An airplane psychrograph has been designed to make measurements in the lowest several thousand feet of the atmosphere. These measurements are necessary in order to understand the phenomena causing anomalous propagation associated with the ultra-high frequency radio waves used for radar. The instrument employs ceramic resistors as wet and dry elements; they are rapid in response and sensitive enough for measuring sharp gradients of temperature and water vapor usually present close to the boundary between the air and the water or land. Detail of the construction and use of the airplane psychrograph are described.
* This paper is based on work done for the Office of Scientific Research and Development under Contract OEMsr–262 with the Radiation Laboratory, Massachusetts Institute of Technology.