scholarly journals Vertical wind profiling from troposphere to the lower mesosphere based on high resolution heterodyne near-infrared spectroradiometry

2019 ◽  
Author(s):  
Alexander V. Rodin ◽  
Dmitry V. Churbanov ◽  
Sergei G. Zenevich ◽  
Artem Yu. Klimchuk ◽  
Vladimir M. Semenov ◽  
...  
Keyword(s):  
Absorption Line ◽  
Line Profile ◽  
Spectral Resolution ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Rotational Line ◽  
Co2 Absorption ◽  
Signal To Noise ◽  
Overtone Band ◽  
Noise Ratio

Abstract. We propose a new technique of remote wind measurements based on Doppler analysis of a CO2 absorption line in the 1.605 μm overtone band measured in the direct Sun observation geometry. Heterodyne spectroradiometric measurements of the solar radiation passed through the atmosphere provides an unprecedented spectral resolution up to λ/δλ ~ 107–108 with a signal-to-noise ratio more than 100. The shape of the individual rotational line profile provides unambiguous relationship between offset from the line centre and altitude where a respective part of the line profile is formed. Therefore, an inverse problem may be posed in order to retrieve vertical distribution of wind, with retrievals vertical resolution compromised by a spectral resolution and signal-to-noise ratio of the measurements. A close coincidence between measured and synthetic absorption line is reached, with retrieved wind profile between the surface and 50 km being in a good agreement with reanalysis models. This method may pose an alternative to widely employed lidar and radar techniques.

scholarly journals Vertical wind profiling from the troposphere to the lower mesosphere based on high-resolution heterodyne near-infrared spectroradiometry

2020 ◽  
Vol 13 (5) ◽  
pp. 2299-2308 ◽  
Author(s):  
Alexander V. Rodin ◽  
Dmitry V. Churbanov ◽  
Sergei G. Zenevich ◽  
Artem Y. Klimchuk ◽  
Vladimir M. Semenov ◽  
...  
Keyword(s):  
Absorption Line ◽  
Line Profile ◽  
Spectral Resolution ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Line Center ◽  
Rotational Line ◽  
Co2 Absorption ◽  
Signal To Noise ◽  
Noise Ratio

Abstract. We propose a new technique of remote wind measurements based on Doppler analysis of a CO2 absorption line in the 1.605 µm overtone band measured in the direct Sun observation geometry. Heterodyne spectroradiometric measurements of the solar radiation passing through the atmosphere provide an unprecedented spectral resolution up to λ/δλ∼6×107, with a signal-to-noise ratio of more than 100. The shape of the individual rotational line profile provides an unambiguous relationship between the offset from the line center and the altitude at which the respective part of the line profile is formed. Therefore, an inverse problem may be posed in order to retrieve the vertical distribution of wind because with retrievals the vertical resolution is compromised by a spectral resolution and the signal-to-noise ratio of the measurements. A close coincidence between the measured and synthetic absorption line is reached, with retrieved wind profiles between the surface and 50 km being in good agreement with reanalysis models. This method may pose an alternative to widely employed lidar and radar techniques.

scholarly journals Evaluation of Measurement Sites for Noninvasive Blood Glucose Sensing with Near-Infrared Transmission Spectroscopy

1999 ◽  
Vol 45 (9) ◽  
pp. 1621-1627 ◽  
Author(s):  
Jason J Burmeister ◽  
Mark A Arnold
Keyword(s):  
Blood Glucose ◽  
Body Fat ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Glucose Sensing ◽  
Infrared Transmission ◽  
Signal To Noise ◽  
Lower Lip ◽  
Percentage Of Body Fat ◽  
Noise Ratio

Abstract Six putative measurement sites were evaluated for noninvasive sensing of blood glucose by first-overtone near-infrared spectroscopy. The cheek, lower lip, upper lip, nasal septum, tongue, and webbing tissue between the thumb and forefinger were examined. These sites were evaluated on the basis of their chemical and physical properties as they pertain to the noninvasive measurement of glucose. Critical features included the effective optical pathlength of aqueous material within the tissue and the percentage of body fat within the optical path. Aqueous optical paths of 5 mm are required to measure clinically relevant concentrations of glucose in the first-overtone region. All of the tested sites met this requirement. The percentage of body fat affects the signal-to-noise ratio of the measurement and must be minimized for reliable glucose sensing. The webbing tissue contains a considerable amount of fat tissue and is clearly the worse measurement site. All other sites possess substantially less fat, with the least amount of fat in tongue tissue. For this reason, the tongue provides spectra with the highest signal-to-noise ratio and is, therefore, the site of choice on the basis of spectral quality.

Bioapplications and biotechnologies of upconversion nanoparticle-based nanosensors

The Analyst ◽  
2016 ◽  
Vol 141 (12) ◽  
pp. 3601-3620 ◽  
Author(s):  
Chengli Wang ◽  
Xiaomin Li ◽  
Fan Zhang
Keyword(s):  
Optical Properties ◽  
High Resistance ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Upconversion Nanoparticles ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Auto Fluorescence ◽  
New Generation ◽  
Narrow Emission

Upconversion nanoparticles (UCNPs), which can emit ultraviolet/visible (UV/Vis) light under near-infrared (NIR) excitation, are regarded as a new generation of nanoprobes because of their unique optical properties, including a virtually zero auto-fluorescence background for the improved signal-to-noise ratio, narrow emission bandwidths and high resistance to photo-bleaching.

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