Two- and Three Dimensional Observation of Trace Gas and Aerosol Distributions by DOAS Techniques

Abstract

Spatially resolved measurements of trace gas abundances by satellite have revolutionised the field of large-scale tropospheric chemistry observation and modelling during recent years. Now a similar revolution is imminent on local and regional scales. A key role in these advances is played by spatially resolving spectroscopic techniques like active and passive – DOAS tomographic measurements of two-dimensional trace gas distributions, as well as ground based and airborne Imaging DOAS (I-DOAS) observation of 2D- and 3D- trace gas patterns. A particularly promising approach is the combination of tomographic techniques with imaging – DOAS on airborne platforms, which can provide three-dimensional trace gas distributions. While satellite-based 2D – mapping of trace gas distributions is now in widespread use for global and regional investigations aircraft based instruments allow complementary studies at much higher spatial resolution (tens of meters instead of tens of km). Since state of the art instruments can be employed rather than technology from the last decade (which is dictated by reliability requirements and long lead times of satellite experiments) novel approaches like tomographic techniques or Short-Wave Infra-Red (SW-IR) observations can be applied. Technological approaches and sample results are discussed.