TY - JOUR T1 - The effects of changes in forest biomass on radar backscatter from tree canopies JF - International Journal of Remote Sensing Y1 - 1995 A1 - Wang, Y. A1 - Davis, F. W. A1 - Melack, J. M. A1 - Kasischke, E. S. A1 - Christensen, N. L., Jr. KW - (Aerospace and Underwater Biological Effects--General KW - (Biophysics--Biocybernetics (1972- )) KW - (Ecology KW - (Mathematical Biology and Statistical Methods) KW - (Plant Physiology, Biochemistry and Biophysics--Growth, Differentiation) KW - Coniferopsida KW - Environmental Biology--Plant) KW - Gymnosperms KW - Mathematical Model KW - Methods) KW - North Carolina KW - Pine KW - Plants KW - Research Article KW - Spermatophyta KW - Spermatophytes KW - Synthetic Aperture Radar KW - Usa KW - Vascular plants VL - 16 N1 - JOURNAL ARTICLE; RESEARCH ARTICLE ER - TY - JOUR T1 - The effects of changes in loblolly pine biomass and soil moisture on ERS-1 SAR backscatter JF - Remote Sensing of Environment Y1 - 1994 A1 - Wang, Y. A1 - Kasischke, E. S. A1 - Melack, J. M. A1 - Davis, F. W. A1 - Christensen, N. L., Jr. KW - (Aerospace and Underwater Biological Effects--General KW - (Biochemistry--Physiological Water Studies (1970- )) KW - (Biophysics--Biocybernetics (1972- )) KW - (Ecology KW - (Forestry and Forest Products) KW - (Mathematical Biology and Statistical Methods) KW - (Plant Physiology, Biochemistry and Biophysics--Growth, Differentiation) KW - (Plant Physiology, Biochemistry and Biophysics--Water Relations) KW - (Soil Science--Fertility and Applied Studies (1970- )) KW - (Soil Science--Physics and Chemistry (1970- )) KW - Coniferopsida KW - Environmental Biology--Plant) KW - European Remote Sensing Satellite Synthetic Aperture Radar KW - Gymnosperms KW - Mathematical Model KW - Methods) KW - North Carolina KW - Plants KW - Research Article KW - Spermatophytes KW - Usa KW - Vascular plants VL - 49 N1 - JOURNAL ARTICLE; RESEARCH ARTICLE ER - TY - JOUR T1 - Modeling L-Band Radar Backscatter of Alaskan Boreal Forest JF - IEEE Transactions on Geoscience & Remote Sensing Y1 - 1993 A1 - Wang, Y. A1 - Day, J. L. A1 - Davis, F. W. A1 - Melack, J. M. KW - Electrical & electronic. KW - Reprint available from: Wang Y. UNIV CALIF SANTA BARBARA, CTR REMOTE KW - SENSING & ENVIRONM OPT, SANTA BARBARA, CA 93106, USA. KW - Vegetation. Layer. AB - Synthetic aperture radar (SAR) data were acquired over Bonanza Creek Experimental Forest (Alaska) in March 1988 under thawed and frozen conditions. For five stands analyzed, L-band backscatter at 42-degrees-45-degrees incidence angle was 2.7-6.9 dB smaller under frozen than under thawed conditions for white spruce and balsam poplar, with the largest difference at HV and the smallest at HH polarization. The differences were smaller for a stand of small black spruce. The VV-HH phase differences observed by SAR were almost-equal-to 0-degrees for all the stands. Ground data were used to parameterize the Santa Barbara canopy backscatter model. For the white spruce and balsam poplar stands under thawed conditions, simulations agreed with the SAR data within the calibration uncertainty. The model underestimated the HH, HV, and VV backscatter for all five stands under frozen conditions, and for the black spruce stand under thawed conditions. The modeled VV-HH phase differences were close to 0-degrees for all the stands except the black spruce stand. The discrepancies in model predictions of backscatter and phase difference were attributed to inadequate surface backscatter modeling. Model results supported the hypothesis that the weaker backscatter from frozen, as compared with thawed stands, was because of the smaller dielectric constant of the frozen trees. [References: 15] 15 VL - 31 N1 - English Article Current Contents/Engineering, Technology & Applied Sciences. Reprint available from: Wang Y UNIV CALIF SANTA BARBARA CTR REMOTE SENSING & ENVIRONM OPT SANTA BARBARA, CA 93106 USA UNIV CALIF SANTA BARBARA DEPT GEOG SANTA BARBARA, CA 93106 USA UNIV CALIF SANTA BARBARA DEPT BIOL SCI SANTA BARBARA, CA 93106 USA 0003 ER - TY - JOUR T1 - Simulated and Observed Backscatter at P-, L-, and C-Bands from Ponderosa Pine Stands JF - IEEE Transactions on Geoscience & Remote Sensing Y1 - 1993 A1 - Wang, Y. A1 - Davis, F. W. A1 - Melack, J. M. KW - Electrical & electronic. KW - Radar. Scattering. Model. KW - Reprint available from: Wang Y. UNIV CALIF SANTA BARBARA, CTR REMOTE KW - SENSING & ENVIRONM OPT, SANTA BARBARA, CA 93106, USA. AB - We compared the output of the Santa Barbara microwave canopy backscatter model to polarimetric synthetic aperture radar (SAR) data for three ponderosa pine stands (ST-2, ST-11, and SP-2) with discontinuous tree canopies near Mt. Shasta, California, at P-band (0.68-m wavelength), L-band (0.235-m wavelength), and C-band (0.056-m wavelength). Given the SAR data calibration uncertainty, the model made good predictions of the P-HH, P-VV, L-HH, C-HH, and C-HV backscatter for the three stands, and the P-HV and L-HV backscatter for ST-2 and SP-2. The model underestimated C-VV for the three stands, and P-HV, L-HV, and L-VV backscatter for ST-11. The observed and modeled VV-HH phase differences were similar or equal to 0 degrees for the three stands at C-band and L-band, and for SP-2 at P-band. At P-band, the observed and modeled VV-HH phase differences were at least -80 degrees for ST-2 and ST-11, which indicates that double-bounce scattering contributes to the total backscatter for the two stands. [References: 10] 10 VL - 31 N1 - English Article Current Contents/Engineering, Technology & Applied Sciences. Reprint available from: Wang Y UNIV CALIF SANTA BARBARA CTR REMOTE SENSING & ENVIRONM OPT SANTA BARBARA, CA 93106 USA 0015 ER -