajuli et al, 2016;Ju et al, 2018), yet the parameterizing of direct aerodynamic entrainment processes has not been implemented in the dust schemes of air quality models. This should be addressed in future work.In this study, we quantitatively evaluated the performance of several physically-based dust emission schemes in the WRF-Chem v3.9.1, CHIMERE v2017r4, CMAQ v5.2.1 and CAMx v6.50 air quality models to simulate a dust event in Northeastern China.…”