Long term monthly mean winds which Sadler derived from his collection of aircraft data (which we have in DS365.0.) and average rawindsonde data. The data are free from the ds208.0 data directory. The aircraft data were obtained from two sources: operational GTS reports collected in Honolulu and the FHWF; and aircraft logs from many routes which often were not reported over the GTS. The aircraft winds were summarized for each month in 5-degree latitude-longitude squares. The average monthly rawindsonde data were then combined with these in manual analyses of streamlines and isotachs. The 2.5- degree grids of wind speed and direction were manually read from these.

Unless you have a special interest in this dataset, DSS recommends that you use one of our reanalysis datasets, such as ds090.2. That's because those are based on a more complete collection of observations, improved analysis methods, and are provided in a common modern format (GRIB).