Upper Air Rawinsonde Observations is DSI-5681, archived at the National Climatic Data Center (NCDC). Major parameters which make up this file are number of levels, pressure of level, height of level, temperature of level, relative humidity of level, wind direction and speed of level. Data set 5681 is a composite data set that NCDC built from upper air data received from the U.S. Air Force Global ... Weather Center (GWC) and the U.S. NOAA National Weather Service's National Meteorological Center (NMC). GWC is now the Air Force Weather Agency (AFWA), and NMC is now the National Centers for Environmental Prediction (NCEP). NCDC converted their data separately into DSI-5681, then merged the two giving priority to the NMC source. Related files include upper air standard levels and upper air (rawinsonde) observations.