Remote Sensing Systems (RSS) is a private research company founded in 1974 by Frank Wentz. It processes microwave data from a variety of NASA satellites. Most of their research is supported by the Earth Science Enterprise program. The company is based in Santa Rosa, California.
They are a widely cited source of data, on the satellite temperature record. Their data is one source of evidence for global warming. Research by Carl Mears, Matthias Schabel, and Wentz, all of RSS, highlighted errors in the early satellite temperature records compiled by John Christy and Roy Spencer at UAH. The UAH data had previously showed no significant temperature trend, bringing the derived satellite data into closer agreement with surface temperature trends, radiosonde data and computer models. The UAH data is now closer to the RSS data but differences remain, for example the Lower Troposphere global average trend since 1979, RSS currently have +0.133K/decade while UAH have 0.140K/decade, while the mid troposphere difference is even more marked at 0.079K/decade and 0.052K/decade respectively. However, in a recent online YouTube video, Dr. Carl Mears, a senior scientist with the team behind the satellite data, explained how he believes his data set needed correction.
I would have to say that the surface data seems that it’s more accurate, because a number of groups analyze the surface data, including some who set out to prove the other ones wrong, and they all get more or less the same answer.