Revised mineral dust emissions in the atmospheric chemistry–climate model EMAC (MESSy 2.52 DU_Astitha1 KKDU2017 patch)

Abstract

Abstract. To improve the aeolian dust budget calculations with the global ECHAM/MESSy atmospheric chemistryclimate model (EMAC), which combines the Modular Earth Submodel System (MESSy) with the ECMWF/Hamburg (ECHAM) climate model developed at the Max Planck Institute for Meteorology in Hamburg based on a weather prediction model of the European Centre for Medium-Range Weather Forecasts (ECMWF), we have implemented new input data and updates of the emission scheme.The data set comprises land cover classification, vegetation, clay fraction and topography. It is based on up-todate observations, which are crucial to account for the rapid changes of deserts and semi-arid regions in recent decades. The new Moderate Resolution Imaging Spectroradiometer (MODIS)-based land cover and vegetation data are time dependent, and the effect of long-term trends and variability of the relevant parameters is therefore considered by the emission scheme. All input data have a spatial resolution of at least 0.1 • compared to 1 • in the previous version, equipping the model for high-resolution simulations.We validate the updates by comparing the aerosol optical depth (AOD) at 550 nm wavelength from a 1-year simulation at T106 (about 1.1 • ) resolution with Aerosol Robotic Network (AERONET) and MODIS observations, the 10 µm dust AOD (DAOD) with Infrared Atmospheric Sounding Interferometer (IASI) retrievals, and dust concentration and deposition results with observations from the Aerosol Comparisons between Observations and Models (AeroCom) dust benchmark data set. The update significantly improves agreement with the observations and is therefore recommended to be used in future simulations.

Stratospheric aerosol radiative forcing simulated by the chemistry climate model EMAC using aerosol CCI satellite data

“…Figure 8 compares results from the T106L31 EMAC simulation for the annual average of the total AOD at visible and near-infrared wavelengths with AASTR retrievals using the ATSR (SU) algorithm version 4.3. Generally good agreement is obtained at 550 nm which is consistent with the good agreement between the 550 nm MODIS 10 (Moderate-resolution Imaging Spectroradiometer) AOD and model results based on the same EMAC version (Klingmüller et al, 2018). As for the T42L90 simulation, the model yields higher sea salt related AOD levels over the oceans.…”

“…Optical properties for the types sulfate, dust, organic and black carbon (OC and BC), sea salt, and aerosol water are calculated and used in radiative transfer calculations which (except for the T106 low top sensitivity studies) feedback to atmospheric dynamics. Desert dust simulations are based on the emission 20 schemes by Astitha et al (2012) and Klingmüller et al (2018). Aerosol module parameters, like for example, the composition of sea salt, were optimized on the basis of the satellite data.…”

“…The satellite retrievals are taken from version 8 of the ULB dataset. The simulation utilizes the dust emission scheme of Klingmüller et al (2018) which calculates the emissions online considering the meteorological conditions. To extract the DAOD from the total EMAC AOD at 10 µm, we apply a filter nullifying sea salt dominated AOD values.…”

Implementation of a comprehensive ice crystal formation parameterization for cirrus and mixed-phase clouds in the EMAC model (based on MESSy 2.53)

“…aerosol number concentrations and physicochemical characteristics) (Pruppacher and Klett, 1997;Kanji et al, 2017;Heymsfield et al, 2017;Korolev et al, 2017). Homogeneous nucleation occurs through the freezing of supercooled liquid droplets at low temperatures (T < 238 K) and high supersaturation over ice (140 %-160 %) (Koop et al, 2000). Heterogeneous nucleation refers to the formation of ice on an aerosol surface, which reduces the energy barrier for ice nucleation and lets ice crystals form at lower supersaturations and/or at higher (subfreezing) temperatures than homogeneous nucleation.…”

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)

“…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.…”