ESCI/CMIP5 Tools - Jeudi 2 octobre CMIP5 Tools Earth System Grid-NetCDF4- CMOR2.0-Gridspec-Hyrax …

ESCI/CMIP5 Tools - Jeudi 2 octobre Fédération de sites Earth System Grid

ESCI/CMIP5 Tools - Jeudi 2 octobre Earth System Grid en 3 Tiers.

ESCI/CMIP5 Tools - Jeudi 2 octobre Architecture Earth System Grid

ESCI/CMIP5 Tools - Jeudi 2 octobre Authorization Use Case 1: BADC User

ESCI/CMIP5 Tools - Jeudi 2 octobre Authorization Use Case 1: CCSM Admin

ESCI/CMIP5 Tools - Jeudi 2 octobre Authorization Use Case 1: BADC User

ESCI/CMIP5 Tools - Jeudi 2 octobre Metadata and query

ESCI/CMIP5 Tools - Jeudi 2 octobre NetCDF 3 Classic Model 11/6/2007HDF and HDF-EOS Workshop XI, Landover, MD

ESCI/CMIP5 Tools - Jeudi 2 octobre 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 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 Horizontal grids in use in ESMs

ESCI/CMIP5 Tools - Jeudi 2 octobre 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 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 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 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.