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Experiment Name

Experiment Long Name

Extended Description

dcppA-hindcast

hindcasts initialized from observations with historical forcing

dcppA-hindcast is a set of retrospective decadal forecasts (known as hindcasts) that are initialised every year mostly from 1960-2019 and performed with a coupled atmosphere-ocean general circulation model (AOGCM).  The hindcasts begin in November to allow for DJF (December, January, February) seasonal averages to be calculated.  There There are 10 hindcasts for each start date and hindcasts run for 10 years.

The models running these hindcasts are initialised using observed data. Prior to the year 2020, the models are forced with historical conditions that are consistent with observations, these conditions include atmospheric composition, land use, volcanic aerosols and solar forcing. When hindcasts extend beyond 2020, the models are forced with future conditions from the ssp245 scenario from 2020 until the end of the simulation.

DCPP hindcast experiments can be used to assess and understand the historical decadal prediction skill of climate models.

dcppB-forecast

forecasts initialised from observations with ssp245 scenario forcing

dcppB-forecast is a set of quasi-real-time decadal forecasts that are initialised every year from 2019 in real time and ongoing. The forecasts are performed with the same coupled atmosphere-ocean general circulation model (AOGCM), which was used to generate the hindcast data. The hindcasts forecasts begin in November to allow DJF (December, January, February) seasonal averages to be calculated. There are 10 forecasts for each start date and forecasts run for 10 years.

The models running these forecasts are initialised using observed data, thereafter they . Prior to the year 2020, the models are forced with future historical conditions from the ssp245 scenario that that are consistent with observations, these conditions include atmospheric composition, land use, volcanic aerosols and solar forcing. When hindcasts extend beyond 2020, the models are forced with future conditions from the ssp245 scenario from 2020 until the end of the simulation.

DCPP forecast experiments form a basis for potential operational decadal forecast production.

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In the table below some practical details of the data is shown including the base year (start year) period covered and the number of ensemble members. Hindcast and forecast periods are not distinguished here as they are not mentioned For each start year there are 10 years of corresponding hindcast or forecast data available. Hindcast and forecast start years are not distinguished in the CDS form neither. Please note that the ensemble members are not available individually, but they are concatenated into one file while the data is downloaded. Generally , and generally users are encouraged to use all members instead of selecting one members member of the predictions. 


Hindcast start years*Forecast start years*Forecast periodEnsemble membersNominal resolution
CMCC (Italy)1960 -2018 2019 - 202010100 km
HadGEM3 (UK)1960 - 20182019 - 202010100 km
EC-EARTH (Europe)1960 - 20182019 - 202010100 km
MPI-ESM1-2-HR (Germany)1960 - 2018201910100 km
MPI-ESM1-2-LR (Germany)1960 - 20182019 - 202121250 km

*Note: Since hindcast and forecast data begins in November, the actual period the data covers only includes the November and December for a given start year, and the last year excludes November and December. For example, for the 1960 start year, 1960 includes November and December, 1961 - 1970 have full coverage, and 1971 covers January to October. 

Start-Date Ensembles

The DCPP experiments published in the CDS, are a suite of overlapping simulations that are initialised every year throughout the duration of the start-date range specified by the experiment. The simulations begin in November to allow for DJF (December, January, February) seasonal averages to be calculated. There are 10 (16) simulations (ensemble members) for each start-date (called "Base year" in he CDS form).

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