The main role of the MFSA radar is to measure the wind speed and direction from 50 km to 100 km in the atmosphere. These heights correspond to the mesosphere (approximately 50 to 85 km) and the lower part of the thermosphere (above 85 km).
At this height, regions of turbulence create a disturbance in the atmosphere strong enough to reflect the radio waves transmitted by the radar. The movement of these turbulent patches can be measured by looking at their radar reflections.
The movement of these patches is measured by 3 antennas spaced out in a triangle. By measuring the movement of the reflected radio waves over the 3 spaced antennas, it is possible to calculate the wind speed.
The radar consists of a radio transmitter that sends radio pulses up through a group of 4 antennas arranged in a square. 3 receive antennas pick up the reflected waves. These are amplified through radio receivers. A computer controls the radar electronics. Another computer converts the received signals into measurements of the wind.
The MFSA radar is part of the AAD’s focus on the global climate system. The MFSA radar measures the wind at heights above those sampled by standard meteorological instruments. This helps us to learn about processes that affect the climate and weather of the southern hemisphere. Atmospheric wind speeds measured by the radar can be combined with measurements from other instruments to collect a unique and useful data set.
The radar is maintained by the Antarctic Climate program’s wintering engineer at Davis. Upgrades and troubleshooting activities are carried out in conjunction with staff from Atmospheric Radar Systems.
In the image above, the 8 masts of the square transmitting array are visible against the blue sky. On the far left, one of the receiver antennas is visible. It has been painted so that it can be seen from the helicopters that sometimes fly over this area. On the horizon (middle right) there is another receiver antenna. The white building houses the radar electronics.