A system for monitoring the hydrogen and oxygen stable isotope ratios of atmospheric water vapor

Abstract

The invention discloses a system for monitoring an atmospheric water vapor hydrogen-oxygen stable isotope ratio. The system is conducive to accurate and efficient production of multiple concentration levels of standard vapor in a bumpy or greatly fluctuant underway environment and saves a cost. The system comprises a dry air generation system, a sample introduction system, an atomization outputting system and a control system. The dry air generation system and the sample introduction system are respectively connected to the atomization outputting system. The control system is connected to the dry air generation system, the sample introduction system and the atomization outputting system. The sample introduction system is used for producing standard vapor with the same hydrogen-oxygen stable isotope ratio and different water vapor concentration levels. The control system is used for controlling operation of the dry air generation system, the sample introduction system and the atomization outputting system and for receiving and analyzing water vapor hydrogen-oxygen stable isotope ratio detection data provided by an isotope spectrometer.

Description

technical field [0001] The invention relates to the field of stable isotope testing, in particular to a system for monitoring the hydrogen and oxygen stable isotope ratio of atmospheric water vapor. Background technique [0002] Stable isotope ratios in atmospheric water vapor (δ 18 O and δD) monitoring, usually mainly rely on two means. The first is atmospheric water vapor cold trap collection, condensing the water vapor in the atmosphere and putting it into a sample bottle, and taking it back to the laboratory for analysis with an isotope mass spectrometer; this method has extremely high requirements for collection efficiency, and cannot achieve a 100% collection rate. Data is lower than actual value. The second method is the isotope spectrometer measurement method, which mainly uses the attenuation rate of infrared spectroscopy through water vapor to determine the composition ratio of specific isotopes. Due to its huge size, mass spectrometers are difficult to transpor...

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Problems solved by technology

2. Affected by subtle voltage changes and the system itself, continuous testing will show a drift error that changes with time, and it is unpredictable, which can be called drift error

This method has the following disadvantages: 1) For the generation of water vapor, the evaporating flask must be fixed, so that the standard water droplets can accurately fall into the evaporation table and instantly become water vapor, so it cannot be applied to mobile observation

2) This method can only produce a standard water vapor, and the drift error can only be corrected by the single-point method, and the error is very large

3) This method is to adjust the concentration of water vapor by adding bypass dry air after the water vapor is generated. In the actual operation process, the dry-wet ratio is difficult to control, and the correction effect on humidity-dependent errors is poor.

4) This method requires a very long period of equilibrium process to match the standard water vapor with a specific water vapor concentration, and the efficiency is very low

However, this method has the following disadvantages: 1) It can only be applied to relatively gentle vehicle-mounted or ship-mounted observations, but because the water-air pressure in the fractionating bottle will change under the sloshing scenario, it cannot be applied to turbulent or undulating environments. Navigation observation

2) This method does not generate standard water vapor with water vapor concentration steps, and cannot perform humidity-dependent correction

3) In this method, the generation of standard water vapor depends on the physical environment in the fractionating bottle. In other words, the value of standard water vapor needs to be calculated by the Rayleigh fractionation formula; and the condition established by the Rayleigh fractionation formula is an ideal equilibrium fractionation Environment, although the balanced fractionating bottle can simulate this environment, it can’t actually achieve it, which causes a certain calculation error

4) During the continuous measurement process, due to the fractional consumption of the standard water in the equilibrium fractionating flask, the stable isotope ratio of hydrogen and oxygen will gradually change, resulting in certain errors

5) A large amount of standard water samples are required for the balanced fractionating bottle, and it needs to be replaced when it is consumed to a certain extent, and the cost is also very high

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