ON-LINE IN-SITU MEASUREMENTS IN THE BOUNDARY LAYER MANNED HYDROGEN BALLOONS AS QUASI LAGRANGE PLATFORMS

摘要

Langrangian measurements in the same air parcel may provide substantial information about the evolution of photochemical processes. Gas ballooning represents the most adequate technique to meet the requirements for such along trajectories within the boundary layer. Within the scope of the BERLIOZ project gas ballon low level flights were carried out in 1997 and in 1998. Apart from meteorological instruments and GPS the gondola was equipped with on-line analyzers for airborne measurements such as ozone, peroxyacetyl nitrate (PAN), NO_2 and NMHC. To our knowledge on-line in-situ NMHC in the range of C_4-C_(10) measurements using GC/FID methods were the first ever carried out aboard a manned gas ballon filled with hydrogen. NMHC measurements were both rapid enough (cycle time 10 min) and sensitive enough (detection limit approx. 10 pptv) to meet the requirements for investigations of photochemical processes inside the same air parcel along Langrangian trajectories. In terms of photochemical significance different types of air masses could be identified using NMHC-patterns: urban/suburban, residual boundary layer aloft, and rural conditions. Results and their use for remote sensing methods will be given together with information about technical necessities to be observed using manned hydrogen ballons in atmospheric research.