Long-term variation of OH peak emission altitude and volume emission rate over Indian low latitudes

Abstract. The OH airglow has been used to investigate the chemistry and dynamics of the mesosphere and the lower thermosphere (MLT) for a long time. The infrared imager (IRI) aboard the Odin satellite has been recording the night-time 1.53 µm OH (3-1) emission for more than 15 years (2001–2015), and we have recently processed the complete data set. The newly derived data products contain the volume emission rate profiles and the Gaussian-approximated layer height, thickness, peak intensity and zenith intensity, and their corresponding error estimates. In this study, we describe the retrieval steps for these data products. We also provide data screening recommendations. The monthly zonal averages depict the well-known annual oscillation and semi-annual oscillation signatures, which demonstrate the fidelity of the data set (https://doi.org/10.5281/zenodo.4746506, Li et al., 2021). The uniqueness of this Odin IRI OH long-term data set makes it valuable for studying various topics, for instance, the sudden stratospheric warming events in the polar regions and solar cycle influences on the MLT.

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The OH (3-1) nightglow volume emission rate retrieved from OSIRIS measurements: 2001 to 2015

10.5194/essd-2021-191 ◽

2021 ◽

Author(s):

Anqi Li ◽

Chris Z. Roth ◽

Adam E. Bourassa ◽

Douglas A. Degenstein ◽

Kristell Pérot ◽

...

Keyword(s):

Emission Rate ◽

Polar Regions ◽

Data Set ◽

Infrared Imager ◽

Data Products ◽

Long Time ◽

Volume Emission ◽

Derived Data ◽

Term Data

Abstract. The OH airglow has been used to investigate the chemistry and dynamics of the mesosphere and the lower thermo-sphere (MLT) for a long time. The infrared imager (IRI) aboard the Odin satellite has been recording the nighttime 1.53 μm OH (3-1) emission for more than 15 years (2001–2015) and we have recently processed the complete data set. The newly derived data products contain the volume emission rate profiles and the Gaussian approximated layer height, thickness, peak intensity and zenith intensity, and their corresponding error estimates. In this study, we describe the retrieval steps of these data products. We also provide data screening recommendations. The monthly zonal averages depict the well known annual oscillation and semi-annual oscillation signatures, which demonstrate the fidelity of the data set (https://doi.org/10.5281/zenodo.4746506, Li et al. (2021)). The uniqueness of this Odin-IRI OH long-term data set makes it valuable for studying various topics, for instance, the sudden stratospheric warming events in the polar regions and solar cycle influences on the MLT.

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Inferring hydroxyl layer peak heights from ground-based measurements of OH(6-2) band integrated emission rate at Longyearbyen (78° N, 16° E)

Annales Geophysicae ◽

10.5194/angeo-27-4197-2009 ◽

2009 ◽

Vol 27 (11) ◽

pp. 4197-4205 ◽

Cited By ~ 25

Author(s):

F. J. Mulligan ◽

M. E. Dyrland ◽

F. Sigernes ◽

C. S. Deehr

Keyword(s):

Emission Rate ◽

Winter Season ◽

Extended Period ◽

Emission Layer ◽

Atmospheric Extinction ◽

Volume Emission ◽

Km Value ◽

Hydroxyl Layer ◽

Peak Emission ◽

Layer Peak

Abstract. Measurements of hydroxyl nightglow emissions over Longyearbyen (78° N, 16° E) recorded simultaneously by the SABER instrument onboard the TIMED satellite and a ground-based Ebert-Fastie spectrometer have been used to derive an empirical formula for the height of the OH layer as a function of the integrated emission rate (IER). Altitude profiles of the OH volume emission rate (VER) derived from SABER observations over a period of more than six years provided a relation between the height of the OH layer peak and the integrated emission rate following the procedure described by Liu and Shepherd (2006). An extended period of overlap of SABER and ground-based spectrometer measurements of OH(6-2) IER during the 2003–2004 winter season allowed us to express ground-based IER values in terms of their satellite equivalents. The combination of these two formulae provided a method for inferring an altitude of the OH emission layer over Longyearbyen from ground-based measurements alone. Such a method is required when SABER is in a southward looking yaw cycle. In the SABER data for the period 2002–2008, the peak altitude of the OH layer ranged from a minimum near 76 km to a maximum near 90 km. The uncertainty in the inferred altitude of the peak emission, which includes a contribution for atmospheric extinction, was estimated to be ±2.7 km and is comparable with the ±2.6 km value quoted for the nominal altitude (87 km) of the OH layer. Longer periods of overlap of satellite and ground-based measurements together with simultaneous on-site measurements of atmospheric extinction could reduce the uncertainty to approximately 2 km.

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