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These NCEP FNL (Final) operational global analysis and forecast data are on 0.25-degree by 0.25-degree grids prepared operationally every six hours. This product is from the Global Data Assimilation System (GDAS), which continuously collects observational data from the Global Telecommunications System (GTS), and other sources, for many analyses. The FNLs are made with the same model which NCEP uses in the Global Forecast System (GFS), but the FNLs are prepared about an hour or so after the GFS is initialized. The FNLs are delayed so that more observational data can be used. The GFS is run earlier in support of time critical forecast needs, and uses the FNL from the previous 6 hour cycle as part of its initialization.
The analyses are available on the surface, at 26 mandatory (and other pressure) levels from 1000 millibars to 10 millibars, in the surface boundary layer and at some sigma layers, the tropopause and a few others. Parameters include surface pressure, sea level pressure, geopotential height, temperature, sea surface temperature, soil values, ice cover, relative humidity, u- and v- winds, vertical motion, vorticity and ozone.
The archive time series is continuously extended to a near-current date. It is not maintained in real-time.
Note: Since this dataset now has a duplicate copy in AWS, we will stop continuous updates of this dataset in the summer 2025.
The NCEP operational Global Data Assimilation System surface flux grids are on a T574 Gaussian global grid. Grids include analysis and forecast time steps at a 3 hourly interval from 0 to 9 hours. Model runs occur at 00, 06, 12, and 18 UTC daily. For real-time data access please use the NCEP data server.
This dataset contains a subset of the level 1b or higher satellite data products used in the NCEP Global Data Assimilation System. These files can be used with the Weather Research Forecast (WRF) Data Assimilation (DA) system. However, they can be useful for a variety of applications, particularly where conventional data is scarce.
File sizes may vary due to operational changes.
NCEP ADP Global Upper Air and Surface Weather Observations (PREPBUFR format) are composed of a global set of surface and upper air reports operationally collected by the National Centers for Environmental Prediction (NCEP). These include land surface, marine surface, radiosonde, pibal and aircraft reports from the Global Telecommunications System (GTS), profiler and US radar derived winds, SSM/I oceanic winds and TCW retrievals, and satellite wind data from the National Environmental Satellite Data and Information Service (NESDIS). The reports can include pressure, geopotential height, temperature, dew point temperature, wind direction and speed. Report time intervals range from hourly to 12 hourly.
These data are the output from the PREPBUFR processing performed at NCEP, which is the final step in preparing the majority of conventional observational data for assimilation into the various NCEP analyses including the North American Model (NAM) and NAM Data Assimilation System (NDAS) unified grid-point statistical interpolation (GSI) analysis (the "NAM" and "NDAS" networks), the Global Forecast System (GFS) and Global Data Assimilation System (GDAS) unified grid-point statistical interpolation (GSI) analysis (the "GFS" and "GDAS" networks), the Rapid Refresh (RAP) unified grid-point statistical interpolation (GSI) analysis (the "RAP" network), the Real Time Mesoscale Analysis (RTMA) unified grid-point statistical interpolation (GSI) analysis (the "RTMA" network), and the Climate Data Assimilation System (CDAS) spectral statistical interpolation (SSI) analysis (the "CDAS" network).
This step involves the execution of series of programs designed to assemble observations dumped from a number of on-line decoder databases, encode information about the observational error for each data type as well the background (first guess) interpolated to each data location, perform both rudimentary multi-platform quality control and more complex platform-specific quality control, and store the output in a monolithic BUFR file, known as PREPBUFR. The background guess information is used by certain quality control programs while the observation error is used by the analysis to weigh the observations. The structure of the BUFR file is such that each PREPBUFR processing step which changes a datum (either the observation itself, or its quality marker) records the change as an "event" with a program code and a reason code. Each time an event is stored, the previous events for the datum are "pushed down" in the stack. In this way, the PREPBUFR file contains a complete history of changes to the data throughout all of the PREPBUFR processing. The most recent changes are always at the top of the stack and are thus read first by any subsequent data decoder routine. It is expected that the data at the top of the stack are of the highest quality.
The data provided here are also available in NetCDF and ASCII formats, which can be accessed by following the "Get a subset" link on the ds337.0 data access page. The NetCDF datafiles are converted from PREPBUFR format using the pb2nc utility in the Model Evaluation Tools (MET) software package.
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, dew point temperature, wind direction and speed. Data may be available at up to 20 mandatory levels from 1000 millibars to 1 millibar, 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).
Full daily data can be downloaded in BUFR or LITTLE_R format. Spatial subsets decoded into ASCII can also be selected by latitude/longitude or station ID.
These NCEP FNL (Final) Operational Global Analysis data are on 1-degree by 1-degree grids prepared operationally every six hours. This product is from the Global Data Assimilation System (GDAS), which continuously collects observational data from the Global Telecommunications System (GTS), and other sources, for many analyses. The FNLs are made with the same model which NCEP uses in the Global Forecast System (GFS), but the FNLs are prepared about an hour or so after the GFS is initialized. The FNLs are delayed so that more observational data can be used. The GFS is run earlier in support of time critical forecast needs, and uses the FNL from the previous 6 hour cycle as part of its initialization.
The analyses are available on the surface, at 26 mandatory (and other pressure) levels from 1000 millibars to 10 millibars, in the surface boundary layer and at some sigma layers, the tropopause and a few others. Parameters include surface pressure, sea level pressure, geopotential height, temperature, sea surface temperature, soil values, ice cover, relative humidity, u- and v- winds, vertical motion, vorticity and ozone.
The archive time series is continuously extended to a near-current date. It is not maintained in real-time.
NCEP ADP Global Surface Observational Weather Data are composed of surface weather reports operationally collected by the National Centers for Environmental Prediction (NCEP). The data includes land and marine surface reports received via the Global Telecommunications System (GTS). Variables recorded in the reports include pressure, air temperature, dew point temperature, wind direction and speed. Precipitation data has been decoded for the U.S. and Canada. Report intervals range from hourly to 3 hourly. These data are the primary input to the NCEP Global Data Assimilation System (GDAS).
Full daily data can be downloaded in BUFR or LITTLE_R format. Spatial subsets decoded into ASCII can also be selected by latitude/longitude or station ID.
