Microelectrode technique for in situ measurement of carbon dioxide concentrations in xylem sap of trees

Research on carbon dioxide (CO2) geological and biogeochemical cycles in the ocean is important to support the geoscience study. Continuous in-situ measurement of dissolved CO2 is critically needed. However, the time and spatial resolution are being restricted due to the challenges of very high submarine pressure and quite low efficiency in water-gas separation, which, therefore, are emerging the main barriers to deep sea investigation. We develop a fiber-integrated sensor based on cavity ring-down spectroscopy for in-situ CO2 measurement. Furthermore, a fast concentration retrieval model using exponential fit is proposed at non-equilibrium condition. The in-situ dissolved CO2 measurement achieves 10 times faster than conventional methods, where an equilibrium condition is needed. As a proof of principle, near-coast in-situ CO2 measurement was implemented in Sanya City, Haina, China, obtaining an effective dissolved CO2 concentration of ~950 ppm. The experimental results prove the feasibly for fast dissolved gas measurement, which would benefit the ocean investigation with more detailed scientific data.

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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

ASME 2009 7th International Conference on Nanochannels, Microchannels and Minichannels ◽

10.1115/icnmm2009-82001 ◽

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%.

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In situ measurement of physical solubility of carbon dioxide in loaded aqueous monoethanolamine by Raman spectroscopy

Journal of Natural Gas Science and Engineering ◽

10.1016/j.jngse.2016.10.029 ◽

2016 ◽

Vol 36 ◽

pp. 305-313 ◽

Cited By ~ 1

Author(s):

M.K. Wong ◽

M.A. Bustam ◽

A.M. Shariff

Keyword(s):

Carbon Dioxide ◽

Raman Spectroscopy ◽

In Situ Measurement

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In Situ Measurement of Dissolved Methane and Carbon Dioxide in Freshwater Ecosystems by Off-Axis Integrated Cavity Output Spectroscopy

Environmental Science & Technology ◽

10.1021/es500987j ◽

2014 ◽

Vol 48 (19) ◽

pp. 11421-11428 ◽

Cited By ~ 29

Author(s):

Rodrigo Gonzalez-Valencia ◽

Felipe Magana-Rodriguez ◽

Oscar Gerardo-Nieto ◽

Armando Sepulveda-Jauregui ◽

Karla Martinez-Cruz ◽

...

Keyword(s):

Carbon Dioxide ◽

Freshwater Ecosystems ◽

In Situ Measurement ◽

Dissolved Methane ◽

Cavity Output

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A framework for comparing remotely sensed and in-situ CO<sub>2</sub> concentrations

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-2555-2008 ◽

2008 ◽

Vol 8 (9) ◽

pp. 2555-2568 ◽

Cited By ~ 12

Author(s):

R. Macatangay ◽

T. Warneke ◽

C. Gerbig ◽

S. Körner ◽

R. Ahmadov ◽

...

Keyword(s):

Carbon Dioxide ◽

Transport Model ◽

Remotely Sensed ◽

Infrared Spectrometry ◽

Solar Absorption ◽

Mixing Ratios ◽

Global Calibration ◽

Carbon Dioxide Concentrations ◽

Made In

Abstract. A framework has been developed that allows validating CO2 column averaged volume mixing ratios (VMRs) retrieved from ground-based solar absorption measurements using Fourier transform infrared spectrometry (FTS) against measurements made in-situ (such as from aircrafts and tall towers). Since in-situ measurements are done frequently and at high accuracy on the global calibration scale, linking this scale with FTS total column retrievals ultimately provides a calibration scale for remote sensing. FTS, tower and aircraft data were analyzed from measurements during the CarboEurope Regional Experiment Strategy (CERES) from May to June 2005 in Biscarrosse, France. Carbon dioxide VMRs from the MetAir Dimona aircraft, the TM3 global transport model and Observations of the Middle Stratosphere (OMS) balloon based experiments were combined and integrated to compare with the FTS measurements. The comparison allows for calibrating the retrieved carbon dioxide VMRs from the FTS. The Stochastic Time Inverted Lagrangian Transport (STILT) model was then utilized to identify differences in surface influence regions or footprints between the FTS and the aircraft CO2 concentrations. Additionally, the STILT model was used to compare carbon dioxide concentrations from a tall tower situated in close proximity to the FTS station. The STILT model was then modified to produce column concentrations of CO2 to facilitate comparison with the FTS data. These comparisons were additionally verified by using the Weather Research and Forecasting – Vegetation Photosynthesis and Respiration Model (WRF-VPRM). The differences between the model-tower and the model-FTS were then used to calculate an effective bias of approximately −2.5 ppm between the FTS and the tower. This bias is attributed to the scaling factor used in the FTS CO2 data, which was to a large extent derived from the aircraft measurements made within a 50 km distance from the FTS station: spatial heterogeneity of carbon dioxide in the coastal area caused a low bias in the FTS calibration. Using STILT for comparing remotely sensed CO2 data with tower measurements of carbon dioxide and quantifying this comparison by means of an effective bias, provided a framework or a "transfer standard" that allowed validating the FTS retrievals versus measurements made in-situ.

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