Recent results from GOME and SCIAMACHY: tropospheric trace gases
John P. Burrows(1,2), Heinrich Bovensmann(1), Andreas Richter(1), Michael Buchwitz(1), Stefan Noel(1), Folkard Wittrock(1), Vrekoussis Mihalis(1) and Anja Schoenhardt(1)
(1) University of Bremen, Postfach 330440, 28334 Bremen, Germany
(2) Centre for Ecology and Hydrology, Maclean Building, , Wallingford, Oxfordshire, OX10 8BB, United Kingdom
A new age of global remote sensing of tropospheric trace gases began with the launch of GOME on ERS-2 in 1995. Its design is derived from that of SCIAMACHY and it made global measurements of the solar radiation up-welling from the top of the atmosphere from July 1995 to June 2003 in nadir viewing. SCIAMACHY, which flies aboard ENVISAT, has been delivering global data from August 2002 to the present in alternate limb and nadir viewing. GOME-2, the first operational instrument of this kind, was launched aboard Metop A in late 2006 and has made global measurements since the beginning of 2007.
The mathematical inversion of the measurements of these instruments in the ultraviolet and visible spectral regions yields unique global information about Ozone, O3,and the precursors of tropospheric O3: NOx (= NO2 +NO) through the retrievals of tropospheric NO2 columns and the Volatile Organic Compounds, VOC, through the retrievals of the amounts of Formaldehyde, HCHO, and Glyoxal, CHO.CHO. The tropospheric columns of Sulphur Dioxide, SO2, and NO2 provide insight into the formation of strong inorganic acids. The amounts of Bromine Oxide, BrO, and Iodine Oxide, IO, are also retrieved. These halogen oxides are both oxidizing agents, but in addition participate in catalytic cycles, which remove O3, and thereby impact on the oxidizing capacity of the troposphere. The reactions of IO result in the formation of hygroscopic higher oxides, which act as aerosol condensation nuclei. In the near infrared and short wave infrared spectral regions SCIAMACHY data yields total columns of Water Vapour, H2O, Carbon Monoxide, CO, and the dry columns of greenhouse gases Carbon Dioxide, CO2, and Methane, CH4. In this presentation the use of satellite data to improve our understanding of the natural biogeochemical cycling and the anthropogenic impact role on tropospheric chemistry will be discussed. Both the monthly, seasonal, annual and decadal changes of these trace constituents and case studies of specific urban rural and remote conditions will be a focus.