Determination of day‐time OH emission heights using simultaneous meteor radar, day‐glow photometer and TIMED/SABER observations over Thumba (8.5°N, 77°E)

Kumar

International Journal of Remote Sensing

et al. 2012

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Variability of mesopause temperature derived from two independent methods using meteor radar and its comparison with SABER and EOS MLS and a collocated multi-wavelength dayglow photometer over an equatorial station, Thumba (8.Two independent methods for deriving mesopause temperature using meteor radar installed at an equatorial station, Thumba (8.5 • N, 76.5 • E), are discussed in this article. This meteor radar-derived mesopause temperature is then compared with two different types of spaceborne measurement, namely (i) Sounding the Atmosphere using Broadband Emission Radiometry (SABER) and (ii) the Earth Observing System Microwave Limb Sounder (EOS MLS), and a collocated multiwavelength dayglow photometer (DGPM). The meteor radar-derived temperature is in fairly good agreement with all the three measurement techniques, with an uncertainty of ±10 • . This study focuses on a detailed evaluation and inter-comparison of mesopause temperature derived from different measurement techniques. An attempt is also made to compare the suitability of these observations to study planetary waves and other oscillation activities in the mesospheric region.

Section: Multi-wavelength Dayglow Photometermentioning

confidence: 57%

Variability of mesopause temperature derived from two independent methods using meteor radar and its comparison with SABER and EOS MLS and a collocated multi-wavelength dayglow photometer over an equatorial station, Thumba (8.5° N, 76.5° E)

Kumar

International Journal of Remote Sensing

et al. 2012

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“…Takahashi et al (2005) reported OH emission heights deduced from cross correlating rotational temperatures from the OH(6-2) band and meteor trail ambipolar diffusion coefficients at Shigaraki (35 • N, 136 • E). Kumar et al (2008) employed a similar technique to infer day-time emission heights over Thumba (8.5 • N, 77 • E) which corresponded well with peak heights observed in SABER OH VER profiles in the same time period. Liu and Shepherd (2006) found that, in the latitude range 40 • S to 40 • N, the altitude of the peak of the OH layer is almost completely described by the integrated emission rates (IER) in their study of WINDII profiles from the UARS satellite.…”

Section: Introductionmentioning

confidence: 93%

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

Mulligan

Dyrland²,

Sigernes³

et al. 2009

Ann. Geophys.

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 onsite measurements of atmospheric extinction could reduce the uncertainty to approximately 2 km.

“…So the height distribution of the emission layer would indirectly affect the measured OH temperature. The temperature has shown to have a negative correlation with the OH height [Kumar et al, 2008]. Similarly, the mesopause altitude has also shown to have a negative correlation with the mesopause temperature [Friedman, 2003].…”

Section: Variability Of Daytime Mesopause Temperature During the Daymentioning

confidence: 95%

“…This may be because of a multitude of reasons including the seasonal variation in the OH layer height and the mesopause altitude. However, a study carried out by Kumar et al [2008] during the February to March 2005 period showed that the OH layer is located at around 90 km over Trivandrum. Therefore, more comprehensive analysis is required to quantify this aspect and will be attempted in future.…”

Section: Seasonal Variabilitymentioning

confidence: 99%

Daytime upper mesospheric energetics over a tropical station, Trivandrum (8.5°N, 77°E): An investigation using the multiwavelength dayglow photometry

2011

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[1] This paper presents the first systematic measurements of "daytime" upper mesosphere temperatures over Trivandrum (8.5°N, 77°E), a near equatorial station in India. The measurements were made using a unique meridional scanning multiwavelength dayglow photometer. The first ever observation of the short-scale (within a day), seasonal (during a year), and spatiotemporal (spanning over a region of ∼300 km centered at Trivandrum) variation of the daytime upper mesospheric temperature have been discussed. In general, the daytime mesospheric temperatures over this latitude exhibit large variability in their short scale seasonal, and spatiotemporal characteristics. The seasonal variation of temperature during the year 2005 exhibited a clear-cut semiannual oscillation pattern with minima around day numbers 75 and 250, which corroborate well with the earlier measurements of temperature over Thumba using the sounding rockets.Citation: Vineeth, C., T. K. Pant, and R. Sridharan (2011), Daytime upper mesospheric energetics over a tropical station, Trivandrum (8.5°N, 77°E): An investigation using the multiwavelength dayglow photometry,