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2.2. STRATOSPHERIC OZONE 35
2.2 Stratospheric Ozone
Participating scientists Pfeilsticker, K., A. Butz, M. Dorf, K. Grunow (*), L. Kritten, A. Lindner,
U. Reichl, J. Schwärzle, B. Simmes, and F. Weidner, (*) also with FU-Berlin
Abstract Stratospheric research at the IUP concentrates on an improved understanding of the
photochemical processes controlling stratospheric ozone and its link to climate.
Figure 2.13: Recent history of stratospheric organic (Brorg y = CH3Br, various man-made halones,
and shorter lived organo-bromines) and inorganic (Brin y ) bromine. The open square denoted Brin y
inferred from balloon-borne BrO measurements of the LPMA/DOAS balloon payload since 1996. Note
that bromine is responsible for ∼ 35% of the recent stratospheric loss in ozone with an anticipated
increasing fraction of the total in the future (adopted from M. Dorf, PhD thesis 2005).
Scientific objectives of our stratospheric ozone research include investigation on:
• the photochemistry and budget of upper tropospheric and stratospheric bromine (BrO, Bry)
and its relevance to stratospheric ozone (see figures 2.13 and 2.2.1).
• the photochemistry and budget of upper tropospheric and stratospheric iodine (IO, OIO, Iy)(see
2.2.2 and 2.2.4)
• the stratospheric chemistry and budget of odd nitrogen (NO, NO2, HNO3, ClONO2) (see
2.2.2)
• the partitioning and photochemistry of chlorine and bromine in the high latitude stratosphere
and the assessment of the instantaneous in-situ ozone loss rate (see 2.2.2)
• prominent natural and anthropogenic sources to the trace gas composition of the tropical
tropopause and lowermost stratosphere (TTL/LMS) (see 2.2.4 and 2.2.5)
• the temporal and spatial dependence of stratospheric radicals concentrations (e.g., NO2/N2O5,
BrO/OClO, . . . ) (see 2.2.3)
• the validation of remote sensing satellite instruments, such as ILAS/ADEOS, POAM II and
III, SAGE II and III, ODIN/OSIRIS, GOME/ERS-2, and SCIAMACHY/ENVISAT satellite
instruments (see 2.2.1 and 2.2.2)
Methods The research objectives imply to probe the stratosphere by high altitude (∼ 40 km)
balloon soundings. For that purpose the research group is operating (1) a lab-built two channel
UV/vis spectrometer with which direct Sun measurements are made, and (2) a novel LIMB scanning
UV/vis spectrometer. Both spectrometers are deployed on the joint French/German LPMA/DOAS
(Laboratoire de Physique Moléculaire et Applications/Differential Optical Absorption Spectroscopy)
balloon payload. Jointly with our direct Sun measurements, our French partner operates a near-IR
Fourier Transform Spectrometer with which mid-IR absorbing gases are measured. Balloon flights
are regularly performed at high (Kiruna/Sweden), mid (Aire sur l’Adour/France) and low latitudes