Simultaneous lidar observations of a noctilucent cloud and an internal wave in the polar mesosphere

Autor: T. Hou, Toshikazu Itabe, T. E. Stern, C. Ramos, Michael C. Kelley, Michael J. Nicolls, Kohei Mizutani, Richard L. Collins
Rok vydání: 2003
Předmět:
Zdroj: Journal of Geophysical Research. 108
ISSN: 0148-0227
DOI: 10.1029/2002jd002427
Popis: [1] Lidar and radar observations of the upper mesosphere and lower thermosphere were conducted in interior Alaska (65°N, 147°W) during the summer of 2001. Lidar observations of a noctilucent cloud (NLC) were made on the night of 20–21 August 2001 during a visible noctilucent cloud display when the midnight solar depression angle was 12°. These nighttime lidar observations in late August have yielded measurements of both the NLC at 82.7 km and the mesospheric temperature profile below the cloud (∼40–80 km). Analysis of the temperature profile indicates the presence of a wave with a vertical wavelength of 7.9 km. The altitude of the NLC coincides with the cold phase of the temperature wave. Located approximately 50 km from the lidar, radar observations yielded measurements of polar mesosphere summer echoes (PMSEs) during daytime on 21 August 2001. The PMSE layer occurs just above the NLC layer and also shows structural characteristics associated with the passage of gravity waves through the layer. The presence of NLCs in late August supports recent reports that the late summer Arctic mesosphere is colder and wetter than represented in “standard” models. These NLC observations are discussed in terms of earlier lidar observations over Alaska, observations at other sites, and current models.
Databáze: OpenAIRE
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