Applications of Spectral Microwave Radiometry to Sensing of Sea Ice and the Ocean Surface.

• Main Author: St Germain, Karen M.
• Other Authors: MASSACHUSETTS UNIV AMHERST DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
• Format: Text
• Language: English
• Published: 1993
• Subjects: Physical and Dynamic Oceanography; Snow; Ice and Permafrost; Meteorology; Non-radio Communications; *POLAR REGIONS; *OCEAN SURFACE; *MONITORING; *MICROWAVE EQUIPMENT; *RADIOMETRY; *SEA ICE; *REMOTE SENSING; *SATELLITE METEOROLOGY; ALGORITHMS; GROUND LEVEL; CLOUDS; UNCERTAINTY; LABORATORY TESTS; MODIFICATION; PARAMETERS; WATER; WIND; ATMOSPHERIC TEMPERATURE; THESES; ICE FORMATION; ESTIMATES; VARIABLES; DIELECTRIC PROPERTIES; BRIGHTNESS; SPECTRA; IMAGES; ATTENUATION; NOISE; LINKAGES; SURFACE TEMPERATURE; LOW FREQUENCY; OPEN WATER; C BAND; EMISSIVITY; SPECTRORADIOMETERS; WEATHER CORRECTING DECISION ALGORITHM; Ice; permafrost; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/ADA289138; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA289138

The dielectric properties and emissivity of several types of sea ice were studied to improve upon the currently available algorithms for interpreting polar radiometric imagery from the SSM/I sensor. Laboratory studies indicated that the relative dielectric constant of new sea ice, as measured with a spectral C-Band radiometer, is approximately 12. This value represents the early stages of ice formation, and decreases rapidly with ice growth to approach the accepted value of 3.2 for first year ice. Atmospheric effects on satellite based passive microwave data were also examined with regard to the 19, 22, 37, and 85 GHz channels of the SSM/I system. The atmospheric vapor and cloud liquid water attenuation was empirically modeled with respect to frequency and atmospheric temperature. The mean atmospheric temperature was empirically linked to surface temperature through an exponential relationship. The surface emissivity was then modelled as a function of surface type via a mixing formalism, where the emissivity of open water depends on surface wind-speed. With the significant environmental variables parameterized, two algorithms for analysis of polar SSM/I data were developed. The first is a simple modification that adds the capability of determining ice temperature to an existing algorithm. The second is a weather correcting algorithm significantly more complex than those currently in use for the lower three frequencies of the Special Sensor Microwave Imager (SSM/I). The uncertainty of the six products due to measurement noise was estimated at 5% for surface parameters and 10% for atmospheric variables.