Visualization software used at DKRZ
The traditional method to look at climate model data is to select two dimensional slices of the data volume and to display physical quantities using isolines or filled contours. Vector quantities are displayed using arrows or streamlines. An overlayed geographical map simplifies the interpretation of the graphics.
For these 2-D applications, DKRZ recommends GrADS and NCAR Graphics.
The large data volumes produced by todays climate models are not easy to
overview and to analyze. The use of 2 D graphical tools within a time dependent
3 D data volume can be limiting in respect to the understanding of 3 D processes
or to find the essentials of the data. As a help to solve this problem, interactive
3 D visualization tools like AVS/Express and Vis5D
are used.
NCAR Graphics
NCAR-Example (GIF,17 KB)
A graphics package especially made for the needs of meteorologists had been developed at NCAR, the National Center for Atmospheric Research in Boulder, Colorado: NCAR Graphics.
ncl is a command language and scripting interface which is available for free in binary format.
The traditional interface NCAR Graphics 4.3 is a FORTRAN and C subroutine library as well as the tools neccessary to display and convert the graphics metafiles. The user has to write a FORTRAN application or to apply a FORTRAN program written by somebody else in order to use NCAR Graphics. This part of the NCAR software is available for free in source or binary format.
One of the most important advantages of NCAR Graphics compared to other utilities is the level of detail of all elements of the graphical output which can be influenced by the user. Of course it will need some time until new users of the package know the most important routines, utlilities and parameter settings.
The interactive documentation for NCAR Graphics Version 4.3 contains a detailed description of the software.
GrADS
GrADS Graphic window (GIF,36 KB)
The Grid Analysis and Display System is a public domain software package. It is designed especially for gridded meteorological data and meteorological station data. Most data produced at DKRZ are gridded and can be analyzed and plotted with GrADS. While the GrADS data model supports time dependent 3 D data volumes, only one and two dimensional display types are available.
GrADS provides an interactive command language and scripting interface. This allows the quick development of interactive applications to fit the needs of end users. The built in animation capabilities help to visualize time dependent processes.
The software is available for free in binary and source formats at the GrADS Homepage (in Maryland, USA).
Vis5D
The Vis5D graphical user Interface (GIF,106 KB)
Vis5D ("Visualization of 5 Dimensional data"), is also a public domain visualization program designed for meteorological model data. 5 D means: the data is three dimensional, time dependent and can contain several physical quantities. The user interface of Vis5D is simple: it consists of a 3 D viewport and buttons to create the desired tools for each physical quantity.
Vis5D doesn't necessarily require powerful 3 D hardware to run, but it makes life much easier if you have it. Compared to other 3 D visualization tools, Vis5D is well suited for real time application.
Vis5D has been developed at the Space Science and Engineering Center (SSEC) in Madison/Wisconsin as part of the visualization project . Now the software source is maintained and distributed for free by the Vis5D+ project.
AVS/Express (Advanced Visual Systems)
AVS/Express graphical user interface (JPG, 110kB)
AVS/Express is not only a 3 D visualization application - it is potentially a visual application development environment.
With AVS/Express, a visualization application can be developed without hand writing any program code. A Network Editor allows visual programming: modules from a module library can be copied to the working area and connections between these modules can be created. The resulting network controls the data flow. Virtually anything can be done with AVS/Express, but it could really take some effort get the desired results.
AVS/Express is a commercial software product. More information on AVS/Express can be found at AVS Inc. and at the International AVS Centre.