The most common ensemble member is “ri1ip1”. For different ensemble member run for a climate model and experiment, the initial conditions are changed by a small amount, but the model and time-varying inputs are identical. Many climate models are run with multiple ensemble members, to allow exploration of uncertainty related to internal climate variability.

“Time frequency”: The time step of model output (e.g., day, month, year).

For more information on the CMIP5 experiment design, see Taylor et al. Standard experiments are “historical” (uses observed or reconstructed data typically from 1850 to 2005 as model inputs), “piControl” (pre-Industrial control), “rcp45” (uses concentrations based on a scenario of forcing agents from 2006 to 2100), and “rcp85” (same period as “rcp45”, but with a different scenario of forcing agents).

“Experiment”: The scenario of external, time-varying values (e.g., greenhouse gas concentrations) that are input to the model.

Chapter 9 of the Intergovernmental Panel on Climate Change (IPCC)’s Fifth Assessment Report provides an evaluation of climate models (available at Flato et al.

“Climate model”: The name of the climate model used to produce the output.

Output from a few groups is restricted to non-commercial use. A list with the full names and IDs for each of these is available at.

“Institute”: The climate modeling group that created the climate model.There are a number of parameters that can be used to search files, including: You will need to register to download climate model output data. The data is stored and distributed across multiple data nodes at different institutions, but this and other data portals allow access to all available data through one website. You can download netCDF files from CMIP5 from the World Climate Research Programme CMIP5 website at, hosted by the Department of Energy’s Lawrence Livermore National Laboratory. This project is currently in its fifth phase (CMIP5). The Coupled Model Intercomparison Project is a key source of climate model output data for researchers studying the potential impact of climate change.

Working with net cdf files in r