The paper is divided into two parts.
Part 1, under the heading of Non-standard Propagation, concerns variations in the apparent performance of marine navigational radar in its use for detecting shipping and land targets. The effects of changes in the density of the lower layers of the atmosphere on radar transmissions, their distortion of radar coverage for better or for worse, and resultant errors in the evaluation of echoes are here examined.
Part 2 describes the way in which weather echoes may influence and restrict radar-assisted navigation. The attenuation of field strength with various types and intensities of precipitation, and the effects of these factors on the navigational and collision-warning uses of radar are examined. The detection, tracking, and application of weather echoes as an aid to short-range weather forecasting are also covered.