ON THE DIMENSIONALITY OF MULTIPARAMETER MICROWAVE IMAGE DATA FROM THIN SEA-ICE IN THE LABRADOR-SEA

Thin ice is typically defined as comprising the World Meteorological O rganization's young and new ice categories, referring to sea ice that is less than 0.3 m thick, This ice type is an extremely important fact or in both the thermodynamic and dynamic properties of both polar and marginal ice covers, In the LIMEX'89 experiment, spatially and tempora lly registered multipolarization data from 5.3 and 9.25 GHz SAR's and from 37 and 90 GHz imaging radiometers were acquired over a region con taining a wide range of new ice growth stages in the Labrador ice pack , The temperatures at the data acquisition time were -10 and correspon d to ice growth conditions. In this paper, the dimensionality of the m ultifrequency, multipolarization active and passive data set is examin ed to determine the complementarity of the sensor parameters and senso r types for thin ice measurements, Principal component analysis is use d to provide estimates of the information content of individual measur ement channels and their combinations, Various measurement subspaces a re examined, Criteria for channel redundance are proposed and tested a nd the classification potential of the multidimensional measurement se t is tested for thin ice growth stages that are known to present class ification difficulties for microwave sensors. Given six nominally inde pendent SAR measurement channels, the information space dimension of t his subspace is shown to be greater than five, The four radiometer cha nnels are shown to have information space dimension two and are redund ant in frequency, The combined, ten element, SAR/radiometer measuremen t space was shown to have information space dimension eight under the criteria used when the scattering polarization ratios are included.