A combined study of micrometeorological flux measurement of carbon dioxide (CO₂) and methane (CH₄) and measurement of their stable carbon isotopes at a paddy field indicated that CH₄ production can affect not only greenhouse gas budget of wetland ecosystem but also isotopic signature of respired CO₂.

We investigated the interannual variability of the partial pressure of carbon dioxide (pCO₂) in the surface waters of the western subarctic gyre (155°E to 165°E, 48°N to 53°N) and the Alaska Gyre (AG, 195°E to 210°E, 45°N to 52°N) for a period of 9 years. We used automated measurements of pCO₂ in the surface water (pCO_2sw) and the air (pCO_2air) as well as sea surface temperature (SST) and salinity (S) obtained from the Japanese-Canadian joint Volunteer Observing Ship (VOS) program. We observed annual trends in the pCO_2sw and based on simple least square fit to observed data, the surface waters in the WSG showed a gradual pCO_2sw increase of 0.4 ppm yr^-1 which was three times larger than in the AG (1.8 ppm yr^-1) for the 9-year period. In the WSG, this was about half of the estimated atmospheric pCO₂ increase for the whole period (10 ppm or 1.2 ppm yr^-1), whereas gas exchange explained much of the increase in the AG (pCO_2air increased 1.6 ppm yr^-1). Interestingly, the two gyres showed opposite annual trends in the SST and salinity and in the WSG we observed a salinity and SST increase of 0.018 yr^-1 and 0.07°C yr^-1 (0.56°C for the whole study period), respectively, whereas we observed a small freshening of 0.015 yr^-1 and a cooling trend of about 0.11°C yr^-1 in the AG. We examine the possible mechanisms to explain the annual trends in pCO₂, based on the observed changes in SST and salinity as well as observations made by other investigators.

We used recent ocean bomb radiocarbon inventory estimates for the time of GEOSECS (mid-1970s) and WOCE (mid-1990s) from Peacock [2004] and Key et al. [2004], corrected for missing ocean areas [Naegler 2005], to develop a new parameterisation of the piston velocity – wind speed relationship of CO₂ air-sea gas exchange. For monthly mean climatological winds on a 1°x1° grid, this results in a gas exchange parameter a_q,660 of 0.32±0.04 (in cm hr^-1 m^-2 s²) and a net oceanic CO₂ uptake of 1.53±0.18 PgC/yr for the mid-1990s, when using the Takahashi et al. [2002] pCO₂ data.

We have carried out the tank experiment in the low-temperature room to clarify the CO₂ gas exchange mechanism between the sea and the overlying air during the sea-ice formation process. The air CO₂ concentration in the headspace of the tank began to increase simultaneously with the sea-ice formation and growth. The CO₂ flux was with in the range from 2.1x10^-4 to 4.5x10^-4 g-C m^-2 hour^-1 at ice thickness of 5cm. The CO₂ flux was mainly dependent on the brine salinity in the upper layer of sea-ice, which suggests that CO₂ was released from the brine in the sea-ice, and transported to the atmosphere.

The measurement results of CO₂ average concentration obtained in the atmospheric column at the Issyk-Kul station (IK) (42.6⁰N, 77.0⁰E, 1650 m a.s.l.) in 1980-2004. A comparison was made with the MBL data (for the IK latitude) presenting mean zonal CO₂ concentrations reduced to the sea level and with the measurement results of CO₂ concentrations obtained at KZD (44.45⁰N, 77.57⁰E, 412 m a.s.l) and KZM (43.25⁰N, 77.88⁰E, 2519 m) sites. The IK station is about 100 km distant from KZM and 220 km distant from KZD.

In the CHIOTTO project (http://www.chiotto.org) as part of the CarboEurope cluster of projects (http://www.carboeurope.org) a network of 8 tall tower stations has been set up in Europe. Most towers are equipped for continuous high precision measurements of ambient CO₂, CH₄, CO and SF₆. Some stations are also equipped for continuous measurement of ²²²Rn and flask sampling. First measurement results are presented and evaluated using forward and inverse model calculations.

We consider the ability of an inverse model framework and observations from the Cooperative Air Sampling Network to resolve fluxes at various scales over a 20-year period. During this time the observational network underwent a significant expansion. We calculate the resolution kernel to determine which continental/ocean basin scale fluxes may be resolved, and which spatial aggregations of fluxes are well resolved. In addition, the resolution kernel is used to obtain insights into how source regions are constrained by individual measurement sites.

The Atlantic's central role in the global thermohaline circulation suggests that this basin should be an important laboratory for understanding the ocean carbon cycle and possible temporal variations in that cycle. Here we present the set up and results from an oceanic box model inversion which focuses on the transport and divergence of total inorganic carbon (TIC) and anthropogenic carbon within the Atlantic.

Begur-Pals site (41,58ºN, 3,14ºE, Catalonia, Spain) is weekly sampled for CO₂ and other GHG (CH₄, CO, N₂O, SF₆) since January 2000. This CO₂ serial data shows at the middle of each summer a sudden increase and decrease of the CO₂ peak. It is a process that can be either attributed to a highest transpiration rate than ecosystem production due to the lack of summer precipitation, to biomass burning from Mediterranean forest fires, to tourist activities in the coast, or to CO₂ pumping from waters in the Western Mediterranean sea (according to wind backtrajectories). A sampling strategy using sites with high towers with continuous measurements has been developed. Sites are placed at the vortexes of a rhombus: two extremes are continental sites in the center of the Ebro’s watershed and a marine site is located in the Menorca Island. The other two are high towers in the Catalonian coast.