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Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 35, 353-363, 2017
http://www.ann-geophys.net/35/353/2017/
doi:10.5194/angeo-35-353-2017
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Regular paper
07 Mar 2017
A comparison of ground-based hydroxyl airglow temperatures with SABER/TIMED measurements over 23° N, India
Navin Parihar1, Dupinder Singh2, and Subramanian Gurubaran2 1Equatorial Geophysical Research Laboratory, Indian Institute of Geomagnetism, Tirunelveli 627 011, India
2Indian Institute of Geomagnetism, Navi Mumbai 410 218, India
Abstract. Ground-based observations of OH (6, 2) Meinel band nightglow were carried out at Ranchi (23.3° N, 85.3° E), India, during January–March 2011, December 2011–May 2012 and December 2012–March 2013 using an all-sky imaging system. Near the mesopause, OH temperatures were derived from the OH (6, 2) Meinel band intensity information. A limited comparison of OH temperatures (TOH) with SABER/TIMED measurements in 30 cases was performed by defining almost coincident criterion of ±1.5° latitude–longitude and ±3 min of the ground-based observations. Using SABER OH 1.6 and 2.0 µm volume emission rate profiles as the weighing function, two sets of OH-equivalent temperature (T1. 6 and T2. 0 respectively) were estimated from its kinetic temperature profile for comparison with OH nightglow measurements. Overall, fair agreement existed between ground-based and SABER measurements in the majority of events within the limits of experimental errors. Overall, the mean value of OH-derived temperatures and SABER OH-equivalent temperatures were 197.3 ± 4.6, 192.0 ± 10.8 and 192.7 ± 10.3 K, and the ground-based temperatures were 4–5 K warmer than SABER values. A difference of 8 K or more is noted between two measurements when the peak of the OH emission layer lies in the vicinity of large temperature inversions. A comparison of OH temperatures derived using different sets of Einstein transition probabilities and SABER measurements was also performed; however, OH temperatures derived using Langhoff et al. (1986) transition probabilities were found to compare well.

Citation: Parihar, N., Singh, D., and Gurubaran, S.: A comparison of ground-based hydroxyl airglow temperatures with SABER/TIMED measurements over 23° N, India, Ann. Geophys., 35, 353-363, doi:10.5194/angeo-35-353-2017, 2017.
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Short summary
Using an all-sky imager, near-mesopause OH temperatures were derived from OH(6, 2) Meinel band intensity measurements. A limited comparison of OH temperatures with SABER/TIMED measurements performed by defining almost-coincident criteria of ±1.5° latitude–longitude and ±3 min indicated fair agreement between ground-based and SABER measurements in general. The difference of two measurements increased when the peak of the OH emission layer lay in the vicinity of large temperature inversions.
Using an all-sky imager, near-mesopause OH temperatures were derived from OH(6, 2) Meinel band...
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