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The recent launch of Landsat-7 ETM+ extends the uninterrupted stream of TM and ETM+ images to a potential span of 32 years. This exceptional image set will allow long-term studies of natural resources, but will require an operational method for converting image digital number (dn) to the temporally comparable surface reflectance factor (rsl). A refinement(More)
Surface roughness is a crucial input for radar backscatter models. Roughness measurements of root meansquared height (hrms) of the same surface can vary depending on the measuring instrument and how the data are processed. This letter addresses the error in hrms associated with instrument bias and instrument deployment issues such as number and length of(More)
The amount and spatial and temporal dynamics of vegtional LAI–SVI approaches to circumvent these limitaetation are important information in environmental studtions. The proposed strategy was implemented in three ies and agricultural practices. There has been a great sequential steps. In the first step, a BRDF model was indeal of interest in estimating(More)
[1] Four approaches for deriving estimates of near-surface soil moisture from radar imagery in a semiarid, sparsely vegetated rangeland were evaluated against in situ measurements of soil moisture. The approaches were based on empirical, physical, semiempirical, and image difference techniques. The empirical approach involved simple linear regression of(More)
The Integral Equation Method (IEM) model and a newly defined delta index were used to estimate near surface soil moisture from C-band radar satellite imagery in a semi-arid rangeland in southern Arizona, USA. Model results were validated against soil moisture measurements made in the field at the time of satellite overpass. The IEM model performed poorly in(More)
Irrigation scheduling requires an operational means to quantify plant water stress. Remote sensing may offer quick measurements with regional coverage that cannot be achieved by current ground-based sampling techniques. This study explored the relation between variability in fine-resolution measurements of canopy temperature and crop water stress in cotton(More)
In this study, high-spatial, low-temporal scale visible remote sensing data were used to calibrate an ecosystem model (EM) for semiarid perennial grasslands. The model was driven by daily meteorological data and simulated plant growth and water budget on the same time step. The model was coupled with a canopy reflectance model to yield the time course of(More)
The Integral Equation Model (IEM) is the most widely-used, physically based radar backscatter model for sparsely vegetated landscapes. In general, IEM quantifies the magnitude of backscattering as a function of moisture content and surface roughness, which are unknown, and the known radar configurations. Estimating surface roughness or soil moisture by(More)
Neglect of the mouth can lead to impairment, disability, and discomfort; as a result, it can have a negative impact on quality of life in old age. Some minority groups in North America shoulder a disproportionate burden of dental impairment compared to people of European origins, possibly because of different cultural beliefs and a distrust of Western oral(More)
Estimation of riparian forest structural attributes, such as the Leaf Area Index (LAI), is an important step in identifying the amount of water use in riparian forest areas. In this study, small-footprint lidar data were used to estimate biophysical properties of young, mature, and old cottonwood trees in the Upper San Pedro River Basin, Arizona, USA.(More)