Combinations of different channels of individual Microwave Sounding Unit (“MSU”) measurements have been used to generate a record of estimated atmospheric temperature change back to 1979, the “MSU Temperature Record”. The complex vertical weighting functions relating the the various channels of the MSU to atmospheric temperatures complicate the interpretation of the MSU data. Moreover, while MSU measurements are available back to 1979, a single, continuous long record does not exist. Rather, measurements from different satellites have been combined to yield a single long record, further complicating the interpretation of the MSU record. Direct comparisons of the MSU Temperature Record with the surface temperature record are therefore difficult. More information on the MSU Temperature Record can be found here.