Common use of Observations do not exist Clause in Contracts

Observations do not exist. For verification with in situ data, missing data in space is inevitable. The CAMS service is interested in all sort of atmospheric composition observations both from in situ observations and ground-based remote sensing. CAMS is also very interested in observations of wet and dry deposition fluxes and precipitation chemistry as well as in dry-deposition velocities for a wide range of atmospheric constituents. Observations of pollen are also of interest for CAMS. In order to follow pollution episodes, track variability and to continuously monitor the performance of CAMS (including yearly system upgrades) it is necessary to have uninterrupted measurement records. Biases or excessive noise in data makes it difficult to achieve goals in validation of the CAMS products over the Arctic. The limited availability of near-real time data is often more limiting than the data quality. The current number of stations (IASOA) is limited given the large area concerned. For an adequate assessment of the transport of pollution to the Arctic during individual events, a larger number of ground stations would be helpful. The longer the data record, the more valuable. In particular for reanalysis evaluation, long time records are needed, ideally for the full period of the reanalysis. These often do not exist.