In Situ Measurement of the Water Vapor 18O/16O Isotope Ratio for Atmospheric and Ecological Applications

2005 ◽  
Vol 22 (5) ◽  
pp. 555-565 ◽  
Author(s):  
Xuhui Lee ◽  
Steve Sargent ◽  
Ronald Smith ◽  
Bert Tanner
Keyword(s):  
Water Vapor ◽  
Standard Deviation ◽  
Isotope Ratio ◽  
In Situ Measurement ◽  
Tunable Diode Laser ◽  
Cold Trap ◽  
Mixing Ratio ◽  
Dewpoint Temperature ◽  
Ecological Applications

Abstract In this paper a system for in situ measurement of H216O/H218O in air based on tunable diode laser (TDL) absorption spectroscopy is described. Laboratory tests showed that its 60-min precision (one standard deviation) was 0.21‰ at a water vapor volume mixing ratio of 2.67 mmol mol−1 (dewpoint temperature −10.8°C at sea level) and improved to 0.09 at 15.3 mmol mol−1 (dewpoint temperature 13.4°C). The TDL measurement of the vapor generated by a dewpoint generator differed from the equilibrium prediction by −0.11 ± 0.43‰ (mean ± one standard deviation). Its measurement of the ambient water vapor differed from the cold-trap/mass spectrometer method by −0.36 ± 1.43‰. The larger noise of the latter comparison was caused primarily by the difficulty in extracting vapor from air without altering its isotope content. In a 1-week test in Logan, Utah, in August 2003, the isotope ratio of water vapor in ambient air was positively correlated with the water vapor mixing ratio and also responded to wetting events (rain and irrigation) in an expected manner. This system has been in continuous operation in New Haven, Connecticut, since December 2003. It is suggested that such uninterrupted measurement may open a new window on the hydrologic cycle, particularly processes involving phase changes of water, and can increase the power of the isotope method in ecological applications.

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

scholarly journals Characteristics of Seasonal Variation of Near-Surface Water Vapor D/H Isotope Ratio Revealed by Continuous in situ Measurement in Sapporo, Japan

SOLA ◽  
2012 ◽  
Vol 8 ◽  
pp. 5-8 ◽  
Author(s):  
‘Niyi Sunmonu ◽  
Ken-ichiro Muramoto ◽  
Naoyuki Kurita ◽  
Kei Yoshimura ◽  
Yasushi Fujiyoshi
Keyword(s):  
Seasonal Variation ◽  
Water Vapor ◽  
Surface Water ◽  
Isotope Ratio ◽  
In Situ Measurement ◽  
Near Surface

scholarly journals Post-caldera volcanism: in situ measurement of U–Pb age and oxygen isotope ratio in Pleistocene zircons from Yellowstone caldera

2001 ◽  
Vol 189 (3-4) ◽  
pp. 197-206 ◽  
Author(s):  
Ilya N. Bindeman ◽  
John W. Valley ◽  
J.L. Wooden ◽  
Harold M. Persing
Keyword(s):  
Oxygen Isotope ◽  
Isotope Ratio ◽  
In Situ Measurement ◽  
Oxygen Isotope Ratio ◽  
Yellowstone Caldera

scholarly journals Aircraft validation of Aura Tropospheric Emission Spectrometer retrievals of HDO / H<sub>2</sub>O

2014 ◽  
Vol 7 (9) ◽  
pp. 3127-3138 ◽  
Author(s):  
R. L. Herman ◽  
J. E. Cherry ◽  
J. Young ◽  
J. M. Welker ◽  
D. Noone ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Standard Deviation ◽  
Lower Troposphere ◽  
Temporal Variations ◽  
Observation Error ◽  
Free Troposphere ◽  
Data Set ◽  
Airborne Measurements

Abstract. The EOS (Earth Observing System) Aura Tropospheric Emission Spectrometer (TES) retrieves the atmospheric HDO / H2O ratio in the mid-to-lower troposphere as well as the planetary boundary layer. TES observations of water vapor and the HDO isotopologue have been compared with nearly coincident in situ airborne measurements for direct validation of the TES products. The field measurements were made with a commercially available Picarro L1115-i isotopic water analyzer on aircraft over the Alaskan interior boreal forest during the three summers of 2011 to 2013. TES special observations were utilized in these comparisons. The TES averaging kernels and a priori constraints have been applied to the in situ data, using version 5 (V005) of the TES data. TES calculated errors are compared with the standard deviation (1σ) of scan-to-scan variability to check consistency with the TES observation error. Spatial and temporal variations are assessed from the in situ aircraft measurements. It is found that the standard deviation of scan-to-scan variability of TES δD is ±34.1‰ in the boundary layer and ± 26.5‰ in the free troposphere. This scan-to-scan variability is consistent with the TES estimated error (observation error) of 10–18‰ after accounting for the atmospheric variations along the TES track of ±16‰ in the boundary layer, increasing to ±30‰ in the free troposphere observed by the aircraft in situ measurements. We estimate that TES V005 δD is biased high by an amount that decreases with pressure: approximately +123‰ at 1000 hPa, +98‰ in the boundary layer and +37‰ in the free troposphere. The uncertainty in this bias estimate is ±20‰. A correction for this bias has been applied to the TES HDO Lite Product data set. After bias correction, we show that TES has accurate sensitivity to water vapor isotopologues in the boundary layer.

scholarly journals Intercomparison of in situ water vapor balloon-borne measurements from Pico-SDLA H<sub>2</sub>O and FLASH-B in the tropical UTLS

2015 ◽  
Vol 8 (12) ◽  
pp. 13693-13727
Author(s):  
M. Ghysels ◽  
E. D. Riviere ◽  
S. Khaykin ◽  
C. Stoeffler ◽  
N. Amarouche ◽  
...  
Keyword(s):  
Water Vapor ◽  
Low Cost ◽  
Deep Convection ◽  
Mixing Ratio ◽  
Stratospheric Water Vapor ◽  
In Situ Techniques ◽  
Scientific Project ◽  
Water Vapor Mixing Ratio ◽  
The Impact

Abstract. In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, Sao Paulo St., Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within a small volume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the cold-point tropopause to within 1.9 and 0.5 % for the first and second flights, respectively. This level of agreement for measured stratospheric water mixing ratio is among the best ever reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B datasets are mutually consistent.

scholarly journals First airborne water vapor lidar measurements in the tropical upper troposphere and mid-latitudes lower stratosphere: accuracy evaluation and intercomparisons with other instruments

2008 ◽  
Vol 8 (17) ◽  
pp. 5245-5261 ◽  
Author(s):  
C. Kiemle ◽  
M. Wirth ◽  
A. Fix ◽  
G. Ehret ◽  
U. Schumann ◽  
...  
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Average Distance ◽  
Tropical Convection ◽  
Water Vapor Transport ◽  
Mixing Ratio ◽  
Upper Troposphere ◽  
Research Aircraft ◽  
Tropical Upper Troposphere

Abstract. In the tropics, deep convection is the major source of uncertainty in water vapor transport to the upper troposphere and into the stratosphere. Although accurate measurements in this region would be of first order importance to better understand the processes that govern stratospheric water vapor concentrations and trends in the context of a changing climate, they are sparse because of instrumental shortcomings and observational challenges. Therefore, the Falcon research aircraft of the Deutsches Zentrum für Luft- und Raumfahrt (DLR) flew a zenith-viewing water vapor differential absorption lidar (DIAL) during the Tropical Convection, Cirrus and Nitrogen Oxides Experiment (TROCCINOX) in 2004 and 2005 in Brazil. The measurements were performed alternatively on three water vapor absorption lines of different strength around 940 nm. These are the first aircraft DIAL measurements in the tropical upper troposphere and in the mid-latitudes lower stratosphere. Sensitivity analyses reveal an accuracy of 5% between altitudes of 8 and 16 km. This is confirmed by intercomparisons with the Fast In-situ Stratospheric Hygrometer (FISH) and the Fluorescent Advanced Stratospheric Hygrometer (FLASH) onboard the Russian M-55 Geophysica research aircraft during five coordinated flights. The average relative differences between FISH and DIAL amount to −3%±8% and between FLASH and DIAL to −8%±14%, negative meaning DIAL is more humid. The average distance between the probed air masses was 129 km. The DIAL is found to have no altitude- or latitude-dependent bias. A comparison with the balloon ascent of a laser absorption spectrometer gives an average difference of 0%±19% at a distance of 75 km. Six tropical DIAL under-flights of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board ENVISAT reveal a mean difference of −8%±49% at an average distance of 315 km. While the comparison with MIPAS is somewhat less significant due to poorer comparison conditions, the agreement with the in-situ hygrometers provides evidence of the excellent quality of FISH, FLASH and DIAL. Most DIAL profiles exhibit a smooth exponential decrease of water vapor mixing ratio in the tropical upper troposphere to lower stratosphere transition. The hygropause with a minimum mixing ratio of 2.5 µmol/mol is found between 15 and 17 km. A high-resolution (2 km horizontal, 0.2 km vertical) DIAL cross section through the anvil outflow of tropical convection shows that the ambient humidity is increased by a factor of three across 100 km.

Novel In-Situ Laser Based Diagnostics for Measurement of Water Vapor and Carbon Dioxide Concentrations in the Gas Distribution Channels of a PEM Fuel Cell

2009 ◽  
Author(s):  
Derek E. Lambe ◽  
Kyle Seleski ◽  
Ranganathan Kumar ◽  
Saptarshi Basu
Keyword(s):  
Carbon Dioxide ◽  
Water Vapor ◽  
Fuel Cell ◽  
Visual Observation ◽  
Test Cell ◽  
Tunable Diode Laser ◽  
Flow Paths ◽  
Laser Absorption ◽  
Carbon Dioxide Concentrations

A novel method has been implemented for measuring the concentration of various gas species (water vapor, carbon dioxide) within fuel cell gas channels and other minichannel applications in a non-invasive manner through the use of tunable diode laser absorption spectroscopy (TDLAS). An optically accessible test cell has been designed to allow for the passage of 1–0.5 millimeter diameter laser beams along 12 mm-12 cm long flow paths, while also allowing for visual observation of the channels in order to detect the formation of liquid water. Concentrations of water vapor and carbon dioxide have been measured in situ within the test cell with a temporal resolution of 0.5 secs and 2.5 secs respectively. The technique is portable to high aspect ratio channels yielding concentration measurements of species over 1 mm long passages with an experimental uncertainty of 5%.

scholarly journals In situ observations of “cold trap" dehydration in the western tropical Pacific

2006 ◽  
Vol 6 (4) ◽  
pp. 6903-6931
Author(s):  
F. Hasebe ◽  
M. Fujiwara ◽  
N. Nishi ◽  
M. Shiotani ◽  
H. Vömel ◽  
...  
Keyword(s):  
Water Vapor ◽  
Trajectory Analysis ◽  
Cold Trap ◽  
Temperature History ◽  
Vapor Concentration ◽  
Tropical Tropopause Layer ◽  
Tropical Tropopause ◽  
History Of ◽  
In Situ Observations

Abstract. Water vapor sonde observations were conducted at Bandung, Indonesia (6.90 S, 107.60 E) and Tarawa, Kiribati (1.35 N, 172.91 E) in December 2003 to examine the efficiency of the "cold trap'' dehydration in the tropical tropopause layer (TTL). Trajectory analysis based on bundles of trajectories suggest that the modification of air parcels' identity due to irreversible mixing by the branching-out and merging-in of nearby trajectories is found to be an important factor, in addition to the routes air parcels are supposed to follow, for interpreting the water vapor concentrations observed by radiosondes in the TTL. Clear correspondence between the observed water vapor concentration and the estimated temperature history of air parcels is found showing that dry air parcels are exposed to low temperatures while humid air parcels do not experience cold conditions during advection, in support of the "cold trap'' hypothesis. It is suggested that the observed air parcel retained the water vapor by roughly twice as much as the minimum saturation mixing ratio after its passage through the "cold trap,'' although appreciable uncertainties remain.

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