Is there any website where can I download ECHAM climate model data?
Where to find the data
Looking for ECHAM provides you with several sets of ECHAM model results: here. You get at least the ECHAM data for the second to fourth IPCC assessment reports and some more data sets.
You need to have a login. It can be easily created.
Information on the structure of the data at CERA
You have projects, experiments, and data (sets).
Projects contain overall information on the model setup, on the data producers, and on the validation.
One experiment can summarize several data sets. For a coupled climate model this could mean, that the physical ocean, the biogeochemical ocean, the meteorology, and the atmospheric chemistry are saved as individual data sets, which are than summarized as one experiment.
Experiments can have a doi (digital object identifier). Thus, they are easily citeable in scientific publications and long-term available.
Access data at the WDCC
You can directly download data via the web-interface. As an alternative, you can use jblob, which is a command line utility for downloading data from the WDCC. Jblob also has some options to pre-process data on the DKRZ servers prior to download it -- which might reduce your file size. For both access pathways you need to have a valid login.