Abstract

An experiment is described that combines in situ measurements made with very fast response sensors on a 300 m tower at the Boulder (Colorado) Atmospheric Observatory (Kaimal and Gaynor, 1983), with remote sensing of atmospheric layer structure by acoustic and FM-CW radar sounders (e.g., Little, 1969; Richter, 1969). A finestructure of laminae is often present within elevated inversion layers that is reminiscent of the sheet and layer structure found in the ocean thermocline and in lakes and estuaries (e.g., Gregg, 1982). Figure 1 shows an acoustic record of such a stepped profile event through which a moving carriage on the tower carried temperature, humidity and wind sensors along time-height trajectories shown by the superimposed staight lines. The temperature measurements were made with platinum wires, humidity was measured with a Lyman-α humidiometer, and wind was measured by three-component sonic anemometers. The_data were then digitized at_a 10 Hz rate, and the carriage rose at 0.56 ms^-1 and descended at 0.58 ms^-1. Figure 2 shows the resulting profiles of temperature, humidity and wind. The transition through the sheets and layers within the inversion is often extremely abrupt with very large gradients. Near_the center of the lower sheet the local gradient of temperature was 6°C m^-1. An experiment is described that combines in situ measurements made with very fast response sensors on a 300 m tower at the Boulder (Colorado) Atmospheric Observatory (Kaimal and Gaynor, 1983), with remote sensing of atmospheric layer structure by acoustic and FM-CW radar sounders (e.g., Little, 1969; Richter, 1969). A finestructure of laminae is often present within elevated inversion layers that is reminiscent of the sheet and layer structure found in the ocean thermocline and in lakes and estuaries (e.g., Gregg, 1982). Figure 1 shows an acoustic record of such a stepped profile event through which a moving carriage on the tower carried temperature, humidity and wind sensors along time-height trajectories shown by the superimposed staight lines. The temperature measurements were made with platinum wires, humidity was measured with a Lyman-α humidiometer, and wind was measured by three-component sonic anemometers. The_data were then digitized at_a 10 Hz rate, and the carriage rose at 0.56 ms^-1 and descended at 0.58 ms^-1. Figure 2 shows the resulting profiles of temperature, humidity and wind. The transition through the sheets and layers within the inversion is often extremely abrupt with very large gradients. Near_the center of the lower sheet the local gradient of temperature was 6°C m^-1.

© 1985 Optical Society of America