The aerosol-climate model ECHAM5-HAM

Stier, Philip; Feichter, J.; Kinne, Stefan; Kloster, Silvia; Vignati, E.; Wilson, J.; Ganzeveld, L.; Tegen, Ina; Werner, Martin; Balkanski, Yves; Schulz, Mıchael; Boucher, O.; Minikin, Andreas; Petzold, A.

doi:10.5194/acp-5-1125-2005

Cited by 1,024 publications

(1,083 citation statements)

References 101 publications

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“…ECHAM6-HAM2 predicts the evolution of micro-physically interacting aerosol populations, their size distribution and composition (Stier et al, 2005;Zhang et al, 2012). For all our simulations, we use model version ECHAM6.1.0-HAM2.2.…”

Section: Echam6-ham2mentioning

confidence: 99%

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Fire emission heights in the climate system – Part 2: Impact on transport, black carbon concentrations and radiation

et al. 2015

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Abstract. Wildfires represent a major source for aerosols impacting atmospheric radiation, atmospheric chemistry and cloud micro-physical properties. Previous case studies indicated that the height of the aerosol-radiation interaction may crucially affect atmospheric radiation, but the sensitivity to emission heights has been examined with only a few models and is still uncertain. In this study we use the general circulation model ECHAM6 extended by the aerosol module HAM2 to investigate the impact of wildfire emission heights on atmospheric long-range transport, black carbon (BC) concentrations and atmospheric radiation. We simulate the wildfire aerosol release using either various versions of a semiempirical plume height parametrization or prescribed standard emission heights in ECHAM6-HAM2. Extreme scenarios of near-surface or free-tropospheric-only injections provide lower and upper constraints on the emission height climate impact. We find relative changes in mean global atmospheric BC burden of up to 7.9 ± 4.4 % caused by average changes in emission heights of 1.5-3.5 km. Regionally, changes in BC burden exceed 30-40 % in the major biomass burning regions. The model evaluation of aerosol optical thickness (AOT) against Moderate Resolution Imaging Spectroradiometer (MODIS), AErosol RObotic NETwork (AERONET) and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations indicates that the implementation of a plume height parametrization slightly reduces the ECHAM6-HAM2 biases regionally, but on the global scale these improvements in model performance are small. For prescribed emission release at the surface, wildfire emissions entail a total sky top-of-atmosphere (TOA) radiative forcing (RF) of −0.16 ± 0.06 W m −2 . The application of a plume height parametrization which agrees reasonably well with observations introduces a slightly stronger negative TOA RF of −0.20 ± 0.07 W m −2 . The standard ECHAM6-HAM2 model in which 25 % of the wildfire emissions are injected into the free troposphere (FT) and 75 % into the planetary boundary layer (PBL), leads to a TOA RF of −0.24 ± 0.06 W m −2 . Overall, we conclude that simple plume height parametrizations provide sufficient representations of emission heights for global climate modeling. Significant improvements in aerosol wildfire modeling likely depend on better emission inventories and aerosol process modeling rather than on improved emission height parametrizations.

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Section: Echam6-ham2mentioning

confidence: 99%

“…For details on the implementation of sedimentation, wet and dry deposition, thermodynamics and aerosol micro-physics parametrization, see Stier et al (2005). A detailed assessment of the processes which drive the evolution of aerosol mass and number concentrations is described in Schutgens and Stier (2014).…”

Section: Echam6-ham2mentioning

confidence: 99%

Fire emission heights in the climate system – Part 2: Impact on transport, black carbon concentrations and radiation

et al. 2015

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“…The approach for below-cloud scavenging does not differentiate between soluble and insoluble aerosol modes (Stier et al, 2005) but between aerosol mass and number as shown in Table 2. Values are updated based on the work by Croft et al (2009) and are substantially lower than the previously used values based on Dana et al (1975).…”

Section: Aerosols and Wet Depositionmentioning

confidence: 99%

“…These changes are documented in this paper. In the current version, in-cloud scavenging is different for liquid, mixed and ice stratiform clouds (Stier et al, 2005). This distinction is based on the local temperature (Croft et al, 2010), where clouds are assumed pure liquid above 0 • C and pure ice below −35 • C. Between these boundaries, the clouds are classified as mixed as shown in Table 1.…”

Section: Aerosols and Wet Depositionmentioning

confidence: 99%

“…Most models adopt a straightforward approach and release aerosols proportional to the fraction of evaporated precipitation (e.g. ECHAM5-HAM, Stier et al, 2005;GOCART, Chin et al, 2000;SPRINTARS, Takemura et al, 2000), but some models have a more advanced treatment. For example, AURAMS takes the raindrop size distribution into account and only releases aerosol from evaporated droplets.…”

Section: Introductionmentioning

confidence: 99%

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The impact of precipitation evaporation on the atmospheric aerosol distribution in EC-Earth v3.2.0

et al. 2018

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Abstract. The representation of aerosol-cloud interaction in global climate models (GCMs) remains a large source of uncertainty in climate projections. Due to its complexity, precipitation evaporation is either ignored or taken into account in a simplified manner in GCMs. This research explores various ways to treat aerosol resuspension and determines the possible impact of precipitation evaporation and subsequent aerosol resuspension on global aerosol burdens and distribution. The representation of aerosol wet deposition by large-scale precipitation in the EC-Earth model has been improved by utilising additional precipitation-related 3-D fields from the dynamical core, the Integrated Forecasting System (IFS) general circulation model, in the chemistry and aerosol module Tracer Model, version 5 (TM5). A simple approach of scaling aerosol release with evaporated precipitation fraction leads to an increase in the global aerosol burden (+7.8 to +15 % for different aerosol species). However, when taking into account the different sizes and evaporation rate of raindrops following , the release of aerosols is strongly reduced, and the total aerosol burden decreases by −3.0 to −8.5 %. Moreover, inclusion of cloud processing based on observations by Mitra et al. (1992) transforms scavenged small aerosol to coarse particles, which enhances removal by sedimentation and hence leads to a −10 to −11 % lower aerosol burden. Finally, when these two effects are combined, the global aerosol burden decreases by −11 to −19 %. Compared to the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations, aerosol optical depth (AOD) is generally underestimated in most parts of the world in all configurations of the TM5 model and although the representation is now physically more realistic, global AOD shows no large improvements in spatial patterns. Similarly, the agreement of the vertical profile with CloudAerosol Lidar with Orthogonal Polarization (CALIOP) satellite measurements does not improve significantly. We show, however, that aerosol resuspension has a considerable impact on the modelled aerosol distribution and needs to be taken into account.

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Solar irradiance reduction via climate engineering: Impact of different techniques on the energy balance and the hydrological cycle

et al. 2013

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[1] Different techniques of solar radiation management (SRM) have been suggested to counteract global warming, among them the injection of sulfur into the stratosphere, mirrors in space, and marine cloud brightening through artificial emissions of sea salt. This study focuses on to what extent climate impacts of these three methods would be different. We present results from simulations with an Earth system model where the forcing from the increase of greenhouse gases in a transient scenario (RCP4.5) was balanced over 50 years by SRM. While global mean temperature increases slightly due to the inertia of the climate system and evolves similar with time for the different SRM methods, responses of global mean precipitation differ considerably among the methods. The hydrological sensitivity is decreased by SRM, most prominently for aerosol-based techniques, sea salt emissions, and injection of sulfate into the stratosphere. Reasons for these differences are discussed through an analysis of the surface energy budget. Furthermore, effects on large-scale tropical dynamics and on regional climate are discussed.Citation: Niemeier, U., H. Schmidt, K. Alterskjaer, and J. E. Kristjánsson (2013), Solar irradiance reduction via climate engineering: Impact of different techniques on the energy balance and the hydrological cycle,

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The aerosol-climate model ECHAM5-HAM

Abstract: Abstract. The aerosol-climate modelling system ECHAM5-HAM is introduced. It is based on a flexible microphysical approach and, as the number of externally imposed parameters is minimised, allows the application in a wide range of climate regimes.

Cited by 1,024 publications

References 101 publications

Fire emission heights in the climate system – Part 2: Impact on transport, black carbon concentrations and radiation

Fire emission heights in the climate system – Part 2: Impact on transport, black carbon concentrations and radiation

The impact of precipitation evaporation on the atmospheric aerosol distribution in EC-Earth v3.2.0

Solar irradiance reduction via climate engineering: Impact of different techniques on the energy balance and the hydrological cycle

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