This is created mostly for the Met Office internal use. Each of HadRT2.0, 2.1 and 2.3 comprises 8 files of temperature anomalies. The data start in January 1958 with the raw anomalies being up to May 1998, the filled data only to December 1997. The data are degree celcius anomalies from 1971-90 means. Like the Global and Hemispherical Mean Temp.
All values are integers.
Missing data are set to -32768. The month and year are stored at the start of each month. Hadley Centre Internal note no. A New Gridded Radiosonde Temperature Data Base and Recent Temperature Trends .