Ruprecht-Karls-Universitšt Heidelberg

Atmosphere and Remote Sensing > Upper Troposphere and Stratosphere > Platforms & tools

Mini-DOAS on the HALO aircraft

HALOThe German research aircraft HALO (High Altitude and LOng Range Research Aircraft) is the new Research Aircraft for atmospheric research and earth observation of the German Science Community. HALO is funded by the Federal Ministry of Education and Research through the Deutsche Forschungsgemeinschaft (DFG), the Helmholtz-Gemeinschaft and the Max-Planck-Gesellschaft and is operated by the Deutsches Zentrum f. Luft- und Raumfahrt (DLR). It is capable of reaching altitudes above 15 km, has a range of more than 10000 km and a maximum payload of 3 tons.

The HALO mini-DOAS instrument aims at measuring a suite of trace gases (O3, O4, NO2, BrO, IO, OIO, OClO, CH2O, C2H2O2) and three phases of water by optical remote sensing techniques, most notably DOAS (Differential Optical Absorption Spectroscopy). To this end, it employs six optical spectrometers in the UV, visible and near-Infrared wavelength ranges. The telescopes are mounted in nadir and limb-scanning geometries, and the roll angle of the aircraft is actively corrected for when aiming at the targeted angles relative to the horizon.

The work in the project so far includes

  • Construction of aperture plate, rack, boxes for electronic equipment etc. by the workshop
  • Laboratory tests and and further development of components like spectrometers and electronics as well as measurement software
  • Tests and certification of airworthiness
  • Deployment in field campaigns (see below)
  • Development of data processing and evaluation software adjusted to the instrument
  • Validation of the scaling method for limb trace gas concentration retrieval
Our current main focus is work on the scientific interpretation of already acquired data and preparation of upcoming campaigns in 2017/2018 (Emerge-EU, Wise, Comet, Emerge-Asia).

Field campaign deployments:

No Date Abbr Name Sorties Flight Hours
1 Aug-Sept 2012 TACTS Transport and Composition in the UTLS 6 53.5
2 Sept 2012 ESMVal Earth System Model Validation 6 57.5
3 Dec 2013 - Jan 2014 NARVAL Next Generation Remote Sensing for Validation Studies 15 120
4 Mar - Apr 2014 ML-Cirrus Mid-Latitude Cirrus 16 77
5 Aug - Oct 2014 Acridicon Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems 14 96
6 July - Aug 2015 OMO Oxidation Mechanism Observations 20 116
7 Dec 2015 - Mar 2016 Polstracc Polar Stratosphere in a Changing Climate 18 156

Main technical features:

  • 6 grating spectrometers in thermostated and evacuated housing
  • Wavelength ranges and resolution:
    • UV: 310 - 440 nm, 0.72 nm FWHM
    • VIS: 415 - 640 nm, 0.76 nm FWHM
    • NIR: 1100 - 1680 nm, 8 nm FWHM
  • Field of View (FOV):
    • UV/VIS: 0.38 deg vertical x 3.15 deg horizontal
    • NIR: 0.76 deg vertical x 1.68 deg horizontal
  • Total power consumption: approx. 200 W
  • Total mass: 58.7 kg

Instrument sketch:

Picture gallery:


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