wux (version 2.1-1)

CMIP5fromESGF: Downloads CMIP5 climate simulations from the ESGF data portal

Description

Downloads available monthly CMIP5 simulations from ESGF data portal. You need an account at any ESGF node (see http://cmip-pcmdi.llnl.gov/cmip5/data_getting_started.html). This function creates subdirectories for each climate simulation in the specified folder, automatically recieves the bash scripts needed for the partiular simulation-variable-experiment combination and then executes the bash scripts one by one. An external PYTHON script is called for this task. If either data or bash-scripts exist, the download will be skipped. Use this function with care. You need a working internet connection for this function to work.

Usage

CMIP5fromESGF(save.to = NULL, variables = NULL,
              experiments = NULL, models = NULL)

Arguments

save.to

Directory location for downloading CMIP5 data and bash scripts. ATTENTION: subdirectories for each model-experiment combination will be created!

variables

Short variable names for meteorological parameters of interest (e.g. "tas" for 2m air temperature or "pr" for precipitation amount). See e.g. the IPCC Standard Output from GCMs (http://www-pcmdi.llnl.gov/ipcc/standard_output.html).

experiments

Experiment of the climate simulation (e.g. c("historical", "rcp45"), see Taylor (2012) for a detailed description.

models

Climate simulations to be downloaded. If no models are provided (default), all available simulations will be retrieved. See the "Model" column at http://cmip-pcmdi.llnl.gov/cmip5/availability.html for

Warning

This function automatically creates new directories on your system, downloads wget scripts, flags them execueable and runs them, which can download quite some data.

Details

Firstly you need an ESGF account. If you do not have any, start here: http://cmip-pcmdi.llnl.gov/cmip5/data_getting_started.html This function calls an external python script which

1. looks for the latest CMIP5 models at ESGFhttp://pcmdi9.llnl.gov
2. generates a local directory structure where the data will be stored
3. receives the corresponding bash files from ESGF
4. executes the bash files.

You can find the location of the script with system.file("exec", "CMIP5_downloader.py", package="wux")

This function is an alternative to downloading the corresponding models by point-and-click on the ESGF node (as http://pcmdi9.llnl.gov or http://esgf-data.dkrz.de), as it takes advantage of the ESGF search API mechanism for automated data screening and wget-script generation. For thei nterested user more information on downloading strategies is available at https://github.com/ESGF/esgf.github.io/wiki/ESGF_Data_Download_Strategies.

References

Karl E. Taylor, Ronald J. Stouffer, and Gerald A. Meehl, 2012: An Overview of CMIP5 and the Experiment Design. Bull. Amer. Meteor. Soc., 93, 485-498. doi: http://dx.doi.org/10.1175/BAMS-D-11-00094.1

Examples

## download temperature fields of two example GCMs (NorESM1-M and
## CanESM2) with the  RCP 8.5 and the historical run
## into your temporary directory. This command will create a folder
## "CMIP5" in "~/tmp" with two subfolders for each model again with
## two subfolders for each experiment.
CMIP5fromESGF(save.to = "~/tmp/CMIP5/",
              models = c("NorESM1-M", "CanESM2"),
              variables = c("tas"),
              experiments= c("historical", "rcp85"))