  We present an improved Global Sky Model (GSM) of diffuse galactic radio
emission from 10 MHz to 5 THz, whose uses include foreground modeling for CMB
and 21 cm cosmology. Our model improves on past work both algorithmically and
by adding new data sets such as the Planck maps and the enhanced Haslam map.
Our method generalizes the Principal Component Analysis approach to handle
non-overlapping regions, enabling the inclusion of 29 sky maps with no region
of the sky common to all. We also perform a blind separation of our GSM into
physical components with a method that makes no assumptions about physical
emission mechanisms (synchrotron, free-free, dust, etc). Remarkably, this blind
method automatically finds five components that have previously only been found
"by hand", which we identify with synchrotron, free-free, cold dust, warm dust,
and the CMB anisotropy, with maps and spectra agreeing with previous work but
in many cases with smaller error bars. The improved GSM is available online at
github.com/jeffzhen/gsm2016.
