NCEP ADP Global Upper Air Observational Weather Data are composed of global upper air weather reports operationally collected by the National Centers for Environmental Prediction (NCEP). These include radiosondes, pibals and aircraft reports from the Global Telecommunications System (GTS), and satellite data from the National ... Environmental Satellite Data and Information Service (NESDIS). The reports can include pressure, geopotential height, air temperature, dewpoint temperautre, wind direction and speed. Data may be available at up to 20 mandatory levels from 1000mb to 1mb, plus a few significant levels. Report intervals range from hourly to 12 hourly. These data are the primary input to the NCEP Global Data Assimilation System (GDAS), which is used to create the NCEP Final Tropospheric Analyses (FNL). .