Volumes and Issues  Contents of Issue 12

Ann. Geophys., 24, 3229-3240, 2006
www.ann-geophys.net/24/3229/2006/
© European Geosciences Union 2006

Mesospheric gravity waves observed near equatorial and low–middle latitude stations: wave characteristics and reverse ray tracing results

C. M. Wrasse¹, T. Nakamura², H. Takahashi¹, A. F. Medeiros³, M. J. Taylor⁴, D. Gobbi¹, C. M. Denardini¹, J. Fechine¹, R. A. Buriti³, A. Salatun⁵, Suratno⁵, E. Achmad⁵, and A. G. Admiranto^5
1Instituto Nacional de Pesquisas Espaciais (INPE), C.P. 515, 12245-970, São José dos Campos, Brazil
²Institute for Sustainable Humanosphere (RISH), Kyoto University, Uji, Kyoto, 611-0011, Japan
³Universidade Federal de Campina Grande (UFCG), Av. Aprígio Veloso 882, Bodocongó, 58109-970, Campina Grande, Brazil
⁴Space Dynamics Laboratory and Physics Department, Logan, UT 84322-4145, USA
⁵Space Science Center, National Institute of Aeronautics and Space, Jalan Pemuda Persil 1, Rawamangun, 13220, Jakarta, Indonesia

Abstract. Gravity wave signatures were extracted from OH airglow observations using all-sky CCD imagers at four different stations: Cachoeira Paulista (CP) (22.7° S, 45° W) and São João do Cariri (7.4° S, 36.5° W), Brazil; Tanjungsari (TJS) (6.9° S, 107.9° E), Indonesia and Shigaraki (34.9° N, 136° E), Japan. The gravity wave parameters are used as an input in a reverse ray tracing model to study the gravity wave vertical propagation trajectory and to estimate the wave source region. Gravity waves observed near the equator showed a shorter period and a larger phase velocity than those waves observed at low-middle latitudes. The waves ray traced down into the troposphere showed the largest horizontal wavelength and phase speed. The ray tracing results also showed that at CP, Cariri and Shigaraki the majority of the ray paths stopped in the mesosphere due to the condition of m²<0, while at TJS most of the waves are traced back into the troposphere. In summer time, most of the back traced waves have their final position stopped in the mesosphere due to m²<0 or critical level interactions (|m|→∞), which suggests the presence of ducting waves and/or waves generated in-situ. In the troposphere, the possible gravity wave sources are related to meteorological front activities and cloud convections at CP, while at Cariri and TJS tropical cloud convections near the equator are the most probable gravity wave sources. The tropospheric jet stream and the orography are thought to be the major responsible sources for the waves observed at Shigaraki.

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Citation: Wrasse, C. M., Nakamura, T., Takahashi, H., Medeiros, A. F., Taylor, M. J., Gobbi, D., Denardini, C. M., Fechine, J., Buriti, R. A., Salatun, A., Suratno, , Achmad, E., and Admiranto, A. G.: Mesospheric gravity waves observed near equatorial and low–middle latitude stations: wave characteristics and reverse ray tracing results, Ann. Geophys., 24, 3229-3240, 2006.   Bibtex   EndNote   Reference Manager