ECHAM6-HAM2 model experiments to characterize the effect of parameterized autoconversion/warm rain on cloud lifetime


Mülmenstädt, Johannes

This experiment contains the model output from a series of sensitivity simulations, called "rain", carried out with the global aerosol-climate model ECHAM6-HAM2 (model version ECHAM6.1-HAM2.2-MOZ0.9). The simulations were performed within the scope of the AeroCom project ( In general, the "rain" sensitivity study aims to provide a process-based observational constraint on the cloud lifetime effect by examining the parameterized precipitation stemming from warm rain. Aerosol (precursor) emission estimates of the year 2000 from the AEROCOM-II ACCMIP dataset were used as forcing. Details can be found in the associated publication of Mülmenstädt et al., (2020). 
The sensitivity simulations aim at investigating the effect of changing the autoconversion tuning factor (gamma) and the critical effective radius (rc) in the parameterization of autoconversion (see Fig.3 and Eq. 3 in Mülmenstädt et al., (2020). The respective setting of these parameters is indicated in the dataset group name (e.g. AeroCom ECHAM6-HAM2 warm rain sensitivity simulation gamma${x_gamma} rc${x_rc}. In the default setting of ECHAM6-HAM2, gamma is 4 and rc is -1. rc=-1 is used for simulations where no critical impact radius is applied.
In addition to microphysical variables, the model output includes simulated radar reflections from CloudSat created with the satellite simulator COSP (Cloud Feedback Model Intercomparison Project Observational Simulator Package, see Bodas-Salcedo et al., (2011)). The radar reflectivities are outputted on so-called subcolumns to include information on the subgrid variability of hydrometeors. The model output is provided as global fields on a reduced Gaussian Grid (N48) with 3-hourly temporal resolution and covers the period January 2000 to December 2004. 
The dataset is well suited for evaluating the sensitivity of warm rain parameterization in ECHAM6-HAM2. The data publication is standardized according to the ATMODAT Standard (v3.0) (Ganske et al. 2021). The data standardization was funded within the framework of “Forschungsvorhaben zur Entwicklung und Erprobung von Kurationskriterien und Qualitätsstandards von Forschungsdaten” by the German Federal Ministry of Education and Research (BMBF; FKZ: 16QK02B).
AeroCom (Aerosol Comparisons between Observations and Models)
Jan Kretzschmar (
Spatial Coverage
Longitude 0 to 360 Latitude -90 to 90
Temporal Coverage
2000-01-01 to 2004-12-31 (proleptic_gregorian)
Use constraints
Creative Commons Attribution 4.0 International (CC BY 4.0) (
Data Catalog
World Data Center for Climate
714.72 GiB (767421994890 Byte)
completely archived
Creation Date
Future Review Date
Cite as
Mülmenstädt, Johannes (2022). ECHAM6-HAM2 model experiments to characterize the effect of parameterized autoconversion/warm rain on cloud lifetime. World Data Center for Climate (WDCC) at DKRZ.

[Entry acronym: Aerocom_ECHAM6-HAM2_rain] [Entry id: 3888265]
Number of checked netCDF files: 3960
Mandatory ATMODAT Standard checks passed: 15840/15840 (0 missing, 0 error(s))
Recommended ATMODAT Standard checks passed: 67320/79200 (11880 missing, 0 error(s))
Optional ATMODAT Standard checks passed: 23760/35640 (11880 missing, 0 error(s))
CF checker errors: 0 (Ignoring errors related to formula_terms in boundary variables. See Known Issues section https:// )
CF checker warnings: 0
ATMODAT Standard Compliance Checker Version: 1.3.2
Method Description
Checking against: ATMODAT Standard 3.0. Metrics documentation: and CF Version 1.8
Method Url
Result Date
The scientific evaluation of the model simulations is described in Mülmenstädt et al., (2020) and Mülmenstädt et al., (2021).
Findable: 6 of 7 level;
Accessible: 2 of 3 level;
Interoperable: 3 of 4 level;
Reusable: 5 of 10 level
F-UJI online v2.2.1 automated
Method Description
Checks performed by WDCC. Metrics documentation: Metric Version: metrics_v0.5
Method Url
Result Date
Result Date
Annotation Jan Kretzschmar/ULei Angelika Heil/DKRZ Nov 2, 2022
- checker results evaluating 3960 aerocom_echam6_ham2_warm_rain_gamma${GAMMA}_rc${RC}_${VAR}_${YEAR}${MONTH}.nc files prior publication at
- the netCDF files do not fulfill the following global attributes which are either recommended or optional in the ATMODAT standard 3.0 because they are not applicable:
- crs
- source_type
- nominal_resolution
- featureType
- further_info_url
- program
1. Number of data sets is correct and > 0: passed;
2. Size of every data set is > 0: passed;
3. The data sets and corresponding metadata are accessible: passed;
4. The data sizes are controlled and correct: passed;
5. The spatial-temporal coverage description (metadata) is consistent to the data, time steps are correct and the time coordinate is continuous: passed;
6. The format is correct: passed;
7. Variable description and data are consistent: passed
WDCC-TQA checklist
Method Description
Checks performed by WDCC. The list of TQA metrics are documented in the 'WDCC User Guide for Data Publication' Chapter 8.1.1
Method Url
Result Date
Contact typePersonORCIDInstitute

Is documented by

[1] DOI Ganske, Anette; Kraft, Angelina; Kaiser, Amandine; Heydebreck, Daniel; Lammert, Andrea; Hoeck, Heinke; Thiemann, Hannes; Voss, Vivien; Grawe, David; Leitl, Bernd; Schlünzen, K. Heinke; Kretzschmar, Jan; Quaas, Johannes. (2021). ATMODAT Standard (v3.0). doi:10.35095/WDCC/atmodat_standard_en_v3_0
[2] DOI Mülmenstädt, Johannes; Nam, Christine; Salzmann, Marc; Kretzschmar, Jan; L’Ecuyer, Tristan S.; Lohmann, Ulrike; Ma, Po-Lun; Myhre, Gunnar; Neubauer, David; Stier, Philip; Suzuki, Kentaroh; Wang, Minghuai; Quaas, Johannes. (2020). Reducing the aerosol forcing uncertainty using observational constraints on warm rain processes. doi:10.1126/sciadv.aaz6433
[3] Aerocom wiki. (2018). Warm rain diagnostics (COSP and non-COSP).[]=cosp)
[4] DOI Mülmenstädt, Johannes; Salzmann, Marc; Kay, Jennifer E.; Zelinka, Mark D.; Ma, Po-Lun; Nam, Christine; Kretzschmar, Jan; Hörnig, Sabine; Quaas, Johannes. (2021). An underestimated negative cloud feedback from cloud lifetime changes. doi:10.1038/s41558-021-01038-1
[5] DOI Zhang, K.; O'Donnell, D.; Kazil, J.; Stier, P.; Kinne, S.; Lohmann, U.; Ferrachat, S.; Croft, B.; Quaas, J.; Wan, H.; Rast, S.; Feichter, J. (2012). The global aerosol-climate model ECHAM-HAM, version 2: sensitivity to improvements in process representations. doi:10.5194/acp-12-8911-2012

Is compiled by

[1] DOI Bodas-Salcedo, A.; Webb, M. J.; Bony, S.; Chepfer, H.; Dufresne, J.-L.; Klein, S. A.; Zhang, Y.; Marchand, R.; Haynes, J. M.; Pincus, R.; John, V. O. (2011). COSP: Satellite simulation software for model assessment. doi:10.1175/2011bams2856.1
[2] DOI Stier, P.; Feichter, J.; Kinne, S.; Kloster, S.; Vignati, E.; Wilson, J.; Ganzeveld, L.; Tegen, I.; Werner, M.; Balkanski, Y.; Schulz, M.; Boucher, O.; Minikin, A.; Petzold, A. (2005). The aerosol-climate model ECHAM5-HAM. doi:10.5194/acp-5-1125-2005

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