| Zugriffsnummer | 37071 |
| Dokumenttyp | Zeitschriftenartikel |
| Peer Review | mit Peer Review |
| Sprache | Englisch |
| Titel | HAI - a new, airborne, absolute, twin dual-channel, multi-phase TDLAS-hygrometer |
| Autor(in); Institution |
Buchholz, Bernhard; 3.2, Gasanalytik und Zustandsverhalten, PTB-Braunschweig
Afchine, Armin; Forschungszentrum Jülich, IEK-7, Jülich, GERMANY
Klein, Alexander; 3.2, Gasanalytik und Zustandsverhalten, PTB-Braunschweig; Universität Heidelberg, Physikalisch-Chemisches Institut, Heidelberg, GERMANY
Schiller, Cornelius; Forschungszentrum Jülich, IEK-7, Jülich, GERMANY
Krämer, Martina; Forschungszentrum Jülich, IEK-7, Jülich, GERMANY
Ebert, Volker; 3.2, Gasanalytik und Zustandsverhalten, PTB-Braunschweig; Universität Heidelberg, Physikalisch-Chemisches Institut, Heidelberg, GERMANY; Technische Universität Darmstadt, Center of Smart Interfaces, Darmstadt, GERMANY
|
| Quelle/Jahr | Atmospheric Measurement Techniques: 10 (2016), 1, 35 - 57 |
| ISSN | 1867-8548 |
| DOI | |
| Verlag | Göttingen: Copernicus |
| Zusammenfassung | The novel Hygrometer for Atmospheric Investigations (HAI) realizes a unique concept for simultaneous gas-phase and total (gas-phase + evaporated cloud particles) water measurement. It has been developed and suc-cessfully employed for the first time on the German HALO research aircraft. This new instrument combines direct Tunable Diode Laser Absorption Spectroscopy (dTDLAS) with a first-principle evaluation method to allow absolute water vapor measurements without any initial or repetitive sensor calibration using a refer-ence gas or a reference humidity generator. HAI contains two completely independent dual-channel (closed-path, open-path) spectrometers, one at 1.4 µm and one at 2.6 my.m, which allow together to cover the entire at-mospheric H2O range from 1 to 40 000 ppmv with a single instrument. Both spectrometers comprise each a separate, wavelength-individual extractive, closed-path cell for total water (ice and gas-phase) measurements. Additionally, both spectrometers couple light into a common, open-path-cell outside of the aircraft fuselage for a direct, sampling-free and contactless determination of the gas-phase water content. This novel twin du-al-channel setup allows for the first time multiple self-validation functions i.e. in particular a reliable, direct, in-flight validation of the open-path channels. During the first field campaigns, the in-flight deviations be-tween the independent and calibration-free channels (i.e. closed-path to closed-path and open-path to closed-path) were on average in the 2 % range. Further, the fully autonomous HAI hygrometer allows measurements up to 240 Hz with a minimal integration time of 1.4 ms. The best precision is achieved by the 1.4 µm closed-path cell at 3.8 Hz (0.18 ppmv) and by the 2.6 µm closed-path cell at 13 Hz (0.055 ppmv). The requirements, design, operation principle and in-flight performance of the hygrometer are described in this work. |
| Kostenfreier Zugang | Open Access Gold |
| Rechteinformation | CC BY 3.0 ; Creative Commons Attribution 3.0 License |