Short Abstract:

The fact that plants, in particular trees emit volatile organic compounds (VOCs), mainly in the form of isoprenes and monoterpenes is well established since many years. However, the uncertainties in total emissions are very high since the amounts emitted depend on several parameters, e.g. on plant species, temperature, humidity and also condition of the plant. First satellite measurements of HCHO, an important intermediate in oxidation processes of VOC; have illustrated the fact, that tropical rain forests are the major sources of VOCs on a global scale and forests are important sources. In addition, burning of biomass emits large quantities of trace gases and aerosols into the atmosphere. Depending on the type of biomass burned and the temperatures of the fire, VOCs including formaldehyde and glyoxal are being emitted from such fires.

Global fields of HCHO and CHOCHO have been retrieved at the IUP Bremen from GOME, SCIAMACHY and GOME-2 measurements. Some aspects of these retrievals still have to be improved, including possible spectral interferences over water and better correction of cloud and aerosol effects, in particular in case of biomass burning when atmospheric aerosol levels are high. Also, the retrieval should be extended to OMI data to increase the amount of available data and to later estimate trends in VOC emissions. In the main part of the project, trajectory analysis will be used to identify sources and transport path ways of HCHO and glyoxal observed in the satellite data. Both forward trajectories (mainly from locations of fires but also from areas with expected biogenic emissions) and backward trajectories (from interesting satellite measurement locations and the ground-based instrument) will be used. The outcome will be statistics on the relation between source regions and HCHO / CHOCHO columns observed as a function of season.

Start of doctoral thesis: 01st October, 2011

Defense of doctoral thesis: 21st June, 2016

Supervisor: Prof. Dr. J. P. Burrows (Uni-Bremen/IUP), Co-Supervisor: Dr. A. Richter (Uni-Bremen/IUP).
Further members: Dr. M. Van Roozendael (BIRA-IASB)

Alvarado, L. M. A.: Investigating the role of glyoxal using satellite and MAX-DOAS measurements, PhD Thesis, University of Bremen, June 2016, http://elib.suub.uni-bremen.de/peid/D00105347.html

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., Hilboll, A., Schreier, S. F., and Burrows, J. P.: Investigating the link between glyoxal and biogenic activities. In Lohmann G., Meggers H., Unnithan V., Wolf-Gladrow D., Notholt J., and Bracher A. (Eds.), Towards an Interdisciplinary Approach in Earth System Science, Springer International Publishing, pp. 59--65, doi:10.1007/\-978-3-319-13865-7\_25, 2015           

Peters, E., Wittrock, F., Richter, A., Alvarado, L. M. A., Rozanov, V. V., and Burrows, J. P.: Liquid water absorption and scattering effects in DOAS retrievals over oceans, Atmos. Meas. Tech., 7, 4203-4221, doi:10.5194/amt-7-4203-2014, 2014

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., Hilboll, A., Schreier, S. F., and Burrows, J. P.: An improved glyoxal retrieval from OMI measurements, Atmos. Meas. Tech., 7, 4133-4150, doi:10.5194/amt-7-4133-2014, 2014

Helmholtz Research School on Earth System Science, Annual Retreat 2012, Bremerhaven, “Deutsches Auswandererhaus“, Poster Presentation: Alvarado, L et al., “Ground based observations of HCHO over Nairobi and Athens“ 30 November, 2012.

Poster presentation, Alvarado L.M.A., Richter, A., Vrekoussis, M., Wittrock, F., Burrows, J.P., Sensitivity studies on glyoxal retrievals from OMI data, 6th International DOAS workshop Boulder, USA, August 2013.

Poster presentation, Alvarado, L.M.A., Richter, A., Vrekoussis, M., Wittrock, F., Burrows, J.P., An improved glyoxal retrieval from OMI satellite data, EGU General Assembly, Vienna, Austria, April 2013.

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., Schreier, S. F., and Burrows, J. P.: Investigating the temporal variation of VOC using a homogenized glyoxal retrieval for different satellite platforms. Presented at the 7th International DOAS Workshop, Brussels, Belgium, July 2015

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., Schreier, S. F., and Burrows, J. P.: What can we learn from glyoxal. Presented at the Helmholtz Research School on Earth System Science Retreat, Bremerhaven, Germany, November 2014

Alvarado, L. M. A., Richter, A., Peters, E.,  Wittrock, F., Burrows, J. P., Vrekoussis, M., Gratsea, M., Gerasopoulo E.: MAX-DOAS observation of HCHO and CHOCHO over Athens and Nairobi. Presented at the EGU General Assembly, Vienna, Austria, April 2014

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., Schreier, S. F., and Burrows, J. P.: Glyoxal columns retrieved from OMI data as an indicator of fire emissions. Presented at the DPG spring meeting, Berlin, Germany, March 2014

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., Schreier, S. F., and Burrows, J. P.: Glyoxal retrieval from satellite observations as indicator of fires emission and biogenic activities. Presented at the Seminar of Physics, University of El Salvador, San Salvador, February 2014

Alvarado, L. M. A., Richter, A., Wittrock, F.,Vrekoussis, M. Burrows, J. P.: Insvestigating the sources of VOC using the ratio of glyoxal to formaldehyde from satellite and ground based measurements. Presented at the DPG Spring meeting, Regensburg, Germany, March 2016

Alvarado, L. M. A., Richter, A., Peters, E.,  Wittrock, F., Burrows, J. P., Vrekoussis, M., Gratsea, M., Gerasopoulo E.: MAX-DOAS observation of CHOCHO, HCHO and NO₂ over Nairobi and Athens. Presented at the DPG Spring meeting, Heidelberg, Germany, March 2015

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., and Burrows, J. P.: Comparison of OMI and GOME--2 CHOCHO columns since 2007. Presented at the EUMETSAT Meteorological Satellite Conference, Geneva, Switzerland, September 2014

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., and Burrows, J. P.: An improved glyoxal retrieval from OMI data and  intercomparison with GOME-2 data. Presented at the Helmholtz Research School on Earth System Science Retreat, Bremen, Germany, November 2013

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., and Burrows, J. P.: Sensitivity study on glyoxal retrieval from OMI data. Presented at the 6th International DOAS workshop, Boulder, USA, August 2013

Alvarado, L. M. A., Richter, A., Vrekoussis, M., Wittrock, F., and Burrows, J. P.: An improved glyoxal retrieval from OMI satellite data. Presented at the EGU-General Assembly, Vienna, Austria, April 2013