A. Inness

Fire carbon emissions over maritime southeast Asia in 2015 largest since 1997

In September and October 2015 widespread forest and peatland fires burned over large parts of maritime southeast Asia, most notably Indonesia, releasing large amounts of terrestrially-stored carbon into the atmosphere, primarily in the form of CO2, CO and CH4. With a mean emission rate of 11.3 Tg CO2 per day during Sept-Oct 2015, emissions from these fires exceeded the fossil fuel CO2 release rate of the European Union (EU28) (8.9 Tg CO2 per day). Although seasonal fires are a frequent occurrence in the human modified landscapes found in Indonesia, the extent of the 2015 fires was greatly inflated by an extended drought period associated with a strong El Niño. We estimate carbon emissions from the 2015 fires to be the largest seen in maritime southeast Asia since those associated with the record breaking El Niño of 1997. Compared to that event, a much better constrained regional total carbon emission estimate can be made for the 2015 fires through the use of present-day satellite observations of the fire’s radiative power output and atmospheric CO concentrations, processed using the modelling and assimilation framework of the Copernicus Atmosphere Monitoring Service (CAMS) and combined with unique in situ smoke measurements made on Kalimantan.

Global reactive gases forecasts and reanalysis in the MACC project

The EU FP7 projects MACC (Monitoring Atmospheric Composition and Climate, 2009–2011) prepared for the operational Global Monitoring for Environment and Security (GMES) atmospheric core service on greenhouse gases, reactive gases and aerosols which is envisaged to start in 2014. This paper describes the data assimilation and modelling system which has been implemented for global monitoring of reactive gases in the troposphere and stratosphere. The MACC reactive gases system uses a coupling software to integrate the Model for Ozone And Related Tracers, version 3 (MOZART-3) chemistry transport model with the Integrated Forecast System (IFS) of the European Centre for Medium-range Weather Forecasts (ECMWF). The focus is placed on the tropospheric simulations with this MACC-IFS-MOZ model. The MACC reanalysis (2003–2010) and the forecasts performed in near real time (NRT) benefit from the multi-sensor approach for data assimilation of total columns, tropospheric columns and vertically resolved observations of ozone, CO and NO2. Daily biomass burning emissions are integrated in real time using the global fire assimilation system (GFAS) that was developed within MACC. Other emissions are taken from a state-of-the-art global inventory that was developed across several EU projects. The MACC reanalysis and tracer forecasts are routinely evaluated with ground-based and airborne in-situ observations and independent satellite retrieval products. We present the system set-up for reactive gases, give an overview on the service and technical developments during the project, and indicate how MACC global reactive gases products could provide information on non-CO2 greenhouse gases.

On the use of MOZAIC-IAGOS data to assess the ability of the MACC reanalysis to reproduce the distribution of ozone and CO in the UTLS over Europe

MOZAIC-IAGOS data are used to assess the ability of the MACC reanalysis (REAN) to reproduce distributions of ozone (O3) and carbon monoxide (CO), along with vertical and inter-annual variability in the upper troposphere/lower stratosphere region (UTLS) over Europe for the period 2003–2010. A control run (CNTRL, without assimilation) is compared with the MACC reanalysis (REAN, with assimilation) to assess the impact of assimilation. On average over the period, REAN underestimates ozone by 60 ppbv in the lower stratosphere (LS), whilst CO is overestimated by 20 ppbv. In the upper troposphere (UT), ozone is overestimated by 50 ppbv, while CO is partly over or underestimated by up to 20 ppbv. As expected, assimilation generally improves model results but there are some exceptions. Assimilation leads to increased CO mixing ratios in the UT which reduce the biases of the model in this region but the difference in CO mixing ratios between LS and UT has not changed and remains underestimated after assimilation. Therefore, this leads to a significant positive bias of CO in the LS after assimilation. Assimilation improves estimates of the amplitude of the seasonal cycle for both species. Additionally, the observations clearly show a general negative trend of CO in the UT which is rather well reproduced by REAN. However, REAN misses the observed inter-annual variability in summer. The O3–CO correlation in the Ex-UTLS is rather well reproduced by the CNTRL and REAN, although REAN tends to miss the lowest CO mixing ratios for the four seasons and tends to oversample the extra-tropical transition layer (ExTL region) in spring. This evaluation stresses the importance of the model gradients for a good description of the mixing in the Ex-UTLS region, which is inherently difficult to observe from satellite instruments.