SHORT-TERM VARIATIONS IN ATMOSPHERIC CO2 AT NY-ALESUND, SPITSBERGEN, DURING SPRING AND SUMMER

Results From the continuous measurements of atmospheric carbon dioxide performed at Ny-Alesund, Spitsbergen are presented. The results are d iscussed with an emphasis on day-today variations during spring and ea rly summer. During all years studied, significant negative anomalies ( ''dips''), lasting for several days, have been observed in the data Fr om late May through July. The timing coincides with a draw down of dis solved carbon dioxide and nutrients in the surface waters of the North Atlantic observed by others. By using 3-dimensional trajectories, we follow the history of the air arriving in Ny-Alesund, and show that th e air, depleted in CO2, had been in contact with these waters. Combini ng the trajectories with a box model yields a simple Lagrangian model, and we demonstrate that the timing and magnitude of the dips are cons istent with the degree of CO2 saturation of the sea during April to mi d-June. In late June and July, the model indicates that a significant portion of the dips must have other causes, e.g., CO2 uptake in the te rrestrial biosphere Further south.