Information Technology: GrADS INTEGRATED USER INTERFACE Maps, Charts, Animations Expressions, Functions of Original Variables General slices of { 4D Grids In Situ Obs Images User Definable, Extensible Arbitrary Domains Optimized for Typical Queries Accessing, SubsettingAnalyzing Visualizing InteractiveQuantitative

GrADS Analysis Model ENABLES VERY SOPHISTICATED ANALYSIS TASKS IN A HIGHLY ENCAPSULATED WAY Scientists only need to specify: dimension constraint list of data sets GrADS expression This unique, innovative approach to geophysical data analysis is the major reason for GrADS’ popularity.

Data Access/Interoperability/Analysis Level 0: FTP & basic Web capability. Level 1: DODS server concept: general data subsetting; metadata. Client can support data interoperability. Level 2: Analysis server. Uses GrADS unique encapsulated analysis capability. Example: Calculate – at the server! – sea level pressure anomaly over N. America when tropical Pacific SSTA > 1.0. Return the result – as data ! – to the desktop. Size of data sets: 3GB (Level 0) Data processed at server: 5 MB (Level 1) Returned to client: 10KB (Level 2)

Examples of GrADS Used on the Web to Deliver Images NCDC - CDC - CPC - DOLMS - DOLMS Ozone - DAO – Terra NCDC NCEP – CPC NOAA – CDC

Data Access/Interoperability/Analysis Level 0: FTP & basic Web capability. Level 1: DODS server concept: general data subsetting; metadata. Client can support data interoperability. Level 2: Analysis server. Uses GrADS unique encapsulated analysis capability. Example: Calculate – at the server! – sea level pressure anomaly over N. America when tropical Pacific SSTA > 1.0. Return the result – as data ! – to the desktop. Size of data sets: 3GB (Level 0) Data processed at server: 5 MB (Level 1) Returned to client: 10KB (Level 2)

DODS Client/server architecture http protocol Generic, flexible data model Metadata distribution capability “Open your data set with a URL instead of a filename”

Data Access/Interoperability/Analysis Level 0: FTP & basic Web capability. Level 1: DODS server concept: general data subsetting; metadata. Client can support data interoperability. Level 2: Analysis server. Uses GrADS unique encapsulated analysis capability. Example: Calculate – at the server! – 500 hPa geopotential height anomaly over N. America when tropical Pacific SSTA > 1.0. Return the result – as data ! – to the desktop. Size of data sets: 3GB (Level 0) Data processed at server: 5 MB (Level 1) Returned to client: 10KB (Level 2)

GrADS-DODS Analysis Server GRIB data NetCDF data GrADS data etc.. datasets in any format supported by GrADS Result cache holds temporary data (uploaded, generated by a previous operation, or transferred directly from another server) for use in remote analysis GrADS batch mode interface code DODS server libraries Server performs analysis operations manages sessions, translates dataset names Java servlet supports extended request types for analysis, upload internet DODS data and requests Joe Wielgosz: 5/25/00 DODS client libraries GrADS Matlab IDL etc.. data appears to client as local file, in a standard format (i.e, NetCDF, etc.) Client Encapsulated Analysis Requests

Summary: GrADS-DODS Server Share data: Enterprise-wide; Internet-wide --- data-format independent Data interoperability: Consistent metadata for many data types Distributed analysis: Reduces network load; improves interactivity Automation of analysis techniques: Analysis techniques can be captured in the form of scripts and provided on server and/or client

Desktop Weather Forecasting NCEP Global Weather Forecasts NCEP Global Weather Forecasts Global Weather Forecasts COLA GrADS-DODS Server GrADS-DODS Server Region-Specific Lateral BCs WWW PC-Based Regional NWP