Altitude-Velocity Doppler-Spectrum Distribution in RASS Observation.
This represents a Doppler-spectrum altitude distribution obtained from RASS observation. The vertical axis represents distance from the radar, and the horizontal axis represents the Doppler velocity of the acoustic plane moving away from the radar. It can be seen that strong signals are received near the 340-348 m/s region, corresponding to the apparent velocity of sound. The distribution of this relatively strong signal angles to the right because the velocity of sound decreases at high altitudes, due to the lower temperatures found in these regions. The radar antennas are aimed in different directions with respect to the left and right figures, at zenith angles of 15° to the south and west, respectively. It can be seen from these figures that the maximum observable range varies significantly depending on the antenna-beam direction. Beam direction is therefore an important factor in RASS observation.
|
