Purpose of simulation: Transient run for describing climate change in the 20th century (1850-2005)

Contact person: Øyvind Seland (oyvind.seland@met.no)

**Data owner: ** Mats Bentsen (mats.bentsen@uni.no)

Revision Number: r112

Production computer used: Cray XT3 in Bergen (hexagon)

Production date: November - March 2010 /2011

Ensemble runs: Yes, 3 members

Storage locations: NorStore (/projects/NS2345K/noresm/cases/N20TRAERCN_f19_g16_0X), where X = ensemble member, X=1,2,3 for this particular set-up

Storage space: 1,6 Tb at NorStore (for each ensemble member)

Projects: EarthClim

Publications: Bentsen, M., I. Bethke, J. B. Debernard, T. Iversen, A. Kirkevåg, Ø. Seland, H. Drange, C. Roelandt, I. A. Seierstad, C. Hoose, and J. E. Kristjansson (2012): The Norwegian Earth System Model, NorESM1-M. Part 1: Description and basic evaluation, Geosci. Model Dev., 6, 687-720, doi:10.5194/gmd-6-687-2013

Papers in preparation:

Simulation name(s): N20TRAERCN_f19_g16_0X), where X = ensemble member, where X = 1,2,3 for this set-up

Compset name used: N20TRAERCN

Model type: Fully coupled

Type of run: Hybrid

Simulation period: 156 years

**Initialisation ** Start from CMIP5 transient simulation, N20TRAERCN_f19_g16_06

Resolution: f19_g16= 1.9×2.5 degree atmosphere/land. Dipolar ocean/ice grid, ~ 1 degree

Emission year(s): 1850-2005 (aerosol and aerosol-precursors)

Greenhouse gases: Prescribed concentrations 1850-2005

Emission inventories IPCC AR5, see references in Kirkevåg et al. (2013)

Frequency for output: Monthly and selected daily 1850-1949: Monthly + daily + 6h +3h as defined by CMIP5: 1950-2005

Active/changing forcing agents: Greenhouse gases: Direct and indirect (1. & 2.) effects of SO4, POM and BC.

** Special considerations: ** An extension to the normal NorESM-M has been created. In the extended version it is possible to specify a vulcanic eruption at some lon/lat location and some height distribution. The volcano can then have several eruptions distributed in time. This is used to simulate the Laki eruption on Iceland 1783.

Tuning parameters which are changed relative to the host model CAM4:

rhminl: 0.90 lower RH threshold for formation of low stratiform clouds (0.91 in CAM4)

critrp: 5.0 mm/day maximum prcipitation rate for suppression of autoconversion of cloud water (0.5 mm/day in CAM4)

r3lc: 14 um critical mean droplet volume radius for onset of autoconversion (10 um in CAM4)