Location
East-West Center, University of Hawai'i at Manoa (Honolulu, Hawai'i)
Start Date
16-10-2012 5:30 PM
End Date
16-10-2012 7:30 PM
Document Type
Poster
Description
Atmospheric thermal tides are global-scale waves with periods that are harmonics of a solar day, mainly excited by diurnally varying diabatic heating in the troposphere and the stratosphere. Some recent studies suggested that the tidal temperature variations in the TTL might affect the appearance of cirrus clouds and, thus, the dehydration process. It should be noted, however, that the global pattern of diurnal temperature variations in the TTL still remains unclear. In this study, we aim at revealing the 3D structure of diurnal temperature variations around the TTL, including its seasonal variations, by using data from global reanalyses for the period of 2002-2006. It is found that the Sun synchronous tides have amplitudes of ~0.3 K (~0.5 K) at 100 hPa (70 hPa) in January. Superposed on these components, the non-Sun-synchronous tides are strong over the continent (South America, Africa); these may be excited by latent heat release associated with deep convections there. The total (i.e., Sun-synchronous plus non-Sun-synchronous) diurnal temperature amplitudes reach ~0.5 K (~1 K) at maxima at 100 hPa (70 hPa) in January. The seasonality and the impact on the dehydration will be discussed in the presentation.
Atmospheric temperature tides in the tropical upper troposphere and lower stratosphere
East-West Center, University of Hawai'i at Manoa (Honolulu, Hawai'i)
Atmospheric thermal tides are global-scale waves with periods that are harmonics of a solar day, mainly excited by diurnally varying diabatic heating in the troposphere and the stratosphere. Some recent studies suggested that the tidal temperature variations in the TTL might affect the appearance of cirrus clouds and, thus, the dehydration process. It should be noted, however, that the global pattern of diurnal temperature variations in the TTL still remains unclear. In this study, we aim at revealing the 3D structure of diurnal temperature variations around the TTL, including its seasonal variations, by using data from global reanalyses for the period of 2002-2006. It is found that the Sun synchronous tides have amplitudes of ~0.3 K (~0.5 K) at 100 hPa (70 hPa) in January. Superposed on these components, the non-Sun-synchronous tides are strong over the continent (South America, Africa); these may be excited by latent heat release associated with deep convections there. The total (i.e., Sun-synchronous plus non-Sun-synchronous) diurnal temperature amplitudes reach ~0.5 K (~1 K) at maxima at 100 hPa (70 hPa) in January. The seasonality and the impact on the dehydration will be discussed in the presentation.
