In Table 2.1, we describe the different experiments for ISIMIP3. Each default experiment is defined by its climate related forcing (CRF) and the assumptions regarding direct human forcing (DHF). The associated specifications all have a label such as obsclim or histsoc that are provided in Table 2.1 and further specified in Tables 2.2 and 2.3. These specifiers are used in the file names of the corresponding input files and should also be used for the names of the output files (see report model results report model results). Sensitivity experiments are described as deviation from a default experiment and represented by labels that are used as a third specifier of the experiments. Their specific meanings are defined in Table 2.4.
Please note that the experiments are different for ISIMIP3a and ISIMIP3b and some are sector specific. You can use the menu on the top-right of the page to select the simulation round and sectors you are interested in.
::: table identifier=experiments caption="Table 2.1: Experiment set-up. Each experiment is specified by the climate related forcing (top row) and the direct human forcing (bottom row). Sensitivity labels indicate deviations from the default settings. Experiments are colored by group: group I (grey), group II (red) and group III (blue). The subtitles in the first row indicate how the experiment is defined in filenames."
::: show simulation_round=ISIMIP3a sector=agriculture,biodiversity,biomes,coastal,diarrhea,energy,fire,forestry,health,labour,lakes_global,lakes_local,peat,permafrost,water_global,water_regional
For models requiring spin-up, we provide 100 years of spinclim data which is identical with the first 100 years of the counterclim data. The files are located under `ISIMIP3a/InputData/climate/atmosphere/spinclim` at DKRZ and in the ISIMIP Repository. If more than 100 years of spin-up are needed, these data can be repeated as often as needed.
For `historical` runs, use the `transclim` climate time series, historical CO₂ concentration and varying DHF, for the transition period from spin-up to the start of the experiment (1850-1900). When using a longer spin-up period that (nominally) extends back further than 1850, please keep CO₂ concentration and DHF constant at 1850 level until reaching the year corresponding to 1850.
For experiments with fixed direct human influences (`1901soc`, `2015soc`), the spin-up should be based on the 1901 DHF or 2015 DHF, respectively.
For sector-specific experiments without direct human influence (`nat`), the spin-up should not use any DHF. Likewise, the `nofire` experiment should include a spin-up without fire.
::: show simulation_round=ISIMIP3a sector=marine-fishery_global,marine-fishery_regional
The model evaluation experiment starts in 1961. To capture historical fishing effort prior
to 1961, we also provide input for a nominal spin-up (1841-1860, fishing held constant
at 1861 levels) and pre-industrial transition period (1861-1960, reconstructed fishing
effort).
To set-up climate-forcing variables for the entire 1841-1960 period, we ask modellers to
use the "control run" (`ctrlclim`) monthly output for the years 1961-1980 (inclusive) on
repeat for six cycles. These years have been selected because they correspond with
an entire ENSO cycle and because no climate trend is detectable prior to 1980 from the
GFDL model.
For models that require longer spin-up prior to 1841, please keep 1841 levels of fishing
effort constant and, if needed, repeat the ENSO cycle (e.g. monthly values for 1961-
1980 inclusive from `ctrlclim`) for as many times necessary.
For the ‘no fishing’ runs (`nat`), the spin-up and pre-industrial transition should not use
any fishing effort.
We ask modellers to include all outputs from 1841 onwards for use in our analyses.
::: show simulation_round=ISIMIP3b
For models requiring spin-up, please use the pre-industrial control data and CO₂ concentration and DHF fixed at 1850 levels for the spin up as long as needed.
Please note that the "pre-industrial control run" from 1601-1849 is part of the regular experiments that should be reported and hence the spin-up has to be finished before that.
For experiments with fixed year-2015 direct human influences (`2015soc`), spin-up should be based on the 2015 DHF.
For sector-specific experiments without direct human influence (nat), the spin-up should not use any DHF.
Please note that there is no "pre-industrial control run" from 1601-1849 for these experiments (`2015soc`, `nat`) and hence the spin-up links directly to the historical period.
The simulations with nitrogen cycling turned off should also be spun up with nitrogen cycling turned off.
Tables 2.2-2.4 describe the different specifiers for the different experiments as described in Table 2.1. They are used in the file names of the corresponding input files and should also be used for the names of the output files (see report model results).
::: table identifier=climate_scenario caption="Table 2.2: Experiment specifiers: Climate-Related Forcings (climate-scenario)."
::: table identifier=soc_scenario caption="Table 2.3: Experiment specifiers: Direct Human Forcing (soc-scenario)."
::: table identifier=sens_scenario caption="Table 2.4: Experiment specifiers: Sensitivity runs (sens-scenario)."
::: show simulation_round=ISIMIP3a
#### General note regarding sensitivity experiments
The sensitivity experiments are meant to be deviations from the default settings. So for example if your model does not at all account for changes in CO₂ concentrations (no option to switch it on or off) the run should be labeled as “default” in the sensitivity specifier of the file name even if the run would be identical to the `1901co2` sensitivity setting.
The particular sensitivity specifier for an experiment is given in the experiments table above. For most experiments no sensitivity specifier is given, so the `default` label applies.
::: show simulation_round=ISIMIP3b
#### General note regarding sensitivity experiments
The sensitivity experiments are meant to be deviations from the default settings. So for example if your model does not at all account for changes in CO₂ concentrations (no option to switch it on or off) the run should be labeled as `default` in the sensitivity specifier of the file name even if the run would be comparable to the `2015co2` sensitivity setting.
The particular sensitivity specifier for an experiment is given in the experiments table above. For most experiments no sensitivity specifier is given, so the `default` label applies.
::: show simulation_round=ISIMIP3b
### 2.3 Group III experiment priorities
Table 2.5 lists the priorities for the different **group III** experiments in ISIMIP3b. We kindly ask you to run the experiments marked as **Tier 1: Core set** in any case and the other experiments with the priority given.
::: table identifier=group3_ranking caption="Table 2.5: Experiment priorities for ISIMIP3b group III."
::: show simulation_round=ISIMIP3b
### 2.4 Group III requirements
Table 2.6 lists the **direct human forcings (DHF)** that are relevant for the different sectors for **group III** simulations in ISIMIP3b. **Required** means that the forcing has to be accounted for in the simulations in the given sectors to count as a group III simulation. In addition a forcing can be **harmonized** by e.g. prescribing the application of a specific forcing data set from Table 2.7, or the specific implementation of the forcing can be left to the individual modellers. The harmonization setting is closely connected to the **mandatory** / **optional** setting in Table 3.1 (mandatory means that all modelling teams must use the same forcings dataset and not an alternative one).
::: table identifier=group3_requirements caption="Table 2.6: Direct Human Forcings (DHF) considered in the group III simulations."