Implementation of aerosol–cloud interactions in the regional atmosphere–aerosol model COSMO-MUSCAT(5.0) and evaluation using satellite data

Dipu, Sudhakar; Quaas, Johannes; Wolke, Ralf; Stoll, Jens; Muhlbauer, Andreas; Sourdeval, Odran; Salzmann, Marc; Heinold, Bernd; Tegen, Ina

doi:10.5194/gmd-10-2231-2017

Cited by 11 publications

(8 citation statements)

References 74 publications

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“…A detailed description of the physical parameterizations applied in the operational version of COSMO can be found in Doms (2008) and Doms et al (2011). For the treatment of cloud processes and precipitation formation an efficient single-moment bulk water-continuity scheme is used, which considers cloud water, rain, cloud ice, snow and optionally graupel (not used here) as hydrometeor classes.…”

Section: Operational Model Configurationmentioning

confidence: 99%

The impact of mineral dust on cloud formation during the Saharan dust event in April 2014 over Europe

et al. 2018

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Abstract. A regional modeling study on the impact of desert dust on cloud formation is presented for a major Saharan dust outbreak over Europe from 2 to 5 April 2014. The dust event coincided with an extensive and dense cirrus cloud layer, suggesting an influence of dust on atmospheric ice nucleation. Using interactive simulation with the regional dust model COSMO-MUSCAT, we investigate cloud and precipitation representation in the model and test the sensitivity of cloud parameters to dust–cloud and dust–radiation interactions of the simulated dust plume. We evaluate model results with ground-based and spaceborne remote sensing measurements of aerosol and cloud properties, as well as the in situ measurements obtained during the ML-CIRRUS aircraft campaign. A run of the model with single-moment bulk microphysics without online dust feedback considerably underestimated cirrus cloud cover over Germany in the comparison with infrared satellite imagery. This was also reflected in simulated upper-tropospheric ice water content (IWC), which accounted for only 20 % of the observed values. The interactive dust simulation with COSMO-MUSCAT, including a two-moment bulk microphysics scheme and dust–cloud as well as dust–radiation feedback, in contrast, led to significant improvements. The modeled cirrus cloud cover and IWC were by at least a factor of 2 higher in the relevant altitudes compared to the noninteractive model run. We attributed these improvements mainly to enhanced deposition freezing in response to the high mineral dust concentrations. This was corroborated further in a significant decrease in ice particle radii towards more realistic values, compared to in situ measurements from the ML-CIRRUS aircraft campaign. By testing different empirical ice nucleation parameterizations, we further demonstrate that remaining uncertainties in the ice-nucleating properties of mineral dust affect the model performance at least as significantly as including the online representation of the mineral dust distribution. Dust–radiation interactions played a secondary role for cirrus cloud formation, but contributed to a more realistic representation of precipitation by suppressing moist convection in southern Germany. In addition, a too-low specific humidity in the 7 to 10 km altitude range in the boundary conditions was identified as one of the main reasons for misrepresentation of cirrus clouds in this model study.

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Section: Operational Model Configurationmentioning

confidence: 99%

The impact of mineral dust on cloud formation during the Saharan dust event in April 2014 over Europe

et al. 2018

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“…In fact, we could see a strong sensitivity of modeled ice particle sizes to mineral dust concentrations, and the smallest particle diameters with best agreement to measurements were found using interactive dust simulation with the U17 parameterization. The occurrence of the positive Twomey effect in response to high mineral dust concentrations fostered the de-900 velopment of more extensive cirrus clouds in our model due to dust-cloud-radiation effects represented in the radiation scheme extended by Dipu et al (2017).…”

mentioning

confidence: 84%

“…In order to make use of the more detailed two-moment microphysics information, the single-moment microphysics approach of parameterizing cloud optical properties in Ritter and Geleyn (1992) was revised by Dipu et al (2017). This way also the impact of the…”

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confidence: 99%

The impact of mineral dust on cloud formation during the Saharan dust event in April 2014 over Europe

Weger¹,

Heinold²,

Tegen³

et al. 2018

Preprint

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Abstract. A regional modeling study on the impact of desert dust on cloud formation is presented for a major Saharan dust outbreak over Europe from 2 April to 5 April 2014. The dust event coincided with an extensive and dense cirrus cloud layer, suggesting an influence of dust on atmospheric ice nucleation. Using interactive simulation with the regional dust model COSMO-MUSCAT, we investigate cloud and precipitation representation in the model and test the sensitivity of cloud parameters to dust-cloud and dust-radiation interactions of the simulated dust plume. We evaluate model results with ground-based and space-borne remote sensings of aerosol and cloud properties, as well as the in situ measurements obtained during the ML-CIRRUS aircraft campaign. A run of the model with single-moment bulk microphysics without online dust feedback considerably underestimated cirrus cloud cover over Germany in the comparison with infrared satellite imagery. This was also reflected in simulated upper-tropospheric ice water content (IWC), which accounted only for 20&#8201;% of the observed values. The interactive dust simulation with COSMO-MUSCAT, including a two-moment bulk microphysics scheme and dust-cloud as well as dust-radiation feedback, in contrast, led to significant improvements. The modeled cirrus cloud cover and IWC were by at least a factor of two higher in the relevant altitudes compared to the non-interactive model run. We attributed these improvements mainly to enhanced deposition freezing in response to the high mineral dust concentrations. This was corroborated further in a significant decrease in ice particle radii towards more realistic values, as compared to in situ measurements from the ML-CIRRUS aircraft campaign. By testing different empirical ice nucleation parameterizations, we further demonstrate that remaining uncertainties in the ice nucleating properties of mineral dust affect the model performance at least as significantly as to whether including the online representation of the mineral distribution. Dust-radiation interactions played a secondary role for cirrus cloud formation, but contributed to a more realistic representation of precipitation by suppressing moist convection in southern Germany. In addition, a too low specific humidity in the 7 to 10&#8201;km altitude range in the boundary conditions was identified as a main reason of misrepresentation of cirrus clouds in this model study.

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“…This enables the advection of the synoptic condition into and out of a domain in the CSRM simulations to occur through the boundary of the domain. All experiments employ a prognostic surface skin temperature scheme (Zeng and Beljaars, 2005) and a revised roughness length formulation (Donelan et al, 2004).…”

Section: The Csrm Simulationsmentioning

confidence: 99%

Effects of model resolution and parameterizations on the simulations of clouds, precipitation, and their interactions with aerosols

Lee¹,

Li²,

Zhang³

et al. 2017

Preprint

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Abstract. This study investigates the effects of model resolution and microphysics parameterizations on the uncertainties or errors in the simulations of clouds, precipitation, and their interactions with aerosols using the Global Forecast System (GFS) model as one of the representative numerical weather prediction (NWP) models. For this investigation, we used the GFS model results and compare them with those from the cloud-system resolving model (CSRM) simulations as benchmark simulations that adopt high resolutions and full-fledged microphysical processes. These simulations were evaluated against observations and this evaluation demonstrated that the CSRM simulations can function as benchmark simulations. Substantially lower updrafts and associated cloud variables (e.g., cloud mass and condensation) were simulated by the GFS model compared to those simulated by the CSRM. This is mainly due to the coarse resolutions in the GFS model. This indicates that the parameterizations that represent sub-grid processes in the GFS model do not work well and thus need to be improved. Results here also indicate that the use of the coarse resolution in the GFS model lowers the sensitivity of updrafts and cloud variables to increasing aerosol concentrations compared to the CSRM simulations. The parameterization of the saturation process plays an important role in the sensitivity of cloud variables to aerosol concentrations while the parameterization of the sedimentation process has a substantial impact on how cloud variables are distributed vertically. The variation in cloud variables with resolution is much greater and contributes to the discrepancy between the GFS and CSRM simulations to a much greater degree than what happens with varying microphysics parameterizations.

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Implementation of aerosol–cloud interactions in the regional atmosphere–aerosol model COSMO-MUSCAT(5.0) and evaluation using satellite data

Cited by 11 publications

References 74 publications

The impact of mineral dust on cloud formation during the Saharan dust event in April 2014 over Europe

The impact of mineral dust on cloud formation during the Saharan dust event in April 2014 over Europe

The impact of mineral dust on cloud formation during the Saharan dust event in April 2014 over Europe

Effects of model resolution and parameterizations on the simulations of clouds, precipitation, and their interactions with aerosols

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