decadals are a group of experiments of the CMIP5 - Coupled Model Intercomparison Project Phase 5 ( https://pcmdi.llnl.gov/mips/cmip5 ). CMIP5 is meant to provide a framework for coordinated climate change experiments for the next five years and thus includes simulations for assessment in the AR5 as well as others that extend beyond the AR5.
1.5 decadal (1.5 decadal hindcast/forecast utilizing alternative initializations.) - Version 1: Decadal hindcast/prediction. Comparison of initialization strategies - for example, a repeat of experiment 1.1 using an alternate initialization strategy or alternate initial data. Individual decadal experiments are named decadalXXXX with starting year XXXX.
Experiment design: https://pcmdi.llnl.gov/mips/cmip5/experiment_design.html
List of output variables: https://pcmdi.llnl.gov/mips/cmip5/datadescription.html
Output: time series per variable in model grid spatial resolution in netCDF format
Earth System model and the simulation information: CIM repository
Entry name/title of data are specified according to the Data Reference Syntax ( https://pcmdi.llnl.gov/mips/cmip5/docs/cmip5_data_reference_syntax.pdf ) as activity/product/institute/model/experiment/frequency/modeling realm/MIP table/ensemble member/version number/variable name/CMOR filename.nc .