811: Download

The Download menu item provides direct access to commonly used datasets in the IRI Data Library. Three types of data can be downloaded:

• 1. Observations
• 2. Reanalyses
• 3. GCM Outputs

Selecting one of the datasets will open a window browser in your default browser. All the datasets accessible from within CPT consist of monthly data, or daily data converted to monthly, but it is possible to calculate seasonal averages or totals. The datasets available for download are detailed in the file download_IRIDL.txt, which is stored in the data subdirectory of CPT. It is possible to modify this file in order to update datasets or add new ones, but the file needs to be formatted carefully. For details on how this file is structured, see Dataset Downloads .

The Download option facilitates access to monthly and seasonal datasets that may be useful as predictor or predictand files in CPT. If monthly data are required, enter the corresponding month number (1 for January, 2 for February, etc.) as the First month of data to download , and 1 for the subsequent prompts. If a seasonal average or total is required, enter the number of the month for the first month of the season, and then the number of months in the season, leaving the Number of lags as 1. For example, for a April - June (AMJ) average, enter 4 (for April), 3 (for a 3-month average) and 1 (one season only). If you want to download April, May and June as separate months (i.e., lagged fields), then the responses should be 4 (for April as the first month), 1 (for no seasonal averaging) and 3 (three months separately). For seasonal averaging and multiple lags the seasons will be sequential; for example, entries of 4 (first month April), 2 (2-month seasons), and 3 (3 consecutive seasons) will download data for (AM, JJ, and AS). It is not possible to download seasonally overlapping data (e.g., JFM, FMA, MAM) using this feature.

If you want to combine datasets, download the individual datasets first, and then use the Data ~ Merge menu item.