Monthly averages of the superposed values of decay times of meteor echoes from underdense meteor trails obtained by meteor radar observations at Cachoeira Paulista (22.7°S, 45°W), Brazil, have been employed to estimate temperature and to study the diurnal temperature fluctuations in the upper mesosphere and lower thermosphere region. The monthly diurnal amplitudes and phases in meteor radar temperatures at Cachoeira Paulista are comparable to those of the westward migrating diurnal tide, with zonal wave number 1, found in the reported temperatures obtained from SABER data, when the observations were obtained during the same period. The diurnal amplitudes in the temperature do not show the semiannual oscillation present in those of the diurnal tide in zonal and meridional winds. The diurnal temperature peaks 4 to 5 h ahead of diurnal tide in the zonal winds and is in anti-phase with the diurnal tide in the meridional winds. The semidiurnal amplitudes of the radar temperature fluctuations also are comparable with SABER westward migrating semidiurnal tide, with zonal wave number 2, and do not present a defined seasonal behavior, while their phases undergo small changes. They lead the semidiurnal tide in the zonal winds by about 4 h during austral summer, but it remains in-phase for the other months, and lead in meridional winds by about 5 to 8 h.

巴西 Cachoeira Paulista (22.7°S, 45°W) 的流星雷达观测获得的来自低密度流星轨迹的流星回波衰减时间叠加值的月平均值已被用于估计温度和研究昼夜温度波动上部中间层和下部热层区域。Cachoeira Paulista 流星雷达温度的月日振幅和相位与向西迁移的昼夜潮汐相当，纬向波数为 1，在从 SABRE 数据获得的报告温度中发现，当时观测是在同一时期获得的。在纬向风和经向风中，昼夜潮汐的温度日振幅没有表现出半年振荡。昼温在纬向风中比日潮提前4～5h达到峰值，在经向风中与日潮成反相。雷达温度波动的半日幅度也与 SABRE 西移半日潮相当，纬向波数为 2，不呈现出明确的季节性行为，而它们的相位变化很小。在南方夏季，它们在纬向风中领先半日潮约 4 小时，但在其他月份保持同相，在经向风中领先约 5 至 8 小时。而它们的相位会发生很小的变化。在南方夏季，它们在纬向风中领先半日潮约 4 小时，但在其他月份保持同相，在经向风中领先约 5 至 8 小时。而它们的相位会发生很小的变化。在南方夏季，它们在纬向风中领先半日潮约 4 小时，但在其他月份保持同相，在经向风中领先约 5 至 8 小时。