After looking it up quickly, it seems that one step really was raising the buoy values by a single constant, but this was only a tiny part of a much more involv

After looking it up quickly, it seems that one step really was raising the buoy values by a single constant, but this was only a tiny part of a much more involved process. "The SSTs from ships or buoys were accepted (rejected) under a QC criterion that observed SSTs differ from the first-guess SST from ERSST.v3b by less (more) than 4 times standard deviation (STD) of SST (Smith and Reynolds 2003). The ship and buoy SSTs that have passed QC were then converted into SSTAs by subtracting the SST climatology (1971–2000) at their in situ locations in monthly resolution. The ship SSTA was adjusted based on theNMATcomparators; buoy SSTA was adjusted by a mean difference of 0.12 C between ship and buoy observations (section 5). The ship and buoy SSTAs were merged and bin-averaged into monthly ‘‘superobservations’’ on a 28 3 28 grid. The number of superobservations was defined here as the count of 28 3 28 grid boxes with valid data. The averaging of ship and buoy SSTAs within each 28 3 28 grid box was based on their proportions to the total number of observations. The number of buoy observations was multiplied by a factor of 6.8, which was determined by the ratio of randomerror variances of ship and buoy observations (Reynolds and Smith 1994), suggesting that buoy observations exhibit much lower random variance than ship observations. The SSTAs of superobservations were further decomposed into low- and high-frequency components. The low-frequency component was constructed by applying a 268 3 268 spatial running mean using monthly superobservations where the sampling ratio is larger than 3% (five superobservations). An annual mean SSTA was then defined with a minimum requirement of two months of valid data. The annual mean SSTA fields were screened and the missing SSTAs were filled by searching the neighboring SSTAs within 108 in longitude, 68 in latitude, and 3-yr in time. The search areas were tested using ranges of 158–208 in longitude, 58–108 in latitude, and 2–5 yr..." http://journals.ametsoc.org/doi/10.1175/JCLI-D-14-00006.1 http://journals.ametsoc.org/doi/10.1175/JCLI-D-14-00006.1 It would be much easier to understand if they just showed us the code...