Note: NCEP decodes the precipitation from the GTS only for North America
Note: NCEP does some Quality Control (QC) on the data, and they set some QC flags in the reports to qualify, but not quantify their corrections. DSS believes that the QC for this surface data is not as rigorous as for the upper air data, which is likely due to its smaller role in the models.
WARNING: From sometime in Feb 2001 until sometime in Jul 2002, NCEP's GTS decoder generated wind speeds which are about twice as much as they should be from SYNOP data. This was due to the false assumption that the speeds came from the GTS in mps when they were actually knots. This applies to all reports except from the U.S., Russia and China. See the document 2xwind_final.pdf for a detailed description of the problem. Contact Doug Schuster for more information.
WARNING: From at least Apr 2000 to May 2002, NCEP's GTS decoder generated wind speeds which are about half as much as they should be from SYNOP data at Scandinavian, Irish, Portuguese, and Eastern European stations. This was due to the false assumption that the speeds came from the GTS in knots when they were actually mps. See the document scand_prob.pdf for a description of the problem.