In-situ sensing of tropospheric water vapor using an airborne near-IR diode laser hygrometer

1998 ◽  
Vol 67 (3) ◽  
pp. 275-282 ◽  
Author(s):  
D.M. Sonnenfroh ◽  
W.J. Kessler ◽  
J.C. Magill ◽  
B.L. Upschulte ◽  
M.G. Allen ◽  
...  
Keyword(s):  
Water Vapor ◽  
Diode Laser ◽  
Near Ir ◽  
In Situ Sensing

scholarly journals In-situ measurement of water-vapor in fire environments using a real-time tunable diode laser based system

2020 ◽  
pp. 103114
Author(s):  
Shruti Ghanekar ◽  
Rajavasanth Rajasegar ◽  
Nicholas Traina ◽  
Constandinos Mitsingas ◽  
Richard M. Kesler ◽  
...  
Keyword(s):  
Water Vapor ◽  
Real Time ◽  
Diode Laser ◽  
In Situ Measurement ◽  
Tunable Diode Laser ◽  
In Fire

Simultaneous diode laser based in situ quantification of oxygen, carbon monoxide, water vapor, and liquid water in a dense water mist environment

2007 ◽  
Vol 31 (1) ◽  
pp. 799-806 ◽  
Author(s):  
Andrew R. Awtry ◽  
Brian T. Fisher ◽  
Robert A. Moffatt ◽  
Volker Ebert ◽  
James W. Fleming
Keyword(s):  
Carbon Monoxide ◽  
Water Vapor ◽  
Diode Laser ◽  
Liquid Water ◽  
Water Mist ◽  
Dense Water

Near-IR diode-laser-based sensor for parts-per-billion-level water vapor in industrial gases

1999 ◽  
Author(s):  
William J. Kessler ◽  
Mark G. Allen ◽  
Steven J. Davis ◽  
Phillip A. Mulhall ◽  
Jan A. Polex
Keyword(s):  
Water Vapor ◽  
Diode Laser ◽  
Near Ir ◽  
Industrial Gases

Lightweight diode laser spectrometer CHILD (Compact High-altitude In-situ Laser Diode) for balloonborne measurements of water vapor and methane

2005 ◽  
Vol 44 (1) ◽  
pp. 91 ◽  
Author(s):  
Wolfgang Gurlit ◽  
Rainer Zimmermann ◽  
Carsten Giesemann ◽  
Thomas Fernholz ◽  
Volker Ebert ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Altitude ◽  
Diode Laser ◽  
Laser Diode ◽  
Laser Spectrometer ◽  
Diode Laser Spectrometer

scholarly journals Comparison of Water Vapor Measurements by Airborne Sun Photometer and Diode Laser Hygrometer on the NASA DC-8

2008 ◽  
Vol 25 (10) ◽  
pp. 1733-1743 ◽  
Author(s):  
J. M. Livingston ◽  
B. Schmid ◽  
P. B. Russell ◽  
J. R. Podolske ◽  
J. Redemann ◽  
...  
Keyword(s):  
Water Vapor ◽  
Diode Laser ◽  
Free Stream ◽  
Vapor Density ◽  
Aircraft Fuselage ◽  
Sun Photometer ◽  
Local Water ◽  
Highly Correlated ◽  
First Time

Abstract In January–February 2003, the 14-channel NASA Ames airborne tracking sun photometer (AATS) and the NASA Langley/Ames diode laser hygrometer (DLH) were flown on the NASA DC-8 aircraft. The AATS measured column water vapor on the aircraft-to-sun path, while the DLH measured local water vapor in the free stream between the aircraft fuselage and an outboard engine cowling. The AATS and DLH measurements have been compared for two DC-8 vertical profiles by differentiating the AATS column measurement and/or integrating the DLH local measurement over the altitude range of each profile (7.7–10 km and 1.1–12.5 km). These comparisons extend, for the first time, tests of AATS water vapor retrievals to altitudes >∼6 km and column contents <0.1 g cm−2. To the authors’ knowledge, this is the first time suborbital spectroscopic water vapor measurements using the 940-nm band have been tested in conditions so high and dry. Values of layer water vapor (LWV) calculated from the AATS and DLH measurements are highly correlated for each profile. The composite dataset yields r 2 0.998, rms difference 7.7%, and bias (AATS minus DLH) 1.0%. For water vapor densities AATS and DLH had r 2 0.968, rms difference 27.6%, and bias (AATS minus DLH) −4.2%. These results for water vapor density compare favorably with previous comparisons of AATS water vapor to in situ results for altitudes <∼6 km, columns ∼0.1 to 5 g cm−2, and densities ∼0.1 to 17 g m−3.

In-Situ Optical Measurements of Water Vapor Concentration and Temperature in a Proton Exchange Membrane Fuel Cell at Steady State and Under Dynamic Cycling

2009 ◽  
Author(s):  
Ritobrata Sur ◽  
Thomas J. Boucher ◽  
Michael W. Renfro ◽  
Baki M. Cetegen
Keyword(s):  
Water Vapor ◽  
Fuel Cell ◽  
Partial Pressure ◽  
Diode Laser ◽  
Pem Fuel Cell ◽  
Tunable Diode Laser ◽  
Cathode Side ◽  
Vapor Concentration ◽  
Water Vapor Concentration

A robust, accurate and fast in-situ sensor was developed for detection of water vapor partial pressure and temperature simultaneously at the anode and cathode channels of a PEM fuel cell. Tunable diode laser absorption spectroscopy (TDLAS) utilizing wavelength modulation (WMS) was employed for these measurements. This method determines the ratio of the second and first harmonics (2f/1f) of the spectroscopic absorption profile of water vapor by the aid of a software lock-in amplifier. Measurements were taken using a diode laser emitting around a wavelength of 1471 nm where the water vapor absorption exhibits significant sensitivity to partial pressure and temperature. Measurements of water vapor concentration and temperature in were taken at steady and dynamic operating conditions in the anode and cathode gas channels near the inlet and outlet ports of a serpentine channel PEM fuel cell with Nafion membrane of active area 50 cm2. Different load and inlet humidity conditions were tested to characterize the operation at different conditions. The partial pressure of water vapor increases towards the exit of both the gas channels, but the increase is found to be more significant on the cathode side. The dynamic operation of the fuel cell was also examined in this study as well as the simultaneous measurements at the anode and cathode gas channels.

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