Differential Optical Absorption Spektoscopy (DOAS) Observations from HALO

• Applicant: Professor Dr. Klaus Pfeilsticker
• Subject Area: Atmospheric Science
• Term: from 2007 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 47530744

Within the first stage of SPP-1294, the design and assembly of two novel DOAS (Differential Optical Absorption Spectrometry) instruments – briefly called HALO mini-DOAS and 2-D imaging DOAS (2-D I-DOAS) spectrometer- were funded for future deployments on the HALO aircraft. At present (late 2009) both instruments await final aircraft certification for participating in upcoming test missions and scientific missions. It is expected that testing of the instruments on HALO will be accomplished before the end of the still ongoing project (late 2010). The follow-on project will then be devoted to scientific applications i.e. to actually making use of the investment of developing and building the two instruments. The two optical spectrometers are design to monitor 1-D and/or 2-D spatial and temporal maps, vertical profiles, and/or column amounts of a suite of atmospheric trace gases (e.g., O3, NO2, CH2O, C2O2H2, BrO, OClO, IO, OIO, O4, O2, H2O) and cloud parameters (e.g., gaseous, liquid, and solid water contents, cloud optical thickness). Due to the wide range of important atmospheric parameters accessible for observation with the two instruments (of which some recent examples are given in the report below) either of the two instruments or both are invited to participate in the upcoming HALO test missions and scientific missions (e.g., TACTS, TACTS/SALSA, CIRRUS-ML, CIRRUS-RS, OMO, POLSTRACC, HALO-EO, EU-SHIVA, SHIVA/NOX-HOX-XOX, NARVAL, and ACRIDION). A full exploitation of the measured field data, e.g., to infer concentration profiles from the measured slant column amounts, however will require further evaluation steps. These steps will involve the interpretation of the spectroscopic measurements with sophisticated radiative transfer calculations in combination with mathematical inversion techniques, which are constraint by outputs of photochemical, microphysical, or dynamical modeling depending on the application.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1294: Atmospheric and Earth System Research with the "High Altitude and Long Range Research Aircraft" (HALO)
• Participating Person: Professor Dr. Ulrich Platt