Identification of tropospheric emissions sources from satellite observations: synergistic use of trace gas measurements of formaldehyde (HCHO), nitrogen dioxide (NO2), and sulfur dioxide (SO2)
Final Report Abstract
The goal of this project was the synergistic use of satellite observations, to identify the sources of tropospheric Formaldehyde (HCHO). Observations of HCHO have been compared with nitrogen dioxide (NO2), fire counts (from ATSR), surface temperatures (from ECMWF), and model results (from EMAC). HCHO observations provide in particular information about the localization of biomass burning (intense source of HCHO over the Amazon basin and in central Africa), biogenic isoprene emissions, industry and traffic. For the HCHO DOAS retrieval we used the spectral measurements from the satellite instruments GOME (aboard ERS-2) and GOME-2 (aboard METOP-A). Important goals submitted in the first DFG proposal have been achieved. The GOME retrieval has been substantially improved and allows having an almost 8 year time series (January 1996 to June 2003). The GOME HCHO analysis has been successfully adapted to the GOME-2 retrieval. Synergistic use of the HCHO and NO2 satellite observations has been made and the data were also compared with ATSR fire counts and ECMWF surface temperatures. Nine regions have been selected to investigate the influence of fire counts (biomass burning proxy) and the temperature (vegetation activity proxy) on the HCHO tropospheric columns. The results show that biogenic sources of HCHO are in many cases the strongest HCHO sources. For example over south east of the USA, the correlation with temperature was very high indicating a strong biogenic source of HCHO (through isoprene emissions). The biomass burning source typically shows more pronounced seasonal patterns or is even of sporadic nature. Over the Amazon region, the correlation with fires is high indicating that in this area most of the HCHO is caused by biomass burning. Furthermore the results show that there seems also to be dependence between the NO2 emissions during biomass burning and the vegetation type: NO2 correlate with HCHO over Africa (grassland fires) but not over Indonesia. An unexpected result was the first satellite measurements of formaldehyde (HCHO) linked to shipping emissions. The line of enhanced HCHO in the Indian Ocean as seen in the 7-year composite of cloud free GOME observations clearly coincides with the distinct ship track corridor from Sri Lanka to Indonesia (all ship tracks follow a single narrow track in the same east-west direction as used for the GOME pixel scanning). The observed mean HCHO column enhancement over this shipping route is about 2.0x1015 molec/cm2, substantially higher compared to the simultaneously observed NO2 values, also the HCHO peaks are found at larger distance from the ship routes. These findings indicate that direct emissions of HCHO or degradation of emitted NMHC cannot explain the observed enhanced HCHO values. Instead increased CH4 degradation due to enhanced OH concentrations related to the ship emissions are the most probable reason. The observed HCHO pattern also agrees qualitatively well with results from the EMAC model but are about two time higher than the modelled HCHO values. This might indicate uncertainties in the satellite data and used emission inventories and/or that the in-plume chemistry taking place in the narrow path of the shipping lanes are not well represented at the rather coarse model resolution. Some submitted goals (e.g. comparison with SO2 results) could not be achieved. This has been caused by the Institute change from IUP Heidelberg to MPI for Chemistry in Mainz. The SO2 product is only recently again a part of our set of retrieval products with a focus on the GOME-2 spectra retrieval.
Publications
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Boreal forest fires in 1997 and 1998: a seasonal comparison using transport model simulations and measurement data. Atmos. Chem. Phys., 4, 1857-1868, 2004
Spichtinger N., R. Damoah, S. Eckhardt, C. Forster, P. James, S. Beirle, T. Marbach, T. Wagner, P. Novelli, and A. Stohl
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Identification of Tropospheric Emissions Sources from Satellite Observations: Synergistic Use of HCHO, NO2 and SO2 Trace Gas Measurements. Proceedings to the 1st ACCENT Symposium, ISBN 88-548-0851-2, 2006
Marbach T., S. Beirle, F. Khokhar, U. Platt and T. Wagner
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Identification of tropospheric trace gas sources: synergistic use of HCHO and other satellite observations. ESA publication SP-636, ISBN 92-9291-200-1, 2007
Marbach, T., Beirle, S., Frankenberg, C., Platt, U. and Wagner, T.
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Biomass burning emissions from satellite observations: synergistic use of formaldehyde (HCHO), fire counts, and surface temperature. Proceedings of the Society of Photo-optical Instrumentation Engineers (SPIE), Remote Sensing of Fire: Science and Application, vol. 7089, pp. 70890J.1-70890J.10, ISBN 978-0-8194-730, 2008
Marbach, T., S. Beirle, C. Liu, U. Platt, and T. Wagner
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Monitoring of atmospheric trace gases, clouds, aerosols and surface properties from UV/vis/NIR satellite instruments. Journal of optics a-pure and applied optics, 10, Article Number: 104019, 2008
Wagner T., S. Beirle, T. Deutschmann, E. Eigemeier, C. Frankenberg, M. Grzegorski, C. Liu, T. Marbach, U. Platt, and M. Pennig de Vries
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Satellite measurements of formaldehyde from shipping emissions. Atmos. Chem. Phys. Discuss., 9, 10487-10511, 2009
Marbach, T., S. Beirle, U. Platt, P. Hoor, F. Wittrock, A. Richter, M. Vrekoussis, M. Grzegorski, J. P. Burrows, and T. Wagner
