Air Chemistry Module

A modular system to measure air chemical parameters aboard the DO128, D-IBUF

In 1998 we completed a project on behalf of the Institute for Meteorology and Climate Research – Troposphere Research of the Forschungszentrum Karlsruhe which demonstrates our concept of modular measuring equipment.

For this project we adapted a comprehensive set of analyzers for air chemical parameters. The analyzer were originally suited for ground use and had to be modified for the use aboard the DO 128 D-IBUF of the TU Braunschweig. The following requirements are met by the system:

Requirements:

1. Modular set-up of the CM with the possibility, to assemble the whole system in aircraft, in monitoring cars, or in ground based stations within just a few hours.
2. Integration of a stand-alone data acquisition system (independent from a/c data acquisition) with graphical on-line data visualisation, and with a data interface to the data acquisition system of the Do 128 D-IBUF.
3. Allocation of interfaces for all current supply and data wires via appropriate connectors
4. Provision of a sample air supply system combined with an inlet system, which meets the different requirements of the analyzers with respect to tubing materials, sample volume flow, air filtering, humidity traps, pre-pressure etc..

met through:

1. Fragmentation of the system into 4 components (inserts), which enables:
   • good manageability (M_max~ 40-50 kg, H_max= 90cm)
   • installation with just two persons without additional support
   • compatibility to standard 19-inch-racks
   • the inserts can easily be transported and stored
   • possible usage of different combinations of inserts (e.g. flights with just 3 inserts)
   • short set-up times
   • utilisation of already existing racks in the aircraft, i.e. minimal certification efforts
   • the design features of the inserts provide the opportunity to utilize 19-inch-inserts with depths more than 550 mm
2. Utilisation of an “open” data acquisition systems with graphical on-line data visualisation under LabView ^TM
   • acquisition of serial data, analogue- and counter signals
   • serial data transfer to the on-board computer of the aircraft
3. internal cabling and tubing of all inserts
   • front-side connectors for all necessary external connections
4. Utilisation of an specially developped air inlet system
   • utilisation of a condensate trap
   • pressure regulated sample air supply: pre-pressure = 1100 hPa, stabilized down to 500 hPa ambient pressure

The Air Chemistry Module has been operated successfully e.g. in summer 1998 during the BERLIn OZone Experiment (BERLIOZ) by the Institute for Meteorology and Climate Research – Troposphere Research of the Forschungszentrum Karlsruhe aboard the D-IBUF.

The compliance of the Air Chemistry Module with the very high quality demands to the measuring instrumentation of the participating institutions has been assured through stringent QA/QC measures and instrument intercomparisons. Another example for an investigation with the Air Chemistry Module is the field experiment EVA II in the area around Augsburg (Southern Germany).