NMC GTS Surface Meteorological Observations - Land is digital data set DSI-6104, archived at the National Climatic Data Center (NCDC). Data was provided from the Global Telecommunications System (GTS) by NMC, which was the old National Meteorological Center of the U. S. NOAA National Weather Service. NMC is now the National Centers for Environmental Prediction (NCEP). This data is a collection of ... observations used to initialize the NMC Global Forecast Model. NMC sent the raw data to NCDC, where it was held in temporary data sets DSI-9610 and DSI-9611. The raw data were split into separate files by data type: DSI-6103 Temp and Temp Ship, DSI-6104 Synop (Synoptic Hours 00, 06, 12, 18 UTC) (Intermediate Hours 03, 09, 15, 21 UTC), DSI-6105 Ship, DSI-6106 AIREP, DSI-6107 SIRS and SATWIND, DSI-6108 BOGUS. Decoding information for these files is provided elsewhere in this documentation. More information about these file formats and codes can be found in NMC Office Note 29/124 and World Meteorological Organization (WMO) Publication No. 306 Manual on Codes - International Codes. These data were subject to various degrees of automated quality control by NMC. NCDC reformats the data without changing any values. Therefore the users must be prepared to perform their own quality checks.