Mudanca global na camada atmosferica de sodio

Clemesha, B. R.; Batista, P. P.; Simonich, D .M

doi:10.3997/2214-4609-pdb.313.41

Cited by 1 publication

(2 citation statements)

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“…Some of the column density variability is due to the existence of sporadic layers, but even without a sporadic layer, the density changes throughout the night. The exact causes of this variation are still in considerable doubt (Clemesha et al 2002). The intranight variations are also quite large.…”

Section: Column Densitymentioning

confidence: 99%

“…The cause of the sporadic layers is still a matter of active research (Collins et al 2002;Prasanth et al 2006). Possible causes are tides, gravity waves, or photochem-istry (Clemesha et al 2002), and they are often linked to sporadic E-layers in the ionosphere. Sporadic layers are quite large: Qian et al (1998) detected 18 sporadic events near Hawaii and measured their horizontal extents to be from 25 to 1560 km, with a mean of 440 km.…”

Section: Introductionmentioning

confidence: 99%

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Measurements of Mesospheric Sodium Abundance above the Hawaiian Islands

Roberts¹,

Bradford²,

Neyman

et al. 2007

PUBL ASTRON SOC PAC

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Laser guide stars have increased the utility of adaptive optics systems by expanding the number of observable objects. The most common type of laser excites sodium in the mesosphere, and mesospheric sodium density is key to the performance of the laser. While a variety of observatories have conducted studies of the mesospheric sodium density, there are no published studies from Hawaii, which is home to some of the largest telescopes in the world. This paper presents mesospheric sodium densities measured by the University of Illinois lidar for 165 hr spanning 25 nights over 3 years. The mean sodium column density is cm Ϫ2 , with a seasonal 9 9 4.3 # 10 ‫ע‬ 0.2 # 10 peak in the winter, as found at many other sites. The variations in a given night can be as high as the seasonal variation. We predict the average photon returns for the 15 W Keck II laser and a proposed 50 W laser at the Advanced Electro-Optical System 3.6 m telescope for the observed sodium abundances.

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Section: Column Densitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%