Cloud microphysics and aerosol indirect effects in the global climate model ECHAM5-HAM

By Ulrike Lohmann, P. Stier, C. Hoose, Sylvaine Ferrachat, S. Kloster, E. Roeckner, J. Zhang. 2007

139 citations recorded by the source corpus.

The double-moment cloud microphysics scheme from ECHAM4 that predicts both the mass mixing ratios and number concentrations of cloud droplets and ice crystals has been coupled to the size-resolved aerosol scheme ECHAM5-HAM. ECHAM5-HAM predicts the aerosol mass, number concentrations and mixing state. The simulated liquid, ice and total water content and the cloud droplet and ice crystal number concentrations as a function of temperature in stratiform mixed-phase clouds between 0 and −35° C agree much better with aircraft observations in the ECHAM5 simulations. ECHAM5 performs better because more realistic aerosol concentrations are available for cloud droplet nucleation and because the Bergeron-Findeisen process is parameterized as being more efficient. The total anthropogenic aerosol effect includes the direct, semi-direct and indirect effects and is defined as the difference in the top-of-the-atmosphere net radiation between present-day and pre-industrial times. It amounts to −1.9 W m^−2 in ECHAM5, when a relative humidity dependent cloud cover scheme and aerosol emissions representative for the years 1750 and 2000 from the AeroCom emission inventory are used. The contribution of the cloud albedo effect amounts to −0.7 W m^−2. The total anthropogenic aerosol effect is larger when either a statistical cloud cover scheme or a different aerosol emission inventory are employed because the cloud lifetime effect increases.

Subfields: Atmospheric Science, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/4656a703258ca470861dc0822d229f39aebaacbd

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Citations in the corpus

Influences of in-cloud aerosol scavenging parameterizations on aerosol concentrations and wet deposition in ECHAM5-HAM (2009, methodology): “Additionally, for this study we have implemented the prognostic20 equations for cloud liquid and ice water, mass and number following Lohmann et al. (2007), and the cirrus scheme of Lohmann and Kärcher (2002).”
Aerosol nucleation and its role for clouds and Earth's radiative forcing in the aerosol-climate model ECHAM5-HAM (2010, methodology): “Aerosol particles in the ECHAM5-HAM model are activated and may become cloud droplets (Lohmann et al., 2007).”
Aerosol indirect effects – general circulation model intercomparison and evaluation with satellite data (2009, methodology): “The prognostic equations for cloud droplet and ice crystal number concentrations follow the approach used in Morrison and Gettelman (2008) with the nucleation term as in Lohmann et al. (2007) and the autoconversion scheme from Rotstayn and Liu (2005).”
Total aerosol effect: radiative forcing or radiative flux perturbation? (2009, background): “2 Cloud albedo, cloud lifetime, direct and semi-direct effect Lohmann and Feichter(2001), Penner et al.(2003), Penner et al. (2006), Lohmann et al.(2007), Rotstayn et al.(2007), Posselt and Lohmann(2008), Posselt and Lohmann(2009), Quaas et al.(2009b) A2.”
Climate impacts of ice nucleation (2012, methodology): “with prognostic number and mass for liquid and ice [Lohmann et al., 2007] coupled to a 7 mode aerosol model (HAM) [Stier et al.”
Impact of nucleation on global CCN (2009, background): “J. Merikanto et al.: Impact of nucleation on CCN particle microphysics have become available (Adams and Seinfeld, 2002; Vignati et al., 2004; Spracklen et al., 2005a; Lohmann et al., 2007; Wang et al., 2009).”
Atmospheric component of the MPI‐M Earth System Model: ECHAM6 (2013, background): “More consistent couplings between the droplet microphysical descriptions and the cloud-active aerosol is an area of active research and development [e.g., Stier et al., 2005; Lohmann et al., 2007].”