The Meteorological Assimilation Data Ingest System (MADIS) is dedicated toward making value-added data available from the National Oceanic and Atmospheric Administration's (NOAA) Earth System Research Laboratory (ESRL) Global Systems Division (GSD) (formerly the Forecast Systems Laboratory (FSL)) for the purpose of improving weather forecasting, by providing support for data assimilation, numerical weather prediction, and other hydrometeorological applications.
MADIS subscribers have access to an integrated, reliable and easy-to-use database containing the real-time and archived observational datasets described below. Also available are real-time gridded surface analyses that assimilate all of the MADIS surface datasets (including the highly-dense integrated mesonet data). The grids are produced by the Rapid Update Cycle (RUC) Surface Assimilation System (RSAS) that runs at ESRL/GSD, which incorporates a 15-km grid stretching from Alaska in the north to Central America in the south, and also covers significant oceanic areas. The RSAS grids are valid at the top of each hour, and are updated every 15 minutes.
The ESRL/GSD database is available via ftp, by using Unidata's Local Data Manager (LDM) software, through the use of OPen source project for Network Data Access Protocol (OPeNDAP (formerly DODS)) clients, or for the surface datasets through the Text/XML Viewer found below. Users can subscribe to the entire database, or ask for only particular datasets of interest.
Quality Control (QC) of MADIS observations is also provided, since considerable evidence exists that the retention of erroneous data, or the rejection of too many good data, can substantially distort forecast products. Observations in the ESRL/GSD database are stored with a series of flags indicating the quality of the observation from a variety of perspectives (e.g. temporal consistency and spatial consistency), or more precisely, a series of flags indicating the results of various QC checks. Users of MADIS can then inspect the flags and decide whether or not to ingest the observation.
MADIS also includes an Application Program Interface (API) that provides users with easy access to the observations and quality control information. The API allows each user to specify station and observation types, as well as QC choices, and domain and time boundaries. Many of the implementation details that arise in data ingest programs are automatically performed. Users of the MADIS API, for example, can choose to have their wind data automatically rotated to a specified grid projection, and/or choose to have mandatory and significant levels from radiosonde data interleaved, sorted by descending pressure, and corrected for hydrostatic consistency. The API is designed so that the underlying format of the database is completely invisible to the user, a design that also allows it to be easily extended to non-ESRL/GSD databases. The current version of the API supports the ESRL/GSD database, and also the database used in the National Weather Service (NWS) Advanced Weather Interactive Processing System (AWIPS) deployed at NWS weather forecast offices. The API can also be used as an OPeNDAP client to access data directly from the MADIS OPeNDAP server.
MADIS data files are compatible with AWIPS and AWIPS-like display systems and the analysis software provided by the Local Analysis and Prediction System (LAPS), the Weather Research and Forecasting (WRF) Model Variational Data Assimilation System, and the Atmospheric Model Evaluation Tool (AMET) provided to the air quality modeling community by the Community Modeling & Analysis System at the University of North Carolina at Chapel Hill.
They have also been used to initialize the Advanced Regional Prediction System (ARPS) , MM5 , and Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPStm) forecast models.
The ESRL/GSD MADIS database and API are freely available to interested parties in the meteorological community.