Measurements of atmospheric O₂/N₂ ratios and CO₂ concentrations can be combined to form the tracer Atmospheric Potential Oxygen (APO), reflecting primarily ocean biogeochemistry and atmospheric circulation. Building on the work of Stephens et al. [1998], we present a new set of APO observations including shipboard collections from the equatorial Pacific. Our data show a smaller interhemispheric gradient than observed in past studies and a substantial APO maximum around the equator. Following a modeling approach developed by Gruber et al. [2001], we compare these observations with APO fields generated by a set of oceanic and atmospheric models. Overall, our model results agree well with observations, but small differences suggest that modeled north-south transport may be too vigorous, air-sea fluxes may be too coarsely resolved in some regions, and seasonal trapping of surface fluxes may be excessive in some model locations.

To understand the difference in CO₂ behavior between planetary boundary layer (PBL) and free troposphere (FT), we conduct CO₂ measurements using a small aircraft and a tower at the forest area in West Siberia. More than 120 vertical CO₂ profiles were observed by newly developed small CO₂ measurement device. Seasonal amplitude in PBL (36.9 ppm) is two times larger than that in FT (15.7 ppm). Diurnal variation in CO₂ profile is affected not only by PBL growth but also by horizontal advection and entrainment flux from FT to PBL.

We present preliminary results from hydrogen isotopic measurements in atmospheric methane obtained from the NOAA CCGG Cooperative Air Sampling Network. Recent developments at INSTAAR, University of Colorado have brought on line the capability to measure hydrogen deuterium ratios in methane using continuous flow mass spectrometry coupled with an extraction combustion sample preparation system. Preliminary results show reproducibility of cylinder air samples to less than ± 2 ‰. Data from several months of samples from six network sites are presented, including data from: Barrow and Cold Bay, Alaska, U.S.A; Tutuila American Samoa; Black Sea, Constanta, Romania; Park Falls Wisconsin, U.S.A.; and Baltic Sea, Poland.

We present a statistical analysis of aircraft and surface measurements of the CO₂ mixing ratio over the US Rocky Mountains during 1993 – 2002 at latitudes close to that of the Issyk-Kul station in Kyrgyzstan. Average characteristics of the CO₂ mixing ratio and its annual variations show only small height variability in the troposphere over well mixed mountain regions. Comparison of Issyk-Kul optical data with US aircraft and surface measurements shows satisfactory agreement. Also some differences at low altitudes were obtained owing to possible regional differences between mountain regions of Central Asia and USA.

The present study made an attempt to analyse the extent of natural and anthropogenic carbon in the atmosphere and oceans particularly with reference to Indian Ocean as major human clusters are responsible for climate change. The study also probes into the spatial patterns and temporal variation using the time series data collected from secondary sources.

We have developed a new data screening technique using an atmospheric transport model and an inverse model. Using this technique, we can use original (not smoothed) observational data for the inversion method. This means that we can enlarge the number of observational data for inversion method and we can estimate carbon dioxide (CO₂) flux history consistently in long period in accordance with the number of the observational sites.  

Systematic measurements of the CO₂ concentration and its carbon isotopic ratio (d¹³C) have been carried out at 7 locations in China since March or July 2003. Seasonal cycles of the CO₂ concentration and d¹³C were clearly observable, especially at Longfengshan, Shangdianzi and Fukang. The d¹³C value of source producing the seasonal CO₂ cycle at each site, d_S, was estimated from the observed CO₂ and d¹³C seasonal cycles.  The average value of d_S derived for the 6 sites was calculated to be -25.6 (±1.8) ‰, which is larger than those observed at mid-latitudes in the western Pacific region, probably due to smaller discrimination of ¹³C by C₄ plants in the continent of China.