Recipe: Retrieve (global) data from FTP server

Problem

We want to access G5NR data by downloading files by ftp/wget.

Solution

The base url for G5NR data is

ftp://G5NR@ftp.nccs.nasa.gov/c1440_NR/DATA

At the ftp base url, the data is organized by resolution (0.5000_deg/0.0625_deg), type (const/inst/tavg/tdav), collection name, year, month and day as follows:

|-- resolution
|   |-- type
|   |   |-- collection
|   |   |   |-- year
|   |   |   |   |-- month
|   |   |   |   |   |-- day

[some details on what the types are etc.]

Download using a web browser

A web browser can be used to browse directories, read and retrieve files. To retrieve the collection inst01hr_3d_T_Cv for the day 2006-09-18, one needs to point to

ftp://G5NR@ftp.nccs.nasa.gov/c1440_NR/DATA/0.5000_deg/inst/inst01hr_3d_T_Cv/Y2006/M09/D18.

At this location, a file may be downloaded by simply clicking on the file name.

Download file(s) using the command line tool wget

The command line tool wget can be used to retrieve the same files as

wget ftp://G5NR:@ftp.nccs.nasa.gov/c1440_NR/DATA/0.5000_deg/inst/inst01hr_3d_T_Cv/Y2006/M09/D18/*

The * at the end would retrieve all (24) files for the given day.

To download a file for a specific time, say 0900z, we can use

wget ftp://G5NR:@ftp.nccs.nasa.gov/c1440_NR/DATA/0.5000_deg/inst/inst01hr_3d_T_Cv/Y2006/M09/D18/c1440_NR.inst01hr_3d_