A new parameterization of ice heterogeneous nucleation coupled to aerosol chemistry in WRF-Chem model version 3.5.1: evaluation through ISDAC measurements

Abstract

Abstract. In the Arctic, during polar night and early spring, ice clouds are separated into two leading types of ice clouds (TICs): (1) TIC1 clouds characterized by a large concentration of very small crystals and TIC2 clouds characterized by a low concentration of large ice crystals. Using a suitable parameterization of heterogeneous ice nucleation is essential for properly representing ice clouds in meteorological and climate models and subsequently understanding their interactions with aerosols and radiation. Here, we describe a new parameterization for ice crystal formation by heterogeneous nucleation in water-subsaturated conditions coupled to aerosol chemistry in the Weather Research and Forecasting model coupled with chemistry (WRF-Chem). The parameterization is implemented in the Milbrandt and Yau (2005a, b) two-moment cloud microphysics scheme, and we assess how the WRF-Chem model responds to the run-time interaction between chemistry and the new parameterization. Well-documented reference cases provided us with in situ data from the spring 2008 Indirect and Semi-Direct Aerosol Campaign (ISDAC) over Alaska. Our analysis reveals that the new parameterization clearly improves the representation of the ice water content (IWC) in polluted or unpolluted air masses and shows the poor performance of the reference parameterization in representing ice clouds with low IWC. The new parameterization is able to represent TIC1 and TIC2 microphysical characteristics at the top of the clouds, where heterogenous ice nucleation is most likely occurring, even with the known bias of simulated aerosols by WRF-Chem over the Arctic.

Two-way coupled meteorology and air quality models in Asia: a systematic review and meta-analysis of impacts of aerosol feedbacks on meteorology and air quality

“…GATOR-GCMOM is the first two-way coupled model adding IN activation processes including heterogeneous and homogeneous freezing (Jacobson, 2003). None of the other four two-way coupled models consider the IN formation processes (including immersion freezing, deposition freezing, contact freezing, and condensation freezing), but they have been included in some specific versions of WRF-Chem (Keita et al, 2020;Lee et al, 2020) (Slinn, 1984;Easter et al, 2004) All aqueous species are scavenged from the cloud top to the ground in both grid-scale and sub-grid clouds (AERO5, AERO6, and AERO7) (CMAQ user guide; Fahey et al, 2017) Aerosol particles between sizes ranging from a 0.5 to 1 µm radius are instantly removed with considering cloud fraction, and scavenged rate depends on aerosol and hydrometeor sizes (Slinn, 1984;Gong et al, 2003a) Employing a scavenging coefficient approach based on relationships described by Seinfeld and Pandis (2008) (Beard, 1976;Jacobson, 1997bJacobson, , 2003 Table 4. Summary of relevant information regarding calculations of aerosol-radiation interaction (ARI) and aerosol-cloud interaction (ACI) in two-way coupled models (WRF-Chem, WRF-CMAQ, GRAPES-CUACE, WRF-NAQPMS, and GATOR-GCMOM) applied in Asia.…”

“…Chen et al, 2017;Jacobson, 2012b). b Some specific versions of WRF-Chem consider IN (Keita et al, 2020;Lee et al, 2020). c The shortwave and longwave radiation calculations in GATOR-GCMOM are based on the algorithm of Toon et al (1989).…”

Inter-comparison of multiple two-way coupled meteorology and air quality models (WRF v4.1.1-CMAQ v5.3.1, WRF-Chem v4.1.1 and WRF v3.7.1-CHIMERE v2020r1) in eastern China

“…to those of WRF-Chem_ARI. Although we have obtained preliminary quantitative results of the ACI effects on regional precipitation, CF, and LWP, it should be kept in mind that several limitations in representing ACI effects still exist in state-of-the-art two-way coupled models; these include a lack of consideration of the responses of convective clouds to ACI (Tuccella et al, 2019), and a lack of numerical descriptions of giant cloud condensation nuclei (Wang et al, 2021) and heterogeneous ice nuclei (Keita et al, 2020). For O3, WRF-CHIMERE (R = 0.62) exhibited the best model performance, followed by WRF-CMAQ (R = 0.55), and WRF-Chem (R = 0.45) (Table 4 and Figure S15).…”

Extremely High Concentrations of Ice Particles in East Asian Dust‐Infused Baroclinic Storm (DIBS) Cirrus Shield: Dominant Role of Dust Ice Nucleation Effect

“…Consequently, the performance of these models is reduced when dust is present, and is especially challenging during dust storms (Li et al., 2017). In the past several years, the modeling community has begun to shift toward aerosol‐aware ice nucleation parameterizations (Q. Chen et al., 2019; Hawker et al., 2021; Keita et al., 2020; Su & Fung, 2018; Weger et al., 2018). These studies mostly focus on the comparison of model results from different ice nucleation parameterizations in mixed phase clouds.…”