M. Susan Moran

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Synthetic Aperture Radar has shown its large potential for retrieving soil moisture maps at regional scales. However, since the backscattered signal is determined by several surface characteristics, the retrieval of soil moisture is an ill-posed problem when using single configuration imagery. Unless accurate surface roughness parameter values are(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)
Spatially distributed soil moisture profiles are required for watershed applications such as drought and flood prediction, crop irrigation scheduling, pest management, and determining mobility with lightweight vehicles. Satellite-based soil moisture can be obtained from passive microwave, active microwave, and optical sensors, although the coarse spatial(More)
There have been several efforts to utilize satellite-based synthetic aperture radar (SAR) measurements to determine surface soil moisture (to 5 cm) conditions of rangeland regions. The results have been mixed since the relation between the SAR signal and surface soil moisture is confounded by variations in topographic features, surface roughness and(More)
The myxoma virus (MV) M-T5 gene encodes an ankyrin repeat protein that is important for virus replication in cells from several species. Insight was gained into the molecular mechanisms underlying the role of M-T5 as a host range determinant when the cell cycle regulatory protein cullin-1 (cul-1) was identified as a cellular binding partner of M-T5 and(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)
Studies over the past 25 years have shown that measurements of surface reflectance and temperature (termed optical remote sensing) are useful for monitoring crop and soil conditions. Far less attention has been given to the use of radar imagery, even though synthetic aperture radar (SAR) systems have the advantages of cloud penetration, all-weather(More)
The amount of photosynthetically active radiation (PAR) absorbed by a canopy (APAR) is an important driving variable for vegetation processes such as photosynthesis. PAR extinction in clumped canopies of shortgrass ecosystems is the focus of this paper. Directional gap fractions estimated at peak biomass on several Mexican shortgrass ecosystems with a(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)