8,602 research outputs found

    Detector Based Calibration of a Portable Imaging Spectrometer for CLARREO Pathfinder Mission

    Get PDF
    The Climate Absolute Refractivity and Reflectance Observatory (CLARREO) Pathfinder (CPF) mission is being developed to demonstrate SI-traceable retrievals of reflectance at unprecedented accuracies for global satellite observations. An Independent Calibration of the CPF sensor using the Goddard Laser for Absolute Measurement of Radiance (GLAMR) is planned to allow validation of CPF accuracies. GLAMR is a detector-based calibration system relies on a set of NIST-calibrated transfer radiometers to assess the spectral radiance from the GLAMR sphere source to better than 0.3 % (k=2). The current work describes the calibration of the Solar, Lunar Absolute Reflectance Imaging Spectroradiometer (SOLARIS) that was originally developed as a calibration demonstration system for the CLARREO mission and is now being used to assess the independent calibration being developed for CPF. The methodology for the radiometric calibration of SOLARIS is presented as well as results from the GLAMR-based calibration of SOLARIS. The portability of SOLARIS makes it capable of collecting field measurements of earth scenes and direct solar and lunar irradiance similar to those expected during the on-orbit operation of the CPF sensor. Results of SOLARIS field measurements are presented. The use of SOLARIS in this effort also allows the testing protocols for GLAMR to be improved and the field measurements by SOLARIS build confidence in the error budget for GLAMR calibrations. Results are compared to accepted solar irradiance models to demonstrate accuracy values giving confidence in the error budget for the CLARREO reflectance retrieval

    Scaling Contributions to the Free Energy in the 1/N Expansion of O(N) Nonlinear Sigma Models in d-Dimensions

    Get PDF
    Within the 1/N expansion of O(N) nonlinear σ\sigma models for d4d \leq 4 it is possible to separate consistently the spin-wave and the massive-mode contributions to the scaling part of the free energy near criticality, and to evaluate them to O(1/N)O(1/N). For critical dimensions d=2+2/nd = 2+2/n the Abe-Hikami anomaly is recovered, while for d=2d=2 the removal of the spin-wave term is justified.Comment: 10 pages, Latex, one figure, submitted to Phys. Lett.

    Proceedings of the Conference on Human and Economic Resources

    Get PDF
    This paper investigates the relative efficiency of public (state) libraries of major cities in Turkey by applying a data envelopment analysis. Scale, technical, and overall efficiency scores are calculated. It is found that there is a negative correlation between economic and social development index of the cities and efficiency scores of state libraries of same cities. In order to understand the sources of technical inefficiencies, the slack analysis is employed. Book collection and library staff are turned out to be the most problematic inputs and library members and lending of the books the most problematic outputs.public libraries, efficiency, data envelopment analysis, Turkey
    corecore