FAQ (CarbonTracker-CH4)
Q1: Can I use whatever I find on these pages?
Q2: How do I cite or acknowledge CarbonTracker work?
Q3: Why is CarbonTracker almost a year behind the current date?
Q4: How reliable are your products?
Q5: Where can I find more technical details on CarbonTracker?
Q6: I'm having trouble using the CarbonTracker results, where can I get help?
Q7: Are CarbonTracker results available for earlier releases?

Q1: Can I use whatever I find on these pages?
A1: Yes, all our results are free to be used by the public, scientists, and others. This includes all figures, numbers, data files, and even the Fortran source code. We encourage you to contact us with questions to ensure proper representation of the results, and we welcome any feedback and possibility for cooperation. Please acknowledge the CarbonTracker efforts when you use them in your scientific endeavors.

Q2: How do I cite or acknowledge CarbonTracker work?
A2: We ask that scientific work that relies heavily on CarbonTracker products is discussed with us before publication, to ensure proper representation of our work and a co-authorship if appropriate. For suggestions, go to citation.

Q3: Why is CarbonTracker almost a year behind the current date?
A3: CarbonTracker operates with about a one-year delay. There are several reasons for this, but the most important one is that there is a large delay between sampling and analysis of air samples from remote regions of the world. Once analyzed, quality control involves many persons and weeks of meticulous work. As a result, the CH4 mole fraction data for one year won't be available for our CarbonTracker modeling efforts until mid-summer the next. Preparing the CarbonTracker product itself requires another several months or more of modeling effort. While CarbonTracker results are lagged by a year, the raw flask and in-situ observations themselves are posted as soon as they are available, even as the quality-control efforts are underway. For the most up-to-date observational data, you can visit our interactive data visualization page at: http://www.esrl.noaa.gov/gmd/dv/iadv/.

Q4: How reliable are your products?
A4: The reliability of our products depends on the time and location for which they are assessed. North American results will generally be more reliable than those in other parts of the world due to the focus of CarbonTracker on this region and the availability of lots of observations. Also, results that are aggregated in space (e.g., whole continents) or time (e.g., monthly averages) will be more robust than local or instantaneous estimates. For the fluxes, formal uncertainty estimates on the estimated fluxes give some indication of the random errors we expect. However, systematic errors (e.g., biases) might dominate these at specific times and locations. Calculated mole fraction data will generally be reliable to within the specified model-data mismatch errors at each site, while mole fractions at other locations will be better constrained in the vicinity of assimilated sites. Assessing our products against independent data and quantifying their reliability is an important and ongoing task for the CarbonTracker team. We welcome any help and assistance, or feedback you might have on this issue. The CarbonTracker team will generally try to quote conservative formal uncertainty estimates on all website products.

Q5: Where can I find more technical details on CarbonTracker?
A5: For technical details beyond the documentation pages, we suggest you read the literature, visit our Collaborators page, see our release notes, or contact us.

Q6: I'm having trouble using the CarbonTracker results, where can I get help?
A6: Send us an email describing in detail what you are trying to do, and what problem you run into. We will make every attempt to help you along.

Q7: Are CarbonTracker results available for earlier releases?
A7: Yes. Previous versions of CarbonTracker will be archived and available here.