A miniDOAS instrument optimised for ammonia field measurements

Sintermann, Jörg; Dietrich, Klaus; Häni, Christoph; Bell, Michael; Jocher, Markus; Neftel, Albrecht (2016). A miniDOAS instrument optimised for ammonia field measurements Atmospheric Measurement Techniques, 9(6), pp. 2721-2734. Copernicus 10.5194/amt-9-2721-2016

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We present a differential optical absorption spectroscopy (DOAS) instrument, called "miniDOAS", optimised for optical open-path field-measurements of ambient ammonia (NH3) alongside nitrogen oxide (NO) and sulfur dioxide (SO2). The instrument is a further development of the miniDOAS presented by Volten et al. (2012). We use a temperature-controlled spectrometer, a deuterium light source and a modified optical arrangement. The system was set up in a robust, field-deployable, temperature-regulated housing. For the evaluation of light spectra we use a new high-pass filter routine based upon robust baseline extraction with local regression. Multiple linear regression including terms of an autoregressive–moving-average model is used to determine concentrations. For NH3 the random uncertainty is about 1.4 % of the concentration, and not better than 0.2 µg m−3. Potential biases for the slope of the calibration are given by the precision of the differential absorption cross sections (±3 %) and for the offset by the precision of the estimation of concentration offsets (cref) introduced by the reference spectrum Iref. Comparisons of miniDOAS measurements to those by NH3 acid trap devices showed good agreement. The miniDOAS can be flexibly used for a wide range of field trials, such as micrometeorological NH3 flux measurements with approaches based upon horizontal or vertical concentration differences. Results from such applications covering concentration dynamics of less than one up to several hundreds of µg m−3 are presented.

Item Type:

Journal Article (Original Article)

Division/Institute:

School of Agricultural, Forest and Food Sciences HAFL > Resource-efficient agricultural production systems

Name:

Sintermann, Jörg;
Dietrich, Klaus;
Häni, Christoph;
Bell, Michael;
Jocher, Markus and
Neftel, Albrecht

Subjects:

G Geography. Anthropology. Recreation > GE Environmental Sciences
S Agriculture > SF Animal culture

ISSN:

1867-8548

Publisher:

Copernicus

Language:

English

Submitter:

Simon Lutz

Date Deposited:

18 Feb 2020 08:20

Last Modified:

18 Feb 2020 08:20

Publisher DOI:

10.5194/amt-9-2721-2016

ARBOR DOI:

10.24451/arbor.8477

URI:

https://arbor.bfh.ch/id/eprint/8477

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