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Objectives of GREENICE AGCM experiments

1. To better understand atmospheric impact of SST, sea ice, and snow cover

2. To assess the relative contributions of SST, sea ice, snow cover, and internal atmospheric dynamics in recent NH climate change


  • Six models: CAM4(0.9x1.25deg.L26)/WACCM(L66), IFS(T255L91), ECHAM5(T106L31), IAP(1.4x1.4deg.L26), LMDZ (2.5x1.25deg.L39)
  • Low and high top, low and high-horizontal resolution



  • AGCM with full sea ice and SST variations
  • AGCM with full sea ice and climatological SST variations
  • Period 1982 to 2013 2014 (revised in May2015)
  • Number of ensemble: 20 member for each experiments to be determined by each group (e.g., different days in January 1981)
  • Daily SST and sea ice variations will be used

Tier 2

  • Case studies based on analysis of tier 1 experiments to better diagnose mechanisms
  • Experiments to assess impact of snow cover variations

Boundary conditions (BCs) and external forcing


  • Under maintainance on missing data periods (Asking NOAA to fix that. 26th March 2015 by Fumiaki Ogawa). Now revised version is available.
  • NOAA Optimum Interpolation 1/4 Degree Daily Sea Surface Temperature Analysis – version2, AVHRR-only product. This extends from September 2001 till present. The sea ice for 1981-2004 is from Cavalieri et al. [1997,2005]. The sea ice from 2005 to present is from Grumbine et al. [1998].
  • Reference for the data Reynolds et al. [2007].
  • Transient forcing following CMIP5 protocol. Specifically, "historical" until the end of 2005 while RCP8.5 from 2006 onward.
  • Boundary conditions for the experiments with observed varying SIC and climatological SST follows Screen et al. [2013]: In any grid box north of 40N, if the daily mean SIC deviated from daily climatology by > 10%, the grid box was set to observed SIC and SST. All the grid boxes south of 40N and at grid boxes north of 40N where the daily mean sea ice concentration was within 10% of the climatological daily mean, observed SIC and climatological SST were used.
  • NOAA original BC data has error, therefore year-to-year daily anomaly was linearly interpolated 29Nov1987-18Jan1988 (SIC) and 27Apr2009-19May2009 (SST&SIC) for the GREENICE experiments.
  • BC data can be downloaded from the links below.

Download BCs

  • Hexagon (SST clim)

  • NorStore

  • Online (currently a place holder)

Some specific issues to be addressed by groups

  • Role of stratosphere-troposphere interaction at medium horizontal resolution ~1deg by comparing low versus high top simulations with daily SST and SIC data (UiB/NERSC)
  • Anti-phase correlation of the Siberia High between November and December-January (NERSC, L Suo, Y Gao)

Downloading monthly outputs

Use web browser:

Note that you need ID and password.

Downloading through a linux terminal is like:

wget --http-user="the ID" --http-password="the password"${EXP}/${MODEL}/${FILE}.nc

Note wget may not work if its version is 1.13 or older (see wget -h).

Output variables

To be made available by each modeling group.

Summary chart for uploading monthly & constant data to Norstore

3D variable- Summary for uploading monthly data
description variable name unit note
temperature ta K
u wind ua m/s positive for eastward
v wind va m/s positive for northward
Specific humidity Humidity hus hur 1 %
vertical velocity wap Pa/s negative for upward motion
GPH zg m
2D variable- Summary for uploading monthly data
description variable name unit note
SLP psl Pa not hPa
Surface pressure ps Pa not hPa
Radiation, Longwave, Downward, Surface rlds W/m2 positive for downward
Radiation, Longwave, Upward, Surface rlus W/m2 positive for upward
Radiation, Shortwave, Downward, Surface rsds W/m2 positive for downward
Radiation, Shortwave, Upward, Surface rsus W/m2 positive for upward
Radiation, Longwave, Upward, TOA rlut W/m2 positive for upward
Radiation, Shortwave, Downward, TOA rsdt W/m2 positive for downward
Radiation, Shortwave, Upward, TOA rsut W/m2 positive for upward
Evaporation evspsbl kg/m2/s
Surface temperature ts K not Celcius
10m u wind uas m/s positive for eastward
10m v wind vas m/s positive for northward
Cloud cover, Total clt  %
Cloud cover, Low-level cll  %
Cloud cover, Mid-level clm  %
Cloud cover, High-level clh  %
Snow cover snc  %
Snow liquid water equivalent lwsnl kg/m2
Precipitation, Total pr kg/m2/s
Precipitation, Large Scale prl prlprof kg/m2/s
Precipitation, Convective prc prcprof kg/m2/s
Precipitation, Snow prsn kg/m2/s
2m tempareture tas K not Celcius
Upward Heat Flux, Latent, Surface hfls W/m2 positive for upward
Upward Heat Flux, Sensible, Surface hfss W/m2 positive for upward
Surface downward U wind stress tauu Pa positive for eastward
Surface downward V wind stress tauv Pa positive for northward
Prescribed SST tos K not Celcius. Name is not SST
Prescribed SIC sic  %
2D Constant- Summary for uploading
description variable name unit note
Surface Altitude orog m
Land Area Fraction sftlf  %

3D-fields (daily)

  • temperature
  • wind u, v
  • humidity
  • vertical velocity
  • GPH

Levels (hPa): 1000 925 850 700 600 500 400 300 250 200 150 100 70 50 30 20 10 7 5

2D-fields (daily)

  • SLP
  • surface pressure
  • all radiation components (both clear and all sky fluxes)
  • evaporation
  • daily max/min temperature
  • surface temperature
  • 10m wind
  • cloud cover (total, low, medium, high)
  • Cloud liquid water content
  • cloud ice water content
  • total column water
  • total column water vapor
  • soil temperature (several layers)
  • soil wetness (several layers)
  • runoff (surface and deep)
  • snow cover
  • snow depth and density or liquid water equivalent.
  • Total precipitation
  • T2m
  • Surface fluxes (latent, sensible, momentum)
  • Precipitation (large scale, convective, snow)

2D fields at 3hrly frequency

  • T2m
  • Surface fluxes (latent, sensible, momentum)
  • Precipitation (large scale, convective, snow)
  • SLP
  • 10m wind

Experiments to start by mid-November to be completed by the first year annual meeting <= delayed a little...

Technical setup of AGCM


  • by Fumiaki Ogawa (WACCM, UiB) and Lingling Suo (CAM4, NERSC)
  • Output levels of WACCM are same as CAM4 below 100hPa, while split above there into 30 levels in total (originally 66).




  • Cavalieri D., C. Parkinson, P. Gloerson, and H.J. Zwally. 1997, updated 2005. Sea ice concentrations from Nimbus-7 SMMR and DMSP SSM/I passive microwave data, June to September 2001. Boulder, CO, USA (from
  • Grumbine, R. W., 1996: Automated passive microwave sea ice concentration analysis at NCEP, 13pp. Unpublished manuscript available from NCEP/NWS/NOAA, 5200 Auth Road, Camp Springs, MD, 20746, USA. (from
  • Reynolds, R. W., T. M. Smith, C. Liu, D. B. Chelton, K. S. Casey, and M. G. Schlax (2007), Daily high-resolution-blended analyses for sea surface temperature, J Climate, 20(22), 5473-5496
  • Screen, J. A., I. Simmonds, C. Deser, and R. Tomas (2013), The Atmospheric Response to Three Decades of Observed Arctic Sea Ice Loss, J Climate, 26(4), 1230-1248, 10.1175/jcli-d-12-00063.1.

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