I have had problems with http downloads of files from GFDL's server terminating before they completed downloading an entire file. Are transfer methods other than downloading using a web browser and http available?  

Some alternatives exist. Rather than downloading large files with a web browser and http, one may use the following:

wget

A free GNU utility for non-interactive download of files from the Web. It is run from the command line and has automatic file retry and continuation capabilities. If a download fails due to a network problem, wget will keep retrying until the entire file has been retrieved. If the server supports regetting, it will instruct the server to continue the download from where it left off. Here is an example:
wget http://nomads.gfdl.noaa.gov/dods-data/gfdl_cm2_1/CM2.1U-H2_SresB1_Y1/pp/atmos/ts/monthly/cl_A1.200101-210012.nc
Though wget is not installed by default on many systems, it is free from the GNU Project (http://www.gnu.org/software/wget/wget.html).

ftp

Though not available when the CM2.0 and CM2.1 files first appeared on the GFDL Data Portal, some server issues have since been resolved so that one can now download files via ftp (the Internet standard File Transfer Protocol). One can use ftp either in its command line version or through web browsers. To determine the path ftp should use to access a file of interest, one can point a browser to ftp://nomads.gfdl.noaa.gov/gfdl_cm2_0/ (for CM2.0) or ftp://nomads.gfdl.noaa.gov/gfdl_cm2_1/ (for CM2.1) and navigate through the directory structure. If desired, the URL path to the file can then be cut and pasted into the command line version of ftp, such as is done in the following example... (user inputs in bold)

ftp nomads.gfdl.noaa.gov
Connected to nomads.gfdl.noaa.gov (140.208.31.103).
220-*************************************************************************
220-*                               WARNING!                                *
220-*************************************************************************
220-* This is a United States Government computer system, which may be      *
220-* accessed and used only for official Government business by authorized *
220-* personnel.  Unauthorized access or use of this computer system may    *
220-* subject violators to criminal, civil, and/or administrative action.   *
220-*                                                                       *
220-* All information on this computer system may be intercepted, recorded, *
220-* read, copied, and disclosed by and to authorized personnel for        *
220-* official purposes, including criminal investigations.  Access or use  *
220-* of this computer system by any person, whether authorized or          *
220-* unauthorized, constitutes consent to these terms.                     *
220-*************************************************************************
220
Name (nomads.gfdl.noaa.gov): anonymous
331 Please specify the password.
Password: your_email_address
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> cd ./gfdl_cm2_1/CM2.1U-H2_SresB1_Y1/pp/atmos/ts/monthly/
ftp> get cl_A1.200101-210012.nc
local: cl_A1.200101-210012.nc remote: cl_A1.200101-210012.nc
227 Entering Passive Mode (140,208,31,103,65,151)
150 Opening BINARY mode data connection for cl_A1.200101-210012.nc (1555241228
bytes).
1555241228 bytes received in 156 secs (9.7e+03 Kbytes/sec)
ftp> quit

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