In this study the open-path LI results were compromised due to a data acquisition problem in our data-logging setup. The Good Project.
Peltola, O. The instruments were positioned close to each other in order to minimise the effect of varying turbulent conditions. The moderate CH4 fluxes observed at the location, of the order of 25 nmol m-2 s-1, provided a suitable signal for testing the instruments' performance.
Generally, all analysers tested were able to quantify the concentration fluctuations at the frequency range relevant for turbulent exchange and were able to deliver high-quality data. The tested cavity ringdown spectrometer CRDS instruments from Picarro, models Gf and Gf, were superior to other CH4 analysers with respect to instrumental noise.
As an open-path instrument susceptible to the effects of rain, the LI-COR LI achieved lower data coverage and also required larger density corrections; however, the system is especially useful for remote sites that are restricted in power availability. In this study the open-path LI results were compromised due to a data Crypt Broker Ag Zurich problem in our data-logging setup.
Some of the older closed-path analysers tested do not measure H2O concentrations alongside CH4 i. FMA1 and DLT by Los Gatos Research and this complicates data processing since the required corrections for dilution and spectroscopic interactions have to be based on external information.
To overcome this issue, we used H2O mole fractions measured by other gas analysers, adjusted them with different methods and then applied them to correct the CH4 fluxes.
Following this procedure we estimated a bias of the order of 0. Finally, cumulative CH4 fluxes over 14 days from three closed-path gas analysers, Gf Picarro Inc.
Jaeger, R. So it becomes necessary that possible changes of the reference stations' coordinates are detected ad hoc. The developments at Karlsruhe University of Applied Sciences in cooperation with the State Survey of Baden-Württemberg are further motivated by a the official resolution of the German state survey departments' association Arbeitsgemeinschaft der Vermessungsverwaltungen Deutschland AdV on coordinate monitoring as a quality-control duty of the GNSS-positioning service provider.