GLOBALVIEW-CO2C13, 2009 is the 3rd annual update of this product. Since August 2007, GLOBALVIEW-CO2C13 has been accessed more than 290 times by users from over 20 countries. The GLOBALVIEW-CO2C13 FTP server averages 11 product requests monthly. This update includes 76 extended records derived from INSTAAR/ESRL observations. Data updates through 2008 have been used to derive GLOBALVIEW-CO2C13, 2009. The data product includes extended records from January 1, 1994 to January 1, 2009.

GLOBALVIEW-CO2C13 is a product of the Carbon Cycle Greenhouse Gases Group of the National Oceanic and Atmospheric Administration (NOAA), Earth System Research Laboratory (ESRL), Global Monitoring Division (GMD). Isotopic measurements from NOAA air samples are made by the University of Colorado (CU), Institute of Arctic and Alpine Research (INSTAAR), Stable Isotope Laboratory (SIL).

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This product is derived using University of Colorado (CU), Institute of Arctic and Alpine Research (INSTAAR) data only. At the moment, inconsistencies among observations made by different laboratories are not well understood [e.g., Masarie et al., 2001] and often exceed the 0.01‰ target level of agreement required to address current scientific objectives. Once laboratories can demonstrate and maintain the desired level of agreement and if there is interest within the carbon cycle modeling community, the measurement community can develop a cooperative data product that utilizes high precision δ13C (CO2) measurements made by other laboratories.

GLOBALVIEW-CO2C13 is derived from measurements but contains no actual data. To facilitate use with carbon cycle modeling studies, the measurements have been processed (smoothed, interpolated, and extrapolated) resulting in extended records that are evenly incremented in time. Be aware that information contained in the actual data may be lost in this process. Users are encouraged to review the actual data in the literature, in data archives (CDIAC, WDCGG), or by contacting the participating laboratories.

GLOBALVIEW-CO2C13 is derived using the data extension and data integration techniques described by Masarie and Tans, [1995]. These techniques were developed using CO2 measurements from the NOAA ESRL cooperative air sampling network.

The impetus for the work done by the many cooperating organizations and institutions is to make atmospheric measurements of trace gas species that will facilitate a better understanding of the processes controlling their abundance. These and other measurements have been widely used to constrain atmospheric models that derive plausible source/sink scenarios. Serious obstacles to this approach are the paucity of sampling sites and the lack of temporal continuity among observations from different locations. Consequently, there is the potential for models to misinterpret these spatial and temporal gaps resulting in derived source/sink scenarios that are unduly influenced by the sampling distribution. GLOBALVIEW-CO213 is an attempt to address these issues of temporal discontinuity and data sparseness and is a tool intended for use in carbon cycle modeling.