author = "Treuhaft, Robert and Gon{\c{c}}alves, Fabio and Santos, Jo{\~a}o 
                         Roberto dos and Keller, Michael and Palace, Michael and Madsen, 
                         Soren N. and Sullivan, Franklin and Gra{\c{c}}a, Paulo M. L. A.",
          affiliation = "{Jet Propulsion Laboratory} and {Woods Hole Research Center} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {International Institute of Tropical Forestry} and {University of 
                         New Hampshire} and {Jet Propulsion Laboratory} and {University of 
                         New Hampshire} and {Instituto Nacional de Pesquisas da 
                title = "Tropical-forest biomass estimation at x-band from the spaceborne 
                         TanDEM-X interferometer",
              journal = "IEEE Geoscience and Remote Sensing Letters",
                 year = "2015",
               volume = "12",
               number = "2",
                pages = "239--243",
                month = "Feb.",
             keywords = "Biomass, interferometric synthetic aperture radar (InSAR), lidar, 
                         tropical forest.",
             abstract = "This letter reports the sensitivity of X-band interferometric 
                         synthetic aperture radar (InSAR) data from the first 
                         dual-spacecraft radar interferometer, TanDEM-X, to variations in 
                         tropical-forest aboveground biomass (AGB). It also reports the 
                         first tropical-forest AGB estimates from TanDEM-X data. Tropical 
                         forests account for about 50% of the world's forested biomass and 
                         play critical roles in the control of atmospheric carbon dioxide 
                         by emission through deforestation and uptake through forest 
                         growth. The TanDEM-X InSAR data used in this analysis were taken 
                         over the Tapajos National Forest, Par, Brazil, where field 
                         measurements from 30 stands were acquired. The magnitude of the 
                         InSAR normalized complex correlation, which is called coherence, 
                         decreases by about 25% as AGB increases from 2 to 430 Mg-ha(-1), 
                         suggesting more vertically distributed return-power profiles with 
                         increasing biomass. Comparison of InSAR coherences to those of 
                         small-spot (15 cm) lidar suggests that lidar penetrates deeper 
                         into the canopies than InSAR. Modeling InSAR profiles from InSAR 
                         coherence and lidar profiles yields an estimate of 0.29 dB/m for 
                         the X-band extinction coefficient relative to that of lidar. 
                         Forest AGB estimated from InSAR observations on 0.25-ha plots 
                         shows RMS scatters about the field-estimated AGB between 52 and 62 
                         Mg-ha(-1), which is between 29% and 35% of the average AGB of 179 
                         Mg-ha(-1), depending on the data analysis mode. The sensitivity 
                         and biomass-estimation performance suggest the potential of 
                         TanDEM-X observations to contribute to global tropical-forest 
                         biomass monitoring.",
                  doi = "10.1109/LGRS.2014.2334140",
                  url = "http://dx.doi.org/10.1109/LGRS.2014.2334140",
                 issn = "1545-598X",
             language = "en",
           targetfile = "tropical forest.pdf",
        urlaccessdate = "27 nov. 2020"