A new research project has started in 2003 to develop Continuous CO₂ Measurement Equipment (CME) and Automatic Air Sampling Equipment (ASE) for commercial airlines. CMEs are planning to be installed on five aircrafts and fly to South East Asia, East Asia, Europe, North America, Pacific and Australia. Routine air sampling by ASE will be done twice a month between Japan and Australia. After issuing the certification, first observation flight by Boeing 747-400 will be conducted in October, 2005. Preliminary observation by small research aircraft indicates that CME produces reasonable results.

Stable isotope measurements of atmospheric carbon dioxide from the CSIRO global flask sampling program with improved traceability to the international primary reference material VPDB (Vienna Pee Dee Belemnite), and with improved uncertainty estimates, are presented. The measurements have been used with an improved time dependent inversion model to reassess terrestrial and oceanic contributions to the interannual variability in atmospheric CO₂.

An inverse modeling system has been developed based on the Bayesian principle for estimating the carbon fluxes of the 48 regions globally and 28 regions over North America in monthly steps for 2003 using CO₂ concentration measurements at 95 atmospheric baseline stations and with regularization using remote sensing-based surface flux field. Preliminary inversion results of global carbon flux and a carbon flux field over North America have been obtained.

Measurements of atmospheric O₂/N₂ ratio and CO₂ concentration are presented over the period 1989 to present from the Scripps Institution of Oceanography global flask sampling network. The data are used to make estimates of land and ocean sinks over various time scales. The oceanic and land biotic sinks are estimated to be 1.9±0.6 (ocean) and 1.2±0.8 Pg C/yr (land) over the period Jan. 1990-Jan. 2000 and 2.2±0.5 (ocean) and 0.5±0.7 Pg C/yr (land) over the period Jan. 1993-Jan. 2003. These estimates make allowance for oceanic O₂ and N₂ outgassing based on observed changes in ocean heat content and estimates of the relative outgassing per unit warming. The recent ocean sink is consistent, to within the uncertainties, with estimates of the accumulation of anthropogenic CO₂ in the ocean since 1800, assuming the oceanic sink varied over time as predicted by a box-diffusion model. The possibility that the ocean sink is being reduced slightly by climate feedbacks, as predicted by some models, is not ruled out, however.

Existing instruments for measuring atmospheric profiles of carbon dioxide can be very sensitive, but are all large and bulky and must be flown using aircraft or large, research gondolas.  This work reports on the development of a stand-alone, lightweight CO₂ sensor for use on balloon sondes.  This device will have sub part-per-million (ppm) sensitivity and weigh less than 1 kg.

Biomass burning is an important source of atmospheric CO₂, aerosols and chemically important gases. It is as important to global chemistry as industrial activities in the developed world [Crutzen and Andreae, 1990]. Biomass burning is a key component of the global carbon budget, currently releasing 2.6 GtC from fires in the tropical and subtropical ecosystems (van der Werf et al. [2003], to be compared to the 5.6 GtC released from fossil fuels) to the atmosphere each year, most of it being emitted in the form of carbon dioxide, although there is important spread amongst various estimates. Biomass burning contributes up to 40% of gross atmospheric CO₂ (IPCC, 2001), 38% of tropospheric O₃, and 10 % of CH₄.

The oxygen isotopic composition of atmospheric CO₂ can help constrain local- to global-scale biophysical processes and partition measured net ecosystem CO₂ fluxes into gross fluxes. Although current models still lack key features controlling gross ecosystem CO¹⁸O fluxes, considerable improvements have been achieved in the last four years. In this study we examine the influence on atmospheric CO¹⁸O of 1) a delayed seasonal cycle in soil water isotopes (relative to rain water) and 2) a new one-way flux model of night-time leaf respiration [Cernusak et al., 2004]. The latter covaries with enhanced night-time stomatal conductance, for which evidence arose recently [e.g. Snyder et al., 2003].

In recent years our knowledge of gas exchange across the air-sea interface at the process level has improved as a consequence of new instrumentation and novel use of injected and natural tracers.  However, there remains significant uncertainty in the extrapolation of these results to larger scales, especially for studies focusing on global-scale processes such as the earth's carbon cycle.

This paper presents estimates of the ¹³C Suess effect and anthropogenic carbon concentration increase in the Nordic Seas since 1981.

Numerical models of the carbon cycle are becoming increasingly sophisticated. One result of this is that these models now require fossil-fuel carbon-dioxide emissions data with sub-annual (e.g., seasonal) time resolution. They also require finer spatial resolution than national averages (i.e., than one point per nation). Finer spatial resolution is especially needed for countries as large in area as the United States of America (U.S.A.). Here we present a summary of monthly data for the entire nation, and annual data for each state in the U.S.A.