TCCON Data License 1. Downloading and/or using the Data will indicate your acceptance to enter into this license agreement. 2. This license grants you a perpetual, royalty-free, non-exclusive and non-assignable license to use the Data subject to the terms and restrictions set forth herein. 3. You have the right to modify and improve on the Data and said modification or improvement will be proprietary to you. In consideration of the royalty-free and collaborative nature of this license agreement, however, you agree to keep the authors informed of the modification and improvement to the Data and hereby grant to TCCON a non-exclusive, unconditional, irrevocable, perpetual and royalty-free right and license to use your modifications or improvements with proper acknowledgement to you as the source. 4. All other rights, including redistribution, display, and publishing adaptations are reserved. 5. At a minimum of 10 weeks prior to publication or presentation of works that include TCCON data, you must contact the individuals listed on the DOI landing page via email and provide a description of the intended publication or presentation. If the TCCON partner makes a significant intellectual contribution to the research, or TCCON data from a site is essential to the work, co−authorship would normally be expected. This should be discussed at an early stage in the work. If the individuals do not respond after 3 emails distributed over the 10 week period, the data are licensed under a cc-by 4.0 license. 6. All Data are assigned a digital object identifier (DOI). Use of these data to support a published work must include a citation that includes the data DOI. Use the standard citation format below, unless a different format is required for publication: Liu C., Wang, W., Sun, Y. 2018. TCCON data from Hefei, China, Release GGG2014R0. TCCON data archive, hosted by CaltechDATA, California Institute of Technology, Pasadena, CA, U.S.A. http://dx.doi.org/10.14291/tccon.ggg2014.hefei01.R0 Failure to comply with the terms of this license will result in forfeit of the right to use this data until the issue is resolved to the satisfaction of the appropriate TCCON PIs.