Ranjan S. Muttiah

A GIS-BASED REGIONAL PLANNING TOOL FOR IRRIGATION DEMAND ASSESSMENT AND SAVINGS USING SWAT

Regional planning for irrigated agriculture requires a thorough understanding of the hydrological processes and spatial and temporal variations associated with hydrological factors such as rainfall, soils, and crops grown in different units of the region. The objective of this study was to improve the capabilities of a basin-scale hydrologic simulation model for regional planning of irrigated agriculture. In this study, a Geographical Information System (GIS) based hydrological model, Soil and Water Assessment Tool (SWAT), was configured as a regional planning tool with a canal irrigation capability for estimating irrigation demand. The tool was capable of simulating hydrological processes associated with soil-plant-water interactions and capable of capturing the spatial and temporal variability of the major factors, which are important in regional planning. The tool was applied to the irrigation districts in the Lower Rio Grande Valley in Texas. It was validated for crop evapotranspiration and canal conveyance efficiency and applied to analyzing the demand and potential water savings of alternative water conservation measures. Estimated potential water savings were 234.2, 65.9, and 194.0 Mm3 for conservation measures related to on-farm management improvements, replacing sugarcane with corn, and improving canal conveyance efficiency, respectively. Results indicated that on-farm management measures might be as beneficial as improving canal conveyance systems. The planning tool (with hydrological modeling and GIS capabilities) and estimations made would be useful for regional planners and irrigation district managers. The tool could be used for other irrigation systems as well.

Eigenanalysis of dichroic, birefringent, and degenerate polarization elements: a Jones-calculus study.

A theoretical analysis of eigenpolarizations and eigenvalues pertaining to the Jones matrices of dichroic, birefringent, and degenerate polarization elements is presented. The analysis is carried out employing a general model of a polarization element. Expressions for the corresponding polarization elements are derived and analyzed. It is shown that, despite the presence of birefringence, a polarization element can, in a general case, demonstrate a totally dichroic behavior. Moreover, it is proved that birefringence necessarily accompanies dichroic elements with orthogonal eigenpolarizations. A transition between degenerate, dichroic, and birefringent eigenvalues is studied, and examples of synthesis of polarization elements are given.

Inverse Polarimetry, and Light Scattering from Leaves

We describe how Mueller matrices from polarization experiments are obtained in practice. A generalized method to determine Mueller matrices and anisotropy parameters from polarimetry apparatus is given. We then devote a section to leaf light scatter.

Multiplicative Mueller matrix model of the Chlorophytum leaf

In this paper the results for measurements of the Mueller matrices of Chlorophytum leaf, of upper and down side epidermis of Chlorophytum leaf are presented. To physically identify the multiplicative model of a Chiorophytum leaf basing on its Mueller matrices, the coherency matrix, its eigenanalysis and matrix of homogeneous anisotropy are discussed.