Air samples taken during the CARIBIC flights were analysed for non-methane hydrocarbons (NMHC). For completeness and to aid the interpretation of the data, the continuously measured O3 and CO integrated over the sampling interval are also given. The air samples were taken by a whole air sampler (WAS) described by Brenninkmeijer et al. [J. Atmos. Oceanic Technol. 16, 1999] into 21 l stainless steel canisters. Since most of the sample was consumed by the isotope analysis an aliquot of the sample (~10 l) was taken into a 2 l stainless steel canister and analysed within 2 weeks after the flight for NMHCs at MPI. The NMHCs were cryogenically enriched, desorbed, separated on capillary column, and detected by a mass spectrometer. For details see ref. Muehle. The NMHC measurements started with the flight #21 and were continued since. Internal consistency checks [Parrish et al., JGR 103, 1998] were applied to CARIBIC measurements to test their plausibility. They revealed implausibly high alkene concentrations probably due to contamination during sampling and/or storage. In addition, toluene could not be measured reliably. Thus only data for alkanes, ethyne, and benzene are reported here. Data format: Dataset consists of 40 columns representing: Sample ID number, Date(UT), Time(UT), Longitude, and Latitude of the sampling begin, Date(UT), Time(UT), lon/lat of the sampling end, Time(UT), lon/lat of the middle of the sampling interval, corresp. Pressure[hPa], Barom. height[m], T[deg C], Tpot[K], O3 [ppb], CO [ppb], Ethane, Propane, Butane, Pentane, Hexane, 2-methyl propane, 2-methyl butane, 2-methyl pentane, 3-methyl pentane, Cyclohexane, Ethyne, Benzene all in [pptv] and with uncertainty (SD). 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 www.caribic-atmospheric.com
Internal consistency checks were applied to CARIBIC measurements to test their plausibility. They revealed implausibly high alkene concentrations prob...
Description
Internal consistency checks were applied to CARIBIC measurements to test their plausibility. They revealed implausibly high alkene concentrations probably due to contamination during sampling and/or storage. In addition, toluene could not be measured reliably. Thus only data for alkanes, ethyne, and benzene are reported here. Multicomponent NMHC standard gas mixtures prepared by National Physical Laboratory (NPL, 30 components, C2-C9) and National Center for Atmospheric Research (NCAR, 39 components, C2-C8) were used to calibrate the apparatus.
Consistency report
Dataset covers usually 12 samples taken during the return flight.
Description
Dataset covers usually 12 samples taken during the return flight.