Climatological study of the latitudinal, longitudinal, and height distribution of atmospheric gravit wave energy

点击翻译按钮获取中文摘要

1. Analyses of the gravity waves with the GPS occultation techniqueThe global distribution of the atmospheric gravity waves was investigated with temperature data obtained by using the occultation technique for the GPS (Global Positioning System)signals. This study revealed the global distribution of the amplitude of gravity waves for the first time [Tsuda et al., 2000a]. We could also observe gravity waves from mountain ranges [Hocke et al., 2002]. Also revealed is the global morphology of the tropopause [Nishida et al., 2000]. We could further show that the occurrence of the ionospheric sporadic E layer is correlated with the activity of gravity waves in the stratosphere [Hocke et al., 2002].2. Radar observationsThe results with the GPS observations mentioned above was confirmed with the MU radar at Shigaraki and the White Sands radar in the United States [Nastrom, 2000]. We further showed that the breaking of gravity waves sometimes cause a large spatial variation of wind speed in a short distance [Nakamura et al., 2002]. Gravity waves in low latitudes were investigated with the MF radar in Indonesia to show their inter-annual and ultra-seasonal variability [Isoda, et al., 2002; Tsuda et al.,2002]. Methods to infer gravity wave excitation using meteorological radars were investigated as well [Horinouchi, 2002].3. Radio sonde observationsLong-term observational data in Indonesia was analyzed to show seasonal variability of the gravity waves in the upper troposphere [Shimizu et al.,2001]. Latitudinal variation of the gravity wave amplitude was also investigated [Alexander et al., 2002].4. Optical observationGravity waves in the mesopause-lower thermosphere region were investigated with CCD imagers,and the seasonal variation of their dominant propagation direction was revealed [Tsuda et al., 2000b, Nakamura, 200l].