scholarly journals Effect of water vapour absorption on hydroxyl temperatures measured from Svalbard

2017 ◽  
Vol 35 (3) ◽  
pp. 481-491 ◽  
Author(s):  
Joshua M. Chadney ◽  
Daniel K. Whiter ◽  
Betty S. Lanchester
Keyword(s):  
Water Vapour ◽  
Atmospheric Water ◽  
Echelle Spectrograph ◽  
Water Vapour Content ◽  
Atmospheric Water Vapour ◽  
Transmission Coefficients ◽  
Hydroxyl Airglow ◽  
Water Vapour Absorption ◽  
Vibrational Bands ◽  
High Throughput Imaging

Abstract. We model absorption by atmospheric water vapour of hydroxyl airglow emission using the HIgh-resolution TRANsmission molecular absorption database (HITRAN2012). Transmission coefficients are provided as a function of water vapour column density for the strongest OH Meinel emission lines in the (8–3), (5–1), (9–4), (8–4), and (6–2) vibrational bands. These coefficients are used to determine precise OH(8–3) rotational temperatures from spectra measured by the High Throughput Imaging Echelle Spectrograph (HiTIES), installed at the Kjell Henriksen Observatory (KHO), Svalbard. The method described in this paper also allows us to estimate atmospheric water vapour content using the HiTIES instrument.

scholarly journals Neutral temperature and atmospheric water vapour retrieval from spectral fitting of auroral and airglow emissions

2018 ◽  
Author(s):  
Joshua M. Chadney ◽  
Daniel K. Whiter
Keyword(s):  
Water Vapour ◽  
Atmospheric Parameter ◽  
Atmospheric Parameters ◽  
Atmospheric Water ◽  
Echelle Spectrograph ◽  
Atmospheric Water Vapour ◽  
Spectral Fitting ◽  
Fitting Method ◽  
Airglow Emissions ◽  
High Throughput Imaging

Abstract. We have developed a spectral fitting method to retrieve upper atmospheric parameters at multiple altitudes simultaneously during times of aurora, allowing us to measure neutral temperatures and column densities of water vapour. We use the method to separate airglow OH emissions from auroral O+ and N2 in observations between 725–740 nm using the High Throughput Imaging Echelle Spectrograph (HiTIES), located on Svalbard. In this paper, we describe our new method and show the results of Monte-Carlo simulations using synthetic spectra which demonstrate the validity of the spectral fitting method as well as provide an indication of uncertainties on the retrieval of each atmospheric parameter.

scholarly journals Neutral temperature and atmospheric water vapour retrieval from spectral fitting of auroral and airglow emissions

2018 ◽  
Vol 7 (4) ◽  
pp. 317-329 ◽  
Author(s):  
Joshua M. Chadney ◽  
Daniel K. Whiter
Keyword(s):  
Water Vapour ◽  
Atmospheric Parameter ◽  
Atmospheric Parameters ◽  
Atmospheric Water ◽  
Echelle Spectrograph ◽  
Atmospheric Water Vapour ◽  
Spectral Fitting ◽  
Fitting Method ◽  
Airglow Emissions ◽  
High Throughput Imaging

Abstract. We have developed a spectral fitting method to retrieve upper atmospheric parameters at multiple altitudes simultaneously during times of aurora, allowing us to measure neutral temperatures and column densities of water vapour. We use the method to separate airglow OH emissions from auroral O+ and N2 in observations between 725 and 740 nm using the High Throughput Imaging Echelle Spectrograph (HiTIES) located on Svalbard. In this paper, we describe our new method and show the results of Monte Carlo simulations using synthetic spectra which demonstrate the validity of the spectral fitting method and provide an indication of uncertainties on the retrieval of each atmospheric parameter. We show that the method allows for the retrieval of OH temperatures with an uncertainty of 6 % when contamination by N2 emission is small. N2 temperatures can be retrieved with uncertainties down to 3 %–5 % when N2 emission intensity is high. We can determine the intensity ratio between the O+ doublets at 732 and 733 nm (which is a function of temperature) with an uncertainty of 5 %.

scholarly journals Atmospheric water vapour content over La Silla Paranal Observatory

2009 ◽  
Vol 5 (H15) ◽  
pp. 537-537
Author(s):  
R. Querel ◽  
F. Kerber ◽  
R. Hanuschik ◽  
G. Lo Curto ◽  
D. Naylor ◽  
...  
Keyword(s):  
Real Time ◽  
Water Vapour ◽  
Atmospheric Water ◽  
Water Vapour Content ◽  
Atmospheric Water Vapour ◽  
Infrared Wavelengths ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Principle Source

Water vapour is the principle source of opacity at infrared wavelengths in the earth's atmosphere. Measurements of atmospheric water vapour serve two primary purposes when considering operation of an observatory: long-term monitoring of precipital water vapour (PWV) is useful for characterizing potential observatory sites, and real-time monitoring of PWV is useful for optimizing use, in particular for mid-IR observations.

scholarly journals Atmospheric water vapour and its effect on aerosol Extinction at a coastal station – Visakhapatnam

MAUSAM ◽  
2022 ◽  
Vol 44 (3) ◽  
pp. 243-248
Author(s):  
K. NIRANJAN ◽  
Y. RAMESH BABU
Keyword(s):  
Water Vapour ◽  
Solar Flux ◽  
Radiosonde Data ◽  
Aerosol Extinction ◽  
Atmospheric Water ◽  
Precipitable Water Vapour ◽  
Water Vapour Content ◽  
Coastal Station ◽  
Atmospheric Water Vapour ◽  
Flux Measurements

Integrated atmospheric water vapour content. has been evaluated from the spectral optical depths around the PaT band of water vapour by making directly transmitted solar flux measurements at 800, 935 and 1025 nm. The temporal variation of the total precipitable water vapour shows significant seasonal variation with maximum during~ pre-monsoon and monsoon months and minimum during winter months. The integrated content shows a positive correlation with surface humidity parameters and the correlation is better during monsoon months compared to other seasons. The experimentally derived variations of water vapour are compared with the model variations formulated using radiosonde data. The aerosol extinctions derived from the, multi-spectral solar flux measurements in the visible and near IR regions increase with increasing atmospheric water vapour and this increase shows .a seasonal dependence the surface temperature also seems to affect the, aerosol extinction probably through Its effect on the mixing heights.

Millimetre Astronomy and Antarctica

1996 ◽  
Vol 13 (2) ◽  
pp. 189-189
Author(s):  
Michael Burton
Keyword(s):  
Water Vapour ◽  
Thermal Emission ◽  
Spectral Features ◽  
Atmospheric Water ◽  
Water Vapour Content ◽  
Atmospheric Water Vapour ◽  
Dense Molecular Cloud ◽  
Molecular Lines ◽  
Days Open ◽  
The Antarctic

The thermal emission from a cold, dense molecular cloud peaks in the far IR, and the spectrum is rich in molecular lines in the submillimetre and millimetre bands. Observation of these bands is hindered, however, by atmospheric water vapour, which absorbs the incoming radiation. Ground-based mm observations from Australia, where the atmospheric water vapour content typically contains ~10 mm precipitable (ppt) H2O, can only probe a few of the molecular transitions from the heavier molecules, such as CO, CS, HCO+ and HCN. Sub-mm observations would enable the higher rotational lines from many of these molecules to be studied, and open up other spectral features to scrutiny, such as the lines from hydrides (e.g. CaH, NH, SH) and neutral carbon at 370 and 610 μm. However, they cannot be made from Australia. While sites such as Mauna Kea, which has ~1 mm ppt H2O on the best days, open the sub-mm band to partial viewing, their utility is limited in comparison to the opportunities possible from the Antarctic Plateau. Here the column of H2O drops to 100–250 μm.

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