Overview
Summary of plans and status of the v1 low-res water cycle DECK simulation campaign for CMIP6. An overview of the CMIP6 experimental design is available in Eyring at al. (2016, GMD). The "entry card" simulations for CMIP6 consist of the DECK and historical simulations as listed in the table below extract from Table 2 of Eyring et al (2016):
While the minimum ensemble members is one, our goal is between 3 and 5 ensemble members for the historical experiments.
Simulation plan
The first DECK simulation is the piControl simulation which requires a minimum of 500 years. Other experiments will all be initialized by branching of from piControl at various stages. A possible scenario is provided in the figure below. Historical_H1, 1pctCO2, and abrupt-4xCO2 would start from year 101 of piControl, amip from year 1870 of historical_H1, historical_H2 from year 151 of piControl and all remaining historical members would be spaced 50 years apart (201, 251, 301).
Final tuning (description)
piControl (simulation page)
Initialization
Due to time constraints, piControl year 1 (0001-01-01) initial conditions are taken from a pre-existing simulation rather than starting a new spin-up from scratch. The initial conditions are 0331-01-01 of 20171228.beta3rc13_1850.ne30_oECv3_ICG.edison.
Provenance of initial conditions:
- MPAS-O stand-alone initialization
- 10 years of G-case (/wiki/spaces/OCNICE/pages/130353452)
- Ocean and sea-ice restart as initial conditions for
- 50 years coupled FCT2 (0001-0051; /wiki/spaces/OCNICE/pages/161349662)
- Year 51 ocean and sea-ice restart as initial conditions for
- 150 years of coupled beta3rc10 (0001-0151; 20171122.beta3rc10_1850.ne30_oECv3_ICG.edison)
- Year 151 atmosphere, land, river, ocean and sea-ice restart as initial conditions for
- 100 years of coupled beta3rc11 (0151-0251; 20171122.beta3rc11_1850.ne30_oECv3_ICG.edison)
- Year 251 atmosphere, land, river, ocean and sea-ice restart as initial conditions for
- 80 years of coupled beta3rc13 (0251-0331; 20171228.beta3rc13_1850.ne30_oECv3_ICG.edison)
- Year 331 atmosphere, land, river, ocean and sea-ice restart as initial conditions for
- DECK v1 piControl
Final tuning
At the time piControl needed to start, we were still in the process of fine tuning the control simulation to reduce its long term drift in surface air temperature as much as possible. 20171228.beta3rc13_1850.ne30_oECv3_ICG.edison was the configuration with the smallest drift at the time. However, due to its limited duration (80 years), we couldn't conclusively determine whether the drift was as small as it could be. As a result, we decided to start two piControl simulations with the goal of running both of them for 50-100 years and then selecting one:
- 20180129.DECKv1a_piControl.ne30_oEC.edison : identical tuning as in beta3rc13, but with a slightly updated version of the code base.
- 20180129.DECKv1b_piControl.ne30_oEC.edison : same, except for a minor retuning of clubb_c14: 1.08 → 1.06. This is expected to only change net TOA fluxes by a few hundreds of a W/m2, but may help further reduce long-term drift (without hopefully changing its sign).
On , both v1a and v1b piControl simulations completed 110 years. Analysis of the global surface temperature trend for years 11 to 110 revealed that v1b had the smallest drift of the two. Comparison of climatologies for years 51-100 between the two configurations showed almost no differences, as expected. As a result, v1b was selected as the final tuning for the Water Cycle low-res model.
abrupt-4xCO2 (simulation page)
- Initialization: 0101-01-01 of v1b piControl
1pctCO2 (simulation page)
- Initialization: 0101-01-01 of v1b piControl
historical (simulation page)
Initialization
- Ensemble member H1: 0101-01-01 of v1b piControl
- Ensemble member H2: 0151-01-01 of v1b piControl
- Ensemble member H3: 0201-01-01 of v1b piControl
- Ensemble member H4: 0251-01-01 of v1b piControl
- Ensemble member H5: 0301-01-01 of v1b piControl
amip (simulation page)
- Initialization: 1870-01-01 of historical H1