Instrument OMCAL (Ozone Monitor CALibrator) is a (modified) u.v. absorption monitor (Environnement O3-41M, Paris, France). It operates automatically. See also experiment summary. Data format: Dataset consists of eight columns representing Date(UT), Time(UT), Longitude, Latitude, Pressure[hPa], p_height[m], Tpot[K] and O3[ppbv]. Coordinates of data probes are given explicitly while the 'boundary box' meta entries just represent the coordinates of start and destination airports. The data rows are headed by a set of text lines in CARIBIC metadata format - for interpretation cf homepage www.caribic-atmospheric.com. Special comments to this flight: New hygrometer from Buck.