US Government security requirements no longer permit CDDIS to offer data via traditional unencrypted anonymous ftp; this service was discontinued on October 31, 2020. All data are still available, however access must be via HTTPS or ftp-ssl.

Instructions with examples and our FAQ can be found at:

If you still have difficulty after reading and attempting the examples on that page, please contact us at

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CDDIS Data Citation and Acknowledgment

Citations: CDDIS is one of the Earth Observing System Data and Information System (EOSDIS) Distributed Active Archive Centers (DAACs), part of the NASA Earth Science Data and Information System (ESDIS) project. Datasets and related data products and services are provided by CDDIS, managed by the NASA ESDIS project. The CDDIS can be cited as follows:

C. Noll, The Crustal Dynamics Data Information System: A resource to support scientific analysis using space geodesy, Advances in Space Research,Volume 45, Issue 12, 15 June 2010, Pages 1421-1440, ISSN 0273-1177, DOI: 10.1016/j.asr.2010.01.018.

NASA data are freely accessible; however, when you publish these data or works based on the data, we request that you cite the datasets within the text of the publication and include a reference to them in your reference list. References to datasets, like the examples below, should have enough detail to provide readers of your publication with the ability to obtain the datasets and conduct their own studies based on your work. For complete provenance and understanding of specifically which parts of data were used and how; it also may be necessary to describe in detail, within the body of the publication, exactly how the data were used.

Examples of dataset citations:

Please note that a recommended citation is provided for many datasets, and when available, appears on the CDDIS webpage that describes the dataset. The elements contained in the recommended citation can be reorganized for compliance with a particular reference style that is specified by a publisher.

Acknowledgments: An acknowledgment is a general statement that can be used to provide credit to the NASA EOSDIS CDDIS for data, assistance, or reviews that have been provided. Please include such statements, either where the use of the data or other resource is described, or within the Acknowledgments section of the publication. An example of an acknowledgment statement is included below.