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Measurement of microwave backscatter from a cypress with and without leaves

1989; Institute of Electrical and Electronics Engineers; Volume: 27; Issue: 6 Linguagem: Inglês

10.1109/tgrs.1989.1398242

1558-0644

H. Hirosawa, Y. Matsuzaka, Osamu Kobayashi,

Precipitation Measurement and Analysis

Radar backscatter from Japanese Cypress has been mea­ sured for S, C, and X bands from two canopy states: With and without leaves. Measurements have been made indoors, forming an extended target of the cypress. The measurements indicate that, after leaf re­ moval, the scattering coefficient aO at X band decreased 4-6 dB in the like (HH and VV) polarizations, although less in the cross (HV and VH) polarizations. At C band, aO decreased 1-2 dB in the like polari­ zation, but no decrease was noted for cross polarization. Similarly, aO at S band decreased slightly in the like case, but not in the cross. The relative contributions of leaves and branches to backscatter are dis­ cussed, based on the changes of the scattering coefficients. A measure­ ment in circular polarization of the backscatter at C band is also de­ scribed. HH, VV, HV, and VH, and the second measurement was made in 1987 using a C-band scatterometer which oper­ ates in circular as well as linear polarization modes. We shall discuss the relative contributions of leaves and branches (including thin vertical trunks) to backscatters in these bands by using the observed changes in the scat­ tering coefficients of the cypress before and after leaf re­ moval. The contribution of thick trunks to radar back­ scatter is not treated in this study.