Study of the (4–1) and (5–2) Hydroxyl Bands in the Night Airglow

1971 ◽  
Vol 49 (19) ◽  
pp. 2509-2517 ◽  
Author(s):  
A. W. Harrison ◽  
W. F. J. Evans ◽  
E. J. Llewellyn
Keyword(s):  
Seasonal Variation ◽  
Rotational Temperature ◽  
Band Intensity ◽  
K Value ◽  
Intensity Fluctuations ◽  
Single Night ◽  
Summer Minimum ◽  
Night Airglow

A 1 year study of the (4–1) and (5–2) hydroxyl bands in the night airglow near 1 μ has revealed a non-uniform rotational temperature across the P branch of each band. The temperature increases with K′ value. There is a pronounced seasonal variation of temperature showing a summer minimum and winter maximum. The average measured brightness for the (4–1) band is 4.6 kR (winter) and 3.5 kR (summer), and for the (5–2) band is 5.8 kR (winter) and 4.3 kR (summer). It is shown that the time-averaged total band intensity fluctuations during a single night are quite large, sometimes a factor of 2, and are not definitely correlated with the rotational temperature during the same period.

scholarly journals Role of Meteorological Parameters in the Diurnal and Seasonal Variation of NO2 in a Romanian Urban Environment

2020 ◽  
Vol 17 (17) ◽  
pp. 6228 ◽  
Author(s):  
Mirela Voiculescu ◽  
Daniel-Eduard Constantin ◽  
Simona Condurache-Bota ◽  
Valentina Călmuc ◽  
Adrian Roșu ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Relative Humidity ◽  
Urban Environment ◽  
Meteorological Parameters ◽  
Time Of Day ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Summer Minimum

The main purpose of this study was to investigate whether meteorological parameters (temperature, relative humidity, direct radiation) play an important role in modifying the NO2 concentration in an urban environment. The diurnal and seasonal variation recorded at a NO2 traffic station was analyzed, based on data collected in situ in a Romanian city, Braila (45.26° N, 27.95° E), during 2009–2014. The NO2 atmospheric content close to the ground had, in general, a summer minimum and a late autumn/winter maximum for most years. Two diurnal peaks were observed, regardless of the season, which were more evident during cold months. Traffic is an important contributor to the NO2 atmospheric pollution during daytime hours. The variability of in situ measurements of NO2 concentration compared relatively well with space-based observations of the NO2 vertical column by the Ozone Monitoring Instrument (OMI) satellite for most of the period under scrutiny. Data for daytime and nighttime (when the traffic is reduced) were analyzed separately, in the attempt to isolate meteorological effects. Meteorological parameters are not fully independent and we used partial correlation analysis to check whether the relationships with one parameter may be induced by another. The correlation between NO2 and temperature was not coherent. Relative humidity and solar radiation seemed to play a role in shaping the NO2 concentration, regardless of the time of day, and these relationships were only partially interconnected.

High-level turbulence over Europe and the Mediterranean

1963 ◽  
Vol 16 (2) ◽  
pp. 220-226
Author(s):  
J. Briggs
Keyword(s):  
Seasonal Variation ◽  
Mediterranean Areas ◽  
The Mediterranean ◽  
Summer Minimum ◽  
High Level

Aircrew reports of turbulence at heights between 20,000 and 40,000 ft. are analysed to show geographical and seasonal variation in incidence of turbulence. It is found that there is generally a summer minimum of turbulence and an autumn or winter maximum.Reports of the occurrence or non-occurrence of turbulence have been made for the flights of Comet 4B aircraft of British European Airways. Although the assessment of the turbulence was no more than subjective it was thought that the uniform nature of the aircraft, operating over a large number of flight sectors in the European and Mediterranean areas, and the fact that ‘nil’ returns were also made, could give useful indications of the geographical and seasonal variation of the incidence of the high-level turbulence. An analysis of the reports, made during a period of twelve months, is presented here.

Spectrum of the night airglow between 3 and 4 microns

1968 ◽  
Vol 46 (23) ◽  
pp. 2575-2578 ◽  
Author(s):  
R. MacDonald ◽  
H. L. Buijs ◽  
H. P. Gush
Keyword(s):  
Rotational Temperature ◽  
Rotational Structure ◽  
Intensity Analysis ◽  
Prominent Feature ◽  
Night Airglow

The spectrum of the night airglow has been measured between 3 and 4 μ at a limit of resolution of 4 cm−1, the observations being made at an altitude of 95 000 feet. The most prominent feature of the spectrum is the Δν = 1 sequence of hydroxyl bands. An intensity analysis of the rotational structure yields a rotational temperature of 234 °K. In addition, the ν3 band of methane near 3000 cm−1 and the ν3 band of CO2 near 2350 cm−1 appear in emission.

Night airglow hydroxyl rotational temperatures

1970 ◽  
Vol 48 (15) ◽  
pp. 1766-1768 ◽  
Author(s):  
A. W. Harrison ◽  
E. J. Llewellyn ◽  
D. C. Nicholls
Keyword(s):  
Rotational Temperature ◽  
Apparent Increase ◽  
Night Airglow

Rotational temperatures have been determined from observations of the OH emission in the night airglow. It is proposed that an apparent increase in the derived rotational temperature with the value of K′ may be explained in terms of a nonisothermal emitting region.

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