Reflection of MM Waves from Snow and Sea Ice

• Main Authors: Sackinger, William M, Byrd, Robert C
• Other Authors: ALASKA UNIV FAIRBANKS INST OF ARCTIC ENVIRONMENTAL ENGINEERING
• Format: Text
• Language: English
• Published: 1972
• Subjects: Snow; Ice and Permafrost; Active & Passive Radar Detection & Equipment; *RADAR REFLECTIONS; *SEA ICE; *SNOW; BACKSCATTERING; DIELECTRIC PROPERTIES; FOG; LOW FREQUENCY; MILLIMETER WAVES; SALINITY; SURFACE ROUGHNESS; TERRAIN; VISIBILITY; Arctic; Ice; permafrost; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/AD0736593; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0736593

The report relates to utility of imaging radars for arctic surface guidance. The program involves field measurements of backscatter from snow, ice and sea ice for a wide variety of meteorological and surface conditions. Laboratory measurements of the complex dielectric constant are presented also, to enable the separation of the roughness contribution to the backscatter. During the first seven months of the program, the dielectric properties of sea ice were measured in the laboratory from 36 to 40 GHz, over a representative range of temperatures, salinities, and orientation. The real part of the dielectric constant is close to 3 for most conditions, but the loss tangent can vary over three orders of magnitude, depending upon the temperature and salinity. Under most conditions, an incident wave of 1 cm wavelength would penetrate less than one meter into the sea ice. Strong distinction of freshly- formed sea ice from old sea ice appears likely. Backscatter from sea ice is currently being measured. Distinction of rough and smooth surfaces is possible, based upon preliminary interpretation of the data. Sponsored in part by DARPA.