The initial strategy was to establish in Europe what is referred to as a HUB laboratory, that is, a source of well-characterized atmospheric air under low-pressure in containers called MELONs for other laboratories within Europe. Similar HUBS were foreseen to be established in North America, Australia, and Japan. In the course of TACOS, the WMO-GAW did not endorse the international HUB programme, but we pursued the proposed work. Summarized below are the main steps needed to accomplish associated deliverables D4-7.
The operational system for quality control of calibration and sample measurement relied on a new, very high precision analyzer LoFlo built in Australia by CSIRO and on new, presumably stable air containers called MELONs.
The LoFlo instrument was delivered and operational by month 20, but numerous problems delayed its proper functioning and it was sent out to Australia for repair. Measurements resumed by month 24, in agreement with D6.
The MELONs were not stable enough containers for CO2 determination. We stopped the measurement of MELONs and restarted it with high-pressure cylinders in the 3rd year, in agreement with D6. Additionally, a successful flask intercomparison programme ensured the completion of that deliverable (see WP3).