How is a teacher similar to a SODAR? Teachers constantly sends out questions to their students throughout the classroom and wait for responses. According to students this can be quite annoying especially when daydreaming. This is similar to the SODAR because it sends out sound pulses in various directions and then waits for the reflected sound to come back as a response. This sound can be quite annoying to some people. The frequency of the sound returning depends upon the density of the air it encounters. This is the same with the frequency of the student responses. Just substitute "air" with the word "students" in the previous statement. (Only kidding) The main difference between a SODAR and a teacher is that a SODAR works 24 hours a day 7 days a week. A teacher only works about 16 hours a day 7 days a week. (We need a little sleep)
Speakers and microphones of the SODAR
Below is a video of Ralf Staebler from OASIS Canada explaining the SODAR. (I apologize for the sun angle in the video, just enjoy the explanation along with the SODAR sound.)
http://
Patrick Lee working on Mercury measurement equipment
Holgar Sihler is a scientist from Germany. He showed me the DOAS instrumentation today. The DOAS uses a telescope to detect light being reflected back from a reflector out in a field. There is a short light path, 1 km, and a long light path 4 km. The light is analyzed in the UV range using spectroscopy to determine the concentrations of various gases in the atmosphere. A smaller instrument measures the output of the sun. (Task for Mrs. Wilkening students: Look for the poster underneath my back board to see an example of spectroscopy and review where UV light is positioned in the EM spectrum.)
Holgar Sihler inside DOAS enclosure