How does it work so fast?

A great effort has been made, to keep JCM very efficient and compact, both considering users with slower computers and web connections, and because the instant "mechanical" response to adjustments helps to demonstrate cause-effect interactions.

Some key features that make this possible are described by the links below.

Efficient calculation methods
Eigenvector prop/step/ramp functions for the core carbon and climate models.

Interaction between Modules and Panels
Only run modules / panels which are both needed for screen output, and have been changed by the user since the last calculation.

Data Compression
Historical / Scenario / Climate-pattern data is compressed to one-byte per number, thus minimising download time.

Model and graphics in one tool

There are many "visualisers" written in java, which simply plot data created using model code in another language (typically fortran), transferred by intermediate text files. This is intrinsically very inefficient -saving and loading data files may take longer than the science calculations, especially if working across the web.

Whereas in JCM, the model and graphics are both written in the same language, and so interact much more smoothly and efficiently. Moreover, by giving people the tool (the model) rather than the product (the data), the scope is much wider, and the package size is kept to a minimum.