Presentation on theme: "ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 1 CMIP5 Tools Earth System Grid-NetCDF4- CMOR2.0-Gridspec-Hyrax …"— Presentation transcript:
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 1 CMIP5 Tools Earth System Grid-NetCDF4- CMOR2.0-Gridspec-Hyrax …
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 2 Fédération de sites Earth System Grid
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 3 Earth System Grid en 3 Tiers.
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 4 Architecture Earth System Grid
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 5 Authorization Use Case 1: BADC User
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 6 Authorization Use Case 1: CCSM Admin
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 7 Authorization Use Case 1: BADC User
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 8 Metadata and query http://dycore.ucar.edu/query/modelComparison.htm
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 9 NetCDF 3 Classic Model 11/6/2007HDF and HDF-EOS Workshop XI, Landover, MD
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 10 Enhanced data model for netCDF4 A file has a top-level unnamed group. Each group may contain one or more named subgroups, user-defined types, variables, dimensions, and attributes. Variables also have attributes. Variables may share dimensions, indicating a common grid. One or more dimensions may be of unlimited length. Dimension name: String length: int isUnlimited( ) Attribute name: String type: DataType values: 1D array Variable name: String shape: Dimension[ ] type: DataType array: read( ), … Group name: String File location: Filename create( ), open( ), … Variables and attributes have one of twelve primitive data types or one of four user-defined types. DataType PrimitiveType char byte short int int64 float double unsigned byte unsigned short unsigned int unsigned int64 string UserDefinedType typename: String Compound VariableLength Enum Opaque
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 11 Why CMOR-2 ? Original CMOR accommodated only data stored on Cartesian longitude-latitude grids. Written in FORTRAN 95 mainly by a climate scientist with limited time to maintain and extend it. CMOR-2 Can write Output on model “native" grids that are not Cartesian longitude-latitude. Station data (needed, for example, by the HTAP project), including metadata for station names and station locations Written in C (with optional FORTRAN 95 interface) by a computer scientist with ongoing commitment to support it. The calls to CMOR-2 are identical to those in CMOR except as needed to make use of the new extended capabilities. NetCDF4 for compression recompile all clients
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 12 Horizontal grids in use in ESMs
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 13 Dependencies across data from many models Model intercomparisons have become a primary research avenue for consensus and uncertainty estimates of anthropogenic climate change. This plot is a composite across the entire AR4 archive. Model chaining: output from one model used as forcing for another “downstream”.
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 14 Grid metadata To be of use by models as well as for interpreting model output, the standard must enable vector calculus and conservative regridding. The following aspects of a grid must be included in the specification: distances between gridpoints, to allow differential operations; angles of grid lines with respect to a reference, usually geographic East and North, to enable vector operations. One may also choose to include an arc type (e.g “great circle”), which specifies families of curves to follow while integrating a grid line along a surface. areas and volumes for integral operations. This is generally done by defining the boundaries of a grid cell represented by a point value. Below we will also consider fractional areas and volumes in the presence of a mask, which defines the sharing of cell between two or more components.
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 15 Projections polar_stereographic, lambert_conformal, mercator, none, etc. May need auxiliary information: e.g north_pole attribute that is not the geographic North Pole. (a “rotated pole” is not a mapping or a projection but an attribute!) Sometimes stored under grid_mapping. The tripolar grid of Murray (1996) is composed of tiles with different projections: two polar stereographic projections with different poles, and a spherical coordinate system below the polar latitude.
ESCI/CMIP5 Tools - Jeudi 2 octobre 2008 16 AR5 open issues and questions What are the set of runs to be done and derived from that the expected data volumes we can expect? Expected participants – where will data be hosted? (Who is going to step up and host the data nodes, and provide the level of support expect in terms of manpower and hardware capability.) minimum software and hardware data holding site requirement (e.g., ftp access and ESG authentication and authorization) skilled staff help desk AR5 archive to be globally distributed with support for WG1, WG2, and WG3. Will there be a need for a central (or core) archive and what will it look like? Replication of holdings - disaster protection, a desire to have a replica of the core data archive on every continent, etc. Number of users and level of access – scientist, policy makers, economists, health officials, etc.
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