The DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures, Version 4 data set, distributed by the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) is now available through July 05 2018. Access to the data and documentation can be found through the data set landing page.
Data Set DOI: https://doi.org/10.5067/AN9AI8EO7PX0