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| Titel |
A field robot for autonomous laser-based N2O flux measurements |
| VerfasserIn |
Lars Molstad, Jan Reent Köster, Lars Bakken, Peter Dörsch, Torgrim Lien, Øyvind Overskeid, Trygve Utstumo, Daniel Løvås, Anders Brevik |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250100216
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| Publikation (Nr.) |
 EGU/EGU2014-16109.pdf |
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| Zusammenfassung |
| N2O measurements in multi-plot field trials are usually carried out by chamber-based manual
gas sampling and subsequent laboratory-based gas chromatographic N2O determination.
Spatial and temporal resolution of these measurements are commonly limited by available
manpower. However, high spatial and temporal variability of N2O fluxes within individual
field plots can add large uncertainties to time- and area-integrated flux estimates. Detailed
mapping of this variability would improve these estimates, as well as help our understanding
of the factors causing N2O emissions.
An autonomous field robot was developed to increase the sampling frequency and to
operate outside normal working hours. The base of this system was designed as an open
platform able to carry versatile instrumentation. It consists of an electrically motorized
platform powered by a lithium-ion battery pack, which is capable of autonomous navigation
by means of a combined high precision real-time kinematic (RTK) GPS and an inertial
measurement unit (IMU) system.
On this platform an elevator is mounted, carrying a lateral boom with a static chamber on
each side of the robot. Each chamber is equipped with a frame of plastic foam to seal the
chamber when lowered onto the ground by the elevator. N2O flux from the soil covered by
the two chambers is sequentially determined by circulating air between each chamber and a
laser spectrometer (DLT-100, Los Gatos Research, Mountain View, CA, USA), which
monitors the increase in N2O concentration. The target enclosure time is 1 – 2 minutes, but
may be longer when emissions are low. CO2 concentrations are determined by a CO2/H2O
gas analyzer (LI-840A, LI-COR Inc., Lincoln, NE, USA). Air temperature and
air pressure inside both chambers are continuously monitored and logged. Wind
speed and direction are monitored by a 3D sonic anemometer on top of the elevator
boom.
This autonomous field robot can operate during day and night time, and its working hours
are only limited by the recharge time of the battery pack. It is therefore suited for field studies
requiring high temporal and/or spatial resolution. |
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