How to access the database server through four IPCC OPeNDAP.
PCMDI’s IPCC fourth EA model database output contains a large set of data generated by groups of different models to support the fourth assessment report. It is available in the form of the output file from the Portal IPCC model as a collection of datasets from OPeNDAP servers.
OPeNDAP is a software framework that allows access to scientific data from a distance. OPeNDAP is the core of the HTTP protocol specifications that describe how clients and servers to send data over the network. There are a number of clients and servers are available that understand, DAP, server PyDAP adjustment used to model the output database of the EA fourth IPCC.
Server provides access to data sets IPCC. Set data aggregation, collection of relevant data files to a virtual file. In general, the data set consists of all variable data for a particular combination of models, scenarios, working time, the experimental frequency and submodel (ocean or atmosphere). The dataset is a file XML CDMS.
Note that there is a charge for accessing data through OPeNDAP servers. Speed ??networks, protocols HTTP Server and delay combine to limit the access speed of reading directly from disk. If you intend to access very large amounts of data, or using the same data multiple times, probably more efficient to download the appropriate files to your computer via the portal. Moreover, because the data sets can consist of hundreds of gigabytes of data, there is a limit imposed on the server the size requests access (see Access to the IPCC fourth EA data using CDMS).
Using a Web browser to view EA’s fourth IPCC Portal
To use the DAP server to see the directory structure, you will need a user account IPCC portals. (Note: .. directory can also be seen here, without the user’s account, however, the GOP-server provides additional information)
Starting from the initial list of the IPCC, by entering a username and password. You will see the database script. Click on any of the lists to see the model presented in this scenario, for example, NCAR CCSM3 model. Clicking on the model of the directory provides a list of available data for the models and scenarios. The name of the dataset is structured as follows:
For example, data for the model of NCAR CCSM3, the climate of the 20th century, scenarios, run every 6 months atmospheric data in the dataset:
See the description of the portal site FTP to explain the different descriptions.
Choose one (Dataset structure description) DDS link to see a structured list of variables, data types and structures to coordinate the data set.
DAS (Data structure of feature sets) shows the reference variables and attributes in the data set.
When you click the name of what she displays a form that can be used to access data in the form of ASCII. (Note: the current writing on this form is not working properly.)
EA’s fourth IPCC data access through CDMS2
IPCC datasets can be accessed via the system has CDAT cdms2 CDAT has been compiled with the library customer OPeNDAP. Form of open competition are:
F = cdms2.open («://username:password @ esgcet.llnl.gov/dap/ipcc4 ///. XML»)
After opening the data may be available OPeNDAP normal CDMS. However, because some very large data sets – 100 GB – no limit on the amount of data that can be accessed through a single operation. Current limit is set to 64MB, but can be changed in the future. There is no limit to the amount of access to data that can be done in one session.Tags: database output, database script, ea model, note directory, protocol specifications